Merge remote-tracking branch 'origin/main'

# Conflicts:
#	LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs
#	LehrerApp.TemplateDesigner/DesignerViewModel.cs
#	LehrerApp.TemplateDesigner/MainWindow.axaml
#	LehrerApp.Templating/LayoutParser.cs
#	LehrerApp.Templating/QuestTemplateRenderer.cs

LehrerApp.TemplateDesigner.Tests/OverlayEditorTests.cs

@@ -70,4 +70,40 @@ public sealed class OverlayEditorTests
         Assert.Equal(200, viewModel.OverlayPageHeight);
         Assert.Equal("pt", viewModel.OverlayPageUnit);
     }
+
+    [Fact]
+    public void FlowSlotVerschieben_AendertNurDasPragmaDerAusgewaehltenSeite()
+    {
+        var viewModel = new DesignerViewModel();
+        var layout = new LehrerApp.Templating.LayoutParser().Parse(viewModel.LayoutSource);
+        var firstSlot = layout.PageTemplates.Single(x => x.Name == "first").FlowSlots.Single();
+        var continuationSlot = layout.PageTemplates.Single(x => x.Name == "continuation").FlowSlots.Single();
+
+        viewModel.ApplyElementGeometry(new(firstSlot.Line, "FLOW", 25, 95, 160, 165));
+
+        var updated = new LehrerApp.Templating.LayoutParser().Parse(viewModel.LayoutSource);
+        var updatedFirst = updated.PageTemplates.Single(x => x.Name == "first").FlowSlots.Single();
+        var updatedContinuation = updated.PageTemplates.Single(x => x.Name == "continuation").FlowSlots.Single();
+        Assert.Equal(25, updatedFirst.X);
+        Assert.Equal(95, updatedFirst.Y);
+        Assert.Equal(continuationSlot.X, updatedContinuation.X);
+        Assert.Equal(continuationSlot.Y, updatedContinuation.Y);
+    }
+
+    [Fact]
+    public void ElementKannGezieltInContentFlowEingefuegtWerden()
+    {
+        var viewModel = new DesignerViewModel
+        {
+            NewElementScope = "Content-Flow", SelectedContentFlow = "body",
+            NewElementType = "TEXT", NewContent = "Nachsatz", NewAttributes = "gap=5",
+        };
+
+        viewModel.AddElement();
+
+        var flow = new LehrerApp.Templating.LayoutParser().Parse(viewModel.LayoutSource).ContentFlows.Single();
+        var text = Assert.IsType<LehrerApp.Templating.TextElement>(flow.Elements.Last());
+        Assert.Equal("Nachsatz", text.Content);
+        Assert.Equal("5", text.Attributes["gap"]);
+    }
 }

LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs

@@ -17,7 +17,9 @@ public sealed class ProjectLifecycleTests
         viewModel.Reset();
 
         Assert.Equal("neue-vorlage", viewModel.TemplateId);
-        Assert.Equal("PAGE 210 297 mm\n", viewModel.LayoutSource);
+        Assert.Contains("#pragma page-template first", viewModel.LayoutSource);
+        Assert.Contains("#pragma page-template continuation", viewModel.LayoutSource);
+        Assert.Contains("#pragma content-flow body", viewModel.LayoutSource);
         Assert.Empty(viewModel.Placeholders);
         Assert.Empty(viewModel.Assets);
         Assert.Empty(viewModel.AssetItems);
@@ -91,6 +93,21 @@ public sealed class ProjectLifecycleTests
         Assert.Contains("mehrfach", exception.Message);
     }
 
+    [Fact]
+    public void AlteAbsoluteLayouts_WerdenBeimOeffnenVerlustfreiInSeitentypEingebettet()
+    {
+        const string source = "PAGE 210 297 mm\nTEXT 20 30 \"Altbestand\" size=12\n";
+        var layout = new LehrerApp.Templating.LayoutParser().Parse(source);
+
+        var migrated = DesignerViewModel.MigrateLegacyLayout(source, layout);
+        var parsed = new LehrerApp.Templating.LayoutParser().Parse(migrated);
+
+        Assert.True(parsed.UsesPageTemplates);
+        Assert.Equal("Altbestand", Assert.IsType<LehrerApp.Templating.TextElement>(
+            parsed.PageTemplates.Single(x => x.Name == "first").Elements.Single()).Content);
+        Assert.Empty(parsed.ContentFlows.Single().Elements);
+    }
+
     [Fact]
     public void AktuelleAnsicht_KannAlsPdfGerendertWerden()
     {

LehrerApp.TemplateDesigner/DesignerViewModel.cs

@@ -8,6 +8,7 @@ namespace LehrerApp.TemplateDesigner;
 
 public partial class DesignerViewModel : ObservableObject
 {
+    private Bitmap? _pageTemplatePreview;
     [ObservableProperty] private string _templateId = "elternbrief-standard";
     [ObservableProperty] private string _templateName = "Elternbrief Standard";
     [ObservableProperty] private string _description = "Briefvorlage mit Schul-Briefkopf";
@@ -25,6 +26,10 @@ public partial class DesignerViewModel : ObservableObject
     [ObservableProperty] private string _newImageScale = "100";
     [ObservableProperty] private string _newContent = "$Brieftext";
     [ObservableProperty] private string _newAttributes = "size=11";
+    [ObservableProperty] private string _newElementScope = "Seitenvorlage (fest)";
+    [ObservableProperty] private string _selectedContentFlow = "body";
+    [ObservableProperty] private string _newPageTemplateName = "continuation";
+    [ObservableProperty] private string _newFlowName = "body";
     [ObservableProperty] private Bitmap? _previewImage;
     [ObservableProperty] private string _status = "Bereit.";
     [ObservableProperty] private string _statusColor = "#475569";
@@ -41,11 +46,14 @@ public partial class DesignerViewModel : ObservableObject
     [ObservableProperty] private double _overlayPageWidth = 210;
     [ObservableProperty] private double _overlayPageHeight = 297;
     [ObservableProperty] private string _overlayPageUnit = "mm";
+    [ObservableProperty] private string _selectedPageTemplate = "first";
+    [ObservableProperty] private DesignerPreviewPage? _selectedPreviewPage;
 
     public IReadOnlyList<string> Units { get; } = ["mm", "cm", "pt", "in"];
     public IReadOnlyList<PlaceholderType> PlaceholderTypes { get; } = Enum.GetValues<PlaceholderType>();
     public IReadOnlyList<string> ElementTypes { get; } =
         ["TEXT", "TEXTBOX", "FLOWBOX", "DRAWBOX", "FLOWDRAWBOX", "IMG", "TABLE", "CHART"];
+    public IReadOnlyList<string> ElementScopes { get; } = ["Seitenvorlage (fest)", "Content-Flow"];
     public ObservableCollection<DesignerPlaceholder> Placeholders { get; } =
     [
         new("Datum", PlaceholderType.Date, true, DateTime.Today.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)),
@@ -62,6 +70,9 @@ public partial class DesignerViewModel : ObservableObject
     public Dictionary<string, byte[]> Assets { get; } = new(StringComparer.OrdinalIgnoreCase);
     public ObservableCollection<DesignerAsset> AssetItems { get; } = [];
     public ObservableCollection<StarterTemplateItem> StarterTemplates { get; } = [];
+    public ObservableCollection<string> PageTemplateNames { get; } = ["first"];
+    public ObservableCollection<string> ContentFlowNames { get; } = ["body"];
+    public ObservableCollection<DesignerPreviewPage> PreviewPages { get; } = [];
     public bool HasSelectedPlaceholder => SelectedPlaceholder is not null;
     public bool HasNoSelectedPlaceholder => SelectedPlaceholder is null;
 
@@ -73,10 +84,12 @@ public partial class DesignerViewModel : ObservableObject
         OnPropertyChanged(nameof(HasNoSelectedPlaceholder));
     }
 
+    partial void OnSelectedPreviewPageChanged(DesignerPreviewPage? value) => PreviewImage = value?.Image;
+
     public void Reset()
     {
         TemplateId = "neue-vorlage"; TemplateName = "Neue Vorlage"; Description = "";
-        PageWidth = 210; PageHeight = 297; Unit = "mm"; LayoutSource = "PAGE 210 297 mm\n";
+        PageWidth = 210; PageHeight = 297; Unit = "mm"; LayoutSource = EmptyStructuredLayout;
         UseContinuationLayout = false;
         ContinuationLayoutSource = "PAGE 210 297 mm\nFLOWBOX 20 20 170 257 $Brieftext size=11\n";
         Placeholders.Clear(); SelectedPlaceholder = null;
@@ -86,7 +99,7 @@ public partial class DesignerViewModel : ObservableObject
         Assets.Clear(); AssetItems.Clear(); SelectedAsset = null;
         NewElementType = "TEXT"; NewX = "20"; NewY = "50"; NewWidth = "170"; NewHeight = "30";
         NewImageScale = "100"; NewContent = "$Brieftext"; NewAttributes = "size=11";
-        PreviewImage?.Dispose(); PreviewImage = null; CanExport = false;
+        ClearPreviewPages(); CanExport = false;
         OverlayMode = OverlayEditorMode.Measure; OverlayCoordinates = "x=– · y=–";
         SelectedOverlayElement = "Kein Element ausgewählt";
         SetStatus("Neues Projekt angelegt.", false);
@@ -118,19 +131,25 @@ public partial class DesignerViewModel : ObservableObject
             issues.Add(new(ValidationSeverity.Error, $"Platzhalter „{used}“ ist nicht deklariert."));
         foreach (var path in layouts.SelectMany(x => x.Elements).Select(x => x switch { BackgroundElement b => b.Path, ImageElement i => i.Path, _ => null }).Where(x => x is not null))
             if (!Assets.ContainsKey(path!)) issues.Add(new(ValidationSeverity.Error, $"Asset „{path}“ fehlt."));
-        var firstFlows = layout.Elements.Where(x => x is FlowBoxElement or FlowDrawBoxElement).ToList();
+        if (layout.UsesPageTemplates && continuationLayout is not null)
-        if (firstFlows.Count > 1)
+            issues.Add(new(ValidationSeverity.Error,
-            issues.Add(new(ValidationSeverity.Error, "Ein Layout darf höchstens eine FLOWBOX enthalten."));
+                "Layoutformat 3 enthält Folgeseiten als page-template und kann nicht zusätzlich continuation.tpl verwenden."));
-        if (continuationLayout is not null)
+        if (!layout.UsesPageTemplates)
         {
-            var continuationFlows = continuationLayout.Elements.Where(x => x is FlowBoxElement or FlowDrawBoxElement).ToList();
+            var firstFlows = layout.Elements.Where(x => x is FlowBoxElement or FlowDrawBoxElement).ToList();
-            if (firstFlows.Count != 1 || continuationFlows.Count != 1)
+            if (firstFlows.Count > 1)
-                issues.Add(new(ValidationSeverity.Error, "Haupt- und Folgeseite müssen jeweils genau ein fließendes Element enthalten."));
+                issues.Add(new(ValidationSeverity.Error, "Ein Legacy-Layout darf höchstens eine FLOWBOX enthalten."));
-            else if (firstFlows[0].GetType() != continuationFlows[0].GetType())
+            if (continuationLayout is not null)
-                issues.Add(new(ValidationSeverity.Error, "Haupt- und Folgeseite müssen denselben fließenden Elementtyp verwenden."));
+            {
-            else if (firstFlows[0].X != continuationFlows[0].X || firstFlows[0].Y != continuationFlows[0].Y
+                var continuationFlows = continuationLayout.Elements.Where(x => x is FlowBoxElement or FlowDrawBoxElement).ToList();
-                || firstFlows[0].Width != continuationFlows[0].Width || firstFlows[0].Height != continuationFlows[0].Height)
+                if (firstFlows.Count != 1 || continuationFlows.Count != 1)
-                issues.Add(new(ValidationSeverity.Error, "Die FLOWBOX muss auf Haupt- und Folgeseiten dieselbe Position und Größe haben."));
+                    issues.Add(new(ValidationSeverity.Error, "Haupt- und Folgeseite müssen jeweils genau ein fließendes Element enthalten."));
+                else if (firstFlows[0].GetType() != continuationFlows[0].GetType())
+                    issues.Add(new(ValidationSeverity.Error, "Haupt- und Folgeseite müssen denselben fließenden Elementtyp verwenden."));
+                else if (firstFlows[0].X != continuationFlows[0].X || firstFlows[0].Y != continuationFlows[0].Y
+                    || firstFlows[0].Width != continuationFlows[0].Width || firstFlows[0].Height != continuationFlows[0].Height)
+                    issues.Add(new(ValidationSeverity.Error, "Die FLOWBOX muss auf Haupt- und Folgeseiten dieselbe Position und Größe haben."));
+            }
         }
         foreach (var issue in TemplateDataResolver.ValidateConstants(manifest))
             issues.Add(new(ValidationSeverity.Error, issue));
@@ -186,10 +205,13 @@ public partial class DesignerViewModel : ObservableObject
 
     public void Load(LoadedTemplate template, string layoutSource, string? continuationLayoutSource = null)
     {
+        if (!template.Layout.UsesPageTemplates && continuationLayoutSource is null)
+            layoutSource = MigrateLegacyLayout(layoutSource, template.Layout);
         TemplateId = template.Manifest.Id; TemplateName = template.Manifest.Name; Description = template.Manifest.Description;
         PageWidth = (decimal)template.Manifest.PageSize.Width; PageHeight = (decimal)template.Manifest.PageSize.Height;
         Unit = template.Manifest.PageSize.Unit; LayoutSource = layoutSource;
-        UseContinuationLayout = template.Manifest.ContinuationLayoutFile is not null;
+        UseContinuationLayout = !template.Layout.UsesPageTemplates
+            && template.Manifest.ContinuationLayoutFile is not null;
         ContinuationLayoutSource = continuationLayoutSource ?? "PAGE 210 297 mm\n";
         MetadataItems.Clear();
         foreach (var item in template.Manifest.Metadata.OrderBy(x => x.Key, StringComparer.OrdinalIgnoreCase))
@@ -207,6 +229,36 @@ public partial class DesignerViewModel : ObservableObject
         CanExport = true; SetStatus($"„{template.Manifest.Name}“ geladen.", false);
     }
 
+    public static string MigrateLegacyLayout(string source, TemplateLayout layout)
+    {
+        if (layout.UsesPageTemplates) return source;
+        var statements = source.Replace("\r\n", "\n", StringComparison.Ordinal).Split('\n')
+            .Where(line =>
+            {
+                var trimmed = line.Trim();
+                return trimmed.Length > 0 && !trimmed.StartsWith('#')
+                    && !trimmed.StartsWith("PAGE ", StringComparison.OrdinalIgnoreCase);
+            }).Select(line => line.Trim()).ToList();
+        var margin = layout.Unit.Equals("mm", StringComparison.OrdinalIgnoreCase) ? 20f : layout.Width * 0.08f;
+        var x = FormatNumber(margin); var y = FormatNumber(margin);
+        var width = FormatNumber(Math.Max(1, layout.Width - margin * 2));
+        var height = FormatNumber(Math.Max(1, layout.Height - margin * 2));
+        var result = new List<string>
+        {
+            $"PAGE {FormatNumber(layout.Width)} {FormatNumber(layout.Height)} {layout.Unit}",
+            "#pragma format-version 3", "", "#pragma page-template first",
+        };
+        result.AddRange(statements);
+        result.AddRange([
+            $"#pragma flow-slot body x={x} y={y} w={width} h={height}",
+            "#pragma end-page-template", "", "#pragma page-template continuation",
+            $"#pragma flow-slot body x={x} y={y} w={width} h={height}",
+            "#pragma end-page-template", "", "#pragma content-flow body",
+            "#pragma end-content-flow", "",
+        ]);
+        return string.Join('\n', result);
+    }
+
     public void LoadAsNewProject(LoadedTemplate template, string layoutSource, string? continuationLayoutSource = null, string? newId = null)
     {
         Load(template, layoutSource, continuationLayoutSource);
@@ -219,10 +271,44 @@ public partial class DesignerViewModel : ObservableObject
     public void PreviewTemplate(LoadedTemplate template)
     {
         var provider = BuildSampleDataProvider(template.Manifest);
-        var bytes = new QuestTemplateRenderer().RenderFirstPageToPng(template, provider);
+        RenderPreviewPages(template, provider);
+        SetStatus($"Vorschau von „{template.Manifest.Name}“ mit {PreviewPages.Count} Seite(n).", false);
+    }
+
+    public void RenderPreviewPages(LoadedTemplate template, ITemplateDataProvider provider)
+    {
+        var pages = new QuestTemplateRenderer().RenderPagesToPng(template, provider);
+        ClearPreviewPages();
+        for (var index = 0; index < pages.Count; index++)
+        {
+            using var stream = new MemoryStream(pages[index]);
+            PreviewPages.Add(new(index + 1, new Bitmap(stream)));
+        }
+        SelectedPreviewPage = PreviewPages.FirstOrDefault();
+    }
+
+    public void PreviewSelectedPageTemplateCanvas()
+    {
+        var loaded = BuildLoaded();
+        var pageTemplate = loaded.Layout.PageTemplates.FirstOrDefault(x =>
+            x.Name.Equals(SelectedPageTemplate, StringComparison.OrdinalIgnoreCase));
+        if (pageTemplate is null) return;
+        var canvasLayout = new TemplateLayout(loaded.Layout.Width, loaded.Layout.Height, loaded.Layout.Unit,
+            pageTemplate.Elements);
+        var canvasTemplate = new LoadedTemplate(loaded.Manifest, canvasLayout, loaded.Assets, loaded.SourceName);
+        var bytes = new QuestTemplateRenderer().RenderFirstPageToPng(canvasTemplate, BuildDataProvider());
         using var stream = new MemoryStream(bytes);
-        PreviewImage?.Dispose(); PreviewImage = new Bitmap(stream);
+        _pageTemplatePreview?.Dispose(); _pageTemplatePreview = new Bitmap(stream);
-        SetStatus($"Vorschau von „{template.Manifest.Name}“.", false);
+        SelectedPreviewPage = null; PreviewImage = _pageTemplatePreview;
+        SetStatus($"Bearbeitungsansicht des Seitentyps „{SelectedPageTemplate}“.", false);
+    }
+
+    private void ClearPreviewPages()
+    {
+        _pageTemplatePreview?.Dispose(); _pageTemplatePreview = null;
+        PreviewImage = null; SelectedPreviewPage = null;
+        foreach (var page in PreviewPages) page.Image.Dispose();
+        PreviewPages.Clear();
     }
 
     public void SetStarterTemplates(IEnumerable<StarterTemplateItem> templates, string? selectedId = null)
@@ -270,22 +356,93 @@ public partial class DesignerViewModel : ObservableObject
     public void AddElement()
     {
         var attrs = string.IsNullOrWhiteSpace(NewAttributes) ? "" : " " + NewAttributes.Trim();
-        var line = NewElementType switch
+        var flowElement = NewElementScope == "Content-Flow";
+        var line = (NewElementType, flowElement) switch
         {
-            "TEXT" => $"TEXT {NewX} {NewY} {QuoteIfLiteral(NewContent)}{attrs}",
+            ("TEXT", false) => $"TEXT {NewX} {NewY} {QuoteIfLiteral(NewContent)}{attrs}",
-            "TEXTBOX" => $"TEXTBOX {NewX} {NewY} {NewWidth} {NewHeight} {QuoteIfLiteral(NewContent)}{attrs}",
+            ("TEXTBOX", false) => $"TEXTBOX {NewX} {NewY} {NewWidth} {NewHeight} {QuoteIfLiteral(NewContent)}{attrs}",
-            "FLOWBOX" => $"FLOWBOX {NewX} {NewY} {NewWidth} {NewHeight} {QuoteIfLiteral(NewContent)}{attrs}",
+            ("FLOWBOX", false) => $"FLOWBOX {NewX} {NewY} {NewWidth} {NewHeight} {QuoteIfLiteral(NewContent)}{attrs}",
-            "DRAWBOX" => $"DRAWBOX {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
+            ("DRAWBOX", false) => $"DRAWBOX {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
-            "FLOWDRAWBOX" => $"FLOWDRAWBOX {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
+            ("FLOWDRAWBOX", false) => $"FLOWDRAWBOX {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
-            "IMG" => $"IMG {NewContent} {NewX} {NewY} {NewWidth} {NewHeight} scale={NormalizedImageScale()}%",
+            ("IMG", false) => $"IMG {NewContent} {NewX} {NewY} {NewWidth} {NewHeight} scale={NormalizedImageScale()}%",
-            "TABLE" => $"TABLE {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
+            ("TABLE", false) => $"TABLE {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
-            "CHART" => $"CHART {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
+            ("CHART", false) => $"CHART {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
+            ("TEXT", true) => $"TEXT {QuoteIfLiteral(NewContent)}{attrs}",
+            ("TEXTBOX", true) => $"TEXTBOX {QuoteIfLiteral(NewContent)}{attrs}",
+            ("FLOWBOX", true) => $"FLOWBOX {QuoteIfLiteral(NewContent)}{attrs}",
+            ("DRAWBOX", true) => $"DRAWBOX {NewContent} w={NewWidth} h={NewHeight}{attrs}",
+            ("FLOWDRAWBOX", true) => $"FLOWDRAWBOX {NewContent} w={NewWidth} h={NewHeight}{attrs}",
+            ("IMG", true) => $"IMG {NewContent} w={NewWidth} h={NewHeight} scale={NormalizedImageScale()}%{attrs}",
+            ("TABLE", true) => $"TABLE {NewContent}{attrs}",
+            ("CHART", true) => $"CHART {NewContent} h={NewHeight}{attrs}",
             _ => throw new InvalidOperationException("Unbekannter Elementtyp."),
         };
-        LayoutSource = LayoutSource.TrimEnd() + Environment.NewLine + line + Environment.NewLine;
+        var parsedLayout = new LayoutParser().Parse(LayoutSource);
+        LayoutSource = parsedLayout.UsesPageTemplates
+            ? InsertIntoSection(LayoutSource, line, flowElement ? "content-flow" : "page-template",
+                flowElement ? SelectedContentFlow : SelectedPageTemplate)
+            : LayoutSource.TrimEnd() + Environment.NewLine + line + Environment.NewLine;
         CanExport = false; SetStatus("Element ergänzt. Vorschau zur Prüfung aktualisieren.", false);
     }
 
+    public void AddPageTemplate()
+    {
+        var name = ValidateSectionName(NewPageTemplateName, "Seitentyp");
+        if (PageTemplateNames.Contains(name, StringComparer.OrdinalIgnoreCase))
+            throw new InvalidDataException($"Seitentyp „{name}“ existiert bereits.");
+        var block = $"#pragma page-template {name}\n#pragma end-page-template\n";
+        var marker = LayoutSource.IndexOf("#pragma content-flow", StringComparison.OrdinalIgnoreCase);
+        LayoutSource = marker < 0 ? LayoutSource.TrimEnd() + "\n\n" + block
+            : LayoutSource.Insert(marker, block + "\n");
+        SelectedPageTemplate = name; CanExport = false;
+        SetStatus($"Seitentyp „{name}“ angelegt.", false);
+    }
+
+    public void AddContentFlow()
+    {
+        var name = ValidateSectionName(NewFlowName, "Flow");
+        if (ContentFlowNames.Contains(name, StringComparer.OrdinalIgnoreCase))
+            throw new InvalidDataException($"Content-Flow „{name}“ existiert bereits.");
+        LayoutSource = LayoutSource.TrimEnd() + $"\n\n#pragma content-flow {name}\n#pragma end-content-flow\n";
+        SelectedContentFlow = name; CanExport = false;
+        SetStatus($"Content-Flow „{name}“ angelegt. Lege nun gleichnamige Slots auf den Seitentypen an.", false);
+    }
+
+    public void AddFlowSlot()
+    {
+        var name = ValidateSectionName(NewFlowName, "Flow-Slot");
+        var line = $"#pragma flow-slot {name} x={NewX} y={NewY} w={NewWidth} h={NewHeight}";
+        LayoutSource = InsertIntoSection(LayoutSource, line, "page-template", SelectedPageTemplate);
+        CanExport = false;
+        SetStatus($"Flow-Slot „{name}“ auf „{SelectedPageTemplate}“ angelegt.", false);
+    }
+
+    private static string ValidateSectionName(string value, string label)
+    {
+        var name = value.Trim();
+        if (name.Length == 0 || name.Any(c => !(char.IsAsciiLetterOrDigit(c) || c is '-' or '_')))
+            throw new InvalidDataException($"{label}-Namen dürfen nur Buchstaben, Ziffern, - und _ enthalten.");
+        return name;
+    }
+
+    private static string InsertIntoSection(string source, string line, string section, string name)
+    {
+        var lines = source.Replace("\r\n", "\n", StringComparison.Ordinal).Split('\n').ToList();
+        var start = lines.FindIndex(x =>
+        {
+            var tokens = x.Trim().Split((char[]?)null, StringSplitOptions.RemoveEmptyEntries);
+            return tokens.Length >= 3 && tokens[0].Equals("#pragma", StringComparison.OrdinalIgnoreCase)
+                && tokens[1].Equals(section, StringComparison.OrdinalIgnoreCase)
+                && tokens[2].Equals(name, StringComparison.OrdinalIgnoreCase);
+        });
+        if (start < 0) throw new InvalidDataException($"{section} „{name}“ wurde nicht gefunden.");
+        var endDirective = section == "content-flow" ? "end-content-flow" : "end-page-template";
+        var end = lines.FindIndex(start + 1, x => x.Trim().Equals($"#pragma {endDirective}", StringComparison.OrdinalIgnoreCase));
+        if (end < 0) throw new InvalidDataException($"{section} „{name}“ ist nicht geschlossen.");
+        lines.Insert(end, line);
+        return string.Join('\n', lines);
+    }
+
     public DesignerAsset ImportAsset(string sourceName, byte[] bytes) => AddOrReplaceAsset(sourceName, bytes, keepName: false);
 
     public DesignerAsset ImportBackground(string sourceName, byte[] bytes)
@@ -346,6 +503,19 @@ public partial class DesignerViewModel : ObservableObject
     public void ApplyElementGeometry(OverlayElementGeometry geometry)
     {
         var layout = new LayoutParser().Parse(LayoutSource);
+        if (geometry.Keyword == "FLOW")
+        {
+            var slot = layout.PageTemplates.SelectMany(x => x.FlowSlots)
+                .FirstOrDefault(x => x.Line == geometry.Line)
+                ?? throw new InvalidDataException($"Flow-Slot in Zeile {geometry.Line} wurde nicht gefunden.");
+            var slotLines = LayoutSource.Replace("\r\n", "\n", StringComparison.Ordinal).Split('\n').ToList();
+            slotLines[geometry.Line - 1] = $"#pragma flow-slot {slot.Name} x={FormatNumber(geometry.X)} "
+                + $"y={FormatNumber(geometry.Y)} w={FormatNumber(geometry.Width)} h={FormatNumber(geometry.Height)}";
+            LayoutSource = string.Join('\n', slotLines); CanExport = false;
+            SelectedOverlayElement = $"Flow {slot.Name} · Zeile {geometry.Line}";
+            SetStatus($"Flow-Slot „{slot.Name}“ verschoben/skaliert.", false);
+            return;
+        }
         var element = layout.Elements.FirstOrDefault(x => x.Line == geometry.Line)
             ?? throw new InvalidDataException($"Element in Zeile {geometry.Line} wurde nicht gefunden.");
         var lines = LayoutSource.Replace("\r\n", "\n", StringComparison.Ordinal).Split('\n').ToList();
@@ -383,6 +553,20 @@ public partial class DesignerViewModel : ObservableObject
         {
             var page = new LayoutParser().Parse(value);
             OverlayPageWidth = page.Width; OverlayPageHeight = page.Height; OverlayPageUnit = page.Unit;
+            var names = page.PageTemplates.Select(x => x.Name).ToList();
+            if (names.Count == 0) names.Add("legacy");
+            var selected = names.Contains(SelectedPageTemplate, StringComparer.OrdinalIgnoreCase)
+                ? SelectedPageTemplate : names[0];
+            PageTemplateNames.Clear();
+            foreach (var name in names) PageTemplateNames.Add(name);
+            SelectedPageTemplate = selected;
+            var flows = page.ContentFlows.Select(x => x.Name).ToList();
+            if (flows.Count == 0) flows.Add("body");
+            var selectedFlow = flows.Contains(SelectedContentFlow, StringComparer.OrdinalIgnoreCase)
+                ? SelectedContentFlow : flows[0];
+            ContentFlowNames.Clear();
+            foreach (var flow in flows) ContentFlowNames.Add(flow);
+            SelectedContentFlow = selectedFlow;
         }
         catch (TemplateValidationException) { }
     }
@@ -465,15 +649,44 @@ public partial class DesignerViewModel : ObservableObject
     { Status = text; StatusColor = error ? "#B91C1C" : "#166534"; }
     private static string QuoteIfLiteral(string value) => value.StartsWith('$') ? value : $"\"{value.Replace("\"", "\\\"")}\"";
 
-    private const string DefaultLayout = """
+    private const string EmptyStructuredLayout = """
-        # Elternbrief Standard
         PAGE 210 297 mm
+        #pragma format-version 3
+
+        #pragma page-template first
+        #pragma flow-slot body x=20 y=30 w=170 h=247
+        #pragma end-page-template
+
+        #pragma page-template continuation
+        #pragma flow-slot body x=20 y=20 w=170 h=257
+        #pragma end-page-template
+
+        #pragma content-flow body
+        #pragma end-content-flow
+        """;
+
+    private const string DefaultLayout = """
+        # Elternbrief Standard · Format 3
+        PAGE 210 297 mm
+        #pragma format-version 3
+
+        #pragma page-template first
         TEXT 20 25 "Elternbrief" size=18 bold=true color=#1E3A8A
         TEXT 20 43 $Datum|dd.MM.yyyy size=10
         TEXT 20 55 $Empfaenger size=11
         TEXT 20 75 "Sehr geehrte/r $Anrede," size=11
-        TEXTBOX 20 90 170 155 $Brieftext size=11 wrap=true
+        #pragma flow-slot body x=20 y=90 w=170 h=175
-        TEXT 20 265 $LehrerName size=10 italic=true
+        #pragma end-page-template
+
+        #pragma page-template continuation
+        #pragma flow-slot body x=20 y=25 w=170 h=240
+        #pragma end-page-template
+
+        #pragma content-flow body
+        TEXTBOX $Brieftext size=11 overflow=continue
+        TEXT "Mit freundlichen Grüßen" size=10 gap=8 keep-with-next=true
+        TEXT $LehrerName size=10 italic=true gap=4
+        #pragma end-content-flow
         """;
 }
 
@@ -483,6 +696,11 @@ public partial class DesignerMetadata(string name, string value) : ObservableObj
     [ObservableProperty] private string _value = value;
 }
 
+public sealed record DesignerPreviewPage(int Number, Bitmap Image)
+{
+    public string Display => $"Dokumentseite {Number}";
+}
+
 public partial class DesignerAsset(string name, int pixelWidth, int pixelHeight, long byteCount) : ObservableObject
 {
     [ObservableProperty] private int _usageCount;

LehrerApp.TemplateDesigner/LayoutOverlayEditor.cs

@@ -30,14 +30,18 @@ public sealed class LayoutOverlayEditor : Control
         AvaloniaProperty.Register<LayoutOverlayEditor, bool>(nameof(SnapToGrid), true);
     public static readonly StyledProperty<double> GridSizeProperty =
         AvaloniaProperty.Register<LayoutOverlayEditor, double>(nameof(GridSize), 1);
+    public static readonly StyledProperty<string> PageTemplateNameProperty =
+        AvaloniaProperty.Register<LayoutOverlayEditor, string>(nameof(PageTemplateName), "first");
 
     private readonly Pen _normalPen = new(new SolidColorBrush(Color.Parse("#2563EB")), 1.5);
     private readonly Pen _selectedPen = new(new SolidColorBrush(Color.Parse("#DC2626")), 2.5);
     private readonly Pen _measurePen = new(new SolidColorBrush(Color.Parse("#D97706")), 2);
     private readonly Pen _gridPen = new(new SolidColorBrush(Color.FromArgb(55, 37, 99, 235)), 1);
+    private readonly Pen _flowPen = new(new SolidColorBrush(Color.Parse("#7C3AED")), 2, dashStyle: DashStyle.Dash);
     private readonly IBrush _normalFill = new SolidColorBrush(Color.FromArgb(30, 37, 99, 235));
     private readonly IBrush _selectedFill = new SolidColorBrush(Color.FromArgb(35, 220, 38, 38));
     private readonly IBrush _handleFill = new SolidColorBrush(Color.Parse("#DC2626"));
+    private readonly IBrush _flowFill = new SolidColorBrush(Color.FromArgb(38, 124, 58, 237));
     private readonly List<OverlayItem> _items = [];
     private OverlayItem? _selected;
     private Point? _pointerStartDsl;
@@ -52,6 +56,7 @@ public sealed class LayoutOverlayEditor : Control
     public OverlayEditorMode Mode { get => GetValue(ModeProperty); set => SetValue(ModeProperty, value); }
     public bool SnapToGrid { get => GetValue(SnapToGridProperty); set => SetValue(SnapToGridProperty, value); }
     public double GridSize { get => GetValue(GridSizeProperty); set => SetValue(GridSizeProperty, value); }
+    public string PageTemplateName { get => GetValue(PageTemplateNameProperty); set => SetValue(PageTemplateNameProperty, value); }
 
     public event EventHandler<OverlayMeasurement>? MeasurementCompleted;
     public event EventHandler<OverlayElementGeometry>? ElementGeometryChanged;
@@ -61,7 +66,8 @@ public sealed class LayoutOverlayEditor : Control
     static LayoutOverlayEditor()
     {
         AffectsRender<LayoutOverlayEditor>(PreviewImageProperty, LayoutSourceProperty, PageWidthProperty,
-            PageHeightProperty, PageUnitProperty, ModeProperty, SnapToGridProperty, GridSizeProperty);
+            PageHeightProperty, PageUnitProperty, ModeProperty, SnapToGridProperty, GridSizeProperty,
+            PageTemplateNameProperty);
     }
 
     public LayoutOverlayEditor() { Focusable = true; ClipToBounds = true; }
@@ -80,7 +86,9 @@ public sealed class LayoutOverlayEditor : Control
             var geometry = ReferenceEquals(item, _selected) && _workingRectDsl is { } working ? working : item.Rect;
             var rect = ToControl(geometry, page);
             var selected = ReferenceEquals(item, _selected);
-            context.DrawRectangle(selected ? _selectedFill : _normalFill, selected ? _selectedPen : _normalPen,
+            var fill = selected ? _selectedFill : item.IsFlowSlot ? _flowFill : _normalFill;
+            var pen = selected ? _selectedPen : item.IsFlowSlot ? _flowPen : _normalPen;
+            context.DrawRectangle(fill, pen,
                 rect, 2, 2);
             if (selected && item.Resizable)
                 context.FillRectangle(_handleFill, new Rect(rect.Right - 6, rect.Bottom - 6, 12, 12), 2);
@@ -188,7 +196,11 @@ public sealed class LayoutOverlayEditor : Control
         try
         {
             var layout = new LayoutParser().Parse(LayoutSource);
-            foreach (var element in layout.Elements)
+            var pageTemplate = layout.PageTemplates.FirstOrDefault(x =>
+                x.Name.Equals(PageTemplateName, StringComparison.OrdinalIgnoreCase))
+                ?? layout.PageTemplates.FirstOrDefault();
+            var visibleElements = pageTemplate?.Elements ?? layout.Elements;
+            foreach (var element in visibleElements)
             {
                 if (element is BackgroundElement) continue;
                 var keyword = element switch
@@ -202,8 +214,11 @@ public sealed class LayoutOverlayEditor : Control
                     ImageElement image => (image.Width * ImageScale(image), image.Height * ImageScale(image), true),
                     _ => ((double)element.Width, element.Height, true),
                 };
-                _items.Add(new(element.Line, keyword, new Rect(element.X, element.Y, width, height), resizable));
+                _items.Add(new(element.Line, keyword, new Rect(element.X, element.Y, width, height), resizable, false));
             }
+            if (pageTemplate is not null)
+                foreach (var slot in pageTemplate.FlowSlots)
+                    _items.Add(new(slot.Line, "FLOW", new Rect(slot.X, slot.Y, slot.Width, slot.Height), true, true));
             if (_selected is not null)
                 _selected = _items.FirstOrDefault(x => x.Line == _selected.Line);
         }
@@ -244,7 +259,7 @@ public sealed class LayoutOverlayEditor : Control
     private double PointsToUnit(double points) => PageUnit.ToLowerInvariant() switch
     { "mm" => points * 25.4 / 72, "cm" => points * 2.54 / 72, "in" => points / 72, _ => points };
 
-    private sealed record OverlayItem(int Line, string Keyword, Rect Rect, bool Resizable);
+    private sealed record OverlayItem(int Line, string Keyword, Rect Rect, bool Resizable, bool IsFlowSlot);
     private enum DragKind { None, Measure, Move, Resize }
 }
 

LehrerApp.TemplateDesigner/MainWindow.axaml

@@ -37,7 +37,7 @@
     <Border Grid.Row="1" Padding="18,12" Background="#172554">
       <Grid ColumnDefinitions="*,Auto">
         <StackPanel><TextBlock Text="Vorlagen-Designer" Foreground="White" FontWeight="Bold" FontSize="20"/>
-          <TextBlock Text="Portable PDF-Briefpakete · Schema 1" Foreground="#BFDBFE" FontSize="12"/></StackPanel>
+          <TextBlock Text="Portable PDF-Briefpakete · Layoutformat 3" Foreground="#BFDBFE" FontSize="12"/></StackPanel>
         <StackPanel Grid.Column="1" HorizontalAlignment="Right">
           <TextBlock x:Name="DocumentNameText" Foreground="White" FontWeight="SemiBold" HorizontalAlignment="Right"/>
           <TextBlock x:Name="DocumentPathText" Foreground="#BFDBFE" FontSize="11" HorizontalAlignment="Right"/>
@@ -174,10 +174,53 @@
           </Grid>
         </TabItem>
 
+        <TabItem Header="Seiten &amp; Flows">
+          <ScrollViewer Padding="8">
+            <StackPanel Spacing="14">
+              <TextBlock Text="Seitentypen" Classes="section"/>
+              <TextBlock Text="Jeder Seitentyp beschreibt nur seine eigenen festen Elemente und Flow-Slots."
+                         TextWrapping="Wrap" Opacity="0.7" FontSize="12"/>
+              <ComboBox ItemsSource="{Binding PageTemplateNames}" SelectedItem="{Binding SelectedPageTemplate, Mode=TwoWay}"/>
+              <Grid ColumnDefinitions="*,8,Auto">
+                <TextBox Text="{Binding NewPageTemplateName}" PlaceholderText="z. B. continuation"/>
+                <Button Grid.Column="2" Content="Seitentyp anlegen" Click="OnAddPageTemplate"/>
+              </Grid>
+              <Separator/>
+              <TextBlock Text="Content-Flows" Classes="section"/>
+              <TextBlock Text="Ein Flow läuft automatisch in den gleichnamigen Slot der ersten und anschließend der Folgeseiten."
+                         TextWrapping="Wrap" Opacity="0.7" FontSize="12"/>
+              <ComboBox ItemsSource="{Binding ContentFlowNames}" SelectedItem="{Binding SelectedContentFlow, Mode=TwoWay}"/>
+              <Grid ColumnDefinitions="*,8,Auto">
+                <TextBox Text="{Binding NewFlowName}" PlaceholderText="z. B. body"/>
+                <Button Grid.Column="2" Content="Flow anlegen" Click="OnAddContentFlow"/>
+              </Grid>
+              <Separator/>
+              <TextBlock Text="Flow-Slot auf ausgewählter Seite" Classes="section"/>
+              <TextBlock Text="Die Bounding Box wird rechts violett gestrichelt dargestellt und kann dort verschoben und skaliert werden."
+                         TextWrapping="Wrap" Opacity="0.7" FontSize="12"/>
+              <Grid ColumnDefinitions="*,6,*,6,*,6,*">
+                <StackPanel><TextBlock Text="X" Classes="label"/><TextBox Text="{Binding NewX}"/></StackPanel>
+                <StackPanel Grid.Column="2"><TextBlock Text="Y" Classes="label"/><TextBox Text="{Binding NewY}"/></StackPanel>
+                <StackPanel Grid.Column="4"><TextBlock Text="Breite" Classes="label"/><TextBox Text="{Binding NewWidth}"/></StackPanel>
+                <StackPanel Grid.Column="6"><TextBlock Text="Höhe" Classes="label"/><TextBox Text="{Binding NewHeight}"/></StackPanel>
+              </Grid>
+              <Button Content="Flow-Slot anlegen" HorizontalAlignment="Left" Click="OnAddFlowSlot"/>
+            </StackPanel>
+          </ScrollViewer>
+        </TabItem>
+
         <TabItem Header="Elemente">
           <ScrollViewer Padding="8">
             <StackPanel Spacing="12">
               <TextBlock Text="Element hinzufügen" Classes="section"/>
+              <StackPanel><TextBlock Text="Einfügen in" Classes="label"/>
+                <ComboBox ItemsSource="{Binding ElementScopes}" SelectedItem="{Binding NewElementScope}"/></StackPanel>
+              <Grid ColumnDefinitions="*,8,*">
+                <StackPanel><TextBlock Text="Seitentyp für feste Elemente" Classes="label"/>
+                  <ComboBox ItemsSource="{Binding PageTemplateNames}" SelectedItem="{Binding SelectedPageTemplate}"/></StackPanel>
+                <StackPanel Grid.Column="2"><TextBlock Text="Content-Flow für fließende Elemente" Classes="label"/>
+                  <ComboBox ItemsSource="{Binding ContentFlowNames}" SelectedItem="{Binding SelectedContentFlow}"/></StackPanel>
+              </Grid>
               <StackPanel><TextBlock Text="Elementtyp" Classes="label"/>
                 <ComboBox ItemsSource="{Binding ElementTypes}" SelectedItem="{Binding NewElementType}"/></StackPanel>
               <Grid ColumnDefinitions="*,6,*,6,*,6,*">
@@ -195,6 +238,8 @@
               <Button Content="Element ins Layout übernehmen" Click="OnAddElement"/>
               <TextBlock Text="Tipp: Koordinaten können rechts im Messmodus direkt aus der Vorschau übernommen werden."
                          TextWrapping="Wrap" Opacity="0.65" FontSize="11"/>
+              <TextBlock Text="Elemente im Content-Flow verwenden Reihenfolge, gap und keep-with-next; ihre X/Y-Koordinaten werden nicht benötigt."
+                         TextWrapping="Wrap" Foreground="#166534" FontSize="12"/>
               <TextBlock Text="FLOWBOX verteilt Text automatisch über beliebig viele Seiten. TEXTBOX bleibt ein fester Bereich."
                          TextWrapping="Wrap" Foreground="#166534" FontSize="12"/>
               <TextBlock Text="Systemvariablen ohne Deklaration: $$today, $$curPage und $$maxPageNum (z. B. &quot;Seite $$curPage von $$maxPageNum&quot;)."
@@ -232,11 +277,19 @@
       <Border Grid.Column="2" Background="#E2E8F0" Padding="18">
         <Grid RowDefinitions="Auto,Auto,*,Auto">
           <Grid ColumnDefinitions="*,Auto">
-            <TextBlock Text="Visueller Layout-Editor" Classes="section"/>
+            <StackPanel><TextBlock Text="Visueller Layout-Editor" Classes="section"/>
+              <ComboBox ItemsSource="{Binding PageTemplateNames}" SelectedItem="{Binding SelectedPageTemplate, Mode=TwoWay}"
+                        MinWidth="150" Margin="0,5,0,0"/>
+              <Button Content="Seitentyp anzeigen" Margin="0,5,0,0" Click="OnPageTemplateSelectionChanged"/></StackPanel>
             <TextBlock Grid.Column="1" Text="{Binding OverlayCoordinates}" FontFamily="Monospace"
                        FontSize="11" VerticalAlignment="Center"/>
           </Grid>
           <StackPanel Grid.Row="1" Spacing="7" Margin="0,10,0,0">
+            <Grid ColumnDefinitions="Auto,8,*">
+              <TextBlock Text="Vorschau" VerticalAlignment="Center" Classes="label"/>
+              <ComboBox Grid.Column="2" ItemsSource="{Binding PreviewPages}" SelectedItem="{Binding SelectedPreviewPage}"
+                        DisplayMemberBinding="{Binding Display}" PlaceholderText="Noch nicht gerendert"/>
+            </Grid>
             <Grid ColumnDefinitions="*,8,*">
               <Button Grid.Column="0" Content="Koordinaten messen" Click="OnMeasureOverlayMode"/>
               <Button Grid.Column="2" Content="Elemente verschieben" Click="OnEditOverlayMode"/>
@@ -254,6 +307,7 @@
                                        LayoutSource="{Binding LayoutSource, Mode=TwoWay}"
                                        PageWidth="{Binding OverlayPageWidth}" PageHeight="{Binding OverlayPageHeight}"
                                        PageUnit="{Binding OverlayPageUnit}" Mode="{Binding OverlayMode}"
+                                       PageTemplateName="{Binding SelectedPageTemplate}"
                                        SnapToGrid="{Binding SnapOverlayToGrid}" GridSize="{Binding OverlayGridSize}"
                                        MeasurementCompleted="OnOverlayMeasurementCompleted"
                                        ElementGeometryChanged="OnOverlayElementGeometryChanged"

LehrerApp.TemplateDesigner/MainWindow.axaml.cs

@@ -58,6 +58,18 @@ public partial class MainWindow : Window
     }
     private void OnAddElement(object? sender, RoutedEventArgs e)
     { try { _viewModel.AddElement(); } catch (Exception ex) { _viewModel.SetStatus(ex.Message, true); } }
+    private void OnAddPageTemplate(object? sender, RoutedEventArgs e)
+    { try { _viewModel.AddPageTemplate(); } catch (Exception ex) { _viewModel.SetStatus(ex.Message, true); } }
+    private void OnAddContentFlow(object? sender, RoutedEventArgs e)
+    { try { _viewModel.AddContentFlow(); } catch (Exception ex) { _viewModel.SetStatus(ex.Message, true); } }
+    private void OnAddFlowSlot(object? sender, RoutedEventArgs e)
+    { try { _viewModel.AddFlowSlot(); } catch (Exception ex) { _viewModel.SetStatus(ex.Message, true); } }
+    private void OnPageTemplateSelectionChanged(object? sender, RoutedEventArgs e)
+    {
+        if (!IsLoaded) return;
+        try { _viewModel.PreviewSelectedPageTemplateCanvas(); }
+        catch (Exception ex) { _viewModel.SetStatus($"Seitentyp-Vorschau fehlgeschlagen: {ex.Message}", true); }
+    }
     private void OnMeasureOverlayMode(object? sender, RoutedEventArgs e)
     { _viewModel.OverlayMode = OverlayEditorMode.Measure; _viewModel.SelectedOverlayElement = "Messmodus aktiv"; }
     private void OnEditOverlayMode(object? sender, RoutedEventArgs e)
@@ -125,10 +137,9 @@ public partial class MainWindow : Window
     {
         try
         {
-            var bytes = new QuestTemplateRenderer().RenderFirstPageToPng(_viewModel.BuildLoaded(), _viewModel.BuildDataProvider());
+            _viewModel.RenderPreviewPages(_viewModel.BuildLoaded(), _viewModel.BuildDataProvider());
-            using var stream = new MemoryStream(bytes);
+            _viewModel.CanExport = true;
-            _viewModel.PreviewImage?.Dispose(); _viewModel.PreviewImage = new Bitmap(stream);
+            _viewModel.SetStatus($"Validierung erfolgreich. Vorschau enthält {_viewModel.PreviewPages.Count} Seite(n).", false);
-            _viewModel.CanExport = true; _viewModel.SetStatus("Validierung erfolgreich. Vorschau ist aktuell.", false);
         }
         catch (Exception ex)
         { _viewModel.CanExport = false; _viewModel.SetStatus(ex.Message, true); }

LehrerApp.Templating.Tests/TemplatingTests.cs

@@ -171,6 +171,71 @@ public sealed class TemplatingTests : IDisposable
         Assert.Equal(3, exception.Result.Issues.Count(issue => issue.Line is not null));
     }
 
+    [Fact]
+    public void LayoutParser_LiestSeitentypenSlotsUndContentFlows()
+    {
+        var layout = new LayoutParser().Parse("""
+            PAGE 210 297 mm
+            #pragma format-version 3
+            #pragma page-template first
+            TEXT 20 20 "Briefkopf"
+            #pragma flow-slot body x=20 y=80 w=170 h=190
+            #pragma end-page-template
+            #pragma page-template continuation
+            #pragma flow-slot body x=20 y=25 w=170 h=245
+            #pragma end-page-template
+            #pragma content-flow body
+            TEXTBOX $Text size=11 overflow=continue
+            TEXT "Gruß" gap=8 keep-with-next=true
+            TEXT $Name
+            #pragma end-content-flow
+            """);
+
+        Assert.Equal(3, layout.FormatVersion);
+        Assert.Equal(2, layout.PageTemplates.Count);
+        Assert.Equal(80, layout.PageTemplates[0].FlowSlots.Single().Y);
+        Assert.Equal(3, layout.ContentFlows.Single().Elements.Count);
+        Assert.IsType<TextBoxElement>(layout.ContentFlows.Single().Elements[0]);
+    }
+
+    [Fact]
+    public void Renderer_FliesstLangenTextAufFolgeseitenWeiter()
+    {
+        var manifest = new TemplateManifest
+        {
+            Id = "flow", Name = "Flow",
+            Placeholders = [new("Text", PlaceholderType.Multiline, true), new("Name", PlaceholderType.Text, true)],
+        };
+        var layout = new LayoutParser().Parse("""
+            PAGE 210 297 mm
+            #pragma format-version 3
+            #pragma page-template first
+            TEXT 20 15 "Erste Seite" size=16
+            #pragma flow-slot body x=20 y=55 w=170 h=215
+            #pragma end-page-template
+            #pragma page-template continuation
+            TEXT 20 12 "Folgeseite" size=9
+            #pragma flow-slot body x=20 y=25 w=170 h=245
+            #pragma end-page-template
+            #pragma content-flow body
+            TEXTBOX $Text size=11 overflow=continue
+            TEXT "Mit freundlichen Grüßen" gap=8 keep-with-next=true
+            TEXT $Name gap=3
+            #pragma end-content-flow
+            """);
+        var loaded = new LoadedTemplate(manifest, layout, new Dictionary<string, byte[]>());
+        var longText = string.Join('\n', Enumerable.Repeat("Dies ist eine ausreichend lange Textzeile für den Seitenumbruch.", 180));
+
+        var pages = new QuestTemplateRenderer().RenderPagesToPng(loaded,
+            new DictionaryProvider(new Dictionary<string, PlaceholderValue>
+            {
+                ["Text"] = new MultilineValue(longText), ["Name"] = new TextValue("M. Mustermann"),
+            }), 40);
+
+        Assert.True(pages.Count >= 3);
+        Assert.All(pages, page => Assert.True(page.Length > 500));
+    }
+
     [Fact]
     public void Loader_BlockiertPathTraversal()
     {

LehrerApp.Templating/LayoutParser.cs

@@ -9,6 +9,12 @@ public sealed class LayoutParser
     {
         var issues = new List<ValidationIssue>();
         var elements = new List<TemplateElement>();
+        var pageTemplates = new List<PageTemplateDefinition>();
+        var contentFlows = new List<ContentFlowDefinition>();
+        string? currentPageName = null, currentFlowName = null;
+        List<TemplateElement>? currentPageElements = null, currentFlowElements = null;
+        List<FlowSlotDefinition>? currentSlots = null;
+        var formatVersion = 1;
         float width = 0, height = 0;
         var unit = "mm";
         var pageSeen = false;
@@ -18,15 +24,75 @@ public sealed class LayoutParser
         {
             var lineNumber = index + 1;
             var raw = lines[index].Trim();
-            if (raw.Length == 0 || raw.StartsWith('#')) continue;
+            if (raw.Length == 0) continue;
             try
             {
+                if (raw.StartsWith("#pragma", StringComparison.OrdinalIgnoreCase))
+                {
+                    var pragma = Tokenize(raw);
+                    Require(pragma, 2);
+                    switch (pragma[1].ToLowerInvariant())
+                    {
+                        case "format-version":
+                            Require(pragma, 3);
+                            if (!int.TryParse(pragma[2], out formatVersion) || formatVersion is < 1 or > 3)
+                                throw new FormatException("format-version muss zwischen 1 und 3 liegen.");
+                            break;
+                        case "page-template":
+                            Require(pragma, 3);
+                            if (currentPageName is not null || currentFlowName is not null)
+                                throw new FormatException("Verschachtelte Bereiche sind nicht erlaubt.");
+                            currentPageName = pragma[2]; currentPageElements = []; currentSlots = [];
+                            break;
+                        case "end-page-template":
+                            if (currentPageName is null || currentPageElements is null || currentSlots is null)
+                                throw new FormatException("Kein page-template ist geöffnet.");
+                            if (pageTemplates.Any(x => x.Name.Equals(currentPageName, StringComparison.OrdinalIgnoreCase)))
+                                throw new FormatException($"page-template „{currentPageName}“ ist mehrfach definiert.");
+                            pageTemplates.Add(new(currentPageName, currentPageElements, currentSlots));
+                            currentPageName = null; currentPageElements = null; currentSlots = null;
+                            break;
+                        case "flow-slot":
+                            Require(pragma, 3);
+                            if (currentPageName is null || currentSlots is null)
+                                throw new FormatException("flow-slot muss innerhalb eines page-template stehen.");
+                            var slotAttributes = Attributes(pragma, 3);
+                            foreach (var required in new[] { "x", "y", "w", "h" })
+                                if (!slotAttributes.ContainsKey(required))
+                                    throw new FormatException($"flow-slot benötigt {required}=…");
+                            var slot = new FlowSlotDefinition(lineNumber, pragma[2], Number(slotAttributes["x"]),
+                                Number(slotAttributes["y"]), Number(slotAttributes["w"]), Number(slotAttributes["h"]));
+                            if (slot.Width <= 0 || slot.Height <= 0) throw new FormatException("Flow-Slot muss eine positive Größe haben.");
+                            if (currentSlots.Any(x => x.Name.Equals(slot.Name, StringComparison.OrdinalIgnoreCase)))
+                                throw new FormatException($"flow-slot „{slot.Name}“ ist in dieser Seitenvorlage mehrfach definiert.");
+                            currentSlots.Add(slot);
+                            break;
+                        case "content-flow":
+                            Require(pragma, 3);
+                            if (currentPageName is not null || currentFlowName is not null)
+                                throw new FormatException("Verschachtelte Bereiche sind nicht erlaubt.");
+                            currentFlowName = pragma[2]; currentFlowElements = [];
+                            break;
+                        case "end-content-flow":
+                            if (currentFlowName is null || currentFlowElements is null)
+                                throw new FormatException("Kein content-flow ist geöffnet.");
+                            if (contentFlows.Any(x => x.Name.Equals(currentFlowName, StringComparison.OrdinalIgnoreCase)))
+                                throw new FormatException($"content-flow „{currentFlowName}“ ist mehrfach definiert.");
+                            contentFlows.Add(new(currentFlowName, currentFlowElements));
+                            currentFlowName = null; currentFlowElements = null;
+                            break;
+                        default: throw new FormatException($"Unbekanntes Pragma „{pragma[1]}“.");
+                    }
+                    continue;
+                }
+                if (raw.StartsWith('#')) continue;
                 var tokens = Tokenize(raw);
                 if (tokens.Count == 0) continue;
                 var keyword = tokens[0].ToUpperInvariant();
                 if (!pageSeen && keyword != "PAGE")
                     throw new FormatException("PAGE muss das erste Statement sein.");
 
+                TemplateElement? parsedElement = null;
                 switch (keyword)
                 {
                     case "PAGE":
@@ -39,56 +105,94 @@ public sealed class LayoutParser
                         pageSeen = true;
                         break;
                     case "BG":
-                        Require(tokens, 2); elements.Add(new BackgroundElement(lineNumber, tokens[1])); break;
+                        if (currentFlowName is not null) throw new FormatException("BG ist in einem content-flow nicht erlaubt.");
+                        Require(tokens, 2); parsedElement = new BackgroundElement(lineNumber, tokens[1]); break;
                     case "IMG":
-                        Require(tokens, 6);
+                        var flowImage = currentFlowName is not null;
-                        var imageAttributes = Attributes(tokens, 6);
+                        Require(tokens, flowImage ? 2 : 6);
+                        var imageAttributes = Attributes(tokens, flowImage ? 2 : 6);
                         if (imageAttributes.TryGetValue("scale", out var scale)) Percentage(scale);
-                        elements.Add(new ImageElement(lineNumber, tokens[1],
+                        parsedElement = flowImage
-                            Number(tokens[2]), Number(tokens[3]), Number(tokens[4]), Number(tokens[5]), imageAttributes));
+                            ? new ImageElement(lineNumber, tokens[1], 0, 0,
+                                OptionalNumber(imageAttributes, "w"), OptionalNumber(imageAttributes, "h"), imageAttributes)
+                            : new ImageElement(lineNumber, tokens[1], Number(tokens[2]), Number(tokens[3]),
+                                Number(tokens[4]), Number(tokens[5]), imageAttributes);
                         break;
                     case "TEXT":
-                        Require(tokens, 4);
+                        var flowText = currentFlowName is not null;
-                        var textRef = Reference(tokens[3]);
+                        Require(tokens, flowText ? 2 : 4);
-                        elements.Add(new TextElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        var textContent = tokens[flowText ? 1 : 3];
-                            tokens[3], textRef.Name, textRef.Format, Attributes(tokens, 4))); break;
+                        var textRef = Reference(textContent);
+                        parsedElement = new TextElement(lineNumber, flowText ? 0 : Number(tokens[1]),
+                            flowText ? 0 : Number(tokens[2]), textContent, textRef.Name, textRef.Format,
+                            Attributes(tokens, flowText ? 2 : 4)); break;
                     case "TEXTBOX":
-                        Require(tokens, 6);
+                        var flowBox = currentFlowName is not null;
-                        var boxRef = Reference(tokens[5]);
+                        Require(tokens, flowBox ? 2 : 6);
-                        elements.Add(new TextBoxElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        var boxContent = tokens[flowBox ? 1 : 5];
-                            Number(tokens[3]), Number(tokens[4]), tokens[5], boxRef.Name, boxRef.Format,
+                        var boxRef = Reference(boxContent);
-                            Attributes(tokens, 6))); break;
+                        parsedElement = new TextBoxElement(lineNumber, flowBox ? 0 : Number(tokens[1]),
+                            flowBox ? 0 : Number(tokens[2]), flowBox ? 0 : Number(tokens[3]),
+                            flowBox ? 0 : Number(tokens[4]), boxContent, boxRef.Name, boxRef.Format,
+                            Attributes(tokens, flowBox ? 2 : 6)); break;
                     case "FLOWBOX":
-                        Require(tokens, 6);
+                        var nestedFlowBox = currentFlowName is not null;
-                        var flowRef = Reference(tokens[5]);
+                        Require(tokens, nestedFlowBox ? 2 : 6);
-                        elements.Add(new FlowBoxElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        var flowContent = tokens[nestedFlowBox ? 1 : 5];
-                            Number(tokens[3]), Number(tokens[4]), tokens[5], flowRef.Name, flowRef.Format,
+                        var flowRef = Reference(flowContent);
-                            Attributes(tokens, 6))); break;
+                        parsedElement = new FlowBoxElement(lineNumber,
+                            nestedFlowBox ? 0 : Number(tokens[1]), nestedFlowBox ? 0 : Number(tokens[2]),
+                            nestedFlowBox ? 0 : Number(tokens[3]), nestedFlowBox ? 0 : Number(tokens[4]),
+                            flowContent, flowRef.Name, flowRef.Format, Attributes(tokens, nestedFlowBox ? 2 : 6));
+                        break;
                     case "DRAWBOX":
-                        Require(tokens, 6);
+                        var flowDrawing = currentFlowName is not null;
-                        elements.Add(new DrawBoxElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        Require(tokens, flowDrawing ? 2 : 6);
-                            Number(tokens[3]), Number(tokens[4]), RequiredReference(tokens[5]), Attributes(tokens, 6)));
+                        var drawingAttributes = Attributes(tokens, flowDrawing ? 2 : 6);
+                        parsedElement = new DrawBoxElement(lineNumber,
+                            flowDrawing ? 0 : Number(tokens[1]), flowDrawing ? 0 : Number(tokens[2]),
+                            flowDrawing ? RequiredPositiveNumber(drawingAttributes, "w") : Number(tokens[3]),
+                            flowDrawing ? RequiredPositiveNumber(drawingAttributes, "h") : Number(tokens[4]),
+                            RequiredReference(tokens[flowDrawing ? 1 : 5]), drawingAttributes);
                         break;
                     case "FLOWDRAWBOX":
-                        Require(tokens, 6);
+                        var nestedFlowDrawing = currentFlowName is not null;
-                        elements.Add(new FlowDrawBoxElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        Require(tokens, nestedFlowDrawing ? 2 : 6);
-                            Number(tokens[3]), Number(tokens[4]), RequiredReference(tokens[5]), Attributes(tokens, 6)));
+                        var flowDrawingAttributes = Attributes(tokens, nestedFlowDrawing ? 2 : 6);
+                        parsedElement = new FlowDrawBoxElement(lineNumber,
+                            nestedFlowDrawing ? 0 : Number(tokens[1]), nestedFlowDrawing ? 0 : Number(tokens[2]),
+                            nestedFlowDrawing ? RequiredPositiveNumber(flowDrawingAttributes, "w") : Number(tokens[3]),
+                            nestedFlowDrawing ? RequiredPositiveNumber(flowDrawingAttributes, "h") : Number(tokens[4]),
+                            RequiredReference(tokens[nestedFlowDrawing ? 1 : 5]), flowDrawingAttributes);
                         break;
                     case "TABLE":
-                        Require(tokens, 6);
+                        var flowTable = currentFlowName is not null;
-                        elements.Add(new TableElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        Require(tokens, flowTable ? 2 : 6);
-                            Number(tokens[3]), Number(tokens[4]), RequiredReference(tokens[5]), Attributes(tokens, 6)));
+                        parsedElement = new TableElement(lineNumber, flowTable ? 0 : Number(tokens[1]),
+                            flowTable ? 0 : Number(tokens[2]), flowTable ? 0 : Number(tokens[3]),
+                            flowTable ? 0 : Number(tokens[4]), RequiredReference(tokens[flowTable ? 1 : 5]),
+                            Attributes(tokens, flowTable ? 2 : 6));
                         break;
                     case "CHART":
-                        Require(tokens, 6);
+                        var flowChart = currentFlowName is not null;
-                        var attributes = Attributes(tokens, 6);
+                        Require(tokens, flowChart ? 2 : 6);
+                        var attributes = Attributes(tokens, flowChart ? 2 : 6);
                         var chartType = attributes.GetValueOrDefault("type", "bar").ToLowerInvariant();
                         if (chartType is not ("line" or "bar")) throw new FormatException("CHART type muss line oder bar sein.");
-                        elements.Add(new ChartElement(lineNumber, Number(tokens[1]), Number(tokens[2]),
+                        parsedElement = new ChartElement(lineNumber, flowChart ? 0 : Number(tokens[1]),
-                            Number(tokens[3]), Number(tokens[4]), RequiredReference(tokens[5]), chartType, attributes));
+                            flowChart ? 0 : Number(tokens[2]), flowChart ? 0 : Number(tokens[3]),
+                            flowChart ? 0 : Number(tokens[4]), RequiredReference(tokens[flowChart ? 1 : 5]), chartType, attributes);
                         break;
                     default: throw new FormatException($"Unbekanntes Element „{tokens[0]}“.");
                 }
+                if (parsedElement is not null)
+                {
+                    elements.Add(parsedElement);
+                    if (currentPageElements is not null) currentPageElements.Add(parsedElement);
+                    else if (currentFlowElements is not null) currentFlowElements.Add(parsedElement);
+                    else if (pageTemplates.Count > 0 || contentFlows.Count > 0 || formatVersion >= 3)
+                        throw new FormatException("Elemente müssen in page-template oder content-flow stehen.");
+                }
             }
             catch (FormatException ex)
             {
@@ -97,8 +201,32 @@ public sealed class LayoutParser
         }
 
         if (!pageSeen) issues.Add(new(ValidationSeverity.Error, "PAGE fehlt."));
+        if (currentPageName is not null) issues.Add(new(ValidationSeverity.Error, $"page-template „{currentPageName}“ wurde nicht geschlossen."));
+        if (currentFlowName is not null) issues.Add(new(ValidationSeverity.Error, $"content-flow „{currentFlowName}“ wurde nicht geschlossen."));
+        if (pageTemplates.Count > 0 || contentFlows.Count > 0)
+        {
+            var firstTemplate = pageTemplates.FirstOrDefault(x => x.Name.Equals("first", StringComparison.OrdinalIgnoreCase));
+            var continuationTemplate = pageTemplates.FirstOrDefault(x => x.Name.Equals("continuation", StringComparison.OrdinalIgnoreCase));
+            if (firstTemplate is null)
+                issues.Add(new(ValidationSeverity.Error, "Die Seitenvorlage „first“ fehlt."));
+            foreach (var flow in contentFlows)
+            {
+                if (firstTemplate is not null && !firstTemplate.FlowSlots.Any(slot => slot.Name.Equals(flow.Name, StringComparison.OrdinalIgnoreCase)))
+                    issues.Add(new(ValidationSeverity.Error, $"Für content-flow „{flow.Name}“ fehlt der gleichnamige flow-slot im Seitentyp „first“."));
+                if (continuationTemplate is not null && !continuationTemplate.FlowSlots.Any(slot => slot.Name.Equals(flow.Name, StringComparison.OrdinalIgnoreCase)))
+                    issues.Add(new(ValidationSeverity.Error, $"Für content-flow „{flow.Name}“ fehlt der gleichnamige flow-slot im Seitentyp „continuation“."));
+            }
+            foreach (var slot in pageTemplates.SelectMany(page => page.FlowSlots))
+                if (slot.X < 0 || slot.Y < 0 || slot.X + slot.Width > width || slot.Y + slot.Height > height)
+                    issues.Add(new(ValidationSeverity.Error, $"Flow-Slot „{slot.Name}“ in Zeile {slot.Line} liegt außerhalb der Seite.", slot.Line));
+        }
         if (issues.Count > 0) throw new TemplateValidationException(new(issues));
-        return new(width, height, unit, elements);
+        return new(width, height, unit, elements)
+        {
+            FormatVersion = formatVersion,
+            PageTemplates = pageTemplates,
+            ContentFlows = contentFlows,
+        };
     }
 
     private static (string? Name, string? Format) Reference(string value)
@@ -116,6 +244,17 @@ public sealed class LayoutParser
     private static float Number(string value) => float.TryParse(value, NumberStyles.Float,
         CultureInfo.InvariantCulture, out var result) ? result : throw new FormatException($"„{value}“ ist keine Zahl.");
 
+    private static float OptionalNumber(IReadOnlyDictionary<string, string> attributes, string name) =>
+        attributes.TryGetValue(name, out var value) ? Number(value) : 0;
+
+    private static float RequiredPositiveNumber(IReadOnlyDictionary<string, string> attributes, string name)
+    {
+        if (!attributes.TryGetValue(name, out var raw))
+            throw new FormatException($"Das Element benötigt {name}=…");
+        var value = Number(raw);
+        return value > 0 ? value : throw new FormatException($"{name} muss positiv sein.");
+    }
+
     public static float Percentage(string value)
     {
         var normalized = value.EndsWith('%') ? value[..^1] : value;

LehrerApp.Templating/Model.cs

@@ -132,6 +132,11 @@ public sealed record ChartElement(int Line, float X, float Y, float Width, float
     string Placeholder, string ChartType, IReadOnlyDictionary<string, string> Attributes)
     : TemplateElement(Line, X, Y, Width, Height, Attributes);
 
+public sealed record FlowSlotDefinition(int Line, string Name, float X, float Y, float Width, float Height);
+public sealed record PageTemplateDefinition(string Name, IReadOnlyList<TemplateElement> Elements,
+    IReadOnlyList<FlowSlotDefinition> FlowSlots);
+public sealed record ContentFlowDefinition(string Name, IReadOnlyList<TemplateElement> Elements);
+
 internal static class EmptyAttributes
 {
     public static readonly IReadOnlyDictionary<string, string> Value =
@@ -139,7 +144,13 @@ internal static class EmptyAttributes
 }
 
 public sealed record TemplateLayout(float Width, float Height, string Unit,
-    IReadOnlyList<TemplateElement> Elements);
+    IReadOnlyList<TemplateElement> Elements)
+{
+    public int FormatVersion { get; init; } = 1;
+    public IReadOnlyList<PageTemplateDefinition> PageTemplates { get; init; } = [];
+    public IReadOnlyList<ContentFlowDefinition> ContentFlows { get; init; } = [];
+    public bool UsesPageTemplates => PageTemplates.Count > 0 || ContentFlows.Count > 0;
+}
 
 public sealed record LoadedTemplate(TemplateManifest Manifest, TemplateLayout Layout,
     IReadOnlyDictionary<string, byte[]> Assets, string SourceName = "",

LehrerApp.Templating/QuestTemplateRenderer.cs

@@ -15,9 +15,14 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
         BuildDocument(template, ValidateData(template, data)).GeneratePdf();
 
     public byte[] RenderFirstPageToPng(LoadedTemplate template, ITemplateDataProvider data, int dpi = 120)
+    {
+        return RenderPagesToPng(template, data, dpi).First();
+    }
+
+    public IReadOnlyList<byte[]> RenderPagesToPng(LoadedTemplate template, ITemplateDataProvider data, int dpi = 120)
     {
         var settings = new ImageGenerationSettings { ImageFormat = ImageFormat.Png, RasterDpi = dpi };
-        return BuildDocument(template, ValidateData(template, data)).GenerateImages(settings).First();
+        return BuildDocument(template, ValidateData(template, data)).GenerateImages(settings).ToList();
     }
 
     private static IReadOnlyDictionary<string, PlaceholderValue> ValidateData(LoadedTemplate template,
@@ -33,6 +38,14 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
         IReadOnlyDictionary<string, PlaceholderValue> values)
     {
         values = PreparePagedDrawings(template, values);
+        return template.Layout.UsesPageTemplates
+            ? BuildFlowDocument(template, values)
+            : BuildLegacyDocument(template, values);
+    }
+
+    private static IDocument BuildLegacyDocument(LoadedTemplate template,
+        IReadOnlyDictionary<string, PlaceholderValue> values)
+    {
         var flowBox = template.Layout.Elements.SingleOrDefault(x => x is FlowBoxElement or FlowDrawBoxElement);
         return Document.Create(document => document.Page(page =>
         {
@@ -45,7 +58,7 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
                     layers.PrimaryLayer().Width(UnitConverter.Points(template.Layout.Width, template.Layout.Unit))
                         .Height(UnitConverter.Points(template.Layout.Height, template.Layout.Unit)).Background(Colors.White);
                 else
-                    RenderFlowElement(layers.PrimaryLayer(), flowBox, template, values);
+                    RenderLegacyFlowElement(layers.PrimaryLayer(), flowBox, template, values);
 
                 RenderStaticLayers(layers, template.Layout, template, values,
                     template.ContinuationLayout is null ? null : static container => container.ShowOnce());
@@ -97,7 +110,7 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
         }
     }
 
-    private static void RenderFlowElement(IContainer container, TemplateElement element, LoadedTemplate template,
+    private static void RenderLegacyFlowElement(IContainer container, TemplateElement element, LoadedTemplate template,
         IReadOnlyDictionary<string, PlaceholderValue> values)
     {
         var unit = template.Layout.Unit;
@@ -117,6 +130,161 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
             });
     }
 
+    private static IDocument BuildFlowDocument(LoadedTemplate template,
+        IReadOnlyDictionary<string, PlaceholderValue> values)
+    {
+        var firstPage = template.Layout.PageTemplates.First(x =>
+            x.Name.Equals("first", StringComparison.OrdinalIgnoreCase));
+        var continuationPage = template.Layout.PageTemplates.FirstOrDefault(x =>
+            x.Name.Equals("continuation", StringComparison.OrdinalIgnoreCase)) ?? firstPage;
+        var populatedFlows = template.Layout.ContentFlows.Where(x => x.Elements.Count > 0).ToList();
+        if (populatedFlows.Count > 1)
+            throw new InvalidDataException("Aktuell darf genau ein Content-Flow Inhalt enthalten. Weitere Flow-Slots können bereits gestaltet werden, parallele paginierende Flows folgen in einer späteren Formatstufe.");
+        var primaryFlow = populatedFlows.FirstOrDefault() ?? template.Layout.ContentFlows.FirstOrDefault();
+
+        return Document.Create(document =>
+        {
+            document.Page(page =>
+            {
+                var pageWidth = UnitConverter.Points(template.Layout.Width, template.Layout.Unit);
+                var pageHeight = UnitConverter.Points(template.Layout.Height, template.Layout.Unit);
+                page.Size(pageWidth, pageHeight);
+                page.Margin(0);
+                ConfigurePageCanvas(page.Background(), firstPage, continuationPage, template, values);
+
+                if (primaryFlow is null)
+                {
+                    page.Content().Height(1);
+                    return;
+                }
+
+                var firstSlot = FindSlot(firstPage, primaryFlow.Name);
+                var continuationSlot = FindSlot(continuationPage, primaryFlow.Name) ?? firstSlot;
+                if (firstSlot is null)
+                    throw new InvalidDataException($"Für content-flow „{primaryFlow.Name}“ fehlt ein flow-slot auf der ersten Seite.");
+
+                if (Math.Abs(firstSlot.X - continuationSlot!.X) > 0.01f ||
+                    Math.Abs(firstSlot.Width - continuationSlot.Width) > 0.01f)
+                    throw new InvalidDataException($"Der primäre Flow „{primaryFlow.Name}“ muss vorerst auf erster und Folgeseite dieselbe X-Position und Breite besitzen.");
+
+                var left = UnitConverter.Points(firstSlot.X, template.Layout.Unit);
+                var right = UnitConverter.Points(template.Layout.Width - firstSlot.X - firstSlot.Width, template.Layout.Unit);
+                page.MarginLeft(left);
+                page.MarginRight(right);
+                ConfigureVariableVerticalSlot(page, firstSlot, continuationSlot, template.Layout);
+                page.Content().Column(column => RenderFlowColumn(column, primaryFlow.Elements, template, values));
+            });
+        });
+    }
+
+    private static void ConfigureVariableVerticalSlot(PageDescriptor page, FlowSlotDefinition first,
+        FlowSlotDefinition continuation, TemplateLayout layout)
+    {
+        var firstTop = UnitConverter.Points(first.Y, layout.Unit);
+        var continuationTop = UnitConverter.Points(continuation.Y, layout.Unit);
+        var firstBottom = UnitConverter.Points(layout.Height - first.Y - first.Height, layout.Unit);
+        var continuationBottom = UnitConverter.Points(layout.Height - continuation.Y - continuation.Height, layout.Unit);
+        page.Header().Column(column =>
+        {
+            column.Item().ShowOnce().Height(firstTop);
+            column.Item().SkipOnce().Height(continuationTop);
+        });
+        page.Footer().Column(column =>
+        {
+            column.Item().ShowOnce().Height(firstBottom);
+            column.Item().SkipOnce().Height(continuationBottom);
+        });
+    }
+
+    private static FlowSlotDefinition? FindSlot(PageTemplateDefinition page, string name) =>
+        page.FlowSlots.FirstOrDefault(x => x.Name.Equals(name, StringComparison.OrdinalIgnoreCase));
+
+    private static void ConfigurePageCanvas(IContainer canvas, PageTemplateDefinition first,
+        PageTemplateDefinition continuation, LoadedTemplate template,
+        IReadOnlyDictionary<string, PlaceholderValue> values)
+    {
+        canvas.Layers(layers =>
+        {
+            layers.PrimaryLayer().Background(Colors.White);
+            foreach (var element in first.Elements)
+            {
+                var current = element;
+                layers.Layer().ShowOnce().Element(root => RenderElement(root, current, template, values));
+            }
+            foreach (var element in continuation.Elements)
+            {
+                var current = element;
+                layers.Layer().SkipOnce().Element(root => RenderElement(root, current, template, values));
+            }
+        });
+    }
+
+    private static void RenderFlowColumn(ColumnDescriptor column, IReadOnlyList<TemplateElement> elements,
+        LoadedTemplate template, IReadOnlyDictionary<string, PlaceholderValue> values)
+    {
+        for (var index = 0; index < elements.Count; index++)
+        {
+            var element = elements[index];
+            var gap = UnitConverter.Points(ParseFloat(element.Attributes, "gap", 0), template.Layout.Unit);
+            var keepWithNext = ParseBool(element.Attributes, "keep-with-next") && index + 1 < elements.Count;
+            if (keepWithNext)
+            {
+                var next = elements[++index];
+                column.Item().PaddingTop(gap).PreventPageBreak().Column(group =>
+                {
+                    group.Item().Element(container => RenderFlowElement(container, element, template, values));
+                    var nextGap = UnitConverter.Points(ParseFloat(next.Attributes, "gap", 0), template.Layout.Unit);
+                    group.Item().PaddingTop(nextGap).Element(container => RenderFlowElement(container, next, template, values));
+                });
+            }
+            else
+                column.Item().PaddingTop(gap).Element(container => RenderFlowElement(container, element, template, values));
+        }
+    }
+
+    private static void RenderFlowElement(IContainer container, TemplateElement element, LoadedTemplate template,
+        IReadOnlyDictionary<string, PlaceholderValue> values)
+    {
+        switch (element)
+        {
+            case TextElement text:
+                RenderResolvedText(container, text.Content, text.Placeholder, text.Format,
+                    values, template.Manifest, text.Attributes);
+                break;
+            case TextBoxElement box:
+                RenderResolvedText(container, box.Content, box.Placeholder, box.Format,
+                    values, template.Manifest, box.Attributes);
+                break;
+            case FlowBoxElement box:
+                RenderResolvedText(container, box.Content, box.Placeholder, box.Format,
+                    values, template.Manifest, box.Attributes);
+                break;
+            case DrawBoxElement drawing when values.GetValueOrDefault(drawing.Placeholder) is { } drawingValue:
+                DrawingElementRenderer.RenderFixed(
+                    container.Width(UnitConverter.Points(drawing.Width, template.Layout.Unit))
+                        .Height(UnitConverter.Points(drawing.Height, template.Layout.Unit)),
+                    drawingValue, drawing.Width, drawing.Height, template.Layout.Unit);
+                break;
+            case FlowDrawBoxElement drawing when values.GetValueOrDefault(drawing.Placeholder) is { } drawingValue:
+                DrawingElementRenderer.RenderFlow(container, drawingValue,
+                    drawing.Width, drawing.Height, template.Layout.Unit);
+                break;
+            case ImageElement image:
+                var imageContainer = container;
+                if (image.Width > 0) imageContainer = imageContainer.Width(UnitConverter.Points(image.Width, template.Layout.Unit));
+                if (image.Height > 0) imageContainer = imageContainer.Height(UnitConverter.Points(image.Height, template.Layout.Unit));
+                imageContainer.Image(GetAsset(template, image.Path)).FitArea();
+                break;
+            case TableElement table when values.GetValueOrDefault(table.Placeholder) is TableValue tableValue:
+                TableElementRenderer.Render(container, tableValue, table.Attributes);
+                break;
+            case ChartElement chart when values.GetValueOrDefault(chart.Placeholder) is ChartValue chartValue:
+                var chartHeight = UnitConverter.Points(ParseFloat(chart.Attributes, "h", 50), template.Layout.Unit);
+                ChartElementRenderer.Render(container.Height(chartHeight), chartValue, chart.ChartType, chart.Attributes);
+                break;
+        }
+    }
+
     private static void RenderElement(IContainer root, TemplateElement element, LoadedTemplate template,
         IReadOnlyDictionary<string, PlaceholderValue> values)
     {
@@ -145,14 +313,19 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
                 RenderResolvedText(Position(root, box, unit).Shrink(), box.Content, box.Placeholder, box.Format,
                     values, template.Manifest, box.Attributes);
                 break;
-            case FlowBoxElement:
+            case FlowBoxElement box:
+                RenderResolvedText(Position(root, box, unit).Shrink(), box.Content, box.Placeholder, box.Format,
+                    values, template.Manifest, box.Attributes);
                 break;
             case DrawBoxElement drawing:
                 if (values.GetValueOrDefault(drawing.Placeholder) is { } drawingValue)
                     DrawingElementRenderer.RenderFixed(Position(root, drawing, unit), drawingValue,
                         drawing.Width, drawing.Height, unit);
                 break;
-            case FlowDrawBoxElement:
+            case FlowDrawBoxElement drawing:
+                if (values.GetValueOrDefault(drawing.Placeholder) is { } flowDrawingValue)
+                    DrawingElementRenderer.RenderFixed(Position(root, drawing, unit), flowDrawingValue,
+                        drawing.Width, drawing.Height, unit);
                 break;
             case TableElement table:
                 if (values.GetValueOrDefault(table.Placeholder) is TableValue tableValue)

docs/Templating-Layoutformat-3.md

@@ -0,0 +1,72 @@
+# Templating-Layoutformat 3
+
+Layoutformat 3 trennt feste Seitengestaltung von fortlaufendem Dokumentinhalt.
+
+## Grundaufbau
+
+```text
+PAGE 210 297 mm
+#pragma format-version 3
+
+#pragma page-template first
+IMG briefkopf.png 0 0 210 55
+#pragma flow-slot body x=20 y=90 w=170 h=175
+#pragma end-page-template
+
+#pragma page-template continuation
+IMG folgeseite.png 0 0 210 25
+#pragma flow-slot body x=20 y=30 w=170 h=235
+#pragma end-page-template
+
+#pragma content-flow body
+TEXTBOX $Brieftext size=11 overflow=continue
+TEXT "Mit freundlichen Grüßen" gap=8 keep-with-next=true
+TEXT $LehrerName gap=3 italic=true
+#pragma end-content-flow
+```
+
+## Seitentypen
+
+- `first` ist verpflichtend und gestaltet die erste Seite.
+- `continuation` gestaltet alle Folgeseiten. Fehlt dieser Typ, wird `first` wiederholt.
+- Elemente innerhalb eines `page-template` sind absolut positioniert und beeinflussen den Textfluss nicht.
+- Jede Seitenvorlage beschreibt ausschließlich ihre eigenen Elemente und Slots.
+
+## Flow-Slots und Content-Flows
+
+Ein `flow-slot` definiert eine Bounding Box innerhalb einer Seitenvorlage. Ein gleichnamiger
+`content-flow` liefert den fortlaufenden Inhalt. Ist `continuation` vorhanden, benötigt jeder
+Content-Flow auf `first` und `continuation` einen gleichnamigen Slot.
+
+Elemente in einem Content-Flow werden ohne X/Y-Koordinaten angegeben:
+
+```text
+TEXT "Absatz" size=11 gap=4
+TEXTBOX $MehrzeiligerText size=11 overflow=continue
+TABLE $Zeilen size=9
+CHART $Werte type=bar h=50
+IMG unterschrift.png w=45 h=18
+```
+
+- `gap` ist der Abstand zum Vorgänger in der Seiteneinheit.
+- `keep-with-next=true` hält das Element nach Möglichkeit mit seinem Nachfolger zusammen.
+- Text und Tabellen dürfen automatisch auf Folgeseiten weiterlaufen.
+
+## Designer
+
+Der Tab **Seiten & Flows** verwaltet Seitentypen, Content-Flows und Flow-Slots. Der visuelle
+Editor zeigt den Slot des gewählten Seitentyps violett gestrichelt an. Er kann wie ein anderes
+Element verschoben und skaliert werden. Die Vorschauseiten-Auswahl zeigt alle tatsächlich aus den
+Beispieldaten erzeugten Dokumentseiten; **Seitentyp anzeigen** rendert stattdessen die feste
+Gestaltung der gewählten Seitenvorlage.
+
+Beim Öffnen eines alten absoluten Layouts bettet der Designer dessen Elemente unverändert in den
+Seitentyp `first` ein und ergänzt leere `body`-Slots sowie einen leeren Content-Flow. Erst beim
+anschließenden Speichern wird das migrierte Layout in das Paket geschrieben.
+
+## Aktuelle Grenzen
+
+Die erste Renderer-Ausbaustufe unterstützt einen mit Inhalt gefüllten, paginierenden Content-Flow.
+Weitere Slots und leere Flows können bereits gestaltet werden. Beim primären Flow müssen X-Position
+und Breite auf erster und Folgeseite noch identisch sein; Y-Position und Höhe dürfen sich unterscheiden.
+Diese Einschränkung wird beim Rendern mit einer verständlichen Fehlermeldung geprüft.