Add PlantUML and Mermaid diagram rendering

- Detect plantuml/mermaid code fences and render as diagrams
- PlantUML: POST to localhost:8080/svg for SVG output
- Mermaid: GET to localhost:8081/img/ with base64 for JPEG output
  (SVG not usable - Qt doesn't support foreignObject)
- Cache rendered diagrams by content hash
- Toggle between source code and rendered image view
- Copy button for source text or image data
- Fall back to source display on render errors
- Add ClipboardHelper for image clipboard support
- Clear diagram cache on session reset

CMakeLists.txt

@@ -81,6 +81,7 @@ if(OLLIE_KF5)
         gui/chatblockmodel.cpp
         gui/thememanager.cpp
         gui/streamfsm.cpp
+        gui/clipboardhelper.cpp
         ${GUI_KF5_QRC}
     )
     target_include_directories(ollie-gui PRIVATE
@@ -92,6 +93,7 @@ if(OLLIE_KF5)
         Qt5::Widgets
         Qt5::Quick
         Qt5::QuickControls2
+        Qt5::Network
         KF5::ConfigCore
         KF5::SyntaxHighlighting
         $ENV{HOME}/.local/lib/libollie9p.so
@@ -102,7 +104,7 @@ if(OLLIE_KF5)
 
 else()
     # --- Qt6 / KF6 ---
-    find_package(Qt6 REQUIRED COMPONENTS Core Widgets Quick QuickControls2)
+    find_package(Qt6 REQUIRED COMPONENTS Core Widgets Quick QuickControls2 Network)
     find_package(KF6 REQUIRED COMPONENTS Runner CoreAddons)
     find_package(KF6Config REQUIRED)
 
@@ -149,6 +151,7 @@ else()
         gui/chatblockmodel.cpp
         gui/thememanager.cpp
         gui/streamfsm.cpp
+        gui/clipboardhelper.cpp
     )
     target_include_directories(ollie-gui PRIVATE
         ${CMAKE_SOURCE_DIR}/gui
@@ -159,6 +162,7 @@ else()
         Qt6::Widgets
         Qt6::Quick
         Qt6::QuickControls2
+        Qt6::Network
         KF6::ConfigCore
         KF6::SyntaxHighlighting
         $ENV{HOME}/.local/lib/libollie9p.so

gui/chatblockmodel.cpp

@@ -4,6 +4,12 @@
 #include <QRegularExpressionMatch>
 #include <QApplication>
 #include <QPalette>
+#include <QNetworkAccessManager>
+#include <QNetworkReply>
+#include <QNetworkRequest>
+#include <QUrl>
+#include <QUrlQuery>
+#include <QCryptographicHash>
 
 #include <KSyntaxHighlighting/Repository>
 #include <KSyntaxHighlighting/Definition>
@@ -107,7 +113,10 @@ const QRegularExpression ChatBlockModel::s_fenceCloseRe(
 ChatBlockModel::ChatBlockModel(QObject *parent)
     : QAbstractListModel(parent)
     , m_repo(new KSyntaxHighlighting::Repository())
+    , m_netManager(new QNetworkAccessManager(this))
 {
+    connect(m_netManager, &QNetworkAccessManager::finished,
+            this, &ChatBlockModel::onDiagramReply);
 }
 
 ChatBlockModel::~ChatBlockModel()
@@ -148,10 +157,32 @@ QVariant ChatBlockModel::data(const QModelIndex &index, int role) const
         return b.content;
     case RenderedHtmlRole:
         return b.renderedHtml;
+    case SegmentsRole:
+        return segmentsToVariant(b.segments);
     }
     return {};
 }
 
+QVariantList ChatBlockModel::segmentsToVariant(const QList<BlockSegment> &segments) const
+{
+    QVariantList result;
+    for (const BlockSegment &seg : segments) {
+        QVariantMap m;
+        m[QStringLiteral("type")] = (seg.type == BlockSegment::Text) 
+            ? QStringLiteral("text") : QStringLiteral("diagram");
+        m[QStringLiteral("html")] = seg.html;
+        if (seg.type == BlockSegment::Diagram) {
+            m[QStringLiteral("lang")] = seg.diagramLang;
+            m[QStringLiteral("source")] = seg.diagramSource;
+            m[QStringLiteral("svg")] = seg.diagramSvg;
+            m[QStringLiteral("error")] = seg.diagramError;
+            m[QStringLiteral("loading")] = seg.diagramLoading;
+        }
+        result.append(m);
+    }
+    return result;
+}
+
 QHash<int, QByteArray> ChatBlockModel::roleNames() const
 {
     return {
@@ -159,6 +190,7 @@ QHash<int, QByteArray> ChatBlockModel::roleNames() const
         {BlockNameRole, "blockName"},
         {ContentRole,  "blockContent"},
         {RenderedHtmlRole, "blockRenderedHtml"},
+        {SegmentsRole, "blockSegments"},
     };
 }
 
@@ -204,6 +236,9 @@ void ChatBlockModel::reset()
     m_inCodeFence = false;
     m_fenceLanguage.clear();
     m_fenceContent.clear();
+    m_pendingDiagrams.clear();
+    m_inFlightRequests.clear();
+    m_diagramCache.clear();  // Clear cache on reset to pick up fixes
     endResetModel();
     emit countChanged();
 }
@@ -223,6 +258,12 @@ void ChatBlockModel::trimFront(int keepCount)
     emit countChanged();
 }
 
+void ChatBlockModel::clearDiagramCache()
+{
+    m_diagramCache.clear();
+    qDebug() << "Diagram cache cleared";
+}
+
 QString ChatBlockModel::getDefaultTextColor() const
 {
     const auto textColor = QApplication::palette().color(QPalette::Text);
@@ -286,6 +327,7 @@ void ChatBlockModel::rebuildBlockHtml(int blockIndex)
 
     ChatBlock &block = m_blocks[blockIndex];
     QString html;
+    QList<BlockSegment> segments;
 
     // Parse the block content for code fences
     const QStringList lines = block.content.split('\n');
@@ -296,17 +338,102 @@ void ChatBlockModel::rebuildBlockHtml(int blockIndex)
 
     auto flushProse = [&]() {
         if (!proseLines.isEmpty()) {
-            html += escapeForHtml(proseLines.join('\n'));
+            QString proseHtml = escapeForHtml(proseLines.join('\n'));
+            html += proseHtml;
+            
+            BlockSegment seg;
+            seg.type = BlockSegment::Text;
+            seg.html = proseHtml;
+            segments.append(seg);
+            
             proseLines.clear();
         }
     };
 
-    auto flushFence = [&]() {
-        if (!fenceLines.isEmpty()) {
-            html += highlightCode(fenceLines.join('\n'), fenceLang);
+    auto flushFence = [&](bool complete) {
+        if (fenceLines.isEmpty()) {
+            fenceLang.clear();
+            return;
+        }
+        
+        const QString code = fenceLines.join('\n');
+        
+        if (isDiagramLanguage(fenceLang)) {
+            BlockSegment seg;
+            seg.type = BlockSegment::Diagram;
+            seg.diagramLang = fenceLang;
+            seg.diagramSource = code;
+            seg.html = highlightCode(code, fenceLang);  // Source view HTML
+            
+            if (!complete) {
+                // Streaming — show placeholder, don't request yet
+                html += diagramPlaceholder(fenceLang);
+                seg.diagramLoading = true;
+            } else {
+                // Complete fence — check cache or request diagram
+                const QString cacheKey = fenceLang + QStringLiteral(":") + 
+                    QString::fromLatin1(QCryptographicHash::hash(
+                        code.toUtf8(), QCryptographicHash::Md5).toHex());
+                
+                if (m_diagramCache.contains(cacheKey)) {
+                    const QByteArray cached = m_diagramCache.value(cacheKey);
+                    if (cached.startsWith("ERROR:")) {
+                        // Error: fall back to source code rendering (not a diagram segment)
+                        QString codeHtml = highlightCode(code, fenceLang);
+                        html += codeHtml;
+                        
+                        BlockSegment textSeg;
+                        textSeg.type = BlockSegment::Text;
+                        textSeg.html = codeHtml;
+                        segments.append(textSeg);
+                        
                         fenceLines.clear();
                         fenceLang.clear();
+                        return;  // Don't append diagram segment
+                    } else {
+                        // Check if JPEG, PNG, or SVG
+                        if (cached.startsWith("JPEG:")) {
+                            QByteArray jpegData = cached.mid(5);  // Skip "JPEG:" prefix
+                            html += diagramJpegHtml(jpegData);
+                            seg.diagramSvg = QStringLiteral("data:image/jpeg;base64,") + 
+                                QString::fromLatin1(jpegData.toBase64());
+                        } else if (cached.startsWith("PNG:")) {
+                            QByteArray pngData = cached.mid(4);  // Skip "PNG:" prefix
+                            html += diagramPngHtml(pngData);
+                            seg.diagramSvg = QStringLiteral("data:image/png;base64,") + 
+                                QString::fromLatin1(pngData.toBase64());
+                        } else if (cached.startsWith("SVG:")) {
+                            QByteArray svgData = cached.mid(4);  // Skip "SVG:" prefix
+                            html += diagramSvgHtml(svgData);
+                            seg.diagramSvg = QStringLiteral("data:image/svg+xml;base64,") + 
+                                QString::fromLatin1(svgData.toBase64());
+                        } else {
+                            // Legacy: assume SVG if no prefix
+                            html += diagramSvgHtml(cached);
+                            seg.diagramSvg = QStringLiteral("data:image/svg+xml;base64,") + 
+                                QString::fromLatin1(cached.toBase64());
                         }
+                    }
+                } else {
+                    html += diagramPlaceholder(fenceLang);
+                    seg.diagramLoading = true;
+                    // Request diagram asynchronously
+                    requestDiagram(fenceLang, code, blockIndex);
+                }
+            }
+            segments.append(seg);
+        } else {
+            QString codeHtml = highlightCode(code, fenceLang);
+            html += codeHtml;
+            
+            BlockSegment seg;
+            seg.type = BlockSegment::Text;
+            seg.html = codeHtml;
+            segments.append(seg);
+        }
+        
+        fenceLines.clear();
+        fenceLang.clear();
     };
 
     for (const QString &line : lines) {
@@ -323,7 +450,7 @@ void ChatBlockModel::rebuildBlockHtml(int blockIndex)
         } else {
             // Inside fence — check for close
             if (s_fenceCloseRe.match(line).hasMatch()) {
-                flushFence();
+                flushFence(true);  // complete
                 inFence = false;
                 continue;
             }
@@ -333,13 +460,14 @@ void ChatBlockModel::rebuildBlockHtml(int blockIndex)
 
     // Handle unclosed fence (streaming) or remaining prose
     if (inFence) {
-        // Still inside a fence — render what we have
-        html += highlightCode(fenceLines.join('\n'), fenceLang);
+        // Still inside a fence — render what we have (incomplete)
+        flushFence(false);
     } else {
         flushProse();
     }
 
     block.renderedHtml = html;
+    block.segments = segments;
 }
 
 void ChatBlockModel::appendContent(const QString &line)
@@ -387,3 +515,154 @@ void ChatBlockModel::processLine(const QString &line)
         return;
     }
 }
+
+// --- Diagram rendering ---
+
+bool ChatBlockModel::isDiagramLanguage(const QString &lang) const
+{
+    const QString l = lang.toLower();
+    return l == QStringLiteral("plantuml") || 
+           l == QStringLiteral("mermaid") ||
+           l == QStringLiteral("puml");
+}
+
+QString ChatBlockModel::diagramPlaceholder(const QString &lang) const
+{
+    const QString defaultColor = getDefaultTextColor();
+    return QStringLiteral("<div style=\"padding:8px;border:1px dashed ") + defaultColor +
+           QStringLiteral(";color:") + defaultColor + 
+           QStringLiteral(";font-style:italic;\">Loading ") + 
+           lang.toHtmlEscaped() + QStringLiteral(" diagram...</div>");
+}
+
+QString ChatBlockModel::diagramErrorHtml(const QString &error) const
+{
+    return QStringLiteral("<div style=\"padding:8px;border:1px solid red;color:red;\">") +
+           QStringLiteral("Diagram error: ") + error.toHtmlEscaped() + 
+           QStringLiteral("</div>");
+}
+
+QString ChatBlockModel::diagramSvgHtml(const QByteArray &svg) const
+{
+    // Embed SVG inline as data URI
+    const QString base64 = QString::fromLatin1(svg.toBase64());
+    return QStringLiteral("<img src=\"data:image/svg+xml;base64,") + base64 + 
+           QStringLiteral("\" style=\"max-width:100%;\" />");
+}
+
+QString ChatBlockModel::diagramPngHtml(const QByteArray &png) const
+{
+    // Embed PNG inline as data URI
+    const QString base64 = QString::fromLatin1(png.toBase64());
+    return QStringLiteral("<img src=\"data:image/png;base64,") + base64 + 
+           QStringLiteral("\" style=\"max-width:100%;\" />");
+}
+
+QString ChatBlockModel::diagramJpegHtml(const QByteArray &jpeg) const
+{
+    // Embed JPEG inline as data URI
+    const QString base64 = QString::fromLatin1(jpeg.toBase64());
+    return QStringLiteral("<img src=\"data:image/jpeg;base64,") + base64 + 
+           QStringLiteral("\" style=\"max-width:100%;\" />");
+}
+
+void ChatBlockModel::requestDiagram(const QString &lang, const QString &code, int blockIndex)
+{
+    const QString cacheKey = lang + QStringLiteral(":") + 
+        QString::fromLatin1(QCryptographicHash::hash(
+            code.toUtf8(), QCryptographicHash::Md5).toHex());
+    
+    // Already have it cached?
+    if (m_diagramCache.contains(cacheKey))
+        return;
+    
+    // Track which blocks need this diagram
+    if (!m_pendingDiagrams.contains(cacheKey)) {
+        m_pendingDiagrams[cacheKey] = QList<int>();
+    }
+    if (!m_pendingDiagrams[cacheKey].contains(blockIndex)) {
+        m_pendingDiagrams[cacheKey].append(blockIndex);
+    }
+    
+    // Already requesting?
+    if (m_inFlightRequests.contains(cacheKey))
+        return;
+    
+    m_inFlightRequests.insert(cacheKey);
+    
+    // Build request
+    QNetworkRequest request;
+    request.setAttribute(QNetworkRequest::User, cacheKey);
+    request.setTransferTimeout(10000);
+    
+    const QString langLower = lang.toLower();
+    
+    if (langLower == QStringLiteral("plantuml") || langLower == QStringLiteral("puml")) {
+        // PlantUML server accepts POST with raw source
+        request.setUrl(QUrl(QStringLiteral("http://localhost:8080/svg")));
+        request.setHeader(QNetworkRequest::ContentTypeHeader, QStringLiteral("text/plain"));
+        m_netManager->post(request, code.toUtf8());
+    } else if (langLower == QStringLiteral("mermaid")) {
+        // Mermaid-ink expects base64 in URL path, /img/ for PNG output
+        // (SVG uses foreignObject which Qt's SVG renderer doesn't support)
+        const QByteArray encoded = code.toUtf8().toBase64();
+        request.setUrl(QUrl(QStringLiteral("http://localhost:8081/img/") + QString::fromLatin1(encoded)));
+        m_netManager->get(request);
+    } else {
+        m_inFlightRequests.remove(cacheKey);
+        return;
+    }
+}
+
+void ChatBlockModel::onDiagramReply(QNetworkReply *reply)
+{
+    reply->deleteLater();
+    
+    const QString cacheKey = reply->request().attribute(QNetworkRequest::User).toString();
+    m_inFlightRequests.remove(cacheKey);
+    
+    QByteArray imageData;
+    bool success = false;
+    QString errorMsg;
+    
+    if (reply->error() == QNetworkReply::NoError) {
+        imageData = reply->readAll();
+        
+        // Check for JPEG/PNG (mermaid) or SVG (plantuml)
+        if (imageData.startsWith("\xff\xd8\xff")) {
+            // JPEG image
+            success = true;
+            imageData.prepend("JPEG:");
+        } else if (imageData.startsWith("\x89PNG")) {
+            // PNG image
+            success = true;
+            imageData.prepend("PNG:");
+        } else if (imageData.contains("<svg") || imageData.startsWith("<?xml")) {
+            // SVG image
+            success = true;
+            imageData.prepend("SVG:");
+        } else {
+            errorMsg = QStringLiteral("Invalid response (not SVG, PNG, or JPEG)");
+        }
+    } else {
+        errorMsg = reply->errorString();
+    }
+    
+    // Update cache
+    if (success) {
+        m_diagramCache[cacheKey] = imageData;
+    } else {
+        // Cache error as empty data with special marker
+        m_diagramCache[cacheKey] = QByteArray("ERROR:") + errorMsg.toUtf8();
+    }
+    
+    // Rebuild all blocks waiting for this diagram
+    const QList<int> blocks = m_pendingDiagrams.take(cacheKey);
+    for (int blockIndex : blocks) {
+        if (blockIndex < m_blocks.size()) {
+            rebuildBlockHtml(blockIndex);
+            QModelIndex idx = index(blockIndex);
+            emit dataChanged(idx, idx, {RenderedHtmlRole, SegmentsRole});
+        }
+    }
+}

gui/chatblockmodel.h

@@ -6,11 +6,29 @@
 #include <QString>
 #include <QStringList>
 #include <QRegularExpression>
+#include <QHash>
+#include <QSet>
+#include <QVariantList>
+
+class QNetworkAccessManager;
+class QNetworkReply;
 
 namespace KSyntaxHighlighting {
 class Repository;
 }
 
+// A segment within a block — either text or a diagram
+struct BlockSegment {
+    enum Type { Text, Diagram };
+    Type type = Text;
+    QString html;           // For Text: rendered HTML; for Diagram: highlighted source HTML
+    QString diagramLang;    // For Diagram: language (plantuml, mermaid)
+    QString diagramSource;  // For Diagram: raw source code
+    QString diagramSvg;     // For Diagram: base64 SVG data URI, or empty if loading/error
+    QString diagramError;   // For Diagram: error message if failed
+    bool diagramLoading = false;  // For Diagram: true if still loading
+};
+
 struct ChatBlock {
     enum Type {
         User,
@@ -28,7 +46,8 @@ struct ChatBlock {
     Type type = Default;
     QString name;
     QString content;
-    QString renderedHtml;  // Rendered HTML with syntax highlighting
+    QString renderedHtml;  // Legacy: full HTML (kept for compatibility)
+    QList<BlockSegment> segments;  // Structured segments for interactive rendering
 };
 
 class ChatBlockModel : public QAbstractListModel
@@ -48,6 +67,7 @@ public:
         BlockNameRole,
         ContentRole,
         RenderedHtmlRole,
+        SegmentsRole,  // QVariantList of segment maps
     };
 
     explicit ChatBlockModel(QObject *parent = nullptr);
@@ -60,10 +80,14 @@ public:
     Q_INVOKABLE void appendData(const QString &text);
     Q_INVOKABLE void reset();
     Q_INVOKABLE void trimFront(int keepCount);
+    Q_INVOKABLE void clearDiagramCache();
 
 signals:
     void countChanged();
 
+private slots:
+    void onDiagramReply(QNetworkReply *reply);
+
 private:
     void processLine(const QString &line);
     void appendContent(const QString &line);
@@ -73,8 +97,21 @@ private:
     QString escapeForHtml(const QString &text) const;
     QString getDefaultTextColor() const;
     
+    // Diagram rendering
+    bool isDiagramLanguage(const QString &lang) const;
+    void requestDiagram(const QString &lang, const QString &code, int blockIndex);
+    QString diagramPlaceholder(const QString &lang) const;
+    QString diagramErrorHtml(const QString &error) const;
+    QString diagramSvgHtml(const QByteArray &svg) const;
+    QString diagramPngHtml(const QByteArray &png) const;
+    QString diagramJpegHtml(const QByteArray &jpeg) const;
+    
+    // Convert segments to QVariantList for QML
+    QVariantList segmentsToVariant(const QList<BlockSegment> &segments) const;
+
     State m_state = State::BlockStart;
     KSyntaxHighlighting::Repository *m_repo = nullptr;
+    QNetworkAccessManager *m_netManager = nullptr;
 
     QList<ChatBlock> m_blocks;
     QString m_lineBuffer;
@@ -84,6 +121,13 @@ private:
     QString m_fenceLanguage;
     QString m_fenceContent;
     
+    // Diagram cache: hash of (lang + code) -> SVG data
+    QHash<QString, QByteArray> m_diagramCache;
+    // Pending requests: hash -> block indices waiting for this diagram
+    QHash<QString, QList<int>> m_pendingDiagrams;
+    // Track which requests are in flight
+    QSet<QString> m_inFlightRequests;
+
     static const QRegularExpression s_headerRe;
     static const QRegularExpression s_endRe;
     static const QRegularExpression s_fenceOpenRe;

gui/clipboardhelper.cpp

@@ -0,0 +1 @@
+#include "clipboardhelper.h"

gui/clipboardhelper.h

@@ -0,0 +1,59 @@
+#ifndef CLIPBOARDHELPER_H
+#define CLIPBOARDHELPER_H
+
+#include <QObject>
+#include <QClipboard>
+#include <QGuiApplication>
+#include <QImage>
+#include <QMimeData>
+
+class ClipboardHelper : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit ClipboardHelper(QObject *parent = nullptr) : QObject(parent) {}
+
+    // Copy image from data URI (data:image/svg+xml;base64,...) to clipboard
+    Q_INVOKABLE void copyImage(const QString &dataUri) {
+        if (!dataUri.startsWith(QStringLiteral("data:image/")))
+            return;
+        
+        // Parse data URI: data:image/TYPE;base64,DATA
+        int commaIdx = dataUri.indexOf(',');
+        if (commaIdx < 0) return;
+        
+        QString header = dataUri.left(commaIdx);
+        QString base64Data = dataUri.mid(commaIdx + 1);
+        QByteArray imageData = QByteArray::fromBase64(base64Data.toLatin1());
+        
+        QClipboard *clipboard = QGuiApplication::clipboard();
+        QMimeData *mimeData = new QMimeData();
+        
+        if (header.contains(QStringLiteral("svg"))) {
+            // For SVG, set as both image/svg+xml and try to render as raster
+            mimeData->setData(QStringLiteral("image/svg+xml"), imageData);
+            
+            // Also try to load as QImage for apps that don't support SVG
+            QImage img;
+            if (img.loadFromData(imageData, "SVG")) {
+                mimeData->setImageData(img);
+            }
+        } else {
+            // PNG, JPEG, etc.
+            QImage img;
+            if (img.loadFromData(imageData)) {
+                mimeData->setImageData(img);
+            }
+        }
+        
+        clipboard->setMimeData(mimeData);
+    }
+    
+    // Copy plain text to clipboard
+    Q_INVOKABLE void copyText(const QString &text) {
+        QGuiApplication::clipboard()->setText(text);
+    }
+};
+
+#endif // CLIPBOARDHELPER_H

gui/main.cpp

@@ -8,6 +8,7 @@
 #include "ollie9pclient.h"
 #include "chatblockmodel.h"
 #include "thememanager.h"
+#include "clipboardhelper.h"
 
 int main(int argc, char *argv[])
 {
@@ -27,6 +28,7 @@ int main(int argc, char *argv[])
     auto *ollie = new Ollie9pClient(&app);
     auto *chatModel = new ChatBlockModel(&app);
     auto *theme = new ThemeManager(&app);
+    auto *clipboard = new ClipboardHelper(&app);
 
     // Route chat stream to the block model.
     // Reset + reload is handled in QML's onActiveSessionIdChanged so the
@@ -37,6 +39,7 @@ int main(int argc, char *argv[])
     engine.rootContext()->setContextProperty("ollie", ollie);
     engine.rootContext()->setContextProperty("chatModel", chatModel);
     engine.rootContext()->setContextProperty("theme", theme);
+    engine.rootContext()->setContextProperty("clipboard", clipboard);
 
 const QUrl url(QStringLiteral("qrc:/main.qml"));
 

gui/main.qml

@@ -1373,12 +1373,31 @@ property bool blockExpanded: {
             }
         }
 
-        // Block content is Markdown rendered by ChatBlockModel.
-        TextEdit {
-            id: blockContent
+        // Block content rendered as segments (text and diagrams)
+        Column {
             Layout.fillWidth: true
             visible: blockItem.blockExpanded
-            text: blockRenderedHtml || ""
+            spacing: 4
+            
+            Repeater {
+                model: blockSegments || []
+                
+                delegate: Loader {
+                    width: parent.width
+                    sourceComponent: modelData.type === "diagram" ? diagramComponent : textComponent
+                    
+                    property var segmentData: modelData
+                }
+            }
+        }
+        
+        // Text segment component
+        Component {
+            id: textComponent
+            
+            TextEdit {
+                width: parent ? parent.width : 100
+                text: segmentData.html || ""
                 textFormat: Text.RichText
                 readOnly: true
                 selectByMouse: true
@@ -1386,43 +1405,35 @@ property bool blockExpanded: {
                 wrapMode: TextEdit.Wrap
                 font.family: theme.fontFamily || Qt.application.font.family
                 font.pointSize: theme.fontSize > 0 ? theme.fontSize : 12
-            // Note: don't set 'color' here — it can override inline styles from
-            // syntax highlighting in Qt5. The HTML content should set colors.
-            
-            // Selection colors
                 selectionColor: theme.highlightColor
                 selectedTextColor: theme.highlightedTextColor
                 
-            // Restore ListView scrolling when focus is lost
                 onActiveFocusChanged: {
                     if (!activeFocus)
                         chatView.interactive = true
                 }
                 
-            // Context menu for text operations
                 Menu {
-                id: textContextMenu
+                    id: textSegmentMenu
                     MenuItem {
                         text: "Copy"
-                    enabled: blockContent.selectedText.length > 0
-                    onTriggered: blockContent.copy()
+                        enabled: parent.parent.selectedText.length > 0
+                        onTriggered: parent.parent.copy()
                     }
                     MenuItem {
                         text: "Select All"
-                    onTriggered: blockContent.selectAll()
+                        onTriggered: parent.parent.selectAll()
                     }
                 }
                 
-            // Mouse handling for selection (left button)
                 MouseArea {
                     anchors.fill: parent
                     acceptedButtons: Qt.LeftButton
                     propagateComposedEvents: true
                     cursorShape: Qt.IBeamCursor
-                
                     onPressed: function(mouse) {
                         chatView.interactive = false
-                    mouse.accepted = false  // Let TextEdit handle selection
+                        mouse.accepted = false
                     }
                     onReleased: function(mouse) {
                         chatView.interactive = true
@@ -1430,14 +1441,145 @@ property bool blockExpanded: {
                     }
                 }
                 
-            // Context menu (right button) - separate to avoid deselection
                 MouseArea {
                     anchors.fill: parent
                     acceptedButtons: Qt.RightButton
                     cursorShape: Qt.IBeamCursor
+                    onClicked: textSegmentMenu.popup()
+                }
+            }
+        }
         
-                onClicked: function(mouse) {
-                    textContextMenu.popup()
+        // Diagram segment component with source/image toggle
+        Component {
+            id: diagramComponent
+            
+            Rectangle {
+                width: parent ? parent.width : 100
+                height: diagramContent.height + diagramHeader.height + 8
+                color: "transparent"
+                border.color: theme.midColor
+                border.width: 1
+                radius: 4
+                
+                property bool showSource: false
+                
+                // Header with language label and toggle button
+                RowLayout {
+                    id: diagramHeader
+                    anchors.top: parent.top
+                    anchors.left: parent.left
+                    anchors.right: parent.right
+                    anchors.margins: 4
+                    height: 24
+                    
+                    Label {
+                        text: segmentData.lang || "diagram"
+                        font.pointSize: theme.fontSize > 0 ? theme.fontSize - 1 : 11
+                        color: theme.textColor
+                        opacity: 0.7
+                    }
+                    
+                    Item { Layout.fillWidth: true }
+                    
+                    Button {
+                        text: parent.parent.showSource ? "📊" : "</>"
+                        font.pointSize: theme.fontSize > 0 ? theme.fontSize - 2 : 10
+                        implicitWidth: 32
+                        implicitHeight: 20
+                        ToolTip.visible: hovered
+                        ToolTip.text: parent.parent.showSource ? "Show diagram" : "Show source"
+                        onClicked: parent.parent.showSource = !parent.parent.showSource
+                    }
+                    
+                    Button {
+                        text: "📋"
+                        font.pointSize: theme.fontSize > 0 ? theme.fontSize - 2 : 10
+                        implicitWidth: 32
+                        implicitHeight: 20
+                        ToolTip.visible: hovered
+                        ToolTip.text: parent.parent.showSource ? "Copy source" : "Copy image"
+                        onClicked: {
+                            if (parent.parent.showSource) {
+                                // Copy source code as plain text
+                                clipboard.copyText(segmentData.source)
+                            } else if (segmentData.svg) {
+                                // Copy image
+                                clipboard.copyImage(segmentData.svg)
+                            }
+                        }
+                    }
+                }
+                
+                // Content area
+                Item {
+                    id: diagramContent
+                    anchors.top: diagramHeader.bottom
+                    anchors.left: parent.left
+                    anchors.right: parent.right
+                    anchors.margins: 4
+                    height: showSource ? diagramSourceEdit.height : diagramImage.height
+                    
+                    // Source view
+                    TextEdit {
+                        id: diagramSourceEdit
+                        width: parent.width
+                        visible: showSource
+                        text: segmentData.html || ""
+                        textFormat: Text.RichText
+                        readOnly: true
+                        selectByMouse: true
+                        persistentSelection: true
+                        wrapMode: TextEdit.Wrap
+                        font.family: theme.fontFamily || Qt.application.font.family
+                        font.pointSize: theme.fontSize > 0 ? theme.fontSize : 12
+                        selectionColor: theme.highlightColor
+                        selectedTextColor: theme.highlightedTextColor
+                        
+                        MouseArea {
+                            anchors.fill: parent
+                            acceptedButtons: Qt.LeftButton
+                            propagateComposedEvents: true
+                            cursorShape: Qt.IBeamCursor
+                            onPressed: function(mouse) {
+                                chatView.interactive = false
+                                mouse.accepted = false
+                            }
+                            onReleased: function(mouse) {
+                                chatView.interactive = true
+                                mouse.accepted = false
+                            }
+                        }
+                    }
+                    
+                    // Image view
+                    Column {
+                        id: diagramImage
+                        width: parent.width
+                        visible: !showSource
+                        
+                        Rectangle {
+                            visible: segmentData.svg && !segmentData.loading
+                            color: "white"
+                            width: diagramImg.width
+                            height: diagramImg.height
+                            
+                            Image {
+                                id: diagramImg
+                                source: segmentData.svg || ""
+                                fillMode: Image.PreserveAspectFit
+                                width: Math.min(implicitWidth, diagramImage.width)
+                            }
+                        }
+                        
+                        Label {
+                            visible: segmentData.loading
+                            text: "Loading " + (segmentData.lang || "diagram") + "..."
+                            font.italic: true
+                            color: theme.textColor
+                            opacity: 0.7
+                        }
+                    }
                 }
             }
         }