Utils: Better size hints for the markdown browser

Change-Id: I5b071cd349a3322bb41dad002c4aeda175831f18
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/libs/utils/markdownbrowser.cpp

@@ -42,6 +42,8 @@ static constexpr std::array<TextFormat, 6> markdownHeadingFormats{
     TextFormat{contentTF.first, UiElement::UiElementH6Capital},
 };
 
+static constexpr int MinimumSizeBlocks = 5;
+
 static QFont font(TextFormat format, bool underlined = false)
 {
     QFont result = Utils::StyleHelper::uiFont(format.second);
@@ -373,6 +375,24 @@ MarkdownBrowser::MarkdownBrowser(QWidget *parent)
     setDocument(new AnimatedDocument(this));
 }
 
+QSize MarkdownBrowser::sizeHint() const
+{
+    return document()->size().toSize();
+}
+QSize MarkdownBrowser::minimumSizeHint() const
+{
+    //Lets use the size of the first few blocks as minimum size hint
+    QTextBlock block = document()->begin();
+    QRectF boundingRect;
+    for (int i = 0; i < MinimumSizeBlocks && block.isValid(); ++i, block = block.next()) {
+        QTextLayout *layout = block.layout();
+        QRectF blockRect = layout->boundingRect();
+        boundingRect.adjust(0, 0, 0, blockRect.height());
+        boundingRect.setWidth(qMax(boundingRect.width(), blockRect.width()));
+    }
+    return boundingRect.size().toSize() + QTextBrowser::minimumSizeHint();
+}
+
 void MarkdownBrowser::setAllowRemoteImages(bool allow)
 {
     static_cast<AnimatedDocument *>(document())->setAllowRemoteImages(allow);

src/libs/utils/markdownbrowser.h

@@ -21,6 +21,9 @@ public:
     void setMarkdown(const QString &markdown);
     void setBasePath(const FilePath &filePath);
     void setAllowRemoteImages(bool allow);
+
+    QSize sizeHint() const override;
+    QSize minimumSizeHint() const override;
 };
 
 } // namespace Utils