Fix the vertical alignment of images in a text document

Try to align with the HTML standard as much as possible.
AlignMiddle is between AlignTop and AlignBottom.

Fixes: QTBUG-84981
Pick-to: 5.15
Change-Id: Ie99aef0d09a6ece751883492748630526c4a1195
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 6 insertions, 4 deletions

diff --git a/src/quick/items/qquicktextnodeengine.cpp b/src/quick/items/qquicktextnodeengine.cpp
index 82bd9cd4ec..19df175115 100644
--- a/src/quick/items/qquicktextnodeengine.cpp
+++ b/src/quick/items/qquicktextnodeengine.cpp
@@ -477,6 +477,9 @@ void QQuickTextNodeEngine::addTextObject(const QTextBlock &block, const QPointF
             }
         }
 
+        // Use https://developer.mozilla.org/de/docs/Web/CSS/vertical-align as a reference
+        // The top/bottom positions are supposed to be higher/lower than the text and reference
+        // the line height, not the text height (using QFontMetrics)
         qreal ascent;
         QTextLine line = block.layout()->lineForTextPosition(pos - block.position());
         switch (format.verticalAlignment())
@@ -484,11 +487,10 @@ void QQuickTextNodeEngine::addTextObject(const QTextBlock &block, const QPointF
         case QTextCharFormat::AlignTop:
             ascent = line.ascent();
             break;
-        case QTextCharFormat::AlignMiddle: {
-            QFontMetrics m(format.font());
-            ascent = (size.height() - m.xHeight()) / 2;
+        case QTextCharFormat::AlignMiddle:
+            //       Middlepoint of line (height - descent) + Half object height
+            ascent = (line.ascent() + line.descent()) / 2 - line.descent() + size.height() / 2;
             break;
-        }
         case QTextCharFormat::AlignBottom:
             ascent = size.height() - line.descent();
             break;