Core: Hack for HighDPI text drawing on QPixmap with Qt6

A QPainter on a QPixmap behaves differently on Qt 5 and 6 when it comes
to the pixmap's devicePixelRatio. On Qt6/DPR>1, the text in this code
would be rendered outside the pixmap. Forcing the DPR of the pixmap
to 1 while rendering the text fixes the issue.

Since I cannot test on all platforms, nor have a multi monitor setup
with different scalings, I added some cargo cult code which resets the
original DPR after rendering. Just to be on the safe side.

Fixes: QTCREATORBUG-26315
Change-Id: I32ce78a45d52a4c75eb437574b925c85b9295402
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/iwizardfactory.cpp

@@ -437,6 +437,8 @@ static QIcon iconWithText(const QIcon &icon, const QString &text)
     QIcon iconWithText;
     for (const QSize &pixmapSize : icon.availableSizes()) {
         QPixmap pixmap = icon.pixmap(pixmapSize);
+        const qreal originalPixmapDpr = pixmap.devicePixelRatio();
+        pixmap.setDevicePixelRatio(1); // Hack for QTCREATORBUG-26315
         const int fontSize = pixmap.height() / 4;
         const int margin = pixmap.height() / 8;
         QFont font;
@@ -447,6 +449,8 @@ static QIcon iconWithText(const QIcon &icon, const QString &text)
         QTextOption textOption(Qt::AlignHCenter | Qt::AlignBottom);
         textOption.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);
         p.drawText(pixmap.rect().adjusted(margin, margin, -margin, -margin), text, textOption);
+        p.end();
+        pixmap.setDevicePixelRatio(originalPixmapDpr);
         iconWithText.addPixmap(pixmap);
     }
     return iconWithText;