QCommonStyle: draw focus rect using qDrawPlainRect

A non-aliased drawRect(r.adjusted(0, 0, -1, -1)) no longer does the job
in Qt6: hi-dpi is now enabled automatically, which scales the painter
and leads to horrible (non symmetric) rendering.

I doubt any actual widget style calls into this code (which draws
a focus rect with a plain line) but it's still a useful example
and fallback when writing a widget style.

Pick-to: 6.6
Change-Id: Ib407a7355033258be568b4826fe01c110f02c018
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>

1 files changed, 7 insertions, 7 deletions

diff --git a/src/widgets/styles/qcommonstyle.cpp b/src/widgets/styles/qcommonstyle.cpp
index 730e9fef1f..54c07c1cbe 100644
--- a/src/widgets/styles/qcommonstyle.cpp
+++ b/src/widgets/styles/qcommonstyle.cpp
@@ -189,20 +189,20 @@ void QCommonStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *opt, Q
     case PE_FrameFocusRect:
         if (const QStyleOptionFocusRect *fropt = qstyleoption_cast<const QStyleOptionFocusRect *>(opt)) {
             QColor bg = fropt->backgroundColor;
-            QPen oldPen = p->pen();
+            QColor color;
             if (bg.isValid()) {
                 int h, s, v;
                 bg.getHsv(&h, &s, &v);
                 if (v >= 128)
-                    p->setPen(Qt::black);
+                    color = Qt::black;
                 else
-                    p->setPen(Qt::white);
+                    color = Qt::white;
             } else {
-                p->setPen(opt->palette.windowText().color());
+                color = opt->palette.windowText().color();
             }
-            QRect focusRect = opt->rect.adjusted(1, 1, -1, -1);
-            p->drawRect(focusRect.adjusted(0, 0, -1, -1)); //draw pen inclusive
-            p->setPen(oldPen);
+            const QRect focusRect = opt->rect.adjusted(1, 1, -1, -1);
+            const QBrush fill(bg);
+            qDrawPlainRect(p, focusRect, color, 1, bg.isValid() ? &fill : nullptr);
         }
         break;
     case PE_IndicatorMenuCheckMark: {