Fall back to using paths for large fonts in drawStaticText()

QStaticText had an implicit risk which meant you had to make sure the
text size did not grow unreasonably large. This was intended to avoid
hiding the performance impact of using QStaticText for such a purpose,
but it's too inconvenient. Thus, the same fall back as in drawTextItem()
has been introduced. This will also fix a bug recently introduced when
we started using the FT cache to draw static text in the raster engine,
since this will fail for large fonts.

Task-number: QTBUG-19084, QTBUG-19370
Reviewed-by: Jiang Jiang

1 files changed, 10 insertions, 2 deletions

diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index f0bc0d6..4f8af48 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -3029,8 +3029,16 @@ void QRasterPaintEngine::drawStaticTextItem(QStaticTextItem *textItem)
     ensurePen();
     ensureState();
 
-    drawCachedGlyphs(textItem->numGlyphs, textItem->glyphs, textItem->glyphPositions,
-                     textItem->fontEngine());
+    QRasterPaintEngineState *s = state();
+
+    QFontEngine *fontEngine = textItem->fontEngine();
+    const qreal pixelSize = fontEngine->fontDef.pixelSize;
+    if (pixelSize * pixelSize * qAbs(s->matrix.determinant()) < 64 * 64) {
+        drawCachedGlyphs(textItem->numGlyphs, textItem->glyphs, textItem->glyphPositions,
+                         fontEngine);
+    } else {
+        QPaintEngineEx::drawStaticTextItem(textItem);
+    }
 }
 
 /*!