Fix text drawing and perspective transforms for the Windows, PDF and

PostScript print engines.

The PDF/PostScript does not support perspective transforms, so it has
to be emulated through our draw_helper() fallback. PostScript doesn't
support alpha blending, so all perspective drawing needs to be forced
through the alpha print engine.

Task-number: 249754
Reviewed-by: Samuel

4 files changed, 17 insertions, 3 deletions

diff --git a/src/gui/painting/qpaintengine_alpha.cpp b/src/gui/painting/qpaintengine_alpha.cpp
index e38f6a4..74cbebe 100644
--- a/src/gui/painting/qpaintengine_alpha.cpp
+++ b/src/gui/painting/qpaintengine_alpha.cpp
@@ -80,6 +80,7 @@ bool QAlphaPaintEngine::begin(QPaintDevice *pdev)
     d->m_advancedPen = false;
     d->m_advancedBrush = false;
     d->m_complexTransform = false;
+    d->m_emulateProjectiveTransforms = false;
 
     // clear alpha region
     d->m_alphargn = QRegion();
@@ -116,6 +117,9 @@ void QAlphaPaintEngine::updateState(const QPaintEngineState &state)
     if (flags & QPaintEngine::DirtyTransform) {
         d->m_transform = state.transform();
         d->m_complexTransform = (d->m_transform.type() > QTransform::TxScale);
+        d->m_emulateProjectiveTransforms = !(d->m_savedcaps & QPaintEngine::PerspectiveTransform)
+                                           && !(d->m_savedcaps & QPaintEngine::AlphaBlend)
+                                           && (d->m_transform.type() >= QTransform::TxProject);
     }
     if (flags & QPaintEngine::DirtyPen) {
         d->m_pen = state.pen();
@@ -163,7 +167,9 @@ void QAlphaPaintEngine::drawPath(const QPainterPath &path)
 
     if (d->m_pass == 0) {
         d->m_continueCall = false;
-        if (d->m_hasalpha || d->m_advancedPen || d->m_advancedBrush) {
+        if (d->m_hasalpha || d->m_advancedPen || d->m_advancedBrush
+            || d->m_emulateProjectiveTransforms)
+        {
             d->addAlphaRect(tr);
         }
         if (d->m_picengine)
@@ -187,7 +193,9 @@ void QAlphaPaintEngine::drawPolygon(const QPointF *points, int pointCount, Polyg
 
     if (d->m_pass == 0) {
         d->m_continueCall = false;
-        if (d->m_hasalpha || d->m_advancedPen || d->m_advancedBrush) {
+        if (d->m_hasalpha || d->m_advancedPen || d->m_advancedBrush
+            || d->m_emulateProjectiveTransforms)
+        {
             d->addAlphaRect(tr);
         }
 
diff --git a/src/gui/painting/qpaintengine_alpha_p.h b/src/gui/painting/qpaintengine_alpha_p.h
index f510c73..f7d7a34 100644
--- a/src/gui/painting/qpaintengine_alpha_p.h
+++ b/src/gui/painting/qpaintengine_alpha_p.h
@@ -113,6 +113,7 @@ public:
     bool m_advancedPen;
     bool m_advancedBrush;
     bool m_complexTransform;
+    bool m_emulateProjectiveTransforms;
     bool m_continueCall;
 
     QTransform m_transform;
diff --git a/src/gui/painting/qpdf.cpp b/src/gui/painting/qpdf.cpp
index b010209..55006f6 100644
--- a/src/gui/painting/qpdf.cpp
+++ b/src/gui/painting/qpdf.cpp
@@ -1106,6 +1106,11 @@ void QPdfBaseEngine::drawTextItem(const QPointF &p, const QTextItem &textItem)
     if (!d->hasPen || (d->clipEnabled && d->allClipped))
         return;
 
+    if (d->stroker.matrix.type() >= QTransform::TxProject) {
+        QPaintEngine::drawTextItem(p, textItem);
+        return;
+    }
+
     *d->currentPage << "q\n";
     if(!d->simplePen)
         *d->currentPage << QPdf::generateMatrix(d->stroker.matrix);
diff --git a/src/gui/painting/qprintengine_win.cpp b/src/gui/painting/qprintengine_win.cpp
index d48b525..c8674b7 100644
--- a/src/gui/painting/qprintengine_win.cpp
+++ b/src/gui/painting/qprintengine_win.cpp
@@ -369,7 +369,7 @@ void QWin32PrintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem
     QRgb brushColor = state->pen().brush().color().rgb();
     bool fallBack = state->pen().brush().style() != Qt::SolidPattern
                     || qAlpha(brushColor) != 0xff
-                    || QT_WA_INLINE(false, d->txop >= QTransform::TxScale)
+                    || QT_WA_INLINE(d->txop >= QTransform::TxProject, d->txop >= QTransform::TxScale)
                     || ti.fontEngine->type() != QFontEngine::Win;