Improve some pathelogical borderImage cases

Makes what the renderer is expected to do more well-defined, and makes
the software and OpenGL backend agree in the rendering of the QML
lancelot tests.

Change-Id: I3991ec06e3b4b5f1713e224bb3b7d57e8f951ab4
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 18 insertions, 8 deletions

diff --git a/src/quick/items/qquickborderimage.cpp b/src/quick/items/qquickborderimage.cpp
index d49829096f..e4e766a129 100644
--- a/src/quick/items/qquickborderimage.cpp
+++ b/src/quick/items/qquickborderimage.cpp
@@ -591,10 +591,18 @@ void QQuickBorderImagePrivate::calculateRects(const QQuickScaleGrid *border,
     *innerTargetRect = *targetRect;
 
     if (border) {
-        *innerSourceRect = QRectF(border->left() * devicePixelRatio / qreal(sourceSize.width()),
-                                  border->top() * devicePixelRatio / qreal(sourceSize.height()),
-                                  qMax<qreal>(0, sourceSize.width() - (border->right() + border->left()) * devicePixelRatio) / sourceSize.width(),
-                                  qMax<qreal>(0, sourceSize.height() - (border->bottom() + border->top()) * devicePixelRatio) / sourceSize.height());
+        qreal borderLeft = border->left() * devicePixelRatio;
+        qreal borderRight = border->right() * devicePixelRatio;
+        qreal borderTop = border->top() * devicePixelRatio;
+        qreal borderBottom = border->bottom() * devicePixelRatio;
+        if (borderLeft + borderRight > sourceSize.width() && borderLeft < sourceSize.width())
+            borderRight = sourceSize.width() - borderLeft;
+        if (borderTop + borderBottom > sourceSize.height() && borderTop < sourceSize.height())
+            borderBottom = sourceSize.height() - borderTop;
+        *innerSourceRect = QRectF(QPointF(borderLeft / qreal(sourceSize.width()),
+                                          borderTop * devicePixelRatio / qreal(sourceSize.height())),
+                                  QPointF((sourceSize.width() - borderRight) / qreal(sourceSize.width()),
+                                          (sourceSize.height() - borderBottom) / qreal(sourceSize.height()))),
         *innerTargetRect = QRectF(border->left(),
                                   border->top(),
                                   qMax<qreal>(0, targetSize.width() - (border->right() + border->left())),
@@ -604,14 +612,16 @@ void QQuickBorderImagePrivate::calculateRects(const QQuickScaleGrid *border,
     qreal hTiles = 1;
     qreal vTiles = 1;
     const QSizeF innerTargetSize = innerTargetRect->size() * devicePixelRatio;
-    if (innerSourceRect->width() != 0
-        && horizontalTileMode != QQuickBorderImage::Stretch) {
+    if (innerSourceRect->width() <= 0)
+        hTiles = 0;
+    else if (horizontalTileMode != QQuickBorderImage::Stretch) {
         hTiles = innerTargetSize.width() / qreal(innerSourceRect->width() * sourceSize.width());
         if (horizontalTileMode == QQuickBorderImage::Round)
             hTiles = qCeil(hTiles);
     }
-    if (innerSourceRect->height() != 0
-        && verticalTileMode != QQuickBorderImage::Stretch) {
+    if (innerSourceRect->height() <= 0)
+        vTiles = 0;
+    else if (verticalTileMode != QQuickBorderImage::Stretch) {
         vTiles = innerTargetSize.height() / qreal(innerSourceRect->height() * sourceSize.height());
         if (verticalTileMode == QQuickBorderImage::Round)
             vTiles = qCeil(vTiles);