Fix boundingbox calculation of rotated items.

Task-number: QTBUG-34328

Change-Id: If0202a67d95500333a0fb6f4ca3eb19ecb027770
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

2 files changed, 34 insertions, 8 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp b/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
index 940b8dd02b..3782cab5d3 100644
--- a/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
+++ b/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
@@ -113,6 +113,7 @@ struct QMatrix4x4_Accessor
     int flagBits;
 
     static bool isTranslate(const QMatrix4x4 &m) { return ((const QMatrix4x4_Accessor &) m).flagBits <= 0x1; }
+    static bool isScale(const QMatrix4x4 &m) { return ((const QMatrix4x4_Accessor &) m).flagBits <= 0x2; }
     static bool is2DSafe(const QMatrix4x4 &m) { return ((const QMatrix4x4_Accessor &) m).flagBits < 0x8; }
 };
 
@@ -533,6 +534,38 @@ int qsg_positionAttribute(QSGGeometry *g) {
     return -1;
 }
 
+
+void Rect::map(const QMatrix4x4 &matrix)
+{
+    const float *m = matrix.constData();
+    if (QMatrix4x4_Accessor::isScale(matrix)) {
+        tl.x = tl.x * m[0] + m[12];
+        tl.y = tl.y * m[5] + m[13];
+        br.x = br.x * m[0] + m[12];
+        br.y = br.y * m[5] + m[13];
+        if (tl.x > br.x)
+            qSwap(tl.x, br.x);
+        if (tl.y > br.y)
+            qSwap(tl.y, br.y);
+    } else {
+        Pt mtl = tl;
+        Pt mtr = { br.x, tl.y };
+        Pt mbl = { tl.x, br.y };
+        Pt mbr = br;
+
+        mtl.map(matrix);
+        mtr.map(matrix);
+        mbl.map(matrix);
+        mbr.map(matrix);
+
+        set(FLT_MAX, FLT_MAX, -FLT_MAX, -FLT_MAX);
+        (*this) |= mtl;
+        (*this) |= mtr;
+        (*this) |= mbl;
+        (*this) |= mbr;
+    }
+}
+
 void Element::computeBounds()
 {
     Q_ASSERT(!boundsComputed);
diff --git a/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h b/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
index 6d95f83d7a..aacf482ead 100644
--- a/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
+++ b/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
@@ -119,14 +119,7 @@ struct Rect {
         Q_ASSERT(tl.y <= br.y);
     }
 
-    void map(const QMatrix4x4 &m) {
-        tl.map(m);
-        br.map(m);
-        if (br.x < tl.x)
-            qSwap(br.x, tl.x);
-        if (br.y < tl.y)
-            qSwap(br.y, tl.y);
-    }
+    void map(const QMatrix4x4 &m);
 
     void set(float left, float top, float right, float bottom) {
         tl.set(left, top);