VectorDrawable: Use the matrix scale only if the matrix has no rotation or skew.

When canvas is rotated or skewed, the scale factor is affected.
Conservatively reset the scale used to modify path stroke size to 1 in these
cases, since the image will be somewhat blurry anyway with rotation / skew..

b/25418943

Change-Id: I6dff1bca5fac5500fa688c68f8b81b6212526b6b

1 files changed, 9 insertions, 2 deletions

diff --git a/libs/hwui/VectorDrawable.cpp b/libs/hwui/VectorDrawable.cpp
index e13a2bb2a38b..56cb10476118 100644
--- a/libs/hwui/VectorDrawable.cpp
+++ b/libs/hwui/VectorDrawable.cpp
@@ -403,8 +403,15 @@ void Tree::draw(Canvas* outCanvas, SkColorFilter* colorFilter,
     // canvas scale.
     outCanvas->getMatrix(&mCanvasMatrix);
     mBounds = bounds;
-    int scaledWidth = (int) (mBounds.width() * mCanvasMatrix.getScaleX());
-    int scaledHeight = (int) (mBounds.height() * mCanvasMatrix.getScaleY());
+    float canvasScaleX = 1.0f;
+    float canvasScaleY = 1.0f;
+    if (mCanvasMatrix.getSkewX() == 0 && mCanvasMatrix.getSkewY() == 0) {
+        // Only use the scale value when there's no skew or rotation in the canvas matrix.
+        canvasScaleX = mCanvasMatrix.getScaleX();
+        canvasScaleY = mCanvasMatrix.getScaleY();
+    }
+    int scaledWidth = (int) (mBounds.width() * canvasScaleX);
+    int scaledHeight = (int) (mBounds.height() * canvasScaleY);
     scaledWidth = std::min(Tree::MAX_CACHED_BITMAP_SIZE, scaledWidth);
     scaledHeight = std::min(Tree::MAX_CACHED_BITMAP_SIZE, scaledHeight);