diff options
| -rw-r--r-- | core/java/android/content/res/CompatibilityInfo.java | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/core/java/android/content/res/CompatibilityInfo.java b/core/java/android/content/res/CompatibilityInfo.java index 50faf57a096f..11c67cc18110 100644 --- a/core/java/android/content/res/CompatibilityInfo.java +++ b/core/java/android/content/res/CompatibilityInfo.java @@ -274,6 +274,25 @@ public class CompatibilityInfo { * Apply translation to the canvas that is necessary to draw the content. */ public void translateCanvas(Canvas canvas) { + if (applicationScale == 1.5f) { + /* When we scale for compatibility, we can put our stretched + bitmaps and ninepatches on exacty 1/2 pixel boundaries, + which can give us inconsistent drawing due to imperfect + float precision in the graphics engine's inverse matrix. + + As a work-around, we translate by a tiny amount to avoid + landing on exact pixel centers and boundaries, giving us + the slop we need to draw consistently. + + This constant is meant to resolve to 1/255 after it is + scaled by 1.5 (applicationScale). Note, this is just a guess + as to what is small enough not to create its own artifacts, + and big enough to avoid the precision problems. Feel free + to experiment with smaller values as you choose. + */ + final float tinyOffset = 2.0f / (3 * 255); + canvas.translate(tinyOffset, tinyOffset); + } canvas.scale(applicationScale, applicationScale); } |