Merge change 26300 into eclair
* changes:
experimental fix for compatibility mode. When we scale up by 1.5 (240 dpi), we put stretched ninepatches on exact pixel boundaries when we walk the inverse matrix (e.g. 2/3, 1+1/3, 2, 2+2/3, 3+1/3, 4, ...).
diff --git a/core/java/android/content/res/CompatibilityInfo.java b/core/java/android/content/res/CompatibilityInfo.java
index 50faf57..11c67cc 100644
--- a/core/java/android/content/res/CompatibilityInfo.java
+++ b/core/java/android/content/res/CompatibilityInfo.java
@@ -274,6 +274,25 @@
* 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);
}