Ensure overdraw, not overdraw, of reused bitmaps
Rounding errors should tilt toward a 1 pixel overdraw. These
errors could occur because the application of a scaling matrix
is opaque to caller within Canvas, and underdrawing can result
in garbage pixels in an extra line. Also added verbose logging.
Bug: 17963089
Change-Id: Id85b50ee646aecdcb7d6b26bd988577bc6fec980
diff --git a/library/src/main/java/com/bumptech/glide/load/resource/bitmap/TransformationUtils.java b/library/src/main/java/com/bumptech/glide/load/resource/bitmap/TransformationUtils.java
index 2714b6a..9cffbd8 100644
--- a/library/src/main/java/com/bumptech/glide/load/resource/bitmap/TransformationUtils.java
+++ b/library/src/main/java/com/bumptech/glide/load/resource/bitmap/TransformationUtils.java
@@ -79,20 +79,41 @@
*/
public static Bitmap fitCenter(Bitmap toFit, BitmapPool pool, int width, int height) {
if (toFit.getWidth() == width && toFit.getHeight() == height) {
+ if (Log.isLoggable(TAG, Log.VERBOSE)) {
+ Log.v(TAG, "requested target size matches input, returning input");
+ }
return toFit;
}
final float widthPercentage = width / (float) toFit.getWidth();
final float heightPercentage = height / (float) toFit.getHeight();
final float minPercentage = Math.min(widthPercentage, heightPercentage);
- final int targetWidth = Math.round(minPercentage * toFit.getWidth());
- final int targetHeight = Math.round(minPercentage * toFit.getHeight());
+ // take the floor of the target width/height, not round. If the matrix
+ // passed into drawBitmap rounds differently, we want to slightly
+ // overdraw, not underdraw, to avoid artifacts from bitmap reuse.
+ final int targetWidth = (int) (minPercentage * toFit.getWidth());
+ final int targetHeight = (int) (minPercentage * toFit.getHeight());
+
+ if (toFit.getWidth() == targetWidth && toFit.getHeight() == targetHeight) {
+ if (Log.isLoggable(TAG, Log.VERBOSE)) {
+ Log.v(TAG, "adjusted target size matches input, returning input");
+ }
+ return toFit;
+ }
Bitmap.Config config = toFit.getConfig() != null ? toFit.getConfig() : Bitmap.Config.ARGB_8888;
Bitmap toReuse = pool.get(targetWidth, targetHeight, config);
if (toReuse == null) {
toReuse = Bitmap.createBitmap(targetWidth, targetHeight, config);
}
+
+ if (Log.isLoggable(TAG, Log.VERBOSE)) {
+ Log.v(TAG, "request: " + width + "x" + height);
+ Log.v(TAG, "toFit: " + toFit.getWidth() + "x" + toFit.getHeight());
+ Log.v(TAG, "toReuse: " + toReuse.getWidth() + "x" + toReuse.getHeight());
+ Log.v(TAG, "minPct: " + minPercentage);
+ }
+
Canvas canvas = new Canvas(toReuse);
Matrix matrix = new Matrix();
matrix.setScale(minPercentage, minPercentage);
