SkTreatAsSprite should take AA into account

Currently we always call SkTreatAsSprite with 0 subpixel bits, which means
subpixel translations are ignored.  This is incorrect for the anti-aliased
case (drawSprite always pixel-snaps, so we lose edge AA).

The CL updates SkTreatAsSprite to take an SkPaint argument and use 8 subpixel
bits when AA is requested.

Also remove unused SkTreatAsSpriteFilter.

BUG=skia:4761
R=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1566943002

Review URL: https://codereview.chromium.org/1566943002

1 files changed, 6 insertions, 23 deletions

diff --git a/src/core/SkMatrixUtils.h b/src/core/SkMatrixUtils.h
index d1b6658d07..0e01fbe953 100644
--- a/src/core/SkMatrixUtils.h
+++ b/src/core/SkMatrixUtils.h
@@ -8,37 +8,20 @@
 #ifndef SkMatrixUtils_DEFINED
 #define SkMatrixUtils_DEFINED
 
-#include "SkMatrix.h"
+#include "SkSize.h"
 
-/**
- *  Number of subpixel bits used in skia's bilerp.
- *  See SkBitmapProcState_procs.h and SkBitmapProcState_filter.h
- */
-#define kSkSubPixelBitsForBilerp   4
+class SkMatrix;
+class SkPaint;
 
 /**
- *  Given a matrix and width/height, return true if the computed dst-rect would
+ *  Given a matrix, size and paint, return true if the computed dst-rect would
  *  align such that there is a 1-to-1 coorspondence between src and dst pixels.
  *  This can be called by drawing code to see if drawBitmap can be turned into
  *  drawSprite (which is faster).
  *
- *  The src-rect is defined to be { 0, 0, width, height }
- *
- *  The "closeness" test is based on the subpixelBits parameter. Pass 0 for
- *  round-to-nearest behavior (e.g. nearest neighbor sampling). Pass the number
- *  of subpixel-bits to simulate filtering.
- */
-bool SkTreatAsSprite(const SkMatrix&, int width, int height,
-                     unsigned subpixelBits);
-
-/**
- *  Calls SkTreatAsSprite() with default subpixelBits value to match Skia's
- *  filter-bitmap implementation (i.e. kSkSubPixelBitsForBilerp).
+ *  The src-rect is defined to be { 0, 0, size.width(), size.height() }
  */
-static inline bool SkTreatAsSpriteFilter(const SkMatrix& matrix,
-                                         int width, int height) {
-    return SkTreatAsSprite(matrix, width, height, kSkSubPixelBitsForBilerp);
-}
+bool SkTreatAsSprite(const SkMatrix&, const SkISize& size, const SkPaint& paint);
 
 /** Decomposes the upper-left 2x2 of the matrix into a rotation (represented by
     the cosine and sine of the rotation angle), followed by a non-uniform scale,