allow subpixel positioning w/ bitmap filtering

src/core/SkDraw.cpp

Index: src/core/SkDraw.cpp
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 84899789cfcbf92e42b10caaeeef5bf0c10163bc..2c0f989a4b2bdb7511597c7a0f307daa6f6564cd 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -1107,17 +1107,28 @@ void SkDraw::drawPath(const SkPath& origSrcPath, const SkPaint& origPaint,
 /** For the purposes of drawing bitmaps, if a matrix is "almost" translate
     go ahead and treat it as if it were, so that subsequent code can go fast.
  */
-static bool just_translate(const SkMatrix& matrix, const SkBitmap& bitmap) {
-    unsigned bits = 0;  // TODO: find a way to allow the caller to tell us to
-                        // respect filtering.
-    return SkTreatAsSprite(matrix, bitmap.width(), bitmap.height(), bits);
+static bool just_translate(const SkMatrix& ctm, const SkBitmap& bm, SkPaint::FilterLevel filter) {
+    unsigned bits = 0;
+    switch (filter) {
+        case SkPaint::kNone_FilterLevel:
+            bits = 0;
+            break;
+        case SkPaint::kLow_FilterLevel:
+        case SkPaint::kMedium_FilterLevel:
+            bits = 4;
+            break;
+        case SkPaint::kHigh_FilterLevel:
+            bits = 4;
+            break;
+    }
+    return SkTreatAsSprite(ctm, bm.width(), bm.height(), bits);
 }
 
 void SkDraw::drawBitmapAsMask(const SkBitmap& bitmap,
                               const SkPaint& paint) const {
     SkASSERT(bitmap.colorType() == kAlpha_8_SkColorType);
 
-    if (just_translate(*fMatrix, bitmap)) {
+    if (just_translate(*fMatrix, bitmap, paint.getFilterLevel())) {
         int ix = SkScalarRoundToInt(fMatrix->getTranslateX());
         int iy = SkScalarRoundToInt(fMatrix->getTranslateY());
 
@@ -1236,7 +1247,8 @@ void SkDraw::drawBitmap(const SkBitmap& bitmap, const SkMatrix& prematrix,
         return;
     }
 
-    if (bitmap.colorType() != kAlpha_8_SkColorType && just_translate(matrix, bitmap)) {
+    if (bitmap.colorType() != kAlpha_8_SkColorType && just_translate(matrix, bitmap,
+                                                                     paint.getFilterLevel())) {
         //
         // It is safe to call lock pixels now, since we know the matrix is
         // (more or less) identity.