Working plumb of image scaling:

src/core/SkBitmapFilter.h

Index: src/core/SkBitmapFilter.h
diff --git a/src/core/SkBitmapFilter.h b/src/core/SkBitmapFilter.h
index 82734200e1cdebcdb54f1e8b52a3b25989cf117a..86884a313d7249854c1631c755795aac57d669e1 100644
--- a/src/core/SkBitmapFilter.h
+++ b/src/core/SkBitmapFilter.h
@@ -23,22 +23,25 @@ class SkBitmapFilter {
       SkBitmapFilter(float width)
       : fWidth(width), fInvWidth(1.f/width) {
           precomputed = false;

[robertphillips, 2013/07/12 19:42:31]

this->invWidth()

[humper, 2013/07/12 21:12:03]

Done.

+          fLookupMultiplier = invWidth() * (SKBITMAP_FILTER_TABLE_SIZE-1);
       }
 
       SkFixed lookup( float x ) const {
           if (!precomputed) {
               precomputeTable();
           }
-          int filter_idx = int(fabsf(x * invWidth() * SKBITMAP_FILTER_TABLE_SIZE));
-          return fFilterTable[ SkTMin(filter_idx, SKBITMAP_FILTER_TABLE_SIZE-1) ];
+          int filter_idx = int(sk_float_abs(x * fLookupMultiplier));
+          SkASSERT(filter_idx < SKBITMAP_FILTER_TABLE_SIZE);
+          return fFilterTable[ filter_idx ];
       }
 
-      float lookupFloat( float x ) const {
+      SkScalar lookupScalar( float x ) const {
           if (!precomputed) {
               precomputeTable();
           }
-          int filter_idx = int(fabsf(x * invWidth() * SKBITMAP_FILTER_TABLE_SIZE));
-          return fFilterTableFloat[ SkTMin(filter_idx, SKBITMAP_FILTER_TABLE_SIZE-1) ];
+          int filter_idx = int(sk_float_abs(x * fLookupMultiplier));
+          SkASSERT(filter_idx < SKBITMAP_FILTER_TABLE_SIZE);
+          return fFilterTableScalar[ filter_idx ];
       }
 
       float width() const { return fWidth; }
@@ -48,19 +51,21 @@ class SkBitmapFilter {
   protected:
       float fWidth;
       float fInvWidth;
+      
+      int fLookupMultiplier;
 
       mutable bool precomputed;

[robertphillips, 2013/07/12 19:42:31]

fPrecomputed

[humper, 2013/07/12 21:12:03]

Done.

       mutable SkFixed fFilterTable[SKBITMAP_FILTER_TABLE_SIZE];
-      mutable float fFilterTableFloat[SKBITMAP_FILTER_TABLE_SIZE];
+      mutable SkScalar fFilterTableScalar[SKBITMAP_FILTER_TABLE_SIZE];
   private:
       void precomputeTable() const {
           precomputed = true;
           SkFixed *ftp = fFilterTable;

[robertphillips, 2013/07/12 19:42:31]

ftpScalar

[humper, 2013/07/12 21:12:03]

Done.

-          float *ftp_float = fFilterTableFloat;
+          SkScalar *ftp_scalar = fFilterTableScalar;
           for (int x = 0; x < SKBITMAP_FILTER_TABLE_SIZE; ++x) {
               float fx = ((float)x + .5f) * this->width() / SKBITMAP_FILTER_TABLE_SIZE;
               float filter_value = evaluate(fx);
-              *ftp_float++ = filter_value;
+              *ftp_scalar++ = SkFloatToScalar(filter_value);
               *ftp++ = SkFloatToFixed(filter_value);
           }
       }