fix off-by-one error with rotated HQ scaling

src/core/SkBitmapFilter.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkErrorInternals.h"
 #include "SkConvolver.h"
 #include "SkBitmapProcState.h"
 #include "SkBitmap.h"
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkConvolver.h"
 #include "SkUnPreMultiply.h"
 #include "SkShader.h"
 #include "SkRTConf.h"
 #include "SkMath.h"
 
 // These are the per-scanline callbacks that are used when we must resort to
 // resampling an image as it is blitted.  Typically these are used only when
 // the image is rotated or has some other complex transformation applied.
 // Scaled images will usually be rescaled directly before rasterization.
 
 namespace {
 
 template <typename Color, typename ColorPacker>
 void highQualityFilter(ColorPacker pack, const SkBitmapProcState& s, int x, int y, Color* SK_RESTRICT colors, int count) {
-    const int maxX = s.fBitmap->width() - 1;
-    const int maxY = s.fBitmap->height() - 1;
+    const int maxX = s.fBitmap->width();
+    const int maxY = s.fBitmap->height();
 
     while (count-- > 0) {
         SkPoint srcPt;
         s.fInvProc(s.fInvMatrix, x + 0.5f,
                     y + 0.5f, &srcPt);
         srcPt.fX -= SK_ScalarHalf;
         srcPt.fY -= SK_ScalarHalf;
 
         SkScalar weight = 0;
         SkScalar fr = 0, fg = 0, fb = 0, fa = 0;
@@ skipping 98 matching lines @@
     }
 
     if (fInvType & SkMatrix::kScale_Mask) {
         fShaderProc32 = highQualityFilter32;
         fShaderProc16 = highQualityFilter16;
         return true;
     } else {
         return false;
     }
 }