More general image filter interface; tested implementation of standalone

image scaler (not yet plumbed).  High quality downsampler.  Fast SSE
resampler.

BUG=
R=reed@google.com

Review URL: https://codereview.chromium.org/17381008

git-svn-id: http://skia.googlecode.com/svn/trunk@9936 2bbb7eff-a529-9590-31e7-b0007b416f81

5 files changed, 545 insertions, 196 deletions

diff --git a/src/core/SkBitmapFilter.cpp b/src/core/SkBitmapFilter.cpp
new file mode 100644
index 0000000000..cc6ad95d1e
--- /dev/null
+++ b/src/core/SkBitmapFilter.cpp
@@ -0,0 +1,378 @@
+/*
+ * 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 "SkBitmapProcState.h"
+#include "SkBitmap.h"
+#include "SkColor.h"
+#include "SkColorPriv.h"
+#include "SkUnPreMultiply.h"
+#include "SkShader.h"
+#include "SkRTConf.h"
+#include "SkMath.h"
+
+void highQualityFilter(const SkBitmapProcState& s, int x, int y,
+                   SkPMColor* SK_RESTRICT colors, int count) {
+
+    const int maxX = s.fBitmap->width() - 1;
+    const int maxY = s.fBitmap->height() - 1;
+
+    while (count-- > 0) {
+        SkPoint srcPt;
+        s.fInvProc(*s.fInvMatrix, SkIntToScalar(x),
+                    SkIntToScalar(y), &srcPt);
+        srcPt.fX -= SK_ScalarHalf;
+        srcPt.fY -= SK_ScalarHalf;
+        SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
+        SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
+
+        int sx = SkScalarFloorToInt(srcPt.fX);
+        int sy = SkScalarFloorToInt(srcPt.fY);
+        
+        SkFixed weight = 0;
+        SkFixed fr = 0, fg = 0, fb = 0, fa = 0;
+        
+        int y0 = SkClampMax(int(ceil(sy-s.getBitmapFilter()->width() + 0.5f)), maxY);
+        int y1 = SkClampMax(int(floor(sy+s.getBitmapFilter()->width() + 0.5f)), maxY);
+        int x0 = SkClampMax(int(ceil(sx-s.getBitmapFilter()->width() + 0.5f)), maxX);
+        int x1 = SkClampMax(int(floor(sx+s.getBitmapFilter()->width() + 0.5f)), maxX);
+        
+        for (int src_y = y0; src_y <= y1; src_y++) {
+            SkFixed yweight = s.getBitmapFilter()->lookup((srcPt.fY - src_y));
+            
+            for (int src_x = x0; src_x <= x1 ; src_x++) {
+                SkFixed xweight = s.getBitmapFilter()->lookup((srcPt.fX - src_x));
+                
+                SkFixed combined_weight = SkFixedMul(xweight, yweight);
+                
+                SkPMColor c = *s.fBitmap->getAddr32(src_x, src_y);
+                fr += combined_weight * SkGetPackedR32(c);
+                fg += combined_weight * SkGetPackedG32(c);
+                fb += combined_weight * SkGetPackedB32(c);
+                fa += combined_weight * SkGetPackedA32(c);
+                weight += combined_weight;
+            }
+        }
+
+        fr = SkFixedDiv(fr, weight);
+        fg = SkFixedDiv(fg, weight);
+        fb = SkFixedDiv(fb, weight);
+        fa = SkFixedDiv(fa, weight);
+
+        int a = SkClampMax(SkFixedRoundToInt(fa), 255);
+        int r = SkClampMax(SkFixedRoundToInt(fr), a);
+        int g = SkClampMax(SkFixedRoundToInt(fg), a);
+        int b = SkClampMax(SkFixedRoundToInt(fb), a);
+
+        *colors++ = SkPackARGB32(a, r, g, b);
+
+        x++;
+    }
+}
+
+void highQualityFilter_ScaleOnly(const SkBitmapProcState &s, int x, int y,
+                             SkPMColor *SK_RESTRICT colors, int count) {
+     const int maxX = s.fBitmap->width() - 1;
+     const int maxY = s.fBitmap->height() - 1;
+     
+     SkPoint srcPt;
+     
+     s.fInvProc(*s.fInvMatrix, SkIntToScalar(x),
+                 SkIntToScalar(y), &srcPt);
+     srcPt.fY -= SK_ScalarHalf;
+     SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
+     int sy = SkScalarFloorToInt(srcPt.fY);
+     int y0 = SkClampMax(int(ceil(sy-s.getBitmapFilter()->width() + 0.5f)), maxY);
+     int y1 = SkClampMax(int(floor(sy+s.getBitmapFilter()->width() + 0.5f)), maxY);
+
+     while (count-- > 0) {
+         s.fInvProc(*s.fInvMatrix, SkIntToScalar(x),
+                     SkIntToScalar(y), &srcPt);
+         srcPt.fX -= SK_ScalarHalf;
+         srcPt.fY -= SK_ScalarHalf;
+         SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
+
+         int sx = SkScalarFloorToInt(srcPt.fX);
+
+         SkFixed weight = 0;
+         SkFixed fr = 0, fg = 0, fb = 0, fa = 0;
+
+         int x0 = SkClampMax(int(ceil(sx-s.getBitmapFilter()->width() + 0.5f)), maxX);
+         int x1 = SkClampMax(int(floor(sx+s.getBitmapFilter()->width() + 0.5f)), maxX);
+
+         for (int src_y = y0; src_y <= y1; src_y++) {
+             SkFixed yweight = s.getBitmapFilter()->lookup((srcPt.fY - src_y));
+
+             for (int src_x = x0; src_x <= x1 ; src_x++) {
+                 SkFixed xweight = s.getBitmapFilter()->lookup((srcPt.fX - src_x));
+
+                 SkFixed combined_weight = SkFixedMul(xweight, yweight);
+
+                 SkPMColor c = *s.fBitmap->getAddr32(src_x, src_y);
+                 fr += combined_weight * SkGetPackedR32(c);
+                 fg += combined_weight * SkGetPackedG32(c);
+                 fb += combined_weight * SkGetPackedB32(c);
+                 fa += combined_weight * SkGetPackedA32(c);
+                 weight += combined_weight;
+             }
+         }
+
+         fr = SkFixedDiv(fr, weight);
+         fg = SkFixedDiv(fg, weight);
+         fb = SkFixedDiv(fb, weight);
+         fa = SkFixedDiv(fa, weight);
+
+         int a = SkClampMax(SkFixedRoundToInt(fa), 255);
+         int r = SkClampMax(SkFixedRoundToInt(fr), a);
+         int g = SkClampMax(SkFixedRoundToInt(fg), a);
+         int b = SkClampMax(SkFixedRoundToInt(fb), a);
+
+         *colors++ = SkPackARGB32(a, r, g, b);
+
+         x++;
+     }                                 
+}
+
+SK_CONF_DECLARE(const char *, c_bitmapFilter, "bitmap.filter", "mitchell", "Which bitmap filter to use [mitchell, sinc, gaussian, triangle, box]");
+
+static SkBitmapFilter *allocateBitmapFilter() {
+    if (!strcmp(c_bitmapFilter, "mitchell")) {
+        return SkNEW_ARGS(SkMitchellFilter,(1.f/3.f,1.f/3.f));
+    } else if (!strcmp(c_bitmapFilter, "sinc")) {
+        return SkNEW_ARGS(SkSincFilter,(3));
+    } else if (!strcmp(c_bitmapFilter, "gaussian")) {
+        return SkNEW_ARGS(SkGaussianFilter,(2));
+    } else if (!strcmp(c_bitmapFilter, "triangle")) {
+        return SkNEW(SkTriangleFilter);
+    } else if (!strcmp(c_bitmapFilter, "box")) {
+        return SkNEW(SkBoxFilter);
+    } else {
+        SkASSERT(!!!"Unknown filter type");
+    }
+    
+    return NULL;
+}
+
+SkBitmapProcState::ShaderProc32
+SkBitmapProcState::chooseBitmapFilterProc(const SkPaint& paint) {
+    // we need to be requested
+    uint32_t mask = SkPaint::kFilterBitmap_Flag
+                  | SkPaint::kHighQualityFilterBitmap_Flag
+                  ;
+    if ((paint.getFlags() & mask) != mask) {
+        return NULL;
+    }
+
+    // TODO: consider supporting other configs (e.g. 565, A8)
+    if (fBitmap->config() != SkBitmap::kARGB_8888_Config) {
+        return NULL;
+    }
+
+    // TODO: consider supporting repeat and mirror
+    if (SkShader::kClamp_TileMode != fTileModeX || SkShader::kClamp_TileMode != fTileModeY) {
+        return NULL;
+    }
+
+    // TODO: support blending inside our procs
+    if (0xFF != paint.getAlpha()) {
+        return NULL;
+    }
+    
+    if (fInvType & (SkMatrix::kAffine_Mask | SkMatrix::kScale_Mask)) {
+        fBitmapFilter = allocateBitmapFilter();
+    }
+    
+    if (fInvType & SkMatrix::kAffine_Mask) {
+        return highQualityFilter;
+    } else if (fInvType & SkMatrix::kScale_Mask) {
+        return highQualityFilter_ScaleOnly;
+    } else {
+        return NULL;
+    }
+}
+
+static void divideByWeights(SkFixed *sums, SkFixed *weights, SkBitmap *dst) {
+    for (int y = 0 ; y < dst->height() ; y++) {
+        for (int x = 0 ; x < dst->width() ; x++) {
+            SkFixed fr = SkFixedDiv(sums[4*(y*dst->width() + x) + 0], weights[y*dst->width() + x]);
+            SkFixed fg = SkFixedDiv(sums[4*(y*dst->width() + x) + 1], weights[y*dst->width() + x]);
+            SkFixed fb = SkFixedDiv(sums[4*(y*dst->width() + x) + 2], weights[y*dst->width() + x]);
+            SkFixed fa = SkFixedDiv(sums[4*(y*dst->width() + x) + 3], weights[y*dst->width() + x]);
+            int a = SkClampMax(SkFixedRoundToInt(fa), 255);
+            int r = SkClampMax(SkFixedRoundToInt(fr), a);
+            int g = SkClampMax(SkFixedRoundToInt(fg), a);
+            int b = SkClampMax(SkFixedRoundToInt(fb), a);
+
+            *dst->getAddr32(x,y) = SkPackARGB32(a, r, g, b);
+        }
+    }
+}
+
+static void upScaleHoriz(const SkBitmap *src, SkBitmap *dst, float scale, SkBitmapFilter *filter) {
+    for (int y = 0 ; y < src->height() ; y++) {
+        for (int x = 0 ; x < dst->width() ; x++) {
+            float sx = x / scale - 0.5f;
+            int x0 = SkClampMax(int(ceil(sx-filter->width() + 0.5f)), src->width()-1);
+            int x1 = SkClampMax(int(floor(sx+filter->width() + 0.5f)), src->width()-1);
+            
+            SkFixed total_weight = 0;
+            SkFixed fr = 0, fg = 0, fb = 0, fa = 0;
+            
+            for (int src_x = x0 ; src_x <= x1 ; src_x++) {
+                SkFixed weight = filter->lookup(sx - src_x);
+                SkPMColor c = *src->getAddr32(src_x,y);
+                fr += weight * SkGetPackedR32(c);
+                fg += weight * SkGetPackedG32(c);
+                fb += weight * SkGetPackedB32(c);
+                fa += weight * SkGetPackedA32(c);
+                total_weight += weight;
+            }
+            fr = SkFixedDiv(fr, total_weight);
+            fg = SkFixedDiv(fg, total_weight);
+            fb = SkFixedDiv(fb, total_weight);
+            fa = SkFixedDiv(fa, total_weight);
+
+            int a = SkClampMax(SkFixedRoundToInt(fa), 255);
+            int r = SkClampMax(SkFixedRoundToInt(fr), a);
+            int g = SkClampMax(SkFixedRoundToInt(fg), a);
+            int b = SkClampMax(SkFixedRoundToInt(fb), a);
+
+            *dst->getAddr32(x,y) = SkPackARGB32(a, r, g, b);
+        }
+    }
+}
+
+static void downScaleHoriz(const SkBitmap *src, SkBitmap *dst, float scale, SkBitmapFilter *filter) {
+    SkFixed *sums = SkNEW_ARRAY(SkFixed, dst->width() * dst->height() * 4);
+    SkFixed *weights = SkNEW_ARRAY(SkFixed, dst->width() * dst->height());
+    
+    SkAutoTDeleteArray<SkFixed> ada1(sums);
+    SkAutoTDeleteArray<SkFixed> ada2(weights);
+
+    memset(sums, 0, dst->width() * dst->height() * sizeof(SkFixed) * 4);
+    memset(weights, 0, dst->width() * dst->height() * sizeof(SkFixed));
+    
+    for (int y = 0 ; y < src->height() ; y++) {
+        for (int x = 0 ; x < src->width() ; x++) {
+            // splat each source pixel into the destination image
+            float dx = (x + 0.5f) * scale;
+            int x0 = SkClampMax(int(ceil(dx-filter->width() + 0.5f)), dst->width()-1);
+            int x1 = SkClampMax(int(floor(dx+filter->width() + 0.5f)), dst->width()-1);
+            
+            SkPMColor c = *src->getAddr32(x,y);
+            
+            for (int dst_x = x0 ; dst_x <= x1 ; dst_x++) {
+                SkFixed weight = filter->lookup(dx - dst_x);
+                sums[4*(y*dst->width() + dst_x) + 0] += weight*SkGetPackedR32(c);
+                sums[4*(y*dst->width() + dst_x) + 1] += weight*SkGetPackedG32(c);
+                sums[4*(y*dst->width() + dst_x) + 2] += weight*SkGetPackedB32(c);
+                sums[4*(y*dst->width() + dst_x) + 3] += weight*SkGetPackedA32(c);
+                weights[y*dst->width() + dst_x] += weight;
+            }
+        }
+    }
+    
+    divideByWeights(sums, weights, dst);
+}
+
+static void upScaleVert(const SkBitmap *src, SkBitmap *dst, float scale, SkBitmapFilter *filter) {
+    for (int y = 0 ; y < dst->height() ; y++) {
+        for (int x = 0 ; x < dst->width() ; x++) {
+            float sy = y / scale - 0.5f;
+            int y0 = SkClampMax(int(ceil(sy-filter->width() + 0.5f)), src->height()-1);
+            int y1 = SkClampMax(int(floor(sy+filter->width() + 0.5f)), src->height()-1);
+            
+            SkFixed total_weight = 0;
+            SkFixed fr = 0, fg = 0, fb = 0, fa = 0;
+            
+            for (int src_y = y0 ; src_y <= y1 ; src_y++) {
+                SkFixed weight = filter->lookup(sy - src_y);
+                SkPMColor c = *src->getAddr32(x,src_y);
+                fr += weight * SkGetPackedR32(c);
+                fg += weight * SkGetPackedG32(c);
+                fb += weight * SkGetPackedB32(c);
+                fa += weight * SkGetPackedA32(c);
+                total_weight += weight;
+            }
+            fr = SkFixedDiv(fr, total_weight);
+            fg = SkFixedDiv(fg, total_weight);
+            fb = SkFixedDiv(fb, total_weight);
+            fa = SkFixedDiv(fa, total_weight);
+
+            int a = SkClampMax(SkFixedRoundToInt(fa), 255);
+            int r = SkClampMax(SkFixedRoundToInt(fr), a);
+            int g = SkClampMax(SkFixedRoundToInt(fg), a);
+            int b = SkClampMax(SkFixedRoundToInt(fb), a);
+
+            *dst->getAddr32(x,y) = SkPackARGB32(a, r, g, b);
+        }
+    }
+}
+
+static void downScaleVert(const SkBitmap *src, SkBitmap *dst, float scale, SkBitmapFilter *filter) {
+    SkFixed *sums = SkNEW_ARRAY(SkFixed, dst->width() * dst->height() * 4);
+    SkFixed *weights = SkNEW_ARRAY(SkFixed, dst->width() * dst->height());
+    
+    SkAutoTDeleteArray<SkFixed> ada1(sums);
+    SkAutoTDeleteArray<SkFixed> ada2(weights);
+
+    memset(sums, 0, dst->width() * dst->height() * sizeof(SkFixed) * 4);
+    memset(weights, 0, dst->width() * dst->height() * sizeof(SkFixed));
+
+    for (int y = 0 ; y < src->height() ; y++) {
+        for (int x = 0 ; x < src->width() ; x++) {
+            // splat each source pixel into the destination image
+            float dy = (y + 0.5f) * scale;
+            int y0 = SkClampMax(int(ceil(dy-filter->width() + 0.5f)), dst->height()-1);
+            int y1 = SkClampMax(int(floor(dy+filter->width() + 0.5f)), dst->height()-1);
+
+            SkPMColor c = *src->getAddr32(x,y);
+
+            for (int dst_y = y0 ; dst_y <= y1 ; dst_y++) {
+                SkFixed weight = filter->lookup(dy - dst_y);
+                sums[4*(dst_y*dst->width() + x) + 0] += weight*SkGetPackedR32(c);
+                sums[4*(dst_y*dst->width() + x) + 1] += weight*SkGetPackedG32(c);
+                sums[4*(dst_y*dst->width() + x) + 2] += weight*SkGetPackedB32(c);
+                sums[4*(dst_y*dst->width() + x) + 3] += weight*SkGetPackedA32(c);
+                weights[dst_y*dst->width() + x] += weight;
+            }
+        }
+    }
+    
+    divideByWeights(sums, weights, dst);
+}
+
+void SkBitmap::scale(SkBitmap *dst) const {
+    
+    SkBitmap horiz_temp;
+    
+    horiz_temp.setConfig(SkBitmap::kARGB_8888_Config, dst->width(), height());
+    horiz_temp.allocPixels();
+    
+    SkBitmapFilter *filter = allocateBitmapFilter();
+    
+    float horiz_scale = float(dst->width()) / width();
+    
+    if (horiz_scale == 1) {
+        this->copyPixelsTo(horiz_temp.getPixels(), getSize());
+    } else if (horiz_scale > 1) {
+        upScaleHoriz(this, &horiz_temp, horiz_scale, filter);
+    } else if (horiz_scale < 1) {
+        downScaleHoriz(this, &horiz_temp, horiz_scale, filter);
+    }
+    
+    float vert_scale = float(dst->height()) / height();
+    
+    if (vert_scale == 1) {
+        horiz_temp.copyPixelsTo(dst->getPixels(), dst->getSize());
+    } else if (vert_scale > 1) {
+        upScaleVert(&horiz_temp, dst, vert_scale, filter);
+    } else if (vert_scale < 1) {
+        downScaleVert(&horiz_temp, dst, vert_scale, filter);
+    }
+    
+    SkDELETE(filter);
+}
diff --git a/src/core/SkBitmapFilter.h b/src/core/SkBitmapFilter.h
new file mode 100644
index 0000000000..4e4778876c
--- /dev/null
+++ b/src/core/SkBitmapFilter.h
@@ -0,0 +1,150 @@
+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef SkBitmapFilter_DEFINED
+#define SkBitmapFilter_DEFINED
+
+#include "SkMath.h"
+
+// size of the precomputed bitmap filter tables for high quality filtering.
+// Used to precompute the shape of the filter kernel.
+// Table size chosen from experiments to see where I could start to see a difference.
+
+#define SKBITMAP_FILTER_TABLE_SIZE 32
+
+class SkBitmapFilter {
+  public:
+      SkBitmapFilter(float width)
+      : fWidth(width), fInvWidth(1.f/width) {
+          precomputed = false;
+      }
+      
+      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) ];
+      }      
+      
+      SkFixed lookupFloat( 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) ];
+      }      
+      
+      float width() const { return fWidth; }
+      float invWidth() const { return fInvWidth; }
+      virtual float evaluate(float x) const = 0;
+  protected:
+      float fWidth;
+      float fInvWidth;
+      
+      mutable bool precomputed;
+      mutable SkFixed fFilterTable[SKBITMAP_FILTER_TABLE_SIZE];
+      mutable float fFilterTableFloat[SKBITMAP_FILTER_TABLE_SIZE];
+  private:
+      void precomputeTable() const {
+          precomputed = true;
+          SkFixed *ftp = fFilterTable;
+          float *ftp_float = fFilterTableFloat;
+          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++ = SkFloatToFixed(filter_value);
+          }
+      }
+};
+
+class SkMitchellFilter: public SkBitmapFilter {
+  public:
+      SkMitchellFilter(float b, float c, float width=2.0f)
+      : SkBitmapFilter(width), B(b), C(c) { 
+      }
+      
+      virtual float evaluate(float x) const SK_OVERRIDE {
+          x = fabsf(x);
+          float ret;
+          if (x > 2.f) {
+              return 0;
+          } else if (x > 1.f) {
+              return ((-B - 6*C) * x*x*x + (6*B + 30*C) * x*x +
+                      (-12*B - 48*C) * x + (8*B + 24*C)) * (1.f/6.f);
+          } else {
+              return ((12 - 9*B - 6*C) * x*x*x +
+                      (-18 + 12*B + 6*C) * x*x +
+                      (6 - 2*B)) * (1.f/6.f);
+          }
+      }
+  protected:
+      float B, C;
+};
+
+class SkGaussianFilter: public SkBitmapFilter {
+  public:
+      SkGaussianFilter(float a, float width=2.0f)
+      : SkBitmapFilter(width), alpha(a), expWidth(expf(-alpha * width * width)) { 
+      }
+      
+      virtual float evaluate(float x) const SK_OVERRIDE {
+          return SkTMax(0.f, float(expf(-alpha*x*x) - expWidth));
+      }
+  protected:
+      float alpha, expWidth;
+};
+
+class SkTriangleFilter: public SkBitmapFilter {
+  public:
+      SkTriangleFilter(float width=1)
+      : SkBitmapFilter(width) { 
+      }
+      
+      virtual float evaluate(float x) const SK_OVERRIDE {
+          return SkTMax(0.f, fWidth - fabsf(x));
+      }
+  protected:
+};
+
+class SkBoxFilter: public SkBitmapFilter {
+  public:
+      SkBoxFilter(float width=0.5f)
+      : SkBitmapFilter(width) { 
+      }
+      
+      virtual float evaluate(float x) const SK_OVERRIDE {
+          return 1;
+      }
+  protected:
+};
+
+
+class SkSincFilter: public SkBitmapFilter {
+  public:
+      SkSincFilter(float t, float width=3.f)
+      : SkBitmapFilter(width), tau(t) { 
+      }
+      
+      virtual float evaluate(float x) const SK_OVERRIDE {
+          x = sk_float_abs(x * fInvWidth);
+          if (x < 1e-5f) return 1.f;
+          if (x > 1.f)   return 0.f;
+          x *= M_PI;
+          float sinc = sk_float_sin(x) / x;
+          float lanczos = sk_float_sin(x * tau) / (x * tau);
+          return sinc * lanczos;
+      }
+  protected:
+      float tau;
+};
+
+
+#endif
diff --git a/src/core/SkBitmapProcBicubic.cpp b/src/core/SkBitmapProcBicubic.cpp
deleted file mode 100644
index f2cd0e30e7..0000000000
--- a/src/core/SkBitmapProcBicubic.cpp
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- * 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 "SkBitmapProcState.h"
-#include "SkBitmap.h"
-#include "SkColor.h"
-#include "SkColorPriv.h"
-#include "SkUnPreMultiply.h"
-#include "SkRTConf.h"
-#include "SkShader.h"
-
-#define DS(x) SkDoubleToScalar(x)
-
-#define MUL(a, b)   ((a) * (b))
-
-static inline SkPMColor cubicBlend(const SkFixed cc[4], SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
-    SkFixed fa = MUL(cc[0], SkGetPackedA32(c0)) + MUL(cc[1], SkGetPackedA32(c1)) + MUL(cc[2], SkGetPackedA32(c2)) + MUL(cc[3], SkGetPackedA32(c3));
-    SkFixed fr = MUL(cc[0], SkGetPackedR32(c0)) + MUL(cc[1], SkGetPackedR32(c1)) + MUL(cc[2], SkGetPackedR32(c2)) + MUL(cc[3], SkGetPackedR32(c3));
-    SkFixed fg = MUL(cc[0], SkGetPackedG32(c0)) + MUL(cc[1], SkGetPackedG32(c1)) + MUL(cc[2], SkGetPackedG32(c2)) + MUL(cc[3], SkGetPackedG32(c3));
-    SkFixed fb = MUL(cc[0], SkGetPackedB32(c0)) + MUL(cc[1], SkGetPackedB32(c1)) + MUL(cc[2], SkGetPackedB32(c2)) + MUL(cc[3], SkGetPackedB32(c3));
-
-    int a = SkClampMax(SkFixedRoundToInt(fa), 255);
-    int r = SkClampMax(SkFixedRoundToInt(fr), a);
-    int g = SkClampMax(SkFixedRoundToInt(fg), a);
-    int b = SkClampMax(SkFixedRoundToInt(fb), a);
-
-    return SkPackARGB32(a, r, g, b);
-}
-
-static float poly_eval(const float cc[4], float t) {
-    return cc[0] + t * (cc[1] + t * (cc[2] + t * cc[3]));
-}
-
-static void build_coeff4(SkFixed dst[4], float t) {
-    static const SkScalar coefficients[16] = {
-        DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
-        DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
-        DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
-        DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS(  7.0 / 18.0),
-    };
-
-    dst[0] = SkFloatToFixed(poly_eval(&coefficients[ 0], t));
-    dst[1] = SkFloatToFixed(poly_eval(&coefficients[ 4], t));
-    dst[2] = SkFloatToFixed(poly_eval(&coefficients[ 8], t));
-    dst[3] = SkFloatToFixed(poly_eval(&coefficients[12], t));
-}
-
-static SkPMColor doBicubicFilter(const SkBitmap *bm, SkFixed coeffX[4], SkFixed coeffY[4],
-                            int x0, int x1, int x2, int x3,
-                            int y0, int y1, int y2, int y3 )
-{
-    SkPMColor s00 = *bm->getAddr32(x0, y0);
-    SkPMColor s10 = *bm->getAddr32(x1, y0);
-    SkPMColor s20 = *bm->getAddr32(x2, y0);
-    SkPMColor s30 = *bm->getAddr32(x3, y0);
-    SkPMColor s0 = cubicBlend(coeffX, s00, s10, s20, s30);
-    SkPMColor s01 = *bm->getAddr32(x0, y1);
-    SkPMColor s11 = *bm->getAddr32(x1, y1);
-    SkPMColor s21 = *bm->getAddr32(x2, y1);
-    SkPMColor s31 = *bm->getAddr32(x3, y1);
-    SkPMColor s1 = cubicBlend(coeffX, s01, s11, s21, s31);
-    SkPMColor s02 = *bm->getAddr32(x0, y2);
-    SkPMColor s12 = *bm->getAddr32(x1, y2);
-    SkPMColor s22 = *bm->getAddr32(x2, y2);
-    SkPMColor s32 = *bm->getAddr32(x3, y2);
-    SkPMColor s2 = cubicBlend(coeffX, s02, s12, s22, s32);
-    SkPMColor s03 = *bm->getAddr32(x0, y3);
-    SkPMColor s13 = *bm->getAddr32(x1, y3);
-    SkPMColor s23 = *bm->getAddr32(x2, y3);
-    SkPMColor s33 = *bm->getAddr32(x3, y3);
-    SkPMColor s3 = cubicBlend(coeffX, s03, s13, s23, s33);
-    return cubicBlend(coeffY, s0, s1, s2, s3);
-}
-
-static void bicubicFilter(const SkBitmapProcState& s, int x, int y,
-                          SkPMColor* SK_RESTRICT colors, int count) {
-
-    const int maxX = s.fBitmap->width() - 1;
-    const int maxY = s.fBitmap->height() - 1;
-
-    while (count-- > 0) {
-        SkPoint srcPt;
-        s.fInvProc(*s.fInvMatrix, SkIntToScalar(x),
-                    SkIntToScalar(y), &srcPt);
-        srcPt.fX -= SK_ScalarHalf;
-        srcPt.fY -= SK_ScalarHalf;
-        SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
-        SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
-
-        SkFixed coeffX[4], coeffY[4];
-        build_coeff4(coeffX, fractx);
-        build_coeff4(coeffY, fracty);
-
-        int sx = SkScalarFloorToInt(srcPt.fX);
-        int sy = SkScalarFloorToInt(srcPt.fY);
-
-        // Here is where we can support other tile modes (e.g. repeat or mirror)
-        int x0 = SkClampMax(sx - 1, maxX);
-        int x1 = SkClampMax(sx    , maxX);
-        int x2 = SkClampMax(sx + 1, maxX);
-        int x3 = SkClampMax(sx + 2, maxX);
-        int y0 = SkClampMax(sy - 1, maxY);
-        int y1 = SkClampMax(sy    , maxY);
-        int y2 = SkClampMax(sy + 1, maxY);
-        int y3 = SkClampMax(sy + 2, maxY);
-
-        *colors++ = doBicubicFilter( s.fBitmap, coeffX, coeffY, x0, x1, x2, x3, y0, y1, y2, y3 );
-
-        x++;
-    }
-}
-
-static void bicubicFilter_ScaleOnly(const SkBitmapProcState &s, int x, int y,
-                                    SkPMColor *SK_RESTRICT colors, int count) {
-    const int maxX = s.fBitmap->width() - 1;
-    const int maxY = s.fBitmap->height() - 1;
-
-    SkPoint srcPt;
-    s.fInvProc(*s.fInvMatrix, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
-    srcPt.fY -= SK_ScalarHalf;
-    SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
-    SkFixed coeffX[4], coeffY[4];
-    build_coeff4(coeffY, fracty);
-    int sy = SkScalarFloorToInt(srcPt.fY);
-    int y0 = SkClampMax(sy - 1, maxY);
-    int y1 = SkClampMax(sy    , maxY);
-    int y2 = SkClampMax(sy + 1, maxY);
-    int y3 = SkClampMax(sy + 2, maxY);
-
-    while (count-- > 0) {
-        s.fInvProc(*s.fInvMatrix, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
-        srcPt.fX -= SK_ScalarHalf;
-        SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
-
-        build_coeff4(coeffX, fractx);
-
-        int sx = SkScalarFloorToInt(srcPt.fX);
-
-        // Here is where we can support other tile modes (e.g. repeat or mirror)
-        int x0 = SkClampMax(sx - 1, maxX);
-        int x1 = SkClampMax(sx    , maxX);
-        int x2 = SkClampMax(sx + 1, maxX);
-        int x3 = SkClampMax(sx + 2, maxX);
-
-        *colors++ = doBicubicFilter( s.fBitmap, coeffX, coeffY, x0, x1, x2, x3, y0, y1, y2, y3 );
-
-        x++;
-    }
-}
-
-SkBitmapProcState::ShaderProc32
-SkBitmapProcState::chooseBicubicFilterProc(const SkPaint& paint) {
-    // we need to be requested
-    uint32_t mask = SkPaint::kFilterBitmap_Flag
-                  | SkPaint::kBicubicFilterBitmap_Flag
-                  ;
-    if ((paint.getFlags() & mask) != mask) {
-        return NULL;
-    }
-
-    // TODO: consider supporting other configs (e.g. 565, A8)
-    if (fBitmap->config() != SkBitmap::kARGB_8888_Config) {
-        return NULL;
-    }
-
-    // TODO: consider supporting repeat and mirror
-    if (SkShader::kClamp_TileMode != fTileModeX || SkShader::kClamp_TileMode != fTileModeY) {
-        return NULL;
-    }
-
-    // TODO: support blending inside our procs
-    if (0xFF != paint.getAlpha()) {
-        return NULL;
-    }
-
-    if (fInvType & SkMatrix::kAffine_Mask) {
-        return bicubicFilter;
-    } else if (fInvType & SkMatrix::kScale_Mask) {
-        return bicubicFilter_ScaleOnly;
-    } else {
-        return NULL;
-    }
-}
diff --git a/src/core/SkBitmapProcState.cpp b/src/core/SkBitmapProcState.cpp
index 2a79f2f490..a2c7f990c2 100644
--- a/src/core/SkBitmapProcState.cpp
+++ b/src/core/SkBitmapProcState.cpp
@@ -302,13 +302,13 @@ bool SkBitmapProcState::chooseProcs(const SkMatrix& inv, const SkPaint& paint) {
         fShaderProc32 = this->chooseShaderProc32();
     }
 
-    // see if our platform has any accelerated overrides
-    this->platformProcs();
-
     if (NULL == fShaderProc32) {
-        fShaderProc32 = this->chooseBicubicFilterProc(paint);
+        fShaderProc32 = this->chooseBitmapFilterProc(paint);
     }
 
+    // see if our platform has any accelerated overrides
+    this->platformProcs();
+
     return true;
 }
 
diff --git a/src/core/SkBitmapProcState.h b/src/core/SkBitmapProcState.h
index 7d754fe509..69de2ca86a 100644
--- a/src/core/SkBitmapProcState.h
+++ b/src/core/SkBitmapProcState.h
@@ -11,6 +11,7 @@
 #define SkBitmapProcState_DEFINED
 
 #include "SkBitmap.h"
+#include "SkBitmapFilter.h"
 #include "SkMatrix.h"
 
 #define FractionalInt_IS_64BIT
@@ -113,6 +114,8 @@ struct SkBitmapProcState {
     // are ignored
     ShaderProc32 getShaderProc32() const { return fShaderProc32; }
     ShaderProc16 getShaderProc16() const { return fShaderProc16; }
+    
+    SkBitmapFilter* getBitmapFilter() const { return fBitmapFilter; }
 
 #ifdef SK_DEBUG
     MatrixProc getMatrixProc() const;
@@ -139,12 +142,11 @@ private:
     MatrixProc chooseMatrixProc(bool trivial_matrix);
     bool chooseProcs(const SkMatrix& inv, const SkPaint&);
     ShaderProc32 chooseShaderProc32();
+    
+    void buildFilterCoefficients(SkFixed dst[4], float t) const;
+    SkBitmapFilter *fBitmapFilter;
 
-
-    /** test method for choosing a bicubic shading filter
-      */
-
-    ShaderProc32 chooseBicubicFilterProc(const SkPaint &paint);
+    ShaderProc32 chooseBitmapFilterProc(const SkPaint &paint);
 
     // Return false if we failed to setup for fast translate (e.g. overflow)
     bool setupForTranslate();
@@ -200,4 +202,10 @@ void ClampX_ClampY_nofilter_affine(const SkBitmapProcState& s,
 void S32_D16_filter_DX(const SkBitmapProcState& s,
                                    const uint32_t* xy, int count, uint16_t* colors);
 
+void highQualityFilter_ScaleOnly(const SkBitmapProcState &s, int x, int y,
+                             SkPMColor *SK_RESTRICT colors, int count);
+void highQualityFilter(const SkBitmapProcState &s, int x, int y,
+                   SkPMColor *SK_RESTRICT colors, int count);
+                              
+
 #endif