Integration of most changes from the GoogleTV project around the convolver/sc...

skia/ext/convolver.h

Index: skia/ext/convolver.h
===================================================================
--- skia/ext/convolver.h	(revision 71667)
+++ skia/ext/convolver.h	(working copy)
@@ -6,11 +6,13 @@
 #define SKIA_EXT_CONVOLVER_H_
 #pragma once
 
+#include <cmath>
 #include <vector>
 
 // avoid confusion with Mac OS X's math library (Carbon)
 #if defined(__APPLE__)
 #undef FloatToFixed
+#undef FixedToFloat
 #endif
 
 namespace skia {
@@ -40,6 +42,13 @@
   static unsigned char FixedToChar(Fixed x) {
     return static_cast<unsigned char>(x >> kShiftBits);
   }
+  static float FixedToFloat(Fixed x) {
+    // The cast relies on Fixed being a short, implying that on
+    // the platforms we care about all (16) bits will fit into
+    // the mantissa of a (32-bit) float.

[brettw, 2011/01/20 21:48:06]

How about adding a COMPILE_ASSERT(sizeof(Fixed) == 2, FixedMustBeSixteenBits)
here? (May need to include base/basictypes.h).

[evannier, 2011/01/24 21:09:58]

Done.

+    float raw = static_cast<float>(x);
+    return ldexpf(raw, -kShiftBits);
+  }
 
   // Returns the maximum pixel span of a filter.
   int max_filter() const { return max_filter_; }
@@ -80,7 +89,11 @@
     const FilterInstance& filter = filters_[value_offset];
     *filter_offset = filter.offset;
     *filter_length = filter.length;
-    return &filter_values_[filter.data_location];
+    if (filter.length == 0) {
+      return NULL;
+    } else {

[brettw, 2011/01/20 21:48:06]

We generally discourage an else after a return, so I'd just move the else case
to the outer level.

[evannier, 2011/01/24 21:09:58]

Done.

+      return &filter_values_[filter.data_location];
+    }
   }
 
  private:
@@ -130,9 +143,9 @@
                     bool source_has_alpha,
                     const ConvolutionFilter1D& xfilter,
                     const ConvolutionFilter1D& yfilter,
+                    int output_byte_row_stride,
                     unsigned char* output);
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_CONVOLVER_H_
-