Move Image operations and convolver to the skia namespace and clean up a few ...

skia/ext/convolver.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SKIA_EXT_CONVOLVER_H_
 #define SKIA_EXT_CONVOLVER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 
 // avoid confusion with Mac OS X's math library (Carbon)
-#if defined(OS_MACOSX)
+#if defined(__APPLE__)
 #undef FloatToFixed
 #endif
 
-namespace gfx {
+namespace skia {
 
 // Represents a filter in one dimension. Each output pixel has one entry in this
 // object for the filter values contributing to it. You build up the filter
 // list by calling AddFilter for each output pixel (in order).
 //
 // We do 2-dimensional convolusion by first convolving each row by one
 // ConvolusionFilter1D, then convolving each column by another one.
 //
 // Entries are stored in fixed point, shifted left by kShiftBits.
 class ConvolusionFilter1D {
  public:
   // The number of bits that fixed point values are shifted by.
   enum { kShiftBits = 14 };
 
+  typedef short Fixed;
+
   ConvolusionFilter1D() : max_filter_(0) {
   }
 
   // Convert between floating point and our fixed point representation.
-  static inline int16 FloatToFixed(float f) {
-    return static_cast<int16>(f * (1 << kShiftBits));
+  static Fixed FloatToFixed(float f) {
+    return static_cast<Fixed>(f * (1 << kShiftBits));
   }
-  static inline unsigned char FixedToChar(int16 x) {
+  static unsigned char FixedToChar(Fixed x) {
     return static_cast<unsigned char>(x >> kShiftBits);
   }
 
   // Returns the maximum pixel span of a filter.
   int max_filter() const { return max_filter_; }
 
   // Returns the number of filters in this filter. This is the dimension of the
   // output image.
   int num_values() const { return static_cast<int>(filters_.size()); }
 
   // Appends the given list of scaling values for generating a given output
   // pixel. |filter_offset| is the distance from the edge of the image to where
   // the scaling factors start. The scaling factors apply to the source pixels
   // starting from this position, and going for the next |filter_length| pixels.
   //
   // You will probably want to make sure your input is normalized (that is,
   // all entries in |filter_values| sub to one) to prevent affecting the overall
   // brighness of the image.
   //
   // The filter_length must be > 0.
   //
   // This version will automatically convert your input to fixed point.
   void AddFilter(int filter_offset,
                  const float* filter_values,
                  int filter_length);
 
   // Same as the above version, but the input is already fixed point.
   void AddFilter(int filter_offset,
-                 const int16* filter_values,
+                 const Fixed* filter_values,
                  int filter_length);
 
   // Retrieves a filter for the given |value_offset|, a position in the output
   // image in the direction we're convolving. The offset and length of the
   // filter values are put into the corresponding out arguments (see AddFilter
   // above for what these mean), and a pointer to the first scaling factor is
   // returned. There will be |filter_length| values in this array.
-  inline const int16* FilterForValue(int value_offset,
+  inline const Fixed* FilterForValue(int value_offset,
                                      int* filter_offset,
                                      int* filter_length) const {
     const FilterInstance& filter = filters_[value_offset];
     *filter_offset = filter.offset;
     *filter_length = filter.length;
     return &filter_values_[filter.data_location];
   }
 
  private:
   struct FilterInstance {
     // Offset within filter_values for this instance of the filter.
     int data_location;
 
     // Distance from the left of the filter to the center. IN PIXELS
     int offset;
 
     // Number of values in this filter instance.
     int length;
   };
 
   // Stores the information for each filter added to this class.
   std::vector<FilterInstance> filters_;
 
   // We store all the filter values in this flat list, indexed by
   // |FilterInstance.data_location| to avoid the mallocs required for storing
   // each one separately.
-  std::vector<int16> filter_values_;
+  std::vector<Fixed> filter_values_;
 
   // The maximum size of any filter we've added.
   int max_filter_;
 };
 
 // Does a two-dimensional convolusion on the given source image.
 //
 // It is assumed the source pixel offsets referenced in the input filters
 // reference only valid pixels, so the source image size is not required. Each
 // row of the source image starts |source_byte_row_stride| after the previous
 // one (this allows you to have rows with some padding at the end).
 //
 // The result will be put into the given output buffer. The destination image
 // size will be xfilter.num_values() * yfilter.num_values() pixels. It will be
 // in rows of exactly xfilter.num_values() * 4 bytes.
 //
 // |source_has_alpha| is a hint that allows us to avoid doing computations on
 // the alpha channel if the image is opaque. If you don't know, set this to
 // true and it will work properly, but setting this to false will be a few
 // percent faster if you know the image is opaque.
 //
 // The layout in memory is assumed to be 4-bytes per pixel in B-G-R-A order
 // (this is ARGB when loaded into 32-bit words on a little-endian machine).
-void BGRAConvolve2D(const uint8* source_data,
+void BGRAConvolve2D(const unsigned char* source_data,
                     int source_byte_row_stride,
                     bool source_has_alpha,
                     const ConvolusionFilter1D& xfilter,
                     const ConvolusionFilter1D& yfilter,
-                    uint8* output);
+                    unsigned char* output);
 
-}  // namespace gfx
+}  // namespace skia
 
 #endif  // SKIA_EXT_CONVOLVER_H_