Move convolver, image_operations, and skia_utils from base/gfx to skia/ext.

This changes the namespace in those files from "gfx" to "skia".

I split skia_utils into two parts, the Windows specific part is now in a separate file called skia_utils_win.

There were several obsolete includes of these headers which I removed. I also removed img_resize_perftest which isn't used and has bitrotted.
Review URL: http://codereview.chromium.org/12842

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6248 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 137 insertions, 0 deletions

diff --git a/skia/ext/convolver.h b/skia/ext/convolver.h
new file mode 100644
index 0000000..62c1e30
--- /dev/null
+++ b/skia/ext/convolver.h
@@ -0,0 +1,137 @@
+// 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)
+#undef FloatToFixed
+#endif
+
+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 };
+
+  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 inline unsigned char FixedToChar(int16 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,
+                 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,
+                                     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_;
+
+  // 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,
+                    int source_byte_row_stride,
+                    bool source_has_alpha,
+                    const ConvolusionFilter1D& xfilter,
+                    const ConvolusionFilter1D& yfilter,
+                    uint8* output);
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_CONVOLVER_H_
+