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authorbrettw@google.com <brettw@google.com@0039d316-1c4b-4281-b951-d872f2087c98>2008-12-03 01:11:58 +0000
committerbrettw@google.com <brettw@google.com@0039d316-1c4b-4281-b951-d872f2087c98>2008-12-03 01:11:58 +0000
commitae615162135445eb0b94365b1a1cfa511e7f4be4 (patch)
treea32c9ad049aa25b3c40038713d546c3521d3d20e /skia/ext/convolver.h
parent693f8e4af78b0bb38cb56cd913c8774c75b43067 (diff)
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Revert my skia file moves because of layout test failures.
Review URL: http://codereview.chromium.org/12892 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6266 0039d316-1c4b-4281-b951-d872f2087c98
Diffstat (limited to 'skia/ext/convolver.h')
-rw-r--r--skia/ext/convolver.h137
1 files changed, 0 insertions, 137 deletions
diff --git a/skia/ext/convolver.h b/skia/ext/convolver.h
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-// 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_
-