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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/image_operations.cc
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/image_operations.cc')
-rw-r--r--skia/ext/image_operations.cc366
1 files changed, 0 insertions, 366 deletions
diff --git a/skia/ext/image_operations.cc b/skia/ext/image_operations.cc
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--- a/skia/ext/image_operations.cc
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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.
-//
-#define _USE_MATH_DEFINES
-#include <cmath>
-#include <limits>
-#include <vector>
-
-#include "skia/ext/image_operations.h"
-
-#include "base/gfx/rect.h"
-#include "base/gfx/size.h"
-#include "base/logging.h"
-#include "base/stack_container.h"
-#include "skia/ext/convolver.h"
-#include "SkBitmap.h"
-
-// TODO(brettw) this should be removed when the base/gfx dependencies are
-// removed.
-using namespace gfx;
-
-namespace skia {
-
-namespace {
-
-// Returns the ceiling/floor as an integer.
-inline int CeilInt(float val) {
- return static_cast<int>(ceil(val));
-}
-inline int FloorInt(float val) {
- return static_cast<int>(floor(val));
-}
-
-// Filter function computation -------------------------------------------------
-
-// Evaluates the box filter, which goes from -0.5 to +0.5.
-float EvalBox(float x) {
- return (x >= -0.5f && x < 0.5f) ? 1.0f : 0.0f;
-}
-
-// Evaluates the Lanczos filter of the given filter size window for the given
-// position.
-//
-// |filter_size| is the width of the filter (the "window"), outside of which
-// the value of the function is 0. Inside of the window, the value is the
-// normalized sinc function:
-// lanczos(x) = sinc(x) * sinc(x / filter_size);
-// where
-// sinc(x) = sin(pi*x) / (pi*x);
-float EvalLanczos(int filter_size, float x) {
- if (x <= -filter_size || x >= filter_size)
- return 0.0f; // Outside of the window.
- if (x > -std::numeric_limits<float>::epsilon() &&
- x < std::numeric_limits<float>::epsilon())
- return 1.0f; // Special case the discontinuity at the origin.
- float xpi = x * static_cast<float>(M_PI);
- return (sin(xpi) / xpi) * // sinc(x)
- sin(xpi / filter_size) / (xpi / filter_size); // sinc(x/filter_size)
-}
-
-// ResizeFilter ----------------------------------------------------------------
-
-// Encapsulates computation and storage of the filters required for one complete
-// resize operation.
-class ResizeFilter {
- public:
- ResizeFilter(ImageOperations::ResizeMethod method,
- const Size& src_full_size,
- const Size& dest_size,
- const Rect& dest_subset);
-
- // Returns the bounds in the input bitmap of data that is used in the output.
- // The filter offsets are within this rectangle.
- const Rect& src_depend() { return src_depend_; }
-
- // Returns the filled filter values.
- const ConvolusionFilter1D& x_filter() { return x_filter_; }
- const ConvolusionFilter1D& y_filter() { return y_filter_; }
-
- private:
- // Returns the number of pixels that the filer spans, in filter space (the
- // destination image).
- float GetFilterSupport(float scale) {
- switch (method_) {
- case ImageOperations::RESIZE_BOX:
- // The box filter just scales with the image scaling.
- return 0.5f; // Only want one side of the filter = /2.
- case ImageOperations::RESIZE_LANCZOS3:
- // The lanczos filter takes as much space in the source image in
- // each direction as the size of the window = 3 for Lanczos3.
- return 3.0f;
- default:
- NOTREACHED();
- return 1.0f;
- }
- }
-
- // Computes one set of filters either horizontally or vertically. The caller
- // will specify the "min" and "max" rather than the bottom/top and
- // right/bottom so that the same code can be re-used in each dimension.
- //
- // |src_depend_lo| and |src_depend_size| gives the range for the source
- // depend rectangle (horizontally or vertically at the caller's discretion
- // -- see above for what this means).
- //
- // Likewise, the range of destination values to compute and the scale factor
- // for the transform is also specified.
- void ComputeFilters(int src_size,
- int dest_subset_lo, int dest_subset_size,
- float scale, float src_support,
- ConvolusionFilter1D* output);
-
- // Computes the filter value given the coordinate in filter space.
- inline float ComputeFilter(float pos) {
- switch (method_) {
- case ImageOperations::RESIZE_BOX:
- return EvalBox(pos);
- case ImageOperations::RESIZE_LANCZOS3:
- return EvalLanczos(2, pos);
- default:
- NOTREACHED();
- return 0;
- }
- }
-
- ImageOperations::ResizeMethod method_;
-
- // Subset of source the filters will touch.
- Rect src_depend_;
-
- // Size of the filter support on one side only in the destination space.
- // See GetFilterSupport.
- float x_filter_support_;
- float y_filter_support_;
-
- // Subset of scaled destination bitmap to compute.
- Rect out_bounds_;
-
- ConvolusionFilter1D x_filter_;
- ConvolusionFilter1D y_filter_;
-
- DISALLOW_EVIL_CONSTRUCTORS(ResizeFilter);
-};
-
-ResizeFilter::ResizeFilter(ImageOperations::ResizeMethod method,
- const Size& src_full_size,
- const Size& dest_size,
- const Rect& dest_subset)
- : method_(method),
- out_bounds_(dest_subset) {
- float scale_x = static_cast<float>(dest_size.width()) /
- static_cast<float>(src_full_size.width());
- float scale_y = static_cast<float>(dest_size.height()) /
- static_cast<float>(src_full_size.height());
-
- x_filter_support_ = GetFilterSupport(scale_x);
- y_filter_support_ = GetFilterSupport(scale_y);
-
- gfx::Rect src_full(0, 0, src_full_size.width(), src_full_size.height());
- gfx::Rect dest_full(0, 0,
- static_cast<int>(src_full_size.width() * scale_x + 0.5),
- static_cast<int>(src_full_size.height() * scale_y + 0.5));
-
- // Support of the filter in source space.
- float src_x_support = x_filter_support_ / scale_x;
- float src_y_support = y_filter_support_ / scale_y;
-
- ComputeFilters(src_full_size.width(), dest_subset.x(), dest_subset.width(),
- scale_x, src_x_support, &x_filter_);
- ComputeFilters(src_full_size.height(), dest_subset.y(), dest_subset.height(),
- scale_y, src_y_support, &y_filter_);
-}
-
-void ResizeFilter::ComputeFilters(int src_size,
- int dest_subset_lo, int dest_subset_size,
- float scale, float src_support,
- ConvolusionFilter1D* output) {
- int dest_subset_hi = dest_subset_lo + dest_subset_size; // [lo, hi)
-
- // When we're doing a magnification, the scale will be larger than one. This
- // means the destination pixels are much smaller than the source pixels, and
- // that the range covered by the filter won't necessarily cover any source
- // pixel boundaries. Therefore, we use these clamped values (max of 1) for
- // some computations.
- float clamped_scale = std::min(1.0f, scale);
-
- // Speed up the divisions below by turning them into multiplies.
- float inv_scale = 1.0f / scale;
-
- StackVector<float, 64> filter_values;
- StackVector<int16, 64> fixed_filter_values;
-
- // Loop over all pixels in the output range. We will generate one set of
- // filter values for each one. Those values will tell us how to blend the
- // source pixels to compute the destination pixel.
- for (int dest_subset_i = dest_subset_lo; dest_subset_i < dest_subset_hi;
- dest_subset_i++) {
- // Reset the arrays. We don't declare them inside so they can re-use the
- // same malloc-ed buffer.
- filter_values->clear();
- fixed_filter_values->clear();
-
- // This is the pixel in the source directly under the pixel in the dest.
- float src_pixel = dest_subset_i * inv_scale;
-
- // Compute the (inclusive) range of source pixels the filter covers.
- int src_begin = std::max(0, FloorInt(src_pixel - src_support));
- int src_end = std::min(src_size - 1, CeilInt(src_pixel + src_support));
-
- // Compute the unnormalized filter value at each location of the source
- // it covers.
- float filter_sum = 0.0f; // Sub of the filter values for normalizing.
- for (int cur_filter_pixel = src_begin; cur_filter_pixel <= src_end;
- cur_filter_pixel++) {
- // Distance from the center of the filter, this is the filter coordinate
- // in source space.
- float src_filter_pos = cur_filter_pixel - src_pixel;
-
- // Since the filter really exists in dest space, map it there.
- float dest_filter_pos = src_filter_pos * clamped_scale;
-
- // Compute the filter value at that location.
- float filter_value = ComputeFilter(dest_filter_pos);
- filter_values->push_back(filter_value);
-
- filter_sum += filter_value;
- }
- DCHECK(!filter_values->empty()) << "We should always get a filter!";
-
- // The filter must be normalized so that we don't affect the brightness of
- // the image. Convert to normalized fixed point.
- int16 fixed_sum = 0;
- for (size_t i = 0; i < filter_values->size(); i++) {
- int16 cur_fixed = output->FloatToFixed(filter_values[i] / filter_sum);
- fixed_sum += cur_fixed;
- fixed_filter_values->push_back(cur_fixed);
- }
-
- // The conversion to fixed point will leave some rounding errors, which
- // we add back in to avoid affecting the brightness of the image. We
- // arbitrarily add this to the center of the filter array (this won't always
- // be the center of the filter function since it could get clipped on the
- // edges, but it doesn't matter enough to worry about that case).
- int16 leftovers = output->FloatToFixed(1.0f) - fixed_sum;
- fixed_filter_values[fixed_filter_values->size() / 2] += leftovers;
-
- // Now it's ready to go.
- output->AddFilter(src_begin, &fixed_filter_values[0],
- static_cast<int>(fixed_filter_values->size()));
- }
-}
-
-} // namespace
-
-// Resize ----------------------------------------------------------------------
-
-// static
-SkBitmap ImageOperations::Resize(const SkBitmap& source,
- ResizeMethod method,
- const Size& dest_size,
- const Rect& dest_subset) {
- DCHECK(Rect(dest_size.width(), dest_size.height()).Contains(dest_subset)) <<
- "The supplied subset does not fall within the destination image.";
-
- // If the size of source or destination is 0, i.e. 0x0, 0xN or Nx0, just
- // return empty
- if (source.width() < 1 || source.height() < 1 ||
- dest_size.width() < 1 || dest_size.height() < 1)
- return SkBitmap();
-
- SkAutoLockPixels locker(source);
-
- ResizeFilter filter(method, Size(source.width(), source.height()),
- dest_size, dest_subset);
-
- // Get a source bitmap encompassing this touched area. We construct the
- // offsets and row strides such that it looks like a new bitmap, while
- // referring to the old data.
- const uint8* source_subset =
- reinterpret_cast<const uint8*>(source.getPixels());
-
- // Convolve into the result.
- SkBitmap result;
- result.setConfig(SkBitmap::kARGB_8888_Config,
- dest_subset.width(), dest_subset.height());
- result.allocPixels();
- BGRAConvolve2D(source_subset, static_cast<int>(source.rowBytes()),
- !source.isOpaque(), filter.x_filter(), filter.y_filter(),
- static_cast<unsigned char*>(result.getPixels()));
-
- // Preserve the "opaque" flag for use as an optimization later.
- result.setIsOpaque(source.isOpaque());
-
- return result;
-}
-
-// static
-SkBitmap ImageOperations::Resize(const SkBitmap& source,
- ResizeMethod method,
- const Size& dest_size) {
- Rect dest_subset(0, 0, dest_size.width(), dest_size.height());
- return Resize(source, method, dest_size, dest_subset);
-}
-
-// static
-SkBitmap ImageOperations::CreateBlendedBitmap(const SkBitmap& first,
- const SkBitmap& second,
- double alpha) {
- DCHECK(alpha <= 1 && alpha >= 0);
- DCHECK(first.width() == second.width());
- DCHECK(first.height() == second.height());
- DCHECK(first.bytesPerPixel() == second.bytesPerPixel());
- DCHECK(first.config() == SkBitmap::kARGB_8888_Config);
-
- // Optimize for case where we won't need to blend anything.
- static const double alpha_min = 1.0 / 255;
- static const double alpha_max = 254.0 / 255;
- if (alpha < alpha_min) {
- return first;
- } else if (alpha > alpha_max) {
- return second;
- }
-
- SkAutoLockPixels lock_first(first);
- SkAutoLockPixels lock_second(second);
-
- SkBitmap blended;
- blended.setConfig(SkBitmap::kARGB_8888_Config, first.width(),
- first.height(), 0);
- blended.allocPixels();
- blended.eraseARGB(0, 0, 0, 0);
-
- double first_alpha = 1 - alpha;
-
- for (int y = 0; y < first.height(); y++) {
- uint32* first_row = first.getAddr32(0, y);
- uint32* second_row = second.getAddr32(0, y);
- uint32* dst_row = blended.getAddr32(0, y);
-
- for (int x = 0; x < first.width(); x++) {
- uint32 first_pixel = first_row[x];
- uint32 second_pixel = second_row[x];
-
- int a = static_cast<int>(
- SkColorGetA(first_pixel) * first_alpha +
- SkColorGetA(second_pixel) * alpha);
- int r = static_cast<int>(
- SkColorGetR(first_pixel) * first_alpha +
- SkColorGetR(second_pixel) * alpha);
- int g = static_cast<int>(
- SkColorGetG(first_pixel) * first_alpha +
- SkColorGetG(second_pixel) * alpha);
- int b = static_cast<int>(
- SkColorGetB(first_pixel) * first_alpha +
- SkColorGetB(second_pixel) * alpha);
-
- dst_row[x] = SkColorSetARGB(a, r, g, b);
- }
- }
-
- return blended;
-}
-
-} // namespace skia
-