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// Copyright (c) 2012 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.
#include "base/gtest_prod_util.h"
#include "ui/gfx/color_utils.h"
#include "ui/gfx/gfx_export.h"
#include "ui/gfx/shadow_value.h"
class SkBitmap;
class GFX_EXPORT SkBitmapOperations {
// Enum for use in rotating images (must be in 90 degree increments),
// see: Rotate.
enum RotationAmount {
// Create a bitmap that is an inverted image of the passed in image.
// Each color becomes its inverse in the color wheel. So (255, 15, 0) becomes
// (0, 240, 255). The alpha value is not inverted.
static SkBitmap CreateInvertedBitmap(const SkBitmap& image);
// Create a bitmap that is a blend of two others. The alpha argument
// specifies the opacity of the second bitmap. The provided bitmaps must
// use have the kARGB_8888_Config config and be of equal dimensions.
static SkBitmap CreateBlendedBitmap(const SkBitmap& first,
const SkBitmap& second,
double alpha);
// Create a bitmap that is the original bitmap masked out by the mask defined
// in the alpha bitmap. The images must use the kARGB_8888_Config config and
// be of equal dimensions.
static SkBitmap CreateMaskedBitmap(const SkBitmap& first,
const SkBitmap& alpha);
// We create a button background image by compositing the color and image
// together, then applying the mask. This is a highly specialized composite
// operation that is the equivalent of drawing a background in |color|,
// tiling |image| over the top, and then masking the result out with |mask|.
// The images must use kARGB_8888_Config config.
static SkBitmap CreateButtonBackground(SkColor color,
const SkBitmap& image,
const SkBitmap& mask);
// Shift a bitmap's HSL values. The shift values are in the range of 0-1,
// with the option to specify -1 for 'no change'. The shift values are
// defined as:
// hsl_shift[0] (hue): The absolute hue value for the image - 0 and 1 map
// to 0 and 360 on the hue color wheel (red).
// hsl_shift[1] (saturation): A saturation shift for the image, with the
// following key values:
// 0 = remove all color.
// 0.5 = leave unchanged.
// 1 = fully saturate the image.
// hsl_shift[2] (lightness): A lightness shift for the image, with the
// following key values:
// 0 = remove all lightness (make all pixels black).
// 0.5 = leave unchanged.
// 1 = full lightness (make all pixels white).
static SkBitmap CreateHSLShiftedBitmap(const SkBitmap& bitmap,
const color_utils::HSL& hsl_shift);
// Create a bitmap that is cropped from another bitmap. This is special
// because it tiles the original bitmap, so your coordinates can extend
// outside the bounds of the original image.
static SkBitmap CreateTiledBitmap(const SkBitmap& bitmap,
int src_x, int src_y,
int dst_w, int dst_h);
// Iteratively downsamples by 2 until the bitmap is no smaller than the
// input size. The normal use of this is to downsample the bitmap "close" to
// the final size, and then use traditional resampling on the result.
// Because the bitmap will be closer to the final size, it will be faster,
// and linear interpolation will generally work well as a second step.
static SkBitmap DownsampleByTwoUntilSize(const SkBitmap& bitmap,
int min_w, int min_h);
// Makes a bitmap half has large in each direction by averaging groups of
// 4 pixels. This is one step in generating a mipmap.
static SkBitmap DownsampleByTwo(const SkBitmap& bitmap);
// Unpremultiplies all pixels in |bitmap|. You almost never want to call
// this, as |SkBitmap|s are always premultiplied by conversion. Call this
// only if you will pass the bitmap's data into a system function that
// doesn't expect premultiplied colors.
static SkBitmap UnPreMultiply(const SkBitmap& bitmap);
// Transpose the pixels in |bitmap| by swapping x and y.
static SkBitmap CreateTransposedBitmap(const SkBitmap& bitmap);
// Create a bitmap by combining alpha channel of |bitmap| and color |c|.
// The image must use the kARGB_8888_Config config.
static SkBitmap CreateColorMask(const SkBitmap& bitmap, SkColor c);
// Create a bitmap with drop shadow added to |bitmap|. |shadows| defines
// the shadows to add. The created bitmap would be padded to have enough space
// for shadows and have original bitmap in the center. The image must use the
// kARGB_8888_Config config.
static SkBitmap CreateDropShadow(const SkBitmap& bitmap,
const gfx::ShadowValues& shadows);
// Rotates the given source bitmap clockwise by the requested amount.
static SkBitmap Rotate(const SkBitmap& source, RotationAmount rotation);
SkBitmapOperations(); // Class for scoping only.
FRIEND_TEST_ALL_PREFIXES(SkBitmapOperationsTest, DownsampleByTwo);
FRIEND_TEST_ALL_PREFIXES(SkBitmapOperationsTest, DownsampleByTwoSmall);