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// Copyright (c) 2009 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_IMAGE_OPERATIONS_H_
#define SKIA_EXT_IMAGE_OPERATIONS_H_
class SkBitmap;
struct SkIRect;
namespace skia {
class ImageOperations {
public:
enum ResizeMethod {
// Box filter. This is a weighted average of all of the pixels touching
// the destination pixel. For enlargement, this is nearest neighbor.
//
// You probably don't want this, it is here for testing since it is easy to
// compute. Use RESIZE_LANCZOS3 instead.
RESIZE_BOX,
// 3-cycle Lanczos filter. This is tall in the middle, goes negative on
// each side, then oscillates 2 more times. It gives nice sharp edges.
RESIZE_LANCZOS3,
// Lanczos filter + subpixel interpolation. If subpixel rendering is not
// appropriate we automatically fall back to Lanczos.
RESIZE_SUBPIXEL,
};
// Resizes the given source bitmap using the specified resize method, so that
// the entire image is (dest_size) big. The dest_subset is the rectangle in
// this destination image that should actually be returned.
//
// The output image will be (dest_subset.width(), dest_subset.height()). This
// will save work if you do not need the entire bitmap.
//
// The destination subset must be smaller than the destination image.
static SkBitmap Resize(const SkBitmap& source,
ResizeMethod method,
int dest_width, int dest_height,
const SkIRect& dest_subset);
// Alternate version for resizing and returning the entire bitmap rather than
// a subset.
static SkBitmap Resize(const SkBitmap& source,
ResizeMethod method,
int dest_width, int dest_height);
private:
ImageOperations(); // Class for scoping only.
// Supports all methods except RESIZE_SUBPIXEL.
static SkBitmap ResizeBasic(const SkBitmap& source,
ResizeMethod method,
int dest_width, int dest_height,
const SkIRect& dest_subset);
// Subpixel renderer.
static SkBitmap ResizeSubpixel(const SkBitmap& source,
int dest_width, int dest_height,
const SkIRect& dest_subset);
};
} // namespace skia
#endif // SKIA_EXT_IMAGE_OPERATIONS_H_
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