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/*
* Copyright (c) 2006,2007,2008, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// All of the functions in this file should move to new homes and this file
// should be deleted.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_SKIA_SKIA_UTILS_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_SKIA_SKIA_UTILS_H_
#include <utility>
#include "base/check_op.h"
#include "components/viz/common/resources/shared_image_format.h"
#include "third_party/blink/renderer/platform/graphics/graphics_context_types.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/cross_thread_copier.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "third_party/skia/include/core/SkColorType.h"
#include "third_party/skia/include/core/SkData.h"
#include "third_party/skia/include/core/SkRefCnt.h"
#include "third_party/skia/include/core/SkScalar.h"
namespace blink {
/**** constants ****/
enum {
// Firefox limits width/height to 32767 pixels, but slows down dramatically
// before it reaches that limit. We limit by area instead, giving us larger
// maximum dimensions, in exchange for a smaller maximum canvas size.
kMaxCanvasArea = 32768 * 8192, // Maximum canvas area in CSS pixels
// In Skia, we will also limit width/height to 65535.
kMaxSkiaDim = 65535 // Maximum width/height in CSS pixels.
};
bool PLATFORM_EXPORT IsValidImageSize(const gfx::Size&);
// Multiply a color's alpha channel by an additional alpha factor where
// alpha is in the range [0, 1].
SkColor PLATFORM_EXPORT ScaleAlpha(SkColor, float);
bool PLATFORM_EXPORT
ApproximatelyEqualSkColorSpaces(sk_sp<SkColorSpace> src_color_space,
sk_sp<SkColorSpace> dst_color_space);
// Temporary utility while converting canvas code to use gfx::ColorSpace.
// TODO(crbug.com/371227617): Remove this once conversion is complete.
inline gfx::ColorSpace SkColorSpaceToGfxColorSpace(
sk_sp<SkColorSpace> sk_color_space) {
return sk_color_space ? gfx::ColorSpace(*sk_color_space)
: gfx::ColorSpace::CreateSRGB();
}
// Temporary utility while converting canvas code to use SharedImageFormat.
// TODO(crbug.com/391903236): Determine best long-term plan once canvas code is
// completely converted to SharedImageFormat (i.e., crbug.com/371227617 is
// resolved).
inline viz::SharedImageFormat GetN32FormatForCanvas() {
return viz::SharedImageFormat::N32Format();
}
bool NearlyIntegral(float value);
InterpolationQuality ComputeInterpolationQuality(float src_width,
float src_height,
float dest_width,
float dest_height,
bool is_data_complete = true);
// Technically, this is driven by the CSS/Canvas2D specs and unrelated to Skia.
// It should probably live in the CSS layer, but the notion of a "blur radius"
// leaks into platform/graphics currently (ideally we should only deal with
// sigma at this level).
// TODO(fmalita): find a better home for this helper.
inline float BlurRadiusToStdDev(float radius) {
DCHECK_GE(radius, 0);
// Per spec, sigma is exactly half the blur radius:
// https://www.w3.org/TR/css-backgrounds-3/#shadow-blur
// https://html.spec.whatwg.org/C/#when-shadows-are-drawn
return radius * 0.5f;
}
// Attempts to allocate an SkData on the PartitionAlloc buffer partition.
// If this fails (e.g. due to low memory), returns a null sk_sp<SkData> instead.
// Otherwise, the returned buffer is guaranteed to be zero-filled.
PLATFORM_EXPORT sk_sp<SkData> TryAllocateSkData(size_t size);
// Skia's smart pointer APIs are preferable over their legacy raw pointer
// counterparts.
//
// General guidelines
//
// When receiving ref counted objects from Skia:
//
// 1) Use sk_sp-based Skia factories if available (e.g. SkShader::MakeFoo()
// instead of SkShader::CreateFoo()).
// 2) Use sk_sp<T> locals for all objects.
//
// When passing ref counted objects to Skia:
//
// 1) Use sk_sp-based Skia APIs when available (e.g.
// SkPaint::setShader(sk_sp<SkShader>) instead of
// SkPaint::setShader(SkShader*)).
// 2) If object ownership is being passed to Skia, use std::move(sk_sp<T>).
//
// Example (creating a SkShader and setting it on SkPaint):
//
// a) ownership transferred
//
// // using Skia smart pointer locals
// sk_sp<SkShader> shader = SkShader::MakeFoo(...);
// paint.setShader(std::move(shader));
//
// // using no locals
// paint.setShader(SkShader::MakeFoo(...));
//
// b) shared ownership
//
// sk_sp<SkShader> shader = SkShader::MakeFoo(...);
// paint.setShader(shader);
} // namespace blink
namespace WTF {
// We define CrossThreadCopier<SKBitMap> here because we cannot include skia
// headers in platform/wtf.
template <>
struct CrossThreadCopier<SkBitmap> {
STATIC_ONLY(CrossThreadCopier);
using Type = SkBitmap;
static SkBitmap Copy(const SkBitmap& bitmap) {
CHECK(bitmap.isImmutable() || bitmap.isNull())
<< "Only immutable bitmaps can be transferred.";
return bitmap;
}
static SkBitmap Copy(SkBitmap&& bitmap) {
CHECK(bitmap.isImmutable() || bitmap.isNull())
<< "Only immutable bitmaps can be transferred.";
return std::move(bitmap);
}
};
} // namespace WTF
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_SKIA_SKIA_UTILS_H_
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