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/*
* Copyright (C) 2017 Apple 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:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
*/
#pragma once
#include "IntSize.h"
#include <optional>
#include <variant>
#include <wtf/EnumTraits.h>
namespace WebCore {
enum class DecodingMode : uint8_t {
Auto,
Synchronous,
Asynchronous
};
class DecodingOptions {
public:
explicit DecodingOptions(DecodingMode decodingMode = DecodingMode::Auto)
: m_decodingModeOrSize(decodingMode)
{
}
DecodingOptions(const std::optional<IntSize>& sizeForDrawing)
: m_decodingModeOrSize(sizeForDrawing)
{
}
bool operator==(const DecodingOptions& other) const
{
return m_decodingModeOrSize == other.m_decodingModeOrSize;
}
bool isAuto() const
{
return hasDecodingMode() && std::get<DecodingMode>(m_decodingModeOrSize) == DecodingMode::Auto;
}
bool isSynchronous() const
{
return hasDecodingMode() && std::get<DecodingMode>(m_decodingModeOrSize) == DecodingMode::Synchronous;
}
bool isAsynchronous() const
{
return hasDecodingMode() && std::get<DecodingMode>(m_decodingModeOrSize) == DecodingMode::Asynchronous;
}
bool isAsynchronousCompatibleWith(const DecodingOptions& decodingOptions) const
{
if (isAuto() || decodingOptions.isAuto())
return false;
// Comparing DecodingOptions with isAsynchronous() should not happen.
ASSERT(!isAsynchronous());
if (isAsynchronous() || decodingOptions.isSynchronous())
return false;
// If the image was synchronously decoded, then it should fit any size.
// If we want an image regardless of its size, then the current decoded
// image should be fine.
if (isSynchronous() || decodingOptions.isAsynchronous())
return true;
ASSERT(decodingOptions.hasSize());
if (decodingOptions.hasFullSize())
return hasFullSize();
ASSERT(decodingOptions.hasSizeForDrawing());
if (hasFullSize())
return true;
ASSERT(hasSizeForDrawing());
return maxDimension(*sizeForDrawing()) >= maxDimension(*decodingOptions.sizeForDrawing());
}
bool hasFullSize() const
{
return hasSize() && !sizeForDrawing();
}
bool hasSizeForDrawing() const
{
return hasSize() && sizeForDrawing();
}
std::optional<IntSize> sizeForDrawing() const
{
ASSERT(hasSize());
return std::get<std::optional<IntSize>>(m_decodingModeOrSize);
}
static int maxDimension(const IntSize& size)
{
return std::max(size.width(), size.height());
}
private:
template<typename T>
bool has() const
{
return std::holds_alternative<T>(m_decodingModeOrSize);
}
bool hasDecodingMode() const
{
return has<DecodingMode>();
}
bool hasSize() const
{
return has<std::optional<IntSize>>();
}
// Four states of the decoding:
// - Synchronous: DecodingMode::Synchronous
// - Asynchronous + anySize: DecodingMode::Asynchronous
// - Asynchronous + intrinsicSize: an empty std::optional<IntSize>>
// - Asynchronous + sizeForDrawing: a none empty std::optional<IntSize>>
using DecodingModeOrSize = std::variant<DecodingMode, std::optional<IntSize>>;
DecodingModeOrSize m_decodingModeOrSize;
};
} // namespace WebCore
namespace WTF {
template<> struct EnumTraits<WebCore::DecodingMode> {
using values = EnumValues<
WebCore::DecodingMode,
WebCore::DecodingMode::Auto,
WebCore::DecodingMode::Synchronous,
WebCore::DecodingMode::Asynchronous
>;
};
} // namespace WTF
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