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cc / paint / skottie_frame_data_provider.h [blame]
// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_PAINT_SKOTTIE_FRAME_DATA_PROVIDER_H_
#define CC_PAINT_SKOTTIE_FRAME_DATA_PROVIDER_H_
#include <optional>
#include <string_view>
#include "base/files/file_path.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_refptr.h"
#include "cc/paint/paint_export.h"
#include "cc/paint/skottie_frame_data.h"
#include "ui/gfx/geometry/size.h"
namespace cc {
// A Chromium-specific version of the skresources::ResourceProvider API, which
// allows the code driving the animation to specify which image should be used
// for each asset in each frame of the animation. Callers rendering Skottie
// animations that may have images embedded in them must implement this API. In
// the most basic case where an image asset does not change throughout the
// course of the animation, the same image can be provided for every frame. But
// more complex logic such as providing a different image at the start of each
// animation cycle can be implemented if desired.
//
// Implementations are not required to be thread-safe (the provider and its
// ImageAssets shall always be invoked from the same sequence).
class CC_PAINT_EXPORT SkottieFrameDataProvider {
public:
class CC_PAINT_EXPORT ImageAsset : public base::RefCounted<ImageAsset> {
public:
// Returns the image to use for an asset in a frame of a skottie animation.
// May return a blank SkottieFrameData instance with an empty |image|.
// Skottie handles this gracefully and simply skips the image asset while
// still rendering the rest of the frame.
//
// |t|: See skresources::ImageAsset::getFrame(). Same semantics. Specifies
// the frame of interest in the animation that's about to be rendered.
// |scale_factor|: See |image_scale| in gfx::Canvas. Can be used to generate
// a PaintImage from a gfx::ImageSkia instance.
virtual SkottieFrameData GetFrameData(float t, float scale_factor) = 0;
protected:
virtual ~ImageAsset() = default;
private:
friend class base::RefCounted<ImageAsset>;
};
virtual ~SkottieFrameDataProvider() = default;
// Loads the image asset in the animation with the given |resource_id|, as it
// appears in the lottie json file. The ImageAsset instance that's returned
// for the given |resource_id| gets re-used for the lifetime of the animation;
// LoadImageAsset() is not called multiple times for the same |resource_id|.
// The returned value must never be null.
//
// |size| contains this asset's dimensions as specified in the Lottie
// animation file. Note that the ultimate image(s) returned by GetFrameData()
// are not required to have dimensions that match this |size|. It's provided
// here as a guide that implementations can optionally use to transform
// their images if desired. May be null if the asset didn't have dimensions
// specified in the Lottie file.
virtual scoped_refptr<ImageAsset> LoadImageAsset(
std::string_view resource_id,
const base::FilePath& resource_path,
const std::optional<gfx::Size>& size) = 0;
};
} // namespace cc
#endif // CC_PAINT_SKOTTIE_FRAME_DATA_PROVIDER_H_