SkExif.h

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/*
 * Copyright 2023 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#ifndef SkExif_DEFINED
#define SkExif_DEFINED
 
#include "include/codec/SkEncodedOrigin.h"
#include "include/private/base/SkAPI.h"
 
#include <cstdint>
#include <optional>
 
class SkData;
 
namespace SkExif {
 
// Tag values that are parsed by Parse and stored in Metadata.
static constexpr uint16_t kOriginTag = 0x112;
static constexpr uint16_t kResolutionUnitTag = 0x0128;
static constexpr uint16_t kXResolutionTag = 0x011a;
static constexpr uint16_t kYResolutionTag = 0x011b;
static constexpr uint16_t kPixelXDimensionTag = 0xa002;
static constexpr uint16_t kPixelYDimensionTag = 0xa003;
 
struct Metadata {
    // The image orientation.
    std::optional<SkEncodedOrigin> fOrigin;
 
    // The HDR headroom property.
    // https://developer.apple.com/documentation/appkit/images_and_pdf/applying_apple_hdr_effect_to_your_photos
    std::optional<float> fHdrHeadroom;
 
    // Resolution.
    std::optional<uint16_t> fResolutionUnit;
    std::optional<float> fXResolution;
    std::optional<float> fYResolution;
 
    // Size in pixels.
    std::optional<uint32_t> fPixelXDimension;
    std::optional<uint32_t> fPixelYDimension;
};
 
/*
 * Parse the metadata specified in |data| and write them to |metadata|. Stop only at an
 * unrecoverable error (allow truncated input).
 */
void SK_API Parse(Metadata& metadata, const SkData* data);
 
}  // namespace SkExif
 
#endif