dec_external_image.h

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// Copyright (c) the JPEG XL Project 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 LIB_JXL_DEC_EXTERNAL_IMAGE_H_

#define LIB_JXL_DEC_EXTERNAL_IMAGE_H_

// Interleaved image for color transforms and Codec.

#include <jxl/types.h>

#include <stddef.h>

#include "lib/jxl/base/data_parallel.h"

#include "lib/jxl/base/status.h"

#include "lib/jxl/dec_cache.h"

#include "lib/jxl/image.h"

#include "lib/jxl/image_bundle.h"

#include "lib/jxl/image_metadata.h"

namespace jxl {

// Maximum number of channels for the ConvertChannelsToExternal function.

const size_t kConvertMaxChannels = 4;

// Converts a list of channels to an interleaved image, applying transformations

// when needed.

// The input channels are given as a (non-const!) array of channel pointers and

// interleaved in that order.

//

// Note: if a pointer in channels[] is nullptr, a 1.0 value will be used

// instead. This is useful for handling when a user requests an alpha channel

// from an image that doesn't have one. The first channel in the list may not

// be nullptr, since it is used to determine the image size.

Status ConvertChannelsToExternal(const ImageF* in_channels[],

                                 size_t num_channels, size_t bits_per_sample,

                                 bool float_out, JxlEndianness endianness,

                                 size_t stride, jxl::ThreadPool* pool,

                                 void* out_image, size_t out_size,

                                 const PixelCallback& out_callback,

                                 jxl::Orientation undo_orientation);

// Converts ib to interleaved void* pixel buffer with the given format.

// bits_per_sample: must be 16 or 32 if float_out is true, and at most 16

// if it is false. No bit packing is done.

// num_channels: must be 1, 2, 3 or 4 for gray, gray+alpha, RGB, RGB+alpha.

// This supports the features needed for the C API and does not perform

// color space conversion.

// TODO(lode): support rectangle crop.

// stride_out is output scanline size in bytes, must be >=

// output_xsize * output_bytes_per_pixel.

// undo_orientation is an EXIF orientation to undo. Depending on the

// orientation, the output xsize and ysize are swapped compared to input

// xsize and ysize.

Status ConvertToExternal(const jxl::ImageBundle& ib, size_t bits_per_sample,

                         bool float_out, size_t num_channels,

                         JxlEndianness endianness, size_t stride_out,

                         jxl::ThreadPool* thread_pool, void* out_image,

                         size_t out_size, const PixelCallback& out_callback,

                         jxl::Orientation undo_orientation,

                         bool unpremul_alpha = false);

}  // namespace jxl

#endif  // LIB_JXL_DEC_EXTERNAL_IMAGE_H_