/* 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. */ /** @addtogroup libjxl_decoder * @{ * @file decode.h * @brief Decoding API for JPEG XL. */ #ifndef JXL_DECODE_H_ #define JXL_DECODE_H_ #include #include #include #include #include #include #include #include // TODO(eustas): remove before v1.0 #include #include #ifdef __cplusplus extern "C" { #endif /** * Decoder library version. * * @return the decoder library version as an integer: * MAJOR_VERSION * 1000000 + MINOR_VERSION * 1000 + PATCH_VERSION. For example, * version 1.2.3 would return 1002003. */ JXL_EXPORT uint32_t JxlDecoderVersion(void); /** The result of @ref JxlSignatureCheck. */ typedef enum { /** Not enough bytes were passed to determine if a valid signature was found. */ JXL_SIG_NOT_ENOUGH_BYTES = 0, /** No valid JPEG XL header was found. */ JXL_SIG_INVALID = 1, /** A valid JPEG XL codestream signature was found, that is a JPEG XL image * without container. */ JXL_SIG_CODESTREAM = 2, /** A valid container signature was found, that is a JPEG XL image embedded * in a box format container. */ JXL_SIG_CONTAINER = 3, } JxlSignature; /** * JPEG XL signature identification. * * Checks if the passed buffer contains a valid JPEG XL signature. The passed @p * buf of size * @p size doesn't need to be a full image, only the beginning of the file. * * @return a flag indicating if a JPEG XL signature was found and what type. * - ::JXL_SIG_NOT_ENOUGH_BYTES if not enough bytes were passed to * determine if a valid signature is there. * - ::JXL_SIG_INVALID if no valid signature found for JPEG XL decoding. * - ::JXL_SIG_CODESTREAM if a valid JPEG XL codestream signature was * found. * - ::JXL_SIG_CONTAINER if a valid JPEG XL container signature was found. */ JXL_EXPORT JxlSignature JxlSignatureCheck(const uint8_t* buf, size_t len); /** * Opaque structure that holds the JPEG XL decoder. * * Allocated and initialized with @ref JxlDecoderCreate(). * Cleaned up and deallocated with @ref JxlDecoderDestroy(). */ typedef struct JxlDecoderStruct JxlDecoder; /** * Creates an instance of @ref JxlDecoder and initializes it. * * @p memory_manager will be used for all the library dynamic allocations made * from this instance. The parameter may be NULL, in which case the default * allocator will be used. See jxl/memory_manager.h for details. * * @param memory_manager custom allocator function. It may be NULL. The memory * manager will be copied internally. * @return @c NULL if the instance can not be allocated or initialized * @return pointer to initialized @ref JxlDecoder otherwise */ JXL_EXPORT JxlDecoder* JxlDecoderCreate(const JxlMemoryManager* memory_manager); /** * Re-initializes a @ref JxlDecoder instance, so it can be re-used for decoding * another image. All state and settings are reset as if the object was * newly created with @ref JxlDecoderCreate, but the memory manager is kept. * * @param dec instance to be re-initialized. */ JXL_EXPORT void JxlDecoderReset(JxlDecoder* dec); /** * Deinitializes and frees @ref JxlDecoder instance. * * @param dec instance to be cleaned up and deallocated. */ JXL_EXPORT void JxlDecoderDestroy(JxlDecoder* dec); /** * Return value for @ref JxlDecoderProcessInput. * The values from ::JXL_DEC_BASIC_INFO onwards are optional informative * events that can be subscribed to, they are never returned if they * have not been registered with @ref JxlDecoderSubscribeEvents. */ typedef enum { /** Function call finished successfully, or decoding is finished and there is * nothing more to be done. * * Note that @ref JxlDecoderProcessInput will return ::JXL_DEC_SUCCESS if * all events that were registered with @ref JxlDecoderSubscribeEvents were * processed, even before the end of the JPEG XL codestream. * * In this case, the return value @ref JxlDecoderReleaseInput will be the same * as it was at the last signaled event. E.g. if ::JXL_DEC_FULL_IMAGE was * subscribed to, then all bytes from the end of the JPEG XL codestream * (including possible boxes needed for jpeg reconstruction) will be returned * as unprocessed. */ JXL_DEC_SUCCESS = 0, /** An error occurred, for example invalid input file or out of memory. * TODO(lode): add function to get error information from decoder. */ JXL_DEC_ERROR = 1, /** The decoder needs more input bytes to continue. Before the next @ref * JxlDecoderProcessInput call, more input data must be set, by calling @ref * JxlDecoderReleaseInput (if input was set previously) and then calling @ref * JxlDecoderSetInput. @ref JxlDecoderReleaseInput returns how many bytes * are not yet processed, before a next call to @ref JxlDecoderProcessInput * all unprocessed bytes must be provided again (the address need not match, * but the contents must), and more bytes must be concatenated after the * unprocessed bytes. * In most cases, @ref JxlDecoderReleaseInput will return no unprocessed bytes * at this event, the only exceptions are if the previously set input ended * within (a) the raw codestream signature, (b) the signature box, (c) a box * header, or (d) the first 4 bytes of a `brob`, `ftyp`, or `jxlp` box. In any * of these cases the number of unprocessed bytes is less than 20. */ JXL_DEC_NEED_MORE_INPUT = 2, /** The decoder is able to decode a preview image and requests setting a * preview output buffer using @ref JxlDecoderSetPreviewOutBuffer. This occurs * if ::JXL_DEC_PREVIEW_IMAGE is requested and it is possible to decode a * preview image from the codestream and the preview out buffer was not yet * set. There is maximum one preview image in a codestream. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the frame header (including ToC) of the preview frame as * unprocessed. */ JXL_DEC_NEED_PREVIEW_OUT_BUFFER = 3, /** The decoder requests an output buffer to store the full resolution image, * which can be set with @ref JxlDecoderSetImageOutBuffer or with @ref * JxlDecoderSetImageOutCallback. This event re-occurs for new frames if * there are multiple animation frames and requires setting an output again. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the frame header (including ToC) as unprocessed. */ JXL_DEC_NEED_IMAGE_OUT_BUFFER = 5, /** The JPEG reconstruction buffer is too small for reconstructed JPEG * codestream to fit. @ref JxlDecoderSetJPEGBuffer must be called again to * make room for remaining bytes. This event may occur multiple times * after ::JXL_DEC_JPEG_RECONSTRUCTION. */ JXL_DEC_JPEG_NEED_MORE_OUTPUT = 6, /** The box contents output buffer is too small. @ref JxlDecoderSetBoxBuffer * must be called again to make room for remaining bytes. This event may occur * multiple times after ::JXL_DEC_BOX. */ JXL_DEC_BOX_NEED_MORE_OUTPUT = 7, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": Basic information such as image dimensions and * extra channels. This event occurs max once per image. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the basic info as unprocessed (including the last byte of basic info * if it did not end on a byte boundary). */ JXL_DEC_BASIC_INFO = 0x40, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": Color encoding or ICC profile from the * codestream header. This event occurs max once per image and always later * than ::JXL_DEC_BASIC_INFO and earlier than any pixel data. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the image header (which is the start of the first frame) as * unprocessed. */ JXL_DEC_COLOR_ENCODING = 0x100, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": Preview image, a small frame, decoded. This * event can only happen if the image has a preview frame encoded. This event * occurs max once for the codestream and always later than @ref * JXL_DEC_COLOR_ENCODING and before ::JXL_DEC_FRAME. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the preview frame as unprocessed. */ JXL_DEC_PREVIEW_IMAGE = 0x200, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": Beginning of a frame. @ref * JxlDecoderGetFrameHeader can be used at this point. A note on frames: * a JPEG XL image can have internal frames that are not intended to be * displayed (e.g. used for compositing a final frame), but this only returns * displayed frames, unless @ref JxlDecoderSetCoalescing was set to @ref * JXL_FALSE "JXL_FALSE": in that case, the individual layers are returned, * without blending. Note that even when coalescing is disabled, only frames * of type kRegularFrame are returned; frames of type kReferenceOnly * and kLfFrame are always for internal purposes only and cannot be accessed. * A displayed frame either has an animation duration or is the only or last * frame in the image. This event occurs max once per displayed frame, always * later than ::JXL_DEC_COLOR_ENCODING, and always earlier than any pixel * data. While JPEG XL supports encoding a single frame as the composition of * multiple internal sub-frames also called frames, this event is not * indicated for the internal frames. In this case, @ref * JxlDecoderReleaseInput will return all bytes from the end of the frame * header (including ToC) as unprocessed. */ JXL_DEC_FRAME = 0x400, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": full frame (or layer, in case coalescing is * disabled) is decoded. @ref JxlDecoderSetImageOutBuffer must be used after * getting the basic image information to be able to get the image pixels, if * not this return status only indicates we're past this point in the * codestream. This event occurs max once per frame. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the frame (or if ::JXL_DEC_JPEG_RECONSTRUCTION is subscribed to, * from the end of the last box that is needed for jpeg reconstruction) as * unprocessed. */ JXL_DEC_FULL_IMAGE = 0x1000, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": JPEG reconstruction data decoded. @ref * JxlDecoderSetJPEGBuffer may be used to set a JPEG reconstruction buffer * after getting the JPEG reconstruction data. If a JPEG reconstruction buffer * is set a byte stream identical to the JPEG codestream used to encode the * image will be written to the JPEG reconstruction buffer instead of pixels * to the image out buffer. This event occurs max once per image and always * before ::JXL_DEC_FULL_IMAGE. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the `jbrd` box as unprocessed. */ JXL_DEC_JPEG_RECONSTRUCTION = 0x2000, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": The header of a box of the container format * (BMFF) is decoded. The following API functions related to boxes can be used * after this event: * - @ref JxlDecoderSetBoxBuffer and @ref JxlDecoderReleaseBoxBuffer * "JxlDecoderReleaseBoxBuffer": set and release a buffer to get the box * data. * - @ref JxlDecoderGetBoxType get the 4-character box typename. * - @ref JxlDecoderGetBoxSizeRaw get the size of the box as it appears in * the container file, not decompressed. * - @ref JxlDecoderSetDecompressBoxes to configure whether to get the box * data decompressed, or possibly compressed. * * Boxes can be compressed. This is so when their box type is * "brob". In that case, they have an underlying decompressed box * type and decompressed data. @ref JxlDecoderSetDecompressBoxes allows * configuring which data to get. Decompressing requires * Brotli. @ref JxlDecoderGetBoxType has a flag to get the compressed box * type, which can be "brob", or the decompressed box type. If a box * is not compressed (its compressed type is not "brob"), then * the output decompressed box type and data is independent of what * setting is configured. * * The buffer set with @ref JxlDecoderSetBoxBuffer must be set again for each * next box to be obtained, or can be left unset to skip outputting this box. * The output buffer contains the full box data when the * ::JXL_DEC_BOX_COMPLETE (if subscribed to) or subsequent ::JXL_DEC_SUCCESS * or ::JXL_DEC_BOX event occurs. ::JXL_DEC_BOX occurs for all boxes, * including non-metadata boxes such as the signature box or codestream boxes. * To check whether the box is a metadata type for respectively EXIF, XMP or * JUMBF, use @ref JxlDecoderGetBoxType and check for types "Exif", "xml " and * "jumb" respectively. * * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * start of the box header as unprocessed. */ JXL_DEC_BOX = 0x4000, /** Informative event by @ref JxlDecoderProcessInput * "JxlDecoderProcessInput": a progressive step in decoding the frame is * reached. When calling @ref JxlDecoderFlushImage at this point, the flushed * image will correspond exactly to this point in decoding, and not yet * contain partial results (such as partially more fine detail) of a next * step. By default, this event will trigger maximum once per frame, when a * 8x8th resolution (DC) image is ready (the image data is still returned at * full resolution, giving upscaled DC). Use @ref * JxlDecoderSetProgressiveDetail to configure more fine-grainedness. The * event is not guaranteed to trigger, not all images have progressive steps * or DC encoded. * In this case, @ref JxlDecoderReleaseInput will return all bytes from the * end of the section that was needed to produce this progressive event as * unprocessed. */ JXL_DEC_FRAME_PROGRESSION = 0x8000, /** The box being decoded is now complete. This is only emitted if a buffer * was set for the box. */ JXL_DEC_BOX_COMPLETE = 0x10000, } JxlDecoderStatus; /** Types of progressive detail. * Setting a progressive detail with value N implies all progressive details * with smaller or equal value. Currently only the following level of * progressive detail is implemented: * - @ref kDC (which implies kFrames) * - @ref kLastPasses (which implies @ref kDC and @ref kFrames) * - @ref kPasses (which implies @ref kLastPasses, kDC and @ref kFrames) */ typedef enum { /** * after completed kRegularFrames */ kFrames = 0, /** * after completed DC (1:8) */ kDC = 1, /** * after completed AC passes that are the last pass for their resolution * target. */ kLastPasses = 2, /** * after completed AC passes that are not the last pass for their resolution * target. */ kPasses = 3, /** * during DC frame when lower resolution are completed (1:32, 1:16) */ kDCProgressive = 4, /** * after completed groups */ kDCGroups = 5, /** * after completed groups */ kGroups = 6, } JxlProgressiveDetail; /** Rewinds decoder to the beginning. The same input must be given again from * the beginning of the file and the decoder will emit events from the beginning * again. When rewinding (as opposed to @ref JxlDecoderReset), the decoder can * keep state about the image, which it can use to skip to a requested frame * more efficiently with @ref JxlDecoderSkipFrames. Settings such as parallel * runner or subscribed events are kept. After rewind, @ref * JxlDecoderSubscribeEvents can be used again, and it is feasible to leave out * events that were already handled before, such as ::JXL_DEC_BASIC_INFO * and ::JXL_DEC_COLOR_ENCODING, since they will provide the same information * as before. * The difference to @ref JxlDecoderReset is that some state is kept, namely * settings set by a call to * - @ref JxlDecoderSetCoalescing, * - @ref JxlDecoderSetDesiredIntensityTarget, * - @ref JxlDecoderSetDecompressBoxes, * - @ref JxlDecoderSetKeepOrientation, * - @ref JxlDecoderSetUnpremultiplyAlpha, * - @ref JxlDecoderSetParallelRunner, * - @ref JxlDecoderSetRenderSpotcolors, and * - @ref JxlDecoderSubscribeEvents. * * @param dec decoder object */ JXL_EXPORT void JxlDecoderRewind(JxlDecoder* dec); /** Makes the decoder skip the next `amount` frames. It still needs to process * the input, but will not output the frame events. It can be more efficient * when skipping frames, and even more so when using this after @ref * JxlDecoderRewind. If the decoder is already processing a frame (could * have emitted ::JXL_DEC_FRAME but not yet ::JXL_DEC_FULL_IMAGE), it * starts skipping from the next frame. If the amount is larger than the amount * of frames remaining in the image, all remaining frames are skipped. Calling * this function multiple times adds the amount to skip to the already existing * amount. * * A frame here is defined as a frame that without skipping emits events such * as ::JXL_DEC_FRAME and ::JXL_DEC_FULL_IMAGE, frames that are internal * to the file format but are not rendered as part of an animation, or are not * the final still frame of a still image, are not counted. * * @param dec decoder object * @param amount the amount of frames to skip */ JXL_EXPORT void JxlDecoderSkipFrames(JxlDecoder* dec, size_t amount); /** * Skips processing the current frame. Can be called after frame processing * already started, signaled by a ::JXL_DEC_NEED_IMAGE_OUT_BUFFER event, * but before the corresponding ::JXL_DEC_FULL_IMAGE event. The next signaled * event will be another ::JXL_DEC_FRAME, or ::JXL_DEC_SUCCESS if there * are no more frames. If pixel data is required from the already processed part * of the frame, @ref JxlDecoderFlushImage must be called before this. * * @param dec decoder object * @return ::JXL_DEC_SUCCESS if there is a frame to skip, and @ref * JXL_DEC_ERROR if the function was not called during frame processing. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSkipCurrentFrame(JxlDecoder* dec); /** * Set the parallel runner for multithreading. May only be set before starting * decoding. * * @param dec decoder object * @param parallel_runner function pointer to runner for multithreading. It may * be NULL to use the default, single-threaded, runner. A multithreaded * runner should be set to reach fast performance. * @param parallel_runner_opaque opaque pointer for parallel_runner. * @return ::JXL_DEC_SUCCESS if the runner was set, ::JXL_DEC_ERROR * otherwise (the previous runner remains set). */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetParallelRunner(JxlDecoder* dec, JxlParallelRunner parallel_runner, void* parallel_runner_opaque); /** * Returns a hint indicating how many more bytes the decoder is expected to * need to make @ref JxlDecoderGetBasicInfo available after the next @ref * JxlDecoderProcessInput call. This is a suggested large enough value for * the amount of bytes to provide in the next @ref JxlDecoderSetInput call, but * it is not guaranteed to be an upper bound nor a lower bound. This number does * not include bytes that have already been released from the input. Can be used * before the first @ref JxlDecoderProcessInput call, and is correct the first * time in most cases. If not, @ref JxlDecoderSizeHintBasicInfo can be called * again to get an updated hint. * * @param dec decoder object * @return the size hint in bytes if the basic info is not yet fully decoded. * @return 0 when the basic info is already available. */ JXL_EXPORT size_t JxlDecoderSizeHintBasicInfo(const JxlDecoder* dec); /** Select for which informative events, i.e. ::JXL_DEC_BASIC_INFO, etc., the * decoder should return with a status. It is not required to subscribe to any * events, data can still be requested from the decoder as soon as it available. * By default, the decoder is subscribed to no events (events_wanted == 0), and * the decoder will then only return when it cannot continue because it needs * more input data or more output buffer. This function may only be be called * before using @ref JxlDecoderProcessInput. * * @param dec decoder object * @param events_wanted bitfield of desired events. * @return ::JXL_DEC_SUCCESS if no error, ::JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSubscribeEvents(JxlDecoder* dec, int events_wanted); /** Enables or disables preserving of as-in-bitstream pixeldata * orientation. Some images are encoded with an Orientation tag * indicating that the decoder must perform a rotation and/or * mirroring to the encoded image data. * * - If skip_reorientation is ::JXL_FALSE (the default): the decoder * will apply the transformation from the orientation setting, hence * rendering the image according to its specified intent. When * producing a @ref JxlBasicInfo, the decoder will always set the * orientation field to JXL_ORIENT_IDENTITY (matching the returned * pixel data) and also align xsize and ysize so that they correspond * to the width and the height of the returned pixel data. * - If skip_reorientation is ::JXL_TRUE "JXL_TRUE": the decoder will skip * applying the transformation from the orientation setting, returning * the image in the as-in-bitstream pixeldata orientation. * This may be faster to decode since the decoder doesn't have to apply the * transformation, but can cause wrong display of the image if the * orientation tag is not correctly taken into account by the user. * * By default, this option is disabled, and the returned pixel data is * re-oriented according to the image's Orientation setting. * * This function must be called at the beginning, before decoding is performed. * * @see JxlBasicInfo for the orientation field, and @ref JxlOrientation for the * possible values. * * @param dec decoder object * @param skip_reorientation JXL_TRUE to enable, JXL_FALSE to disable. * @return ::JXL_DEC_SUCCESS if no error, ::JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetKeepOrientation(JxlDecoder* dec, JXL_BOOL skip_reorientation); /** * Enables or disables preserving of associated alpha channels. If * unpremul_alpha is set to ::JXL_FALSE then for associated alpha channel, * the pixel data is returned with premultiplied colors. If it is set to @ref * JXL_TRUE, The colors will be unpremultiplied based on the alpha channel. This * function has no effect if the image does not have an associated alpha * channel. * * By default, this option is disabled, and the returned pixel data "as is". * * This function must be called at the beginning, before decoding is performed. * * @param dec decoder object * @param unpremul_alpha JXL_TRUE to enable, JXL_FALSE to disable. * @return ::JXL_DEC_SUCCESS if no error, ::JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetUnpremultiplyAlpha(JxlDecoder* dec, JXL_BOOL unpremul_alpha); /** Enables or disables rendering spot colors. By default, spot colors * are rendered, which is OK for viewing the decoded image. If render_spotcolors * is ::JXL_FALSE, then spot colors are not rendered, and have to be * retrieved separately using @ref JxlDecoderSetExtraChannelBuffer. This is * useful for e.g. printing applications. * * @param dec decoder object * @param render_spotcolors JXL_TRUE to enable (default), JXL_FALSE to disable. * @return ::JXL_DEC_SUCCESS if no error, ::JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetRenderSpotcolors(JxlDecoder* dec, JXL_BOOL render_spotcolors); /** Enables or disables coalescing of zero-duration frames. By default, frames * are returned with coalescing enabled, i.e. all frames have the image * dimensions, and are blended if needed. When coalescing is disabled, frames * can have arbitrary dimensions, a non-zero crop offset, and blending is not * performed. For display, coalescing is recommended. For loading a multi-layer * still image as separate layers (as opposed to the merged image), coalescing * has to be disabled. * * @param dec decoder object * @param coalescing JXL_TRUE to enable coalescing (default), JXL_FALSE to * disable it. * @return ::JXL_DEC_SUCCESS if no error, ::JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetCoalescing(JxlDecoder* dec, JXL_BOOL coalescing); /** * Decodes JPEG XL file using the available bytes. Requires input has been * set with @ref JxlDecoderSetInput. After @ref JxlDecoderProcessInput, input * can optionally be released with @ref JxlDecoderReleaseInput and then set * again to next bytes in the stream. @ref JxlDecoderReleaseInput returns how * many bytes are not yet processed, before a next call to @ref * JxlDecoderProcessInput all unprocessed bytes must be provided again (the * address need not match, but the contents must), and more bytes may be * concatenated after the unprocessed bytes. * * The returned status indicates whether the decoder needs more input bytes, or * more output buffer for a certain type of output data. No matter what the * returned status is (other than ::JXL_DEC_ERROR), new information, such * as @ref JxlDecoderGetBasicInfo, may have become available after this call. * When the return value is not ::JXL_DEC_ERROR or ::JXL_DEC_SUCCESS, the * decoding requires more @ref JxlDecoderProcessInput calls to continue. * * @param dec decoder object * @return ::JXL_DEC_SUCCESS when decoding finished and all events handled. * If you still have more unprocessed input data anyway, then you can still * continue by using @ref JxlDecoderSetInput and calling @ref * JxlDecoderProcessInput again, similar to handling @ref * JXL_DEC_NEED_MORE_INPUT. ::JXL_DEC_SUCCESS can occur instead of @ref * JXL_DEC_NEED_MORE_INPUT when, for example, the input data ended right at * the boundary of a box of the container format, all essential codestream * boxes were already decoded, but extra metadata boxes are still present in * the next data. @ref JxlDecoderProcessInput cannot return success if all * codestream boxes have not been seen yet. * @return ::JXL_DEC_ERROR when decoding failed, e.g. invalid codestream. * TODO(lode): document the input data mechanism * @return ::JXL_DEC_NEED_MORE_INPUT when more input data is necessary. * @return ::JXL_DEC_BASIC_INFO when basic info such as image dimensions is * available and this informative event is subscribed to. * @return ::JXL_DEC_COLOR_ENCODING when color profile information is * available and this informative event is subscribed to. * @return ::JXL_DEC_PREVIEW_IMAGE when preview pixel information is * available and output in the preview buffer. * @return ::JXL_DEC_FULL_IMAGE when all pixel information at highest detail * is available and has been output in the pixel buffer. */ JXL_EXPORT JxlDecoderStatus JxlDecoderProcessInput(JxlDecoder* dec); /** * Sets input data for @ref JxlDecoderProcessInput. The data is owned by the * caller and may be used by the decoder until @ref JxlDecoderReleaseInput is * called or the decoder is destroyed or reset so must be kept alive until then. * Cannot be called if @ref JxlDecoderSetInput was already called and @ref * JxlDecoderReleaseInput was not yet called, and cannot be called after @ref * JxlDecoderCloseInput indicating the end of input was called. * * @param dec decoder object * @param data pointer to next bytes to read from * @param size amount of bytes available starting from data * @return ::JXL_DEC_ERROR if input was already set without releasing or @ref * JxlDecoderCloseInput was already called, ::JXL_DEC_SUCCESS otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetInput(JxlDecoder* dec, const uint8_t* data, size_t size); /** * Releases input which was provided with @ref JxlDecoderSetInput. Between @ref * JxlDecoderProcessInput and @ref JxlDecoderReleaseInput, the user may not * alter the data in the buffer. Calling @ref JxlDecoderReleaseInput is required * whenever any input is already set and new input needs to be added with @ref * JxlDecoderSetInput, but is not required before @ref JxlDecoderDestroy or @ref * JxlDecoderReset. Calling @ref JxlDecoderReleaseInput when no input is set is * not an error and returns `0`. * * @param dec decoder object * @return The amount of bytes the decoder has not yet processed that are still * remaining in the data set by @ref JxlDecoderSetInput, or `0` if no input * is set or @ref JxlDecoderReleaseInput was already called. For a next call to * @ref JxlDecoderProcessInput, the buffer must start with these unprocessed * bytes. From this value it is possible to infer the position of certain JPEG * XL codestream elements (e.g. end of headers, frame start/end). See the * documentation of individual values of @ref JxlDecoderStatus for more * information. */ JXL_EXPORT size_t JxlDecoderReleaseInput(JxlDecoder* dec); /** * Marks the input as finished, indicates that no more @ref JxlDecoderSetInput * will be called. This function allows the decoder to determine correctly if it * should return success, need more input or error in certain cases. For * backwards compatibility with a previous version of the API, using this * function is optional when not using the ::JXL_DEC_BOX event (the decoder * is able to determine the end of the image frames without marking the end), * but using this function is required when using ::JXL_DEC_BOX for getting * metadata box contents. This function does not replace @ref * JxlDecoderReleaseInput, that function should still be called if its return * value is needed. * * @ref JxlDecoderCloseInput should be called as soon as all known input bytes * are set (e.g. at the beginning when not streaming but setting all input * at once), before the final @ref JxlDecoderProcessInput calls. * * @param dec decoder object */ JXL_EXPORT void JxlDecoderCloseInput(JxlDecoder* dec); /** * Outputs the basic image information, such as image dimensions, bit depth and * all other JxlBasicInfo fields, if available. * * @param dec decoder object * @param info struct to copy the information into, or NULL to only check * whether the information is available through the return value. * @return ::JXL_DEC_SUCCESS if the value is available, @ref * JXL_DEC_NEED_MORE_INPUT if not yet available, ::JXL_DEC_ERROR * in case of other error conditions. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetBasicInfo(const JxlDecoder* dec, JxlBasicInfo* info); /** * Outputs information for extra channel at the given index. The index must be * smaller than num_extra_channels in the associated @ref JxlBasicInfo. * * @param dec decoder object * @param index index of the extra channel to query. * @param info struct to copy the information into, or NULL to only check * whether the information is available through the return value. * @return ::JXL_DEC_SUCCESS if the value is available, @ref * JXL_DEC_NEED_MORE_INPUT if not yet available, ::JXL_DEC_ERROR * in case of other error conditions. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetExtraChannelInfo( const JxlDecoder* dec, size_t index, JxlExtraChannelInfo* info); /** * Outputs name for extra channel at the given index in UTF-8. The index must be * smaller than `num_extra_channels` in the associated @ref JxlBasicInfo. The * buffer for name must have at least `name_length + 1` bytes allocated, gotten * from the associated @ref JxlExtraChannelInfo. * * @param dec decoder object * @param index index of the extra channel to query. * @param name buffer to copy the name into * @param size size of the name buffer in bytes * @return ::JXL_DEC_SUCCESS if the value is available, @ref * JXL_DEC_NEED_MORE_INPUT if not yet available, ::JXL_DEC_ERROR * in case of other error conditions. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetExtraChannelName(const JxlDecoder* dec, size_t index, char* name, size_t size); /** Defines which color profile to get: the profile from the codestream * metadata header, which represents the color profile of the original image, * or the color profile from the pixel data produced by the decoder. Both are * the same if the JxlBasicInfo has uses_original_profile set. */ typedef enum { /** Get the color profile of the original image from the metadata. */ JXL_COLOR_PROFILE_TARGET_ORIGINAL = 0, /** Get the color profile of the pixel data the decoder outputs. */ JXL_COLOR_PROFILE_TARGET_DATA = 1, } JxlColorProfileTarget; /** * Outputs the color profile as JPEG XL encoded structured data, if available. * This is an alternative to an ICC Profile, which can represent a more limited * amount of color spaces, but represents them exactly through enum values. * * It is often possible to use @ref JxlDecoderGetColorAsICCProfile as an * alternative anyway. The following scenarios are possible: * - The JPEG XL image has an attached ICC Profile, in that case, the encoded * structured data is not available and this function will return an error * status. @ref JxlDecoderGetColorAsICCProfile should be called instead. * - The JPEG XL image has an encoded structured color profile, and it * represents an RGB or grayscale color space. This function will return it. * You can still use @ref JxlDecoderGetColorAsICCProfile as well as an * alternative if desired, though depending on which RGB color space is * represented, the ICC profile may be a close approximation. It is also not * always feasible to deduce from an ICC profile which named color space it * exactly represents, if any, as it can represent any arbitrary space. * HDR color spaces such as those using PQ and HLG are also potentially * problematic, in that: while ICC profiles can encode a transfer function * that happens to approximate those of PQ and HLG (HLG for only one given * system gamma at a time, and necessitating a 3D LUT if gamma is to be * different from `1`), they cannot (before ICCv4.4) semantically signal that * this is the color space that they represent. Therefore, they will * typically not actually be interpreted as representing an HDR color space. * This is especially detrimental to PQ which will then be interpreted as if * the maximum signal value represented SDR white instead of 10000 cd/m^2, * meaning that the image will be displayed two orders of magnitude (5-7 EV) * too dim. * - The JPEG XL image has an encoded structured color profile, and it * indicates an unknown or xyb color space. In that case, @ref * JxlDecoderGetColorAsICCProfile is not available. * * When rendering an image on a system where ICC-based color management is used, * @ref JxlDecoderGetColorAsICCProfile should generally be used first as it will * return a ready-to-use profile (with the aforementioned caveat about HDR). * When knowledge about the nominal color space is desired if available, @ref * JxlDecoderGetColorAsEncodedProfile should be used first. * * @param dec decoder object * @param target whether to get the original color profile from the metadata * or the color profile of the decoded pixels. * @param color_encoding struct to copy the information into, or NULL to only * check whether the information is available through the return value. * @return ::JXL_DEC_SUCCESS if the data is available and returned, @ref * JXL_DEC_NEED_MORE_INPUT if not yet available, ::JXL_DEC_ERROR in * case the encoded structured color profile does not exist in the * codestream. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetColorAsEncodedProfile( const JxlDecoder* dec, JxlColorProfileTarget target, JxlColorEncoding* color_encoding); /** * Outputs the size in bytes of the ICC profile returned by @ref * JxlDecoderGetColorAsICCProfile, if available, or indicates there is none * available. In most cases, the image will have an ICC profile available, but * if it does not, @ref JxlDecoderGetColorAsEncodedProfile must be used instead. * * @see JxlDecoderGetColorAsEncodedProfile for more information. The ICC * profile is either the exact ICC profile attached to the codestream metadata, * or a close approximation generated from JPEG XL encoded structured data, * depending of what is encoded in the codestream. * * @param dec decoder object * @param target whether to get the original color profile from the metadata * or the color profile of the decoded pixels. * @param size variable to output the size into, or NULL to only check the * return status. * @return ::JXL_DEC_SUCCESS if the ICC profile is available, @ref * JXL_DEC_NEED_MORE_INPUT if the decoder has not yet received enough * input data to determine whether an ICC profile is available or what its * size is, ::JXL_DEC_ERROR in case the ICC profile is not available and * cannot be generated. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetICCProfileSize( const JxlDecoder* dec, JxlColorProfileTarget target, size_t* size); /** * Outputs ICC profile if available. The profile is only available if @ref * JxlDecoderGetICCProfileSize returns success. The output buffer must have * at least as many bytes as given by @ref JxlDecoderGetICCProfileSize. * * @param dec decoder object * @param target whether to get the original color profile from the metadata * or the color profile of the decoded pixels. * @param icc_profile buffer to copy the ICC profile into * @param size size of the icc_profile buffer in bytes * @return ::JXL_DEC_SUCCESS if the profile was successfully returned, * ::JXL_DEC_NEED_MORE_INPUT if not yet available, @ref * JXL_DEC_ERROR if the profile doesn't exist or the output size is not * large enough. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetColorAsICCProfile( const JxlDecoder* dec, JxlColorProfileTarget target, uint8_t* icc_profile, size_t size); /** Sets the desired output color profile of the decoded image by calling * @ref JxlDecoderSetOutputColorProfile, passing on @c color_encoding and * setting @c icc_data to NULL. See @ref JxlDecoderSetOutputColorProfile for * details. * * @param dec decoder object * @param color_encoding the default color encoding to set * @return ::JXL_DEC_SUCCESS if the preference was set successfully, @ref * JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetPreferredColorProfile( JxlDecoder* dec, const JxlColorEncoding* color_encoding); /** Requests that the decoder perform tone mapping to the peak display luminance * passed as @c desired_intensity_target, if appropriate. * @note This is provided for convenience and the exact tone mapping that is * performed is not meant to be considered authoritative in any way. It may * change from version to version. * @param dec decoder object * @param desired_intensity_target the intended target peak luminance * @return ::JXL_DEC_SUCCESS if the preference was set successfully, @ref * JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetDesiredIntensityTarget( JxlDecoder* dec, float desired_intensity_target); /** * Sets the desired output color profile of the decoded image either from a * color encoding or an ICC profile. Valid calls of this function have either @c * color_encoding or @c icc_data set to NULL and @c icc_size must be `0` if and * only if @c icc_data is NULL. * * Depending on whether a color management system (CMS) has been set the * behavior is as follows: * * If a color management system (CMS) has been set with @ref JxlDecoderSetCms, * and the CMS supports output to the desired color encoding or ICC profile, * then it will provide the output in that color encoding or ICC profile. If the * desired color encoding or the ICC is not supported, then an error will be * returned. * * If no CMS has been set with @ref JxlDecoderSetCms, there are two cases: * * (1) Calling this function with a color encoding will convert XYB images to * the desired color encoding. In this case, if the requested color encoding has * a narrower gamut, or the white points differ, then the resulting image can * have significant color distortion. Non-XYB images will not be converted to * the desired color space. * * (2) Calling this function with an ICC profile will result in an error. * * If called with an ICC profile (after a call to @ref JxlDecoderSetCms), the * ICC profile has to be a valid RGB or grayscale color profile. * * Can only be set after the ::JXL_DEC_COLOR_ENCODING event occurred and * before any other event occurred, and should be used before getting * ::JXL_COLOR_PROFILE_TARGET_DATA. * * This function must not be called before @ref JxlDecoderSetCms. * * @param dec decoder object * @param color_encoding the output color encoding * @param icc_data bytes of the icc profile * @param icc_size size of the icc profile in bytes * @return ::JXL_DEC_SUCCESS if the color profile was set successfully, @ref * JXL_DEC_ERROR otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetOutputColorProfile( JxlDecoder* dec, const JxlColorEncoding* color_encoding, const uint8_t* icc_data, size_t icc_size); /** * Sets the color management system (CMS) that will be used for color * conversion (if applicable) during decoding. May only be set before starting * decoding and must not be called after @ref JxlDecoderSetOutputColorProfile. * * See @ref JxlDecoderSetOutputColorProfile for how color conversions are done * depending on whether or not a CMS has been set with @ref JxlDecoderSetCms. * * @param dec decoder object. * @param cms structure representing a CMS implementation. See @ref * JxlCmsInterface for more details. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetCms(JxlDecoder* dec, JxlCmsInterface cms); // TODO(firsching): add a function JxlDecoderSetDefaultCms() for setting a // default in case libjxl is build with a CMS. /** * Returns the minimum size in bytes of the preview image output pixel buffer * for the given format. This is the buffer for @ref * JxlDecoderSetPreviewOutBuffer. Requires the preview header information is * available in the decoder. * * @param dec decoder object * @param format format of pixels * @param size output value, buffer size in bytes * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * information not available yet. */ JXL_EXPORT JxlDecoderStatus JxlDecoderPreviewOutBufferSize( const JxlDecoder* dec, const JxlPixelFormat* format, size_t* size); /** * Sets the buffer to write the low-resolution preview image * to. The size of the buffer must be at least as large as given by @ref * JxlDecoderPreviewOutBufferSize. The buffer follows the format described * by @ref JxlPixelFormat. The preview image dimensions are given by the * @ref JxlPreviewHeader. The buffer is owned by the caller. * * @param dec decoder object * @param format format of pixels. Object owned by user and its contents are * copied internally. * @param buffer buffer type to output the pixel data to * @param size size of buffer in bytes * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * size too small. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetPreviewOutBuffer( JxlDecoder* dec, const JxlPixelFormat* format, void* buffer, size_t size); /** * Outputs the information from the frame, such as duration when have_animation. * This function can be called when ::JXL_DEC_FRAME occurred for the current * frame, even when have_animation in the JxlBasicInfo is JXL_FALSE. * * @param dec decoder object * @param header struct to copy the information into, or NULL to only check * whether the information is available through the return value. * @return ::JXL_DEC_SUCCESS if the value is available, @ref * JXL_DEC_NEED_MORE_INPUT if not yet available, ::JXL_DEC_ERROR in * case of other error conditions. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetFrameHeader(const JxlDecoder* dec, JxlFrameHeader* header); /** * Outputs name for the current frame. The buffer for name must have at least * `name_length + 1` bytes allocated, gotten from the associated JxlFrameHeader. * * @param dec decoder object * @param name buffer to copy the name into * @param size size of the name buffer in bytes, including zero termination * character, so this must be at least @ref JxlFrameHeader.name_length + 1. * @return ::JXL_DEC_SUCCESS if the value is available, @ref * JXL_DEC_NEED_MORE_INPUT if not yet available, ::JXL_DEC_ERROR in * case of other error conditions. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetFrameName(const JxlDecoder* dec, char* name, size_t size); /** * Outputs the blend information for the current frame for a specific extra * channel. This function can be called once the ::JXL_DEC_FRAME event occurred * for the current frame, even if the `have_animation` field in the @ref * JxlBasicInfo is @ref JXL_FALSE. This information is only useful if coalescing * is disabled; otherwise the decoder will have performed blending already. * * @param dec decoder object * @param index the index of the extra channel * @param blend_info struct to copy the information into * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetExtraChannelBlendInfo( const JxlDecoder* dec, size_t index, JxlBlendInfo* blend_info); /** * Returns the minimum size in bytes of the image output pixel buffer for the * given format. This is the buffer for @ref JxlDecoderSetImageOutBuffer. * Requires that the basic image information is available in the decoder in the * case of coalescing enabled (default). In case coalescing is disabled, this * can only be called after the ::JXL_DEC_FRAME event occurs. In that case, * it will return the size required to store the possibly cropped frame (which * can be larger or smaller than the image dimensions). * * @param dec decoder object * @param format format of the pixels. * @param size output value, buffer size in bytes * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * information not available yet. */ JXL_EXPORT JxlDecoderStatus JxlDecoderImageOutBufferSize( const JxlDecoder* dec, const JxlPixelFormat* format, size_t* size); /** * Sets the buffer to write the full resolution image to. This can be set when * the ::JXL_DEC_FRAME event occurs, must be set when the @ref * JXL_DEC_NEED_IMAGE_OUT_BUFFER event occurs, and applies only for the * current frame. The size of the buffer must be at least as large as given * by @ref JxlDecoderImageOutBufferSize. The buffer follows the format described * by @ref JxlPixelFormat. The buffer is owned by the caller. * * @param dec decoder object * @param format format of the pixels. Object owned by user and its contents * are copied internally. * @param buffer buffer type to output the pixel data to * @param size size of buffer in bytes * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * size too small. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetImageOutBuffer( JxlDecoder* dec, const JxlPixelFormat* format, void* buffer, size_t size); /** * Function type for @ref JxlDecoderSetImageOutCallback. * * The callback may be called simultaneously by different threads when using a * threaded parallel runner, on different pixels. * * @param opaque optional user data, as given to @ref * JxlDecoderSetImageOutCallback. * @param x horizontal position of leftmost pixel of the pixel data. * @param y vertical position of the pixel data. * @param num_pixels amount of pixels included in the pixel data, horizontally. * This is not the same as xsize of the full image, it may be smaller. * @param pixels pixel data as a horizontal stripe, in the format passed to @ref * JxlDecoderSetImageOutCallback. The memory is not owned by the user, and * is only valid during the time the callback is running. */ typedef void (*JxlImageOutCallback)(void* opaque, size_t x, size_t y, size_t num_pixels, const void* pixels); /** * Initialization callback for @ref JxlDecoderSetMultithreadedImageOutCallback. * * @param init_opaque optional user data, as given to @ref * JxlDecoderSetMultithreadedImageOutCallback. * @param num_threads maximum number of threads that will call the @c run * callback concurrently. * @param num_pixels_per_thread maximum number of pixels that will be passed in * one call to @c run. * @return a pointer to data that will be passed to the @c run callback, or * @c NULL if initialization failed. */ typedef void* (*JxlImageOutInitCallback)(void* init_opaque, size_t num_threads, size_t num_pixels_per_thread); /** * Worker callback for @ref JxlDecoderSetMultithreadedImageOutCallback. * * @param run_opaque user data returned by the @c init callback. * @param thread_id number in `[0, num_threads)` identifying the thread of the * current invocation of the callback. * @param x horizontal position of the first (leftmost) pixel of the pixel data. * @param y vertical position of the pixel data. * @param num_pixels number of pixels in the pixel data. May be less than the * full @c xsize of the image, and will be at most equal to the @c * num_pixels_per_thread that was passed to @c init. * @param pixels pixel data as a horizontal stripe, in the format passed to @ref * JxlDecoderSetMultithreadedImageOutCallback. The data pointed to * remains owned by the caller and is only guaranteed to outlive the current * callback invocation. */ typedef void (*JxlImageOutRunCallback)(void* run_opaque, size_t thread_id, size_t x, size_t y, size_t num_pixels, const void* pixels); /** * Destruction callback for @ref JxlDecoderSetMultithreadedImageOutCallback, * called after all invocations of the @c run callback to perform any * appropriate clean-up of the @c run_opaque data returned by @c init. * * @param run_opaque user data returned by the @c init callback. */ typedef void (*JxlImageOutDestroyCallback)(void* run_opaque); /** * Sets pixel output callback. This is an alternative to @ref * JxlDecoderSetImageOutBuffer. This can be set when the ::JXL_DEC_FRAME * event occurs, must be set when the ::JXL_DEC_NEED_IMAGE_OUT_BUFFER event * occurs, and applies only for the current frame. Only one of @ref * JxlDecoderSetImageOutBuffer or @ref JxlDecoderSetImageOutCallback may be used * for the same frame, not both at the same time. * * The callback will be called multiple times, to receive the image * data in small chunks. The callback receives a horizontal stripe of pixel * data, `1` pixel high, xsize pixels wide, called a scanline. The xsize here is * not the same as the full image width, the scanline may be a partial section, * and xsize may differ between calls. The user can then process and/or copy the * partial scanline to an image buffer. The callback may be called * simultaneously by different threads when using a threaded parallel runner, on * different pixels. * * If @ref JxlDecoderFlushImage is not used, then each pixel will be visited * exactly once by the different callback calls, during processing with one or * more @ref JxlDecoderProcessInput calls. These pixels are decoded to full * detail, they are not part of a lower resolution or lower quality progressive * pass, but the final pass. * * If @ref JxlDecoderFlushImage is used, then in addition each pixel will be * visited zero or one times during the blocking @ref JxlDecoderFlushImage call. * Pixels visited as a result of @ref JxlDecoderFlushImage may represent a lower * resolution or lower quality intermediate progressive pass of the image. Any * visited pixel will be of a quality at least as good or better than previous * visits of this pixel. A pixel may be visited zero times if it cannot be * decoded yet or if it was already decoded to full precision (this behavior is * not guaranteed). * * @param dec decoder object * @param format format of the pixels. Object owned by user; its contents are * copied internally. * @param callback the callback function receiving partial scanlines of pixel * data. * @param opaque optional user data, which will be passed on to the callback, * may be NULL. * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such * as @ref JxlDecoderSetImageOutBuffer already set. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetImageOutCallback(JxlDecoder* dec, const JxlPixelFormat* format, JxlImageOutCallback callback, void* opaque); /** Similar to @ref JxlDecoderSetImageOutCallback except that the callback is * allowed an initialization phase during which it is informed of how many * threads will call it concurrently, and those calls are further informed of * which thread they are occurring in. * * @param dec decoder object * @param format format of the pixels. Object owned by user; its contents are * copied internally. * @param init_callback initialization callback. * @param run_callback the callback function receiving partial scanlines of * pixel data. * @param destroy_callback clean-up callback invoked after all calls to @c * run_callback. May be NULL if no clean-up is necessary. * @param init_opaque optional user data passed to @c init_callback, may be NULL * (unlike the return value from @c init_callback which may only be NULL if * initialization failed). * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such * as @ref JxlDecoderSetImageOutBuffer having already been called. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetMultithreadedImageOutCallback( JxlDecoder* dec, const JxlPixelFormat* format, JxlImageOutInitCallback init_callback, JxlImageOutRunCallback run_callback, JxlImageOutDestroyCallback destroy_callback, void* init_opaque); /** * Returns the minimum size in bytes of an extra channel pixel buffer for the * given format. This is the buffer for @ref JxlDecoderSetExtraChannelBuffer. * Requires the basic image information is available in the decoder. * * @param dec decoder object * @param format format of the pixels. The num_channels value is ignored and is * always treated to be `1`. * @param size output value, buffer size in bytes * @param index which extra channel to get, matching the index used in @ref * JxlDecoderGetExtraChannelInfo. Must be smaller than num_extra_channels in * the associated @ref JxlBasicInfo. * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * information not available yet or invalid index. */ JXL_EXPORT JxlDecoderStatus JxlDecoderExtraChannelBufferSize( const JxlDecoder* dec, const JxlPixelFormat* format, size_t* size, uint32_t index); /** * Sets the buffer to write an extra channel to. This can be set when * the ::JXL_DEC_FRAME or ::JXL_DEC_NEED_IMAGE_OUT_BUFFER event occurs, * and applies only for the current frame. The size of the buffer must be at * least as large as given by @ref JxlDecoderExtraChannelBufferSize. The buffer * follows the format described by @ref JxlPixelFormat, but where num_channels * is `1`. The buffer is owned by the caller. The amount of extra channels is * given by the num_extra_channels field in the associated @ref JxlBasicInfo, * and the information of individual extra channels can be queried with @ref * JxlDecoderGetExtraChannelInfo. To get multiple extra channels, this function * must be called multiple times, once for each wanted index. Not all images * have extra channels. The alpha channel is an extra channel and can be gotten * as part of the color channels when using an RGBA pixel buffer with @ref * JxlDecoderSetImageOutBuffer, but additionally also can be gotten * separately as extra channel. The color channels themselves cannot be gotten * this way. * * * @param dec decoder object * @param format format of the pixels. Object owned by user and its contents * are copied internally. The num_channels value is ignored and is always * treated to be `1`. * @param buffer buffer type to output the pixel data to * @param size size of buffer in bytes * @param index which extra channel to get, matching the index used in @ref * JxlDecoderGetExtraChannelInfo. Must be smaller than num_extra_channels in * the associated @ref JxlBasicInfo. * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * size too small or invalid index. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetExtraChannelBuffer(JxlDecoder* dec, const JxlPixelFormat* format, void* buffer, size_t size, uint32_t index); /** * Sets output buffer for reconstructed JPEG codestream. * * The data is owned by the caller and may be used by the decoder until @ref * JxlDecoderReleaseJPEGBuffer is called or the decoder is destroyed or * reset so must be kept alive until then. * * If a JPEG buffer was set before and released with @ref * JxlDecoderReleaseJPEGBuffer, bytes that the decoder has already output * should not be included, only the remaining bytes output must be set. * * @param dec decoder object * @param data pointer to next bytes to write to * @param size amount of bytes available starting from data * @return ::JXL_DEC_ERROR if output buffer was already set and @ref * JxlDecoderReleaseJPEGBuffer was not called on it, ::JXL_DEC_SUCCESS * otherwise */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetJPEGBuffer(JxlDecoder* dec, uint8_t* data, size_t size); /** * Releases buffer which was provided with @ref JxlDecoderSetJPEGBuffer. * * Calling @ref JxlDecoderReleaseJPEGBuffer is required whenever * a buffer is already set and a new buffer needs to be added with @ref * JxlDecoderSetJPEGBuffer, but is not required before @ref * JxlDecoderDestroy or @ref JxlDecoderReset. * * Calling @ref JxlDecoderReleaseJPEGBuffer when no buffer is set is * not an error and returns `0`. * * @param dec decoder object * @return the amount of bytes the decoder has not yet written to of the data * set by @ref JxlDecoderSetJPEGBuffer, or `0` if no buffer is set or @ref * JxlDecoderReleaseJPEGBuffer was already called. */ JXL_EXPORT size_t JxlDecoderReleaseJPEGBuffer(JxlDecoder* dec); /** * Sets output buffer for box output codestream. * * The data is owned by the caller and may be used by the decoder until @ref * JxlDecoderReleaseBoxBuffer is called or the decoder is destroyed or * reset so must be kept alive until then. * * If for the current box a box buffer was set before and released with @ref * JxlDecoderReleaseBoxBuffer, bytes that the decoder has already output * should not be included, only the remaining bytes output must be set. * * The @ref JxlDecoderReleaseBoxBuffer must be used at the next ::JXL_DEC_BOX * event or final ::JXL_DEC_SUCCESS event to compute the size of the output * box bytes. * * @param dec decoder object * @param data pointer to next bytes to write to * @param size amount of bytes available starting from data * @return ::JXL_DEC_ERROR if output buffer was already set and @ref * JxlDecoderReleaseBoxBuffer was not called on it, ::JXL_DEC_SUCCESS * otherwise */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetBoxBuffer(JxlDecoder* dec, uint8_t* data, size_t size); /** * Releases buffer which was provided with @ref JxlDecoderSetBoxBuffer. * * Calling @ref JxlDecoderReleaseBoxBuffer is required whenever * a buffer is already set and a new buffer needs to be added with @ref * JxlDecoderSetBoxBuffer, but is not required before @ref * JxlDecoderDestroy or @ref JxlDecoderReset. * * Calling @ref JxlDecoderReleaseBoxBuffer when no buffer is set is * not an error and returns `0`. * * @param dec decoder object * @return the amount of bytes the decoder has not yet written to of the data * set by @ref JxlDecoderSetBoxBuffer, or `0` if no buffer is set or @ref * JxlDecoderReleaseBoxBuffer was already called. */ JXL_EXPORT size_t JxlDecoderReleaseBoxBuffer(JxlDecoder* dec); /** * Configures whether to get boxes in raw mode or in decompressed mode. In raw * mode, boxes are output as their bytes appear in the container file, which may * be decompressed, or compressed if their type is "brob". In decompressed mode, * "brob" boxes are decompressed with Brotli before outputting them. The size of * the decompressed stream is not known before the decompression has already * finished. * * The default mode is raw. This setting can only be changed before decoding, or * directly after a ::JXL_DEC_BOX event, and is remembered until the decoder * is reset or destroyed. * * Enabling decompressed mode requires Brotli support from the library. * * @param dec decoder object * @param decompress ::JXL_TRUE to transparently decompress, ::JXL_FALSE * to get boxes in raw mode. * @return ::JXL_DEC_ERROR if decompressed mode is set and Brotli is not * available, ::JXL_DEC_SUCCESS otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetDecompressBoxes(JxlDecoder* dec, JXL_BOOL decompress); /** * Outputs the type of the current box, after a ::JXL_DEC_BOX event occurred, * as `4` characters without null termination character. In case of a compressed * "brob" box, this will return "brob" if the decompressed argument is * JXL_FALSE, or the underlying box type if the decompressed argument is * JXL_TRUE. * * The following box types are currently described in ISO/IEC 18181-2: * - "Exif": a box with EXIF metadata. Starts with a 4-byte tiff header offset * (big-endian uint32) that indicates the start of the actual EXIF data * (which starts with a tiff header). Usually the offset will be zero and the * EXIF data starts immediately after the offset field. The Exif orientation * should be ignored by applications; the JPEG XL codestream orientation * takes precedence and libjxl will by default apply the correct orientation * automatically (see @ref JxlDecoderSetKeepOrientation). * - "xml ": a box with XML data, in particular XMP metadata. * - "jumb": a JUMBF superbox (JPEG Universal Metadata Box Format, ISO/IEC * 19566-5). * - "JXL ": mandatory signature box, must come first, `12` bytes long * including the box header * - "ftyp": a second mandatory signature box, must come second, `20` bytes * long including the box header * - "jxll": a JXL level box. This indicates if the codestream is level `5` or * level `10` compatible. If not present, it is level `5`. Level `10` allows * more features such as very high image resolution and bit-depths above `16` * bits per channel. Added automatically by the encoder when * @ref JxlEncoderSetCodestreamLevel is used * - "jxlc": a box with the image codestream, in case the codestream is not * split across multiple boxes. The codestream contains the JPEG XL image * itself, including the basic info such as image dimensions, ICC color * profile, and all the pixel data of all the image frames. * - "jxlp": a codestream box in case it is split across multiple boxes. * The contents are the same as in case of a jxlc box, when concatenated. * - "brob": a Brotli-compressed box, which otherwise represents an existing * type of box such as Exif or "xml ". When @ref JxlDecoderSetDecompressBoxes * is set to JXL_TRUE, these boxes will be transparently decompressed by the * decoder. * - "jxli": frame index box, can list the keyframes in case of a JPEG XL * animation allowing the decoder to jump to individual frames more * efficiently. * - "jbrd": JPEG reconstruction box, contains the information required to * byte-for-byte losslessly reconstruct a JPEG-1 image. The JPEG DCT * coefficients (pixel content) themselves as well as the ICC profile are * encoded in the JXL codestream (jxlc or jxlp) itself. EXIF, XMP and JUMBF * metadata is encoded in the corresponding boxes. The jbrd box itself * contains information such as the remaining app markers of the JPEG-1 file * and everything else required to fit the information together into the * exact original JPEG file. * * Other application-specific boxes can exist. Their typename should not begin * with "jxl" or "JXL" or conflict with other existing typenames. * * The signature, jxl* and jbrd boxes are processed by the decoder and would * typically be ignored by applications. The typical way to use this function is * to check if an encountered box contains metadata that the application is * interested in (e.g. EXIF or XMP metadata), in order to conditionally set a * box buffer. * * @param dec decoder object * @param type buffer to copy the type into * @param decompressed which box type to get: JXL_FALSE to get the raw box type, * which can be "brob", JXL_TRUE, get the underlying box type. * @return ::JXL_DEC_SUCCESS if the value is available, ::JXL_DEC_ERROR if * not, for example the JPEG XL file does not use the container format. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetBoxType(JxlDecoder* dec, JxlBoxType type, JXL_BOOL decompressed); /** * Returns the size of a box as it appears in the container file, after the @ref * JXL_DEC_BOX event. This includes all the box headers. * * @param dec decoder object * @param size raw size of the box in bytes * @return ::JXL_DEC_ERROR if no box size is available, ::JXL_DEC_SUCCESS * otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetBoxSizeRaw(const JxlDecoder* dec, uint64_t* size); /** * Returns the size of the contents of a box, after the @ref * JXL_DEC_BOX event. This does not include any of the headers of the box. For * compressed "brob" boxes, this is the size of the compressed content. Even * when @ref JxlDecoderSetDecompressBoxes is enabled, the return value of * function does not change, and the decompressed size is not known before it * has already been decompressed and output. * * @param dec decoder object * @param size size of the payload of the box in bytes * @return @ref JXL_DEC_ERROR if no box size is available, @ref JXL_DEC_SUCCESS * otherwise. */ JXL_EXPORT JxlDecoderStatus JxlDecoderGetBoxSizeContents(const JxlDecoder* dec, uint64_t* size); /** * Configures at which progressive steps in frame decoding these @ref * JXL_DEC_FRAME_PROGRESSION event occurs. The default value for the level * of detail if this function is never called is `kDC`. * * @param dec decoder object * @param detail at which level of detail to trigger @ref * JXL_DEC_FRAME_PROGRESSION * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * an invalid value for the progressive detail. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetProgressiveDetail(JxlDecoder* dec, JxlProgressiveDetail detail); /** * Returns the intended downsampling ratio for the progressive frame produced * by @ref JxlDecoderFlushImage after the latest ::JXL_DEC_FRAME_PROGRESSION * event. * * @param dec decoder object * @return The intended downsampling ratio, can be `1`, `2`, `4` or `8`. */ JXL_EXPORT size_t JxlDecoderGetIntendedDownsamplingRatio(JxlDecoder* dec); /** * Outputs progressive step towards the decoded image so far when only partial * input was received. If the flush was successful, the buffer set with @ref * JxlDecoderSetImageOutBuffer will contain partial image data. * * Can be called when @ref JxlDecoderProcessInput returns @ref * JXL_DEC_NEED_MORE_INPUT, after the ::JXL_DEC_FRAME event already occurred * and before the ::JXL_DEC_FULL_IMAGE event occurred for a frame. * * @param dec decoder object * @return ::JXL_DEC_SUCCESS if image data was flushed to the output buffer, * or ::JXL_DEC_ERROR when no flush was done, e.g. if not enough image * data was available yet even for flush, or no output buffer was set yet. * This error is not fatal, it only indicates no flushed image is available * right now. Regular decoding can still be performed. */ JXL_EXPORT JxlDecoderStatus JxlDecoderFlushImage(JxlDecoder* dec); /** * Sets the bit depth of the output buffer or callback. * * Can be called after @ref JxlDecoderSetImageOutBuffer or @ref * JxlDecoderSetImageOutCallback. For float pixel data types, only the default * ::JXL_BIT_DEPTH_FROM_PIXEL_FORMAT setting is supported. * * @param dec decoder object * @param bit_depth the bit depth setting of the pixel output * @return ::JXL_DEC_SUCCESS on success, ::JXL_DEC_ERROR on error, such as * incompatible custom bit depth and pixel data type. */ JXL_EXPORT JxlDecoderStatus JxlDecoderSetImageOutBitDepth(JxlDecoder* dec, const JxlBitDepth* bit_depth); #ifdef __cplusplus } #endif #endif /* JXL_DECODE_H_ */ /** @}*/