/* * Copyright (C)2009-2015, 2017, 2020-2021, 2023 D. R. 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IN NO EVENT SHALL THE COPYRIGHT HOLDERS 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. */ #ifndef __TURBOJPEG_H__ #define __TURBOJPEG_H__ #if defined(_WIN32) && defined(DLLDEFINE) #define DLLEXPORT … #else #define DLLEXPORT #endif #define DLLCALL /** * @addtogroup TurboJPEG * TurboJPEG API. This API provides an interface for generating, decoding, and * transforming planar YUV and JPEG images in memory. * * @anchor YUVnotes * YUV Image Format Notes * ---------------------- * Technically, the JPEG format uses the YCbCr colorspace (which is technically * not a colorspace but a color transform), but per the convention of the * digital video community, the TurboJPEG API uses "YUV" to refer to an image * format consisting of Y, Cb, and Cr image planes. * * Each plane is simply a 2D array of bytes, each byte representing the value * of one of the components (Y, Cb, or Cr) at a particular location in the * image. The width and height of each plane are determined by the image * width, height, and level of chrominance subsampling. The luminance plane * width is the image width padded to the nearest multiple of the horizontal * subsampling factor (1 in the case of 4:4:4, grayscale, or 4:4:0; 2 in the * case of 4:2:2 or 4:2:0; 4 in the case of 4:1:1.) Similarly, the luminance * plane height is the image height padded to the nearest multiple of the * vertical subsampling factor (1 in the case of 4:4:4, 4:2:2, grayscale, or * 4:1:1; 2 in the case of 4:2:0 or 4:4:0.) This is irrespective of any * additional padding that may be specified as an argument to the various YUV * functions. The chrominance plane width is equal to the luminance plane * width divided by the horizontal subsampling factor, and the chrominance * plane height is equal to the luminance plane height divided by the vertical * subsampling factor. * * For example, if the source image is 35 x 35 pixels and 4:2:2 subsampling is * used, then the luminance plane would be 36 x 35 bytes, and each of the * chrominance planes would be 18 x 35 bytes. If you specify a row alignment * of 4 bytes on top of this, then the luminance plane would be 36 x 35 bytes, * and each of the chrominance planes would be 20 x 35 bytes. * * @{ */ /** * The number of chrominance subsampling options */ #define TJ_NUMSAMP … /** * Chrominance subsampling options. * When pixels are converted from RGB to YCbCr (see #TJCS_YCbCr) or from CMYK * to YCCK (see #TJCS_YCCK) as part of the JPEG compression process, some of * the Cb and Cr (chrominance) components can be discarded or averaged together * to produce a smaller image with little perceptible loss of image clarity. * (The human eye is more sensitive to small changes in brightness than to * small changes in color.) This is called "chrominance subsampling". */ enum TJSAMP { … }; /** * MCU block width (in pixels) for a given level of chrominance subsampling. * MCU block sizes: * - 8x8 for no subsampling or grayscale * - 16x8 for 4:2:2 * - 8x16 for 4:4:0 * - 16x16 for 4:2:0 * - 32x8 for 4:1:1 */ static const int tjMCUWidth[TJ_NUMSAMP] = …; /** * MCU block height (in pixels) for a given level of chrominance subsampling. * MCU block sizes: * - 8x8 for no subsampling or grayscale * - 16x8 for 4:2:2 * - 8x16 for 4:4:0 * - 16x16 for 4:2:0 * - 32x8 for 4:1:1 */ static const int tjMCUHeight[TJ_NUMSAMP] = …; /** * The number of pixel formats */ #define TJ_NUMPF … /** * Pixel formats */ enum TJPF { … }; /** * Red offset (in bytes) for a given pixel format. This specifies the number * of bytes that the red component is offset from the start of the pixel. For * instance, if a pixel of format TJPF_BGRX is stored in * `unsigned char pixel[]`, then the red component will be *`pixel[tjRedOffset[TJPF_BGRX]]`. This will be -1 if the pixel format does * not have a red component. */ static const int tjRedOffset[TJ_NUMPF] = …; /** * Green offset (in bytes) for a given pixel format. This specifies the number * of bytes that the green component is offset from the start of the pixel. * For instance, if a pixel of format TJPF_BGRX is stored in * `unsigned char pixel[]`, then the green component will be * `pixel[tjGreenOffset[TJPF_BGRX]]`. This will be -1 if the pixel format does * not have a green component. */ static const int tjGreenOffset[TJ_NUMPF] = …; /** * Blue offset (in bytes) for a given pixel format. This specifies the number * of bytes that the blue component is offset from the start of the pixel. For * instance, if a pixel of format TJPF_BGRX is stored in * `unsigned char pixel[]`, then the blue component will be * `pixel[tjBlueOffset[TJPF_BGRX]]`. This will be -1 if the pixel format does * not have a blue component. */ static const int tjBlueOffset[TJ_NUMPF] = …; /** * Alpha offset (in bytes) for a given pixel format. This specifies the number * of bytes that the alpha component is offset from the start of the pixel. * For instance, if a pixel of format TJPF_BGRA is stored in * `unsigned char pixel[]`, then the alpha component will be * `pixel[tjAlphaOffset[TJPF_BGRA]]`. This will be -1 if the pixel format does * not have an alpha component. */ static const int tjAlphaOffset[TJ_NUMPF] = …; /** * Pixel size (in bytes) for a given pixel format */ static const int tjPixelSize[TJ_NUMPF] = …; /** * The number of JPEG colorspaces */ #define TJ_NUMCS … /** * JPEG colorspaces */ enum TJCS { … }; /** * Rows in the packed-pixel source/destination image are stored in bottom-up * (Windows, OpenGL) order rather than in top-down (X11) order. */ #define TJFLAG_BOTTOMUP … /** * When decompressing an image that was compressed using chrominance * subsampling, use the fastest chrominance upsampling algorithm available. * The default is to use smooth upsampling, which creates a smooth transition * between neighboring chrominance components in order to reduce upsampling * artifacts in the decompressed image. */ #define TJFLAG_FASTUPSAMPLE … /** * Disable JPEG buffer (re)allocation. If passed to one of the JPEG * compression or transform functions, this flag will cause those functions to * generate an error if the JPEG destination buffer is invalid or too small, * rather than attempt to allocate or reallocate that buffer. */ #define TJFLAG_NOREALLOC … /** * Use the fastest DCT/IDCT algorithm available. The default if this flag is * not specified is implementation-specific. For example, the implementation * of the TurboJPEG API in libjpeg-turbo uses the fast algorithm by default * when compressing, because this has been shown to have only a very slight * effect on accuracy, but it uses the accurate algorithm when decompressing, * because this has been shown to have a larger effect. */ #define TJFLAG_FASTDCT … /** * Use the most accurate DCT/IDCT algorithm available. The default if this * flag is not specified is implementation-specific. For example, the * implementation of the TurboJPEG API in libjpeg-turbo uses the fast algorithm * by default when compressing, because this has been shown to have only a very * slight effect on accuracy, but it uses the accurate algorithm when * decompressing, because this has been shown to have a larger effect. */ #define TJFLAG_ACCURATEDCT … /** * Immediately discontinue the current compression/decompression/transform * operation if a warning (non-fatal error) occurs. The default behavior is to * allow the operation to complete unless a fatal error is encountered. */ #define TJFLAG_STOPONWARNING … /** * Use progressive entropy coding in JPEG images generated by the compression * and transform functions. Progressive entropy coding will generally improve * compression relative to baseline entropy coding (the default), but it will * reduce compression and decompression performance considerably. */ #define TJFLAG_PROGRESSIVE … /** * Limit the number of progressive JPEG scans that the decompression and * transform functions will process. If a progressive JPEG image contains an * unreasonably large number of scans, then this flag will cause the * decompression and transform functions to return an error. The primary * purpose of this is to allow security-critical applications to guard against * an exploit of the progressive JPEG format described in * <a href="https://libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf" target="_blank">this report</a>. */ #define TJFLAG_LIMITSCANS … /** * The number of error codes */ #define TJ_NUMERR … /** * Error codes */ enum TJERR { … }; /** * The number of transform operations */ #define TJ_NUMXOP … /** * Transform operations for #tjTransform() */ enum TJXOP { … }; /** * This option will cause #tjTransform() to return an error if the transform is * not perfect. Lossless transforms operate on MCU blocks, whose size depends * on the level of chrominance subsampling used (see #tjMCUWidth and * #tjMCUHeight.) If the image's width or height is not evenly divisible by * the MCU block size, then there will be partial MCU blocks on the right * and/or bottom edges. It is not possible to move these partial MCU blocks to * the top or left of the image, so any transform that would require that is * "imperfect." If this option is not specified, then any partial MCU blocks * that cannot be transformed will be left in place, which will create * odd-looking strips on the right or bottom edge of the image. */ #define TJXOPT_PERFECT … /** * This option will cause #tjTransform() to discard any partial MCU blocks that * cannot be transformed. */ #define TJXOPT_TRIM … /** * This option will enable lossless cropping. See #tjTransform() for more * information. */ #define TJXOPT_CROP … /** * This option will discard the color data in the source image and produce a * grayscale destination image. */ #define TJXOPT_GRAY … /** * This option will prevent #tjTransform() from outputting a JPEG image for * this particular transform. (This can be used in conjunction with a custom * filter to capture the transformed DCT coefficients without transcoding * them.) */ #define TJXOPT_NOOUTPUT … /** * This option will enable progressive entropy coding in the JPEG image * generated by this particular transform. Progressive entropy coding will * generally improve compression relative to baseline entropy coding (the * default), but it will reduce decompression performance considerably. */ #define TJXOPT_PROGRESSIVE … /** * This option will prevent #tjTransform() from copying any extra markers * (including EXIF and ICC profile data) from the source image to the * destination image. */ #define TJXOPT_COPYNONE … /** * Scaling factor */ tjscalingfactor; /** * Cropping region */ tjregion; /** * Lossless transform */ tjtransform; /** * TurboJPEG instance handle */ tjhandle; /** * Pad the given width to the nearest multiple of 4 */ #define TJPAD(width) … /** * Compute the scaled value of `dimension` using the given scaling factor. * This macro performs the integer equivalent of `ceil(dimension * * scalingFactor)`. */ #define TJSCALED(dimension, scalingFactor) … #ifdef __cplusplus extern "C" { #endif /** * Create a TurboJPEG compressor instance. * * @return a handle to the newly-created instance, or NULL if an error occurred * (see #tjGetErrorStr2().) */ DLLEXPORT tjhandle tjInitCompress(void); /** * Compress a packed-pixel RGB, grayscale, or CMYK image into a JPEG image. * * @param handle a handle to a TurboJPEG compressor or transformer instance * * @param srcBuf pointer to a buffer containing a packed-pixel RGB, grayscale, * or CMYK source image to be compressed * * @param width width (in pixels) of the source image * * @param pitch bytes per row in the source image. Normally this should be * <tt>width * #tjPixelSize[pixelFormat]</tt>, if the image is unpadded, or * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each row of the image * is padded to the nearest multiple of 4 bytes, as is the case for Windows * bitmaps. You can also be clever and use this parameter to skip rows, etc. * Setting this parameter to 0 is the equivalent of setting it to * <tt>width * #tjPixelSize[pixelFormat]</tt>. * * @param height height (in pixels) of the source image * * @param pixelFormat pixel format of the source image (see @ref TJPF * "Pixel formats".) * * @param jpegBuf address of a pointer to a byte buffer that will receive the * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer to * accommodate the size of the JPEG image. Thus, you can choose to: * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and * let TurboJPEG grow the buffer as needed, * -# set `*jpegBuf` to NULL to tell TurboJPEG to allocate the buffer for you, * or * -# pre-allocate the buffer to a "worst case" size determined by calling * #tjBufSize(). This should ensure that the buffer never has to be * re-allocated. (Setting #TJFLAG_NOREALLOC guarantees that it won't be.) * . * If you choose option 1, then `*jpegSize` should be set to the size of your * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC, * you should always check `*jpegBuf` upon return from this function, as it may * have changed. * * @param jpegSize pointer to an unsigned long variable that holds the size of * the JPEG buffer. If `*jpegBuf` points to a pre-allocated buffer, then * `*jpegSize` should be set to the size of the buffer. Upon return, * `*jpegSize` will contain the size of the JPEG image (in bytes.) If * `*jpegBuf` points to a JPEG buffer that is being reused from a previous call * to one of the JPEG compression functions, then `*jpegSize` is ignored. * * @param jpegSubsamp the level of chrominance subsampling to be used when * generating the JPEG image (see @ref TJSAMP * "Chrominance subsampling options".) * * @param jpegQual the image quality of the generated JPEG image (1 = worst, * 100 = best) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjCompress2(tjhandle handle, const unsigned char *srcBuf, int width, int pitch, int height, int pixelFormat, unsigned char **jpegBuf, unsigned long *jpegSize, int jpegSubsamp, int jpegQual, int flags); /** * Compress a unified planar YUV image into a JPEG image. * * @param handle a handle to a TurboJPEG compressor or transformer instance * * @param srcBuf pointer to a buffer containing a unified planar YUV source * image to be compressed. The size of this buffer should match the value * returned by #tjBufSizeYUV2() for the given image width, height, row * alignment, and level of chrominance subsampling. The Y, U (Cb), and V (Cr) * image planes should be stored sequentially in the buffer. (Refer to * @ref YUVnotes "YUV Image Format Notes".) * * @param width width (in pixels) of the source image. If the width is not an * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate * buffer copy will be performed. * * @param align row alignment (in bytes) of the source image (must be a power * of 2.) Setting this parameter to n indicates that each row in each plane of * the source image is padded to the nearest multiple of n bytes * (1 = unpadded.) * * @param height height (in pixels) of the source image. If the height is not * an even multiple of the MCU block height (see #tjMCUHeight), then an * intermediate buffer copy will be performed. * * @param subsamp the level of chrominance subsampling used in the source image * (see @ref TJSAMP "Chrominance subsampling options".) * * @param jpegBuf address of a pointer to a byte buffer that will receive the * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer to * accommodate the size of the JPEG image. Thus, you can choose to: * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and * let TurboJPEG grow the buffer as needed, * -# set `*jpegBuf` to NULL to tell TurboJPEG to allocate the buffer for you, * or * -# pre-allocate the buffer to a "worst case" size determined by calling * #tjBufSize(). This should ensure that the buffer never has to be * re-allocated. (Setting #TJFLAG_NOREALLOC guarantees that it won't be.) * . * If you choose option 1, then `*jpegSize` should be set to the size of your * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC, * you should always check `*jpegBuf` upon return from this function, as it may * have changed. * * @param jpegSize pointer to an unsigned long variable that holds the size of * the JPEG buffer. If `*jpegBuf` points to a pre-allocated buffer, then * `*jpegSize` should be set to the size of the buffer. Upon return, * `*jpegSize` will contain the size of the JPEG image (in bytes.) If * `*jpegBuf` points to a JPEG buffer that is being reused from a previous call * to one of the JPEG compression functions, then `*jpegSize` is ignored. * * @param jpegQual the image quality of the generated JPEG image (1 = worst, * 100 = best) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjCompressFromYUV(tjhandle handle, const unsigned char *srcBuf, int width, int align, int height, int subsamp, unsigned char **jpegBuf, unsigned long *jpegSize, int jpegQual, int flags); /** * Compress a set of Y, U (Cb), and V (Cr) image planes into a JPEG image. * * @param handle a handle to a TurboJPEG compressor or transformer instance * * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes * (or just a Y plane, if compressing a grayscale image) that contain a YUV * source image to be compressed. These planes can be contiguous or * non-contiguous in memory. The size of each plane should match the value * returned by #tjPlaneSizeYUV() for the given image width, height, strides, * and level of chrominance subsampling. Refer to @ref YUVnotes * "YUV Image Format Notes" for more details. * * @param width width (in pixels) of the source image. If the width is not an * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate * buffer copy will be performed. * * @param strides an array of integers, each specifying the number of bytes per * row in the corresponding plane of the YUV source image. Setting the stride * for any plane to 0 is the same as setting it to the plane width (see * @ref YUVnotes "YUV Image Format Notes".) If `strides` is NULL, then the * strides for all planes will be set to their respective plane widths. You * can adjust the strides in order to specify an arbitrary amount of row * padding in each plane or to create a JPEG image from a subregion of a larger * planar YUV image. * * @param height height (in pixels) of the source image. If the height is not * an even multiple of the MCU block height (see #tjMCUHeight), then an * intermediate buffer copy will be performed. * * @param subsamp the level of chrominance subsampling used in the source image * (see @ref TJSAMP "Chrominance subsampling options".) * * @param jpegBuf address of a pointer to a byte buffer that will receive the * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer to * accommodate the size of the JPEG image. Thus, you can choose to: * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and * let TurboJPEG grow the buffer as needed, * -# set `*jpegBuf` to NULL to tell TurboJPEG to allocate the buffer for you, * or * -# pre-allocate the buffer to a "worst case" size determined by calling * #tjBufSize(). This should ensure that the buffer never has to be * re-allocated. (Setting #TJFLAG_NOREALLOC guarantees that it won't be.) * . * If you choose option 1, then `*jpegSize` should be set to the size of your * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC, * you should always check `*jpegBuf` upon return from this function, as it may * have changed. * * @param jpegSize pointer to an unsigned long variable that holds the size of * the JPEG buffer. If `*jpegBuf` points to a pre-allocated buffer, then * `*jpegSize` should be set to the size of the buffer. Upon return, * `*jpegSize` will contain the size of the JPEG image (in bytes.) If * `*jpegBuf` points to a JPEG buffer that is being reused from a previous call * to one of the JPEG compression functions, then `*jpegSize` is ignored. * * @param jpegQual the image quality of the generated JPEG image (1 = worst, * 100 = best) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjCompressFromYUVPlanes(tjhandle handle, const unsigned char **srcPlanes, int width, const int *strides, int height, int subsamp, unsigned char **jpegBuf, unsigned long *jpegSize, int jpegQual, int flags); /** * The maximum size of the buffer (in bytes) required to hold a JPEG image with * the given parameters. The number of bytes returned by this function is * larger than the size of the uncompressed source image. The reason for this * is that the JPEG format uses 16-bit coefficients, so it is possible for a * very high-quality source image with very high-frequency content to expand * rather than compress when converted to the JPEG format. Such images * represent very rare corner cases, but since there is no way to predict the * size of a JPEG image prior to compression, the corner cases have to be * handled. * * @param width width (in pixels) of the image * * @param height height (in pixels) of the image * * @param jpegSubsamp the level of chrominance subsampling to be used when * generating the JPEG image (see @ref TJSAMP * "Chrominance subsampling options".) * * @return the maximum size of the buffer (in bytes) required to hold the * image, or -1 if the arguments are out of bounds. */ DLLEXPORT unsigned long tjBufSize(int width, int height, int jpegSubsamp); /** * The size of the buffer (in bytes) required to hold a unified planar YUV * image with the given parameters. * * @param width width (in pixels) of the image * * @param align row alignment (in bytes) of the image (must be a power of 2.) * Setting this parameter to n specifies that each row in each plane of the * image will be padded to the nearest multiple of n bytes (1 = unpadded.) * * @param height height (in pixels) of the image * * @param subsamp level of chrominance subsampling in the image (see * @ref TJSAMP "Chrominance subsampling options".) * * @return the size of the buffer (in bytes) required to hold the image, or -1 * if the arguments are out of bounds. */ DLLEXPORT unsigned long tjBufSizeYUV2(int width, int align, int height, int subsamp); /** * The size of the buffer (in bytes) required to hold a YUV image plane with * the given parameters. * * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr) * * @param width width (in pixels) of the YUV image. NOTE: this is the width of * the whole image, not the plane width. * * @param stride bytes per row in the image plane. Setting this to 0 is the * equivalent of setting it to the plane width. * * @param height height (in pixels) of the YUV image. NOTE: this is the height * of the whole image, not the plane height. * * @param subsamp level of chrominance subsampling in the image (see * @ref TJSAMP "Chrominance subsampling options".) * * @return the size of the buffer (in bytes) required to hold the YUV image * plane, or -1 if the arguments are out of bounds. */ DLLEXPORT unsigned long tjPlaneSizeYUV(int componentID, int width, int stride, int height, int subsamp); /** * The plane width of a YUV image plane with the given parameters. Refer to * @ref YUVnotes "YUV Image Format Notes" for a description of plane width. * * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr) * * @param width width (in pixels) of the YUV image * * @param subsamp level of chrominance subsampling in the image (see * @ref TJSAMP "Chrominance subsampling options".) * * @return the plane width of a YUV image plane with the given parameters, or * -1 if the arguments are out of bounds. */ DLLEXPORT int tjPlaneWidth(int componentID, int width, int subsamp); /** * The plane height of a YUV image plane with the given parameters. Refer to * @ref YUVnotes "YUV Image Format Notes" for a description of plane height. * * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr) * * @param height height (in pixels) of the YUV image * * @param subsamp level of chrominance subsampling in the image (see * @ref TJSAMP "Chrominance subsampling options".) * * @return the plane height of a YUV image plane with the given parameters, or * -1 if the arguments are out of bounds. */ DLLEXPORT int tjPlaneHeight(int componentID, int height, int subsamp); /** * Encode a packed-pixel RGB or grayscale image into a unified planar YUV * image. This function performs color conversion (which is accelerated in the * libjpeg-turbo implementation) but does not execute any of the other steps in * the JPEG compression process. * * @param handle a handle to a TurboJPEG compressor or transformer instance * * @param srcBuf pointer to a buffer containing a packed-pixel RGB or grayscale * source image to be encoded * * @param width width (in pixels) of the source image * * @param pitch bytes per row in the source image. Normally this should be * <tt>width * #tjPixelSize[pixelFormat]</tt>, if the image is unpadded, or * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each row of the image * is padded to the nearest multiple of 4 bytes, as is the case for Windows * bitmaps. You can also be clever and use this parameter to skip rows, etc. * Setting this parameter to 0 is the equivalent of setting it to * <tt>width * #tjPixelSize[pixelFormat]</tt>. * * @param height height (in pixels) of the source image * * @param pixelFormat pixel format of the source image (see @ref TJPF * "Pixel formats".) * * @param dstBuf pointer to a buffer that will receive the unified planar YUV * image. Use #tjBufSizeYUV2() to determine the appropriate size for this * buffer based on the image width, height, row alignment, and level of * chrominance subsampling. The Y, U (Cb), and V (Cr) image planes will be * stored sequentially in the buffer. (Refer to @ref YUVnotes * "YUV Image Format Notes".) * * @param align row alignment (in bytes) of the YUV image (must be a power of * 2.) Setting this parameter to n will cause each row in each plane of the * YUV image to be padded to the nearest multiple of n bytes (1 = unpadded.) * To generate images suitable for X Video, `align` should be set to 4. * * @param subsamp the level of chrominance subsampling to be used when * generating the YUV image (see @ref TJSAMP * "Chrominance subsampling options".) To generate images suitable for X * Video, `subsamp` should be set to @ref TJSAMP_420. This produces an image * compatible with the I420 (AKA "YUV420P") format. * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjEncodeYUV3(tjhandle handle, const unsigned char *srcBuf, int width, int pitch, int height, int pixelFormat, unsigned char *dstBuf, int align, int subsamp, int flags); /** * Encode a packed-pixel RGB or grayscale image into separate Y, U (Cb), and * V (Cr) image planes. This function performs color conversion (which is * accelerated in the libjpeg-turbo implementation) but does not execute any of * the other steps in the JPEG compression process. * * @param handle a handle to a TurboJPEG compressor or transformer instance * * @param srcBuf pointer to a buffer containing a packed-pixel RGB or grayscale * source image to be encoded * * @param width width (in pixels) of the source image * * @param pitch bytes per row in the source image. Normally this should be * <tt>width * #tjPixelSize[pixelFormat]</tt>, if the image is unpadded, or * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each row of the image * is padded to the nearest multiple of 4 bytes, as is the case for Windows * bitmaps. You can also be clever and use this parameter to skip rows, etc. * Setting this parameter to 0 is the equivalent of setting it to * <tt>width * #tjPixelSize[pixelFormat]</tt>. * * @param height height (in pixels) of the source image * * @param pixelFormat pixel format of the source image (see @ref TJPF * "Pixel formats".) * * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes * (or just a Y plane, if generating a grayscale image) that will receive the * encoded image. These planes can be contiguous or non-contiguous in memory. * Use #tjPlaneSizeYUV() to determine the appropriate size for each plane based * on the image width, height, strides, and level of chrominance subsampling. * Refer to @ref YUVnotes "YUV Image Format Notes" for more details. * * @param strides an array of integers, each specifying the number of bytes per * row in the corresponding plane of the YUV image. Setting the stride for any * plane to 0 is the same as setting it to the plane width (see @ref YUVnotes * "YUV Image Format Notes".) If `strides` is NULL, then the strides for all * planes will be set to their respective plane widths. You can adjust the * strides in order to add an arbitrary amount of row padding to each plane or * to encode an RGB or grayscale image into a subregion of a larger planar YUV * image. * * @param subsamp the level of chrominance subsampling to be used when * generating the YUV image (see @ref TJSAMP * "Chrominance subsampling options".) To generate images suitable for X * Video, `subsamp` should be set to @ref TJSAMP_420. This produces an image * compatible with the I420 (AKA "YUV420P") format. * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjEncodeYUVPlanes(tjhandle handle, const unsigned char *srcBuf, int width, int pitch, int height, int pixelFormat, unsigned char **dstPlanes, int *strides, int subsamp, int flags); /** * Create a TurboJPEG decompressor instance. * * @return a handle to the newly-created instance, or NULL if an error occurred * (see #tjGetErrorStr2().) */ DLLEXPORT tjhandle tjInitDecompress(void); /** * Retrieve information about a JPEG image without decompressing it, or prime * the decompressor with quantization and Huffman tables. * * @param handle a handle to a TurboJPEG decompressor or transformer instance * * @param jpegBuf pointer to a byte buffer containing a JPEG image or an * "abbreviated table specification" (AKA "tables-only") datastream. Passing a * tables-only datastream to this function primes the decompressor with * quantization and Huffman tables that can be used when decompressing * subsequent "abbreviated image" datastreams. This is useful, for instance, * when decompressing video streams in which all frames share the same * quantization and Huffman tables. * * @param jpegSize size of the JPEG image or tables-only datastream (in bytes) * * @param width pointer to an integer variable that will receive the width (in * pixels) of the JPEG image. If `jpegBuf` points to a tables-only datastream, * then `width` is ignored. * * @param height pointer to an integer variable that will receive the height * (in pixels) of the JPEG image. If `jpegBuf` points to a tables-only * datastream, then `height` is ignored. * * @param jpegSubsamp pointer to an integer variable that will receive the * level of chrominance subsampling used when the JPEG image was compressed * (see @ref TJSAMP "Chrominance subsampling options".) If `jpegBuf` points to * a tables-only datastream, then `jpegSubsamp` is ignored. * * @param jpegColorspace pointer to an integer variable that will receive one * of the JPEG colorspace constants, indicating the colorspace of the JPEG * image (see @ref TJCS "JPEG colorspaces".) If `jpegBuf` points to a * tables-only datastream, then `jpegColorspace` is ignored. * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjDecompressHeader3(tjhandle handle, const unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height, int *jpegSubsamp, int *jpegColorspace); /** * Returns a list of fractional scaling factors that the JPEG decompressor * supports. * * @param numScalingFactors pointer to an integer variable that will receive * the number of elements in the list * * @return a pointer to a list of fractional scaling factors, or NULL if an * error is encountered (see #tjGetErrorStr2().) */ DLLEXPORT tjscalingfactor *tjGetScalingFactors(int *numScalingFactors); /** * Decompress a JPEG image into a packed-pixel RGB, grayscale, or CMYK image. * * @param handle a handle to a TurboJPEG decompressor or transformer instance * * @param jpegBuf pointer to a byte buffer containing the JPEG image to * decompress * * @param jpegSize size of the JPEG image (in bytes) * * @param dstBuf pointer to a buffer that will receive the packed-pixel * decompressed image. This buffer should normally be `pitch * scaledHeight` * bytes in size, where `scaledHeight` can be determined by calling #TJSCALED() * with the JPEG image height and one of the scaling factors returned by * #tjGetScalingFactors(). The `dstBuf` pointer may also be used to decompress * into a specific region of a larger buffer. * * @param width desired width (in pixels) of the destination image. If this is * different than the width of the JPEG image being decompressed, then * TurboJPEG will use scaling in the JPEG decompressor to generate the largest * possible image that will fit within the desired width. If `width` is set to * 0, then only the height will be considered when determining the scaled image * size. * * @param pitch bytes per row in the destination image. Normally this should * be set to <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt>, if the * destination image should be unpadded, or * <tt>#TJPAD(scaledWidth * #tjPixelSize[pixelFormat])</tt> if each row of the * destination image should be padded to the nearest multiple of 4 bytes, as is * the case for Windows bitmaps. (NOTE: `scaledWidth` can be determined by * calling #TJSCALED() with the JPEG image width and one of the scaling factors * returned by #tjGetScalingFactors().) You can also be clever and use the * pitch parameter to skip rows, etc. Setting this parameter to 0 is the * equivalent of setting it to * <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt>. * * @param height desired height (in pixels) of the destination image. If this * is different than the height of the JPEG image being decompressed, then * TurboJPEG will use scaling in the JPEG decompressor to generate the largest * possible image that will fit within the desired height. If `height` is set * to 0, then only the width will be considered when determining the scaled * image size. * * @param pixelFormat pixel format of the destination image (see @ref * TJPF "Pixel formats".) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjDecompress2(tjhandle handle, const unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf, int width, int pitch, int height, int pixelFormat, int flags); /** * Decompress a JPEG image into a unified planar YUV image. This function * performs JPEG decompression but leaves out the color conversion step, so a * planar YUV image is generated instead of a packed-pixel image. * * @param handle a handle to a TurboJPEG decompressor or transformer instance * * @param jpegBuf pointer to a byte buffer containing the JPEG image to * decompress * * @param jpegSize size of the JPEG image (in bytes) * * @param dstBuf pointer to a buffer that will receive the unified planar YUV * decompressed image. Use #tjBufSizeYUV2() to determine the appropriate size * for this buffer based on the scaled image width, scaled image height, row * alignment, and level of chrominance subsampling. The Y, U (Cb), and V (Cr) * image planes will be stored sequentially in the buffer. (Refer to * @ref YUVnotes "YUV Image Format Notes".) * * @param width desired width (in pixels) of the YUV image. If this is * different than the width of the JPEG image being decompressed, then * TurboJPEG will use scaling in the JPEG decompressor to generate the largest * possible image that will fit within the desired width. If `width` is set to * 0, then only the height will be considered when determining the scaled image * size. If the scaled width is not an even multiple of the MCU block width * (see #tjMCUWidth), then an intermediate buffer copy will be performed. * * @param align row alignment (in bytes) of the YUV image (must be a power of * 2.) Setting this parameter to n will cause each row in each plane of the * YUV image to be padded to the nearest multiple of n bytes (1 = unpadded.) * To generate images suitable for X Video, `align` should be set to 4. * * @param height desired height (in pixels) of the YUV image. If this is * different than the height of the JPEG image being decompressed, then * TurboJPEG will use scaling in the JPEG decompressor to generate the largest * possible image that will fit within the desired height. If `height` is set * to 0, then only the width will be considered when determining the scaled * image size. If the scaled height is not an even multiple of the MCU block * height (see #tjMCUHeight), then an intermediate buffer copy will be * performed. * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjDecompressToYUV2(tjhandle handle, const unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf, int width, int align, int height, int flags); /** * Decompress a JPEG image into separate Y, U (Cb), and V (Cr) image * planes. This function performs JPEG decompression but leaves out the color * conversion step, so a planar YUV image is generated instead of a * packed-pixel image. * * @param handle a handle to a TurboJPEG decompressor or transformer instance * * @param jpegBuf pointer to a byte buffer containing the JPEG image to * decompress * * @param jpegSize size of the JPEG image (in bytes) * * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes * (or just a Y plane, if decompressing a grayscale image) that will receive * the decompressed image. These planes can be contiguous or non-contiguous in * memory. Use #tjPlaneSizeYUV() to determine the appropriate size for each * plane based on the scaled image width, scaled image height, strides, and * level of chrominance subsampling. Refer to @ref YUVnotes * "YUV Image Format Notes" for more details. * * @param width desired width (in pixels) of the YUV image. If this is * different than the width of the JPEG image being decompressed, then * TurboJPEG will use scaling in the JPEG decompressor to generate the largest * possible image that will fit within the desired width. If `width` is set to * 0, then only the height will be considered when determining the scaled image * size. If the scaled width is not an even multiple of the MCU block width * (see #tjMCUWidth), then an intermediate buffer copy will be performed. * * @param strides an array of integers, each specifying the number of bytes per * row in the corresponding plane of the YUV image. Setting the stride for any * plane to 0 is the same as setting it to the scaled plane width (see * @ref YUVnotes "YUV Image Format Notes".) If `strides` is NULL, then the * strides for all planes will be set to their respective scaled plane widths. * You can adjust the strides in order to add an arbitrary amount of row * padding to each plane or to decompress the JPEG image into a subregion of a * larger planar YUV image. * * @param height desired height (in pixels) of the YUV image. If this is * different than the height of the JPEG image being decompressed, then * TurboJPEG will use scaling in the JPEG decompressor to generate the largest * possible image that will fit within the desired height. If `height` is set * to 0, then only the width will be considered when determining the scaled * image size. If the scaled height is not an even multiple of the MCU block * height (see #tjMCUHeight), then an intermediate buffer copy will be * performed. * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjDecompressToYUVPlanes(tjhandle handle, const unsigned char *jpegBuf, unsigned long jpegSize, unsigned char **dstPlanes, int width, int *strides, int height, int flags); /** * Decode a unified planar YUV image into a packed-pixel RGB or grayscale * image. This function performs color conversion (which is accelerated in the * libjpeg-turbo implementation) but does not execute any of the other steps in * the JPEG decompression process. * * @param handle a handle to a TurboJPEG decompressor or transformer instance * * @param srcBuf pointer to a buffer containing a unified planar YUV source * image to be decoded. The size of this buffer should match the value * returned by #tjBufSizeYUV2() for the given image width, height, row * alignment, and level of chrominance subsampling. The Y, U (Cb), and V (Cr) * image planes should be stored sequentially in the source buffer. (Refer to * @ref YUVnotes "YUV Image Format Notes".) * * @param align row alignment (in bytes) of the YUV source image (must be a * power of 2.) Setting this parameter to n indicates that each row in each * plane of the YUV source image is padded to the nearest multiple of n bytes * (1 = unpadded.) * * @param subsamp the level of chrominance subsampling used in the YUV source * image (see @ref TJSAMP "Chrominance subsampling options".) * * @param dstBuf pointer to a buffer that will receive the packed-pixel decoded * image. This buffer should normally be `pitch * height` bytes in size, but * the `dstBuf` pointer can also be used to decode into a specific region of a * larger buffer. * * @param width width (in pixels) of the source and destination images * * @param pitch bytes per row in the destination image. Normally this should * be set to <tt>width * #tjPixelSize[pixelFormat]</tt>, if the destination * image should be unpadded, or * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each row of the * destination image should be padded to the nearest multiple of 4 bytes, as is * the case for Windows bitmaps. You can also be clever and use the pitch * parameter to skip rows, etc. Setting this parameter to 0 is the equivalent * of setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>. * * @param height height (in pixels) of the source and destination images * * @param pixelFormat pixel format of the destination image (see @ref TJPF * "Pixel formats".) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjDecodeYUV(tjhandle handle, const unsigned char *srcBuf, int align, int subsamp, unsigned char *dstBuf, int width, int pitch, int height, int pixelFormat, int flags); /** * Decode a set of Y, U (Cb), and V (Cr) image planes into a packed-pixel RGB * or grayscale image. This function performs color conversion (which is * accelerated in the libjpeg-turbo implementation) but does not execute any of * the other steps in the JPEG decompression process. * * @param handle a handle to a TurboJPEG decompressor or transformer instance * * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes * (or just a Y plane, if decoding a grayscale image) that contain a YUV image * to be decoded. These planes can be contiguous or non-contiguous in memory. * The size of each plane should match the value returned by #tjPlaneSizeYUV() * for the given image width, height, strides, and level of chrominance * subsampling. Refer to @ref YUVnotes "YUV Image Format Notes" for more * details. * * @param strides an array of integers, each specifying the number of bytes per * row in the corresponding plane of the YUV source image. Setting the stride * for any plane to 0 is the same as setting it to the plane width (see * @ref YUVnotes "YUV Image Format Notes".) If `strides` is NULL, then the * strides for all planes will be set to their respective plane widths. You * can adjust the strides in order to specify an arbitrary amount of row * padding in each plane or to decode a subregion of a larger planar YUV image. * * @param subsamp the level of chrominance subsampling used in the YUV source * image (see @ref TJSAMP "Chrominance subsampling options".) * * @param dstBuf pointer to a buffer that will receive the packed-pixel decoded * image. This buffer should normally be `pitch * height` bytes in size, but * the `dstBuf` pointer can also be used to decode into a specific region of a * larger buffer. * * @param width width (in pixels) of the source and destination images * * @param pitch bytes per row in the destination image. Normally this should * be set to <tt>width * #tjPixelSize[pixelFormat]</tt>, if the destination * image should be unpadded, or * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each row of the * destination image should be padded to the nearest multiple of 4 bytes, as is * the case for Windows bitmaps. You can also be clever and use the pitch * parameter to skip rows, etc. Setting this parameter to 0 is the equivalent * of setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>. * * @param height height (in pixels) of the source and destination images * * @param pixelFormat pixel format of the destination image (see @ref TJPF * "Pixel formats".) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjDecodeYUVPlanes(tjhandle handle, const unsigned char **srcPlanes, const int *strides, int subsamp, unsigned char *dstBuf, int width, int pitch, int height, int pixelFormat, int flags); /** * Create a new TurboJPEG transformer instance. * * @return a handle to the newly-created instance, or NULL if an error * occurred (see #tjGetErrorStr2().) */ DLLEXPORT tjhandle tjInitTransform(void); /** * Losslessly transform a JPEG image into another JPEG image. Lossless * transforms work by moving the raw DCT coefficients from one JPEG image * structure to another without altering the values of the coefficients. While * this is typically faster than decompressing the image, transforming it, and * re-compressing it, lossless transforms are not free. Each lossless * transform requires reading and performing Huffman decoding on all of the * coefficients in the source image, regardless of the size of the destination * image. Thus, this function provides a means of generating multiple * transformed images from the same source or applying multiple transformations * simultaneously, in order to eliminate the need to read the source * coefficients multiple times. * * @param handle a handle to a TurboJPEG transformer instance * * @param jpegBuf pointer to a byte buffer containing the JPEG source image to * transform * * @param jpegSize size of the JPEG source image (in bytes) * * @param n the number of transformed JPEG images to generate * * @param dstBufs pointer to an array of n byte buffers. `dstBufs[i]` will * receive a JPEG image that has been transformed using the parameters in * `transforms[i]`. TurboJPEG has the ability to reallocate the JPEG * destination buffer to accommodate the size of the transformed JPEG image. * Thus, you can choose to: * -# pre-allocate the JPEG destination buffer with an arbitrary size using * #tjAlloc() and let TurboJPEG grow the buffer as needed, * -# set `dstBufs[i]` to NULL to tell TurboJPEG to allocate the buffer for * you, or * -# pre-allocate the buffer to a "worst case" size determined by calling * #tjBufSize() with the transformed or cropped width and height. Under normal * circumstances, this should ensure that the buffer never has to be * re-allocated. (Setting #TJFLAG_NOREALLOC guarantees that it won't be.) * Note, however, that there are some rare cases (such as transforming images * with a large amount of embedded EXIF or ICC profile data) in which the * transformed JPEG image will be larger than the worst-case size, and * #TJFLAG_NOREALLOC cannot be used in those cases. * . * If you choose option 1, then `dstSizes[i]` should be set to the size of your * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC, * you should always check `dstBufs[i]` upon return from this function, as it * may have changed. * * @param dstSizes pointer to an array of n unsigned long variables that will * receive the actual sizes (in bytes) of each transformed JPEG image. If * `dstBufs[i]` points to a pre-allocated buffer, then `dstSizes[i]` should be * set to the size of the buffer. Upon return, `dstSizes[i]` will contain the * size of the transformed JPEG image (in bytes.) * * @param transforms pointer to an array of n #tjtransform structures, each of * which specifies the transform parameters and/or cropping region for the * corresponding transformed JPEG image. * * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT * "flags" * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2() * and #tjGetErrorCode().) */ DLLEXPORT int tjTransform(tjhandle handle, const unsigned char *jpegBuf, unsigned long jpegSize, int n, unsigned char **dstBufs, unsigned long *dstSizes, tjtransform *transforms, int flags); /** * Destroy a TurboJPEG compressor, decompressor, or transformer instance. * * @param handle a handle to a TurboJPEG compressor, decompressor or * transformer instance * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2().) */ DLLEXPORT int tjDestroy(tjhandle handle); /** * Allocate a byte buffer for use with TurboJPEG. You should always use this * function to allocate the JPEG destination buffer(s) for the compression and * transform functions unless you are disabling automatic buffer (re)allocation * (by setting #TJFLAG_NOREALLOC.) * * @param bytes the number of bytes to allocate * * @return a pointer to a newly-allocated buffer with the specified number of * bytes. * * @sa tjFree() */ DLLEXPORT unsigned char *tjAlloc(int bytes); /** * Load a packed-pixel image from disk into memory. * * @param filename name of a file containing a packed-pixel image in Windows * BMP or PBMPLUS (PPM/PGM) format * * @param width pointer to an integer variable that will receive the width (in * pixels) of the packed-pixel image * * @param align row alignment of the packed-pixel buffer to be returned (must * be a power of 2.) Setting this parameter to n will cause all rows in the * buffer to be padded to the nearest multiple of n bytes (1 = unpadded.) * * @param height pointer to an integer variable that will receive the height * (in pixels) of the packed-pixel image * * @param pixelFormat pointer to an integer variable that specifies or will * receive the pixel format of the packed-pixel buffer. The behavior of * #tjLoadImage() will vary depending on the value of `*pixelFormat` passed to * the function: * - @ref TJPF_UNKNOWN : The packed-pixel buffer returned by this function will * use the most optimal pixel format for the file type, and `*pixelFormat` will * contain the ID of that pixel format upon successful return from this * function. * - @ref TJPF_GRAY : Only PGM files and 8-bit-per-pixel BMP files with a * grayscale colormap can be loaded. * - @ref TJPF_CMYK : The RGB or grayscale pixels stored in the file will be * converted using a quick & dirty algorithm that is suitable only for testing * purposes. (Proper conversion between CMYK and other formats requires a * color management system.) * - Other @ref TJPF "pixel formats" : The packed-pixel buffer will use the * specified pixel format, and pixel format conversion will be performed if * necessary. * * @param flags the bitwise OR of one or more of the @ref TJFLAG_BOTTOMUP * "flags". * * @return a pointer to a newly-allocated buffer containing the packed-pixel * image, converted to the chosen pixel format and with the chosen row * alignment, or NULL if an error occurred (see #tjGetErrorStr2().) This * buffer should be freed using #tjFree(). */ DLLEXPORT unsigned char *tjLoadImage(const char *filename, int *width, int align, int *height, int *pixelFormat, int flags); /** * Save a packed-pixel image from memory to disk. * * @param filename name of a file to which to save the packed-pixel image. The * image will be stored in Windows BMP or PBMPLUS (PPM/PGM) format, depending * on the file extension. * * @param buffer pointer to a buffer containing a packed-pixel RGB, grayscale, * or CMYK image to be saved * * @param width width (in pixels) of the packed-pixel image * * @param pitch bytes per row in the packed-pixel image. Setting this * parameter to 0 is the equivalent of setting it to * <tt>width * #tjPixelSize[pixelFormat]</tt>. * * @param height height (in pixels) of the packed-pixel image * * @param pixelFormat pixel format of the packed-pixel image (see @ref TJPF * "Pixel formats".) If this parameter is set to @ref TJPF_GRAY, then the * image will be stored in PGM or 8-bit-per-pixel (indexed color) BMP format. * Otherwise, the image will be stored in PPM or 24-bit-per-pixel BMP format. * If this parameter is set to @ref TJPF_CMYK, then the CMYK pixels will be * converted to RGB using a quick & dirty algorithm that is suitable only for * testing purposes. (Proper conversion between CMYK and other formats * requires a color management system.) * * @param flags the bitwise OR of one or more of the @ref TJFLAG_BOTTOMUP * "flags". * * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2().) */ DLLEXPORT int tjSaveImage(const char *filename, unsigned char *buffer, int width, int pitch, int height, int pixelFormat, int flags); /** * Free a byte buffer previously allocated by TurboJPEG. You should always use * this function to free JPEG destination buffer(s) that were automatically * (re)allocated by the compression and transform functions or that were * manually allocated using #tjAlloc(). * * @param buffer address of the buffer to free. If the address is NULL, then * this function has no effect. * * @sa tjAlloc() */ DLLEXPORT void tjFree(unsigned char *buffer); /** * Returns a descriptive error message explaining why the last command failed. * * @param handle a handle to a TurboJPEG compressor, decompressor, or * transformer instance, or NULL if the error was generated by a global * function (but note that retrieving the error message for a global function * is thread-safe only on platforms that support thread-local storage.) * * @return a descriptive error message explaining why the last command failed. */ DLLEXPORT char *tjGetErrorStr2(tjhandle handle); /** * Returns a code indicating the severity of the last error. See * @ref TJERR "Error codes". * * @param handle a handle to a TurboJPEG compressor, decompressor or * transformer instance * * @return a code indicating the severity of the last error. See * @ref TJERR "Error codes". */ DLLEXPORT int tjGetErrorCode(tjhandle handle); /* Backward compatibility functions and macros (nothing to see here) */ /* TurboJPEG 1.0+ */ #define NUMSUBOPT … #define TJ_444 … #define TJ_422 … #define TJ_420 … #define TJ_411 … #define TJ_GRAYSCALE … #define TJ_BGR … #define TJ_BOTTOMUP … #define TJ_FORCEMMX … #define TJ_FORCESSE … #define TJ_FORCESSE2 … #define TJ_ALPHAFIRST … #define TJ_FORCESSE3 … #define TJ_FASTUPSAMPLE … DLLEXPORT unsigned long TJBUFSIZE(int width, int height); DLLEXPORT int tjCompress(tjhandle handle, unsigned char *srcBuf, int width, int pitch, int height, int pixelSize, unsigned char *dstBuf, unsigned long *compressedSize, int jpegSubsamp, int jpegQual, int flags); DLLEXPORT int tjDecompress(tjhandle handle, unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf, int width, int pitch, int height, int pixelSize, int flags); DLLEXPORT int tjDecompressHeader(tjhandle handle, unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height); DLLEXPORT char *tjGetErrorStr(void); /* TurboJPEG 1.1+ */ #define TJ_YUV … DLLEXPORT unsigned long TJBUFSIZEYUV(int width, int height, int jpegSubsamp); DLLEXPORT int tjDecompressHeader2(tjhandle handle, unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height, int *jpegSubsamp); DLLEXPORT int tjDecompressToYUV(tjhandle handle, unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf, int flags); DLLEXPORT int tjEncodeYUV(tjhandle handle, unsigned char *srcBuf, int width, int pitch, int height, int pixelSize, unsigned char *dstBuf, int subsamp, int flags); /* TurboJPEG 1.2+ */ #define TJFLAG_FORCEMMX … #define TJFLAG_FORCESSE … #define TJFLAG_FORCESSE2 … #define TJFLAG_FORCESSE3 … DLLEXPORT unsigned long tjBufSizeYUV(int width, int height, int subsamp); DLLEXPORT int tjEncodeYUV2(tjhandle handle, unsigned char *srcBuf, int width, int pitch, int height, int pixelFormat, unsigned char *dstBuf, int subsamp, int flags); /** * @} */ #ifdef __cplusplus } #endif #endif
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