/*
* Copyright (C)2009-2013 D. R. Commander. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the libjpeg-turbo Project nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS",
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. 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 __declspec(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.
*
* @{
*/
/**
* The number of chrominance subsampling options
*/
#define TJ_NUMSAMP 5
/**
* Chrominance subsampling options.
* When an image is converted from the RGB to the YCbCr colorspace 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 small changes in color.) This is called
* "chrominance subsampling".
* <p>
* NOTE: Technically, the JPEG format uses the YCbCr colorspace, 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.
*/
enum TJSAMP
{
/**
* 4:4:4 chrominance subsampling (no chrominance subsampling). The JPEG or
* YUV image will contain one chrominance component for every pixel in the
* source image.
*/
TJSAMP_444=0,
/**
* 4:2:2 chrominance subsampling. The JPEG or YUV image will contain one
* chrominance component for every 2x1 block of pixels in the source image.
*/
TJSAMP_422,
/**
* 4:2:0 chrominance subsampling. The JPEG or YUV image will contain one
* chrominance component for every 2x2 block of pixels in the source image.
*/
TJSAMP_420,
/**
* Grayscale. The JPEG or YUV image will contain no chrominance components.
*/
TJSAMP_GRAY,
/**
* 4:4:0 chrominance subsampling. The JPEG or YUV image will contain one
* chrominance component for every 1x2 block of pixels in the source image.
* Note that 4:4:0 subsampling is not fully accelerated in libjpeg-turbo.
*/
TJSAMP_440
};
/**
* 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
*/
static const int tjMCUWidth[TJ_NUMSAMP] = {8, 16, 16, 8, 8};
/**
* 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
*/
static const int tjMCUHeight[TJ_NUMSAMP] = {8, 8, 16, 8, 16};
/**
* The number of pixel formats
*/
#define TJ_NUMPF 11
/**
* Pixel formats
*/
enum TJPF
{
/**
* RGB pixel format. The red, green, and blue components in the image are
* stored in 3-byte pixels in the order R, G, B from lowest to highest byte
* address within each pixel.
*/
TJPF_RGB=0,
/**
* BGR pixel format. The red, green, and blue components in the image are
* stored in 3-byte pixels in the order B, G, R from lowest to highest byte
* address within each pixel.
*/
TJPF_BGR,
/**
* RGBX pixel format. The red, green, and blue components in the image are
* stored in 4-byte pixels in the order R, G, B from lowest to highest byte
* address within each pixel. The X component is ignored when compressing
* and undefined when decompressing.
*/
TJPF_RGBX,
/**
* BGRX pixel format. The red, green, and blue components in the image are
* stored in 4-byte pixels in the order B, G, R from lowest to highest byte
* address within each pixel. The X component is ignored when compressing
* and undefined when decompressing.
*/
TJPF_BGRX,
/**
* XBGR pixel format. The red, green, and blue components in the image are
* stored in 4-byte pixels in the order R, G, B from highest to lowest byte
* address within each pixel. The X component is ignored when compressing
* and undefined when decompressing.
*/
TJPF_XBGR,
/**
* XRGB pixel format. The red, green, and blue components in the image are
* stored in 4-byte pixels in the order B, G, R from highest to lowest byte
* address within each pixel. The X component is ignored when compressing
* and undefined when decompressing.
*/
TJPF_XRGB,
/**
* Grayscale pixel format. Each 1-byte pixel represents a luminance
* (brightness) level from 0 to 255.
*/
TJPF_GRAY,
/**
* RGBA pixel format. This is the same as @ref TJPF_RGBX, except that when
* decompressing, the X component is guaranteed to be 0xFF, which can be
* interpreted as an opaque alpha channel.
*/
TJPF_RGBA,
/**
* BGRA pixel format. This is the same as @ref TJPF_BGRX, except that when
* decompressing, the X component is guaranteed to be 0xFF, which can be
* interpreted as an opaque alpha channel.
*/
TJPF_BGRA,
/**
* ABGR pixel format. This is the same as @ref TJPF_XBGR, except that when
* decompressing, the X component is guaranteed to be 0xFF, which can be
* interpreted as an opaque alpha channel.
*/
TJPF_ABGR,
/**
* ARGB pixel format. This is the same as @ref TJPF_XRGB, except that when
* decompressing, the X component is guaranteed to be 0xFF, which can be
* interpreted as an opaque alpha channel.
*/
TJPF_ARGB
};
/**
* 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 TJ_BGRX is stored in <tt>char pixel[]</tt>,
* then the red component will be <tt>pixel[tjRedOffset[TJ_BGRX]]</tt>.
*/
static const int tjRedOffset[TJ_NUMPF] = {0, 2, 0, 2, 3, 1, 0, 0, 2, 3, 1};
/**
* 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 TJ_BGRX is stored in
* <tt>char pixel[]</tt>, then the green component will be
* <tt>pixel[tjGreenOffset[TJ_BGRX]]</tt>.
*/
static const int tjGreenOffset[TJ_NUMPF] = {1, 1, 1, 1, 2, 2, 0, 1, 1, 2, 2};
/**
* 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 TJ_BGRX is stored in <tt>char pixel[]</tt>,
* then the blue component will be <tt>pixel[tjBlueOffset[TJ_BGRX]]</tt>.
*/
static const int tjBlueOffset[TJ_NUMPF] = {2, 0, 2, 0, 1, 3, 0, 2, 0, 1, 3};
/**
* Pixel size (in bytes) for a given pixel format.
*/
static const int tjPixelSize[TJ_NUMPF] = {3, 3, 4, 4, 4, 4, 1, 4, 4, 4, 4};
/**
* The uncompressed source/destination image is stored in bottom-up (Windows,
* OpenGL) order, not top-down (X11) order.
*/
#define TJFLAG_BOTTOMUP 2
/**
* Turn off CPU auto-detection and force TurboJPEG to use MMX code (if the
* underlying codec supports it.)
*/
#define TJFLAG_FORCEMMX 8
/**
* Turn off CPU auto-detection and force TurboJPEG to use SSE code (if the
* underlying codec supports it.)
*/
#define TJFLAG_FORCESSE 16
/**
* Turn off CPU auto-detection and force TurboJPEG to use SSE2 code (if the
* underlying codec supports it.)
*/
#define TJFLAG_FORCESSE2 32
/**
* Turn off CPU auto-detection and force TurboJPEG to use SSE3 code (if the
* underlying codec supports it.)
*/
#define TJFLAG_FORCESSE3 128
/**
* When decompressing an image that was compressed using chrominance
* subsampling, use the fastest chrominance upsampling algorithm available in
* the underlying codec. 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 256
/**
* Disable buffer (re)allocation. If passed to #tjCompress2() or
* #tjTransform(), this flag will cause those functions to generate an error if
* the JPEG image buffer is invalid or too small rather than attempting to
* allocate or reallocate that buffer. This reproduces the behavior of earlier
* versions of TurboJPEG.
*/
#define TJFLAG_NOREALLOC 1024
/**
* Use the fastest DCT/IDCT algorithm available in the underlying codec. The
* default if this flag is not specified is implementation-specific. For
* example, the implementation of TurboJPEG for 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 2048
/**
* Use the most accurate DCT/IDCT algorithm available in the underlying codec.
* The default if this flag is not specified is implementation-specific. For
* example, the implementation of TurboJPEG for 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 4096
/**
* The number of transform operations
*/
#define TJ_NUMXOP 8
/**
* Transform operations for #tjTransform()
*/
enum TJXOP
{
/**
* Do not transform the position of the image pixels
*/
TJXOP_NONE=0,
/**
* Flip (mirror) image horizontally. This transform is imperfect if there
* are any partial MCU blocks on the right edge (see #TJXOPT_PERFECT.)
*/
TJXOP_HFLIP,
/**
* Flip (mirror) image vertically. This transform is imperfect if there are
* any partial MCU blocks on the bottom edge (see #TJXOPT_PERFECT.)
*/
TJXOP_VFLIP,
/**
* Transpose image (flip/mirror along upper left to lower right axis.) This
* transform is always perfect.
*/
TJXOP_TRANSPOSE,
/**
* Transverse transpose image (flip/mirror along upper right to lower left
* axis.) This transform is imperfect if there are any partial MCU blocks in
* the image (see #TJXOPT_PERFECT.)
*/
TJXOP_TRANSVERSE,
/**
* Rotate image clockwise by 90 degrees. This transform is imperfect if
* there are any partial MCU blocks on the bottom edge (see
* #TJXOPT_PERFECT.)
*/
TJXOP_ROT90,
/**
* Rotate image 180 degrees. This transform is imperfect if there are any
* partial MCU blocks in the image (see #TJXOPT_PERFECT.)
*/
TJXOP_ROT180,
/**
* Rotate image counter-clockwise by 90 degrees. This transform is imperfect
* if there are any partial MCU blocks on the right edge (see
* #TJXOPT_PERFECT.)
*/
TJXOP_ROT270
};
/**
* 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 1
/**
* This option will cause #tjTransform() to discard any partial MCU blocks that
* cannot be transformed.
*/
#define TJXOPT_TRIM 2
/**
* This option will enable lossless cropping. See #tjTransform() for more
* information.
*/
#define TJXOPT_CROP 4
/**
* This option will discard the color data in the input image and produce
* a grayscale output image.
*/
#define TJXOPT_GRAY 8
/**
* 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 16
/**
* Scaling factor
*/
typedef struct
{
/**
* Numerator
*/
int num;
/**
* Denominator
*/
int denom;
} tjscalingfactor;
/**
* Cropping region
*/
typedef struct
{
/**
* The left boundary of the cropping region. This must be evenly divisible
* by the MCU block width (see #tjMCUWidth.)
*/
int x;
/**
* The upper boundary of the cropping region. This must be evenly divisible
* by the MCU block height (see #tjMCUHeight.)
*/
int y;
/**
* The width of the cropping region. Setting this to 0 is the equivalent of
* setting it to the width of the source JPEG image - x.
*/
int w;
/**
* The height of the cropping region. Setting this to 0 is the equivalent of
* setting it to the height of the source JPEG image - y.
*/
int h;
} tjregion;
/**
* Lossless transform
*/
typedef struct tjtransform
{
/**
* Cropping region
*/
tjregion r;
/**
* One of the @ref TJXOP "transform operations"
*/
int op;
/**
* The bitwise OR of one of more of the @ref TJXOPT_CROP "transform options"
*/
int options;
/**
* Arbitrary data that can be accessed within the body of the callback
* function
*/
void *data;
/**
* A callback function that can be used to modify the DCT coefficients
* after they are losslessly transformed but before they are transcoded to a
* new JPEG image. This allows for custom filters or other transformations
* to be applied in the frequency domain.
*
* @param coeffs pointer to an array of transformed DCT coefficients. (NOTE:
* this pointer is not guaranteed to be valid once the callback
* returns, so applications wishing to hand off the DCT coefficients
* to another function or library should make a copy of them within
* the body of the callback.)
* @param arrayRegion #tjregion structure containing the width and height of
* the array pointed to by <tt>coeffs</tt> as well as its offset
* relative to the component plane. TurboJPEG implementations may
* choose to split each component plane into multiple DCT coefficient
* arrays and call the callback function once for each array.
* @param planeRegion #tjregion structure containing the width and height of
* the component plane to which <tt>coeffs</tt> belongs
* @param componentID ID number of the component plane to which
* <tt>coeffs</tt> belongs (Y, Cb, and Cr have, respectively, ID's of
* 0, 1, and 2 in typical JPEG images.)
* @param transformID ID number of the transformed image to which
* <tt>coeffs</tt> belongs. This is the same as the index of the
* transform in the <tt>transforms</tt> array that was passed to
* #tjTransform().
* @param transform a pointer to a #tjtransform structure that specifies the
* parameters and/or cropping region for this transform
*
* @return 0 if the callback was successful, or -1 if an error occurred.
*/
int (*customFilter)(short *coeffs, tjregion arrayRegion,
tjregion planeRegion, int componentIndex, int transformIndex,
struct tjtransform *transform);
} tjtransform;
/**
* TurboJPEG instance handle
*/
typedef void* tjhandle;
/**
* Pad the given width to the nearest 32-bit boundary
*/
#define TJPAD(width) (((width)+3)&(~3))
/**
* Compute the scaled value of <tt>dimension</tt> using the given scaling
* factor. This macro performs the integer equivalent of <tt>ceil(dimension *
* scalingFactor)</tt>.
*/
#define TJSCALED(dimension, scalingFactor) ((dimension * scalingFactor.num \
+ scalingFactor.denom - 1) / scalingFactor.denom)
#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 #tjGetErrorStr().)
*/
DLLEXPORT tjhandle DLLCALL tjInitCompress(void);
/**
* Compress an RGB or grayscale image into a JPEG image.
*
* @param handle a handle to a TurboJPEG compressor or transformer instance
* @param srcBuf pointer to an image buffer containing RGB or grayscale pixels
* to be compressed
* @param width width (in pixels) of the source image
* @param pitch bytes per line of 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 line of
* the image is padded to the nearest 32-bit boundary, as is the case
* for Windows bitmaps. You can also be clever and use this parameter
* to skip lines, 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 an image 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 <tt>*jpegBuf</tt> 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 this.)
* .
* If you choose option 1, <tt>*jpegSize</tt> should be set to the
* size of your pre-allocated buffer. In any case, unless you have
* set #TJFLAG_NOREALLOC, you should always check <tt>*jpegBuf</tt> 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 image buffer. If <tt>*jpegBuf</tt> points to a
* pre-allocated buffer, then <tt>*jpegSize</tt> should be set to the
* size of the buffer. Upon return, <tt>*jpegSize</tt> will contain the
* size of the JPEG image (in bytes.)
* @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_BOTTOMUP
* "flags".
*
* @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjCompress2(tjhandle handle, unsigned char *srcBuf,
int width, int pitch, int height, int pixelFormat, unsigned char **jpegBuf,
unsigned long *jpegSize, int jpegSubsamp, 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, and it is thus possible
* for a very high-quality JPEG image with very high-frequency content to
* expand rather than compress when converted to the JPEG format. Such images
* represent a very rare corner case, but since there is no way to predict the
* size of a JPEG image prior to compression, the corner case has to be
* handled.
*
* @param width width of the image (in pixels)
* @param height height of the image (in pixels)
* @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 DLLCALL tjBufSize(int width, int height,
int jpegSubsamp);
/**
* The size of the buffer (in bytes) required to hold a YUV planar image with
* the given parameters.
*
* @param width width of the image (in pixels)
* @param height height of the image (in pixels)
* @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 DLLCALL tjBufSizeYUV(int width, int height,
int subsamp);
/**
* Encode an RGB or grayscale image into a YUV planar image. This function
* uses the accelerated color conversion routines in TurboJPEG's underlying
* codec to produce a planar YUV image that is suitable for X Video.
* Specifically, if the chrominance components are subsampled along the
* horizontal dimension, then the width of the luminance plane is padded to the
* nearest multiple of 2 in the output image (same goes for the height of the
* luminance plane, if the chrominance components are subsampled along the
* vertical dimension.) Also, each line of each plane in the output image is
* padded to 4 bytes. Although this will work with any subsampling option, it
* is really only useful in combination with TJ_420, which produces an image
* compatible with the I420 (AKA "YUV420P") format.
* <p>
* NOTE: Technically, the JPEG format uses the YCbCr colorspace, 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.
*
* @param handle a handle to a TurboJPEG compressor or transformer instance
* @param srcBuf pointer to an image buffer containing RGB or grayscale pixels
* to be encoded
* @param width width (in pixels) of the source image
* @param pitch bytes per line of 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 line of
* the image is padded to the nearest 32-bit boundary, as is the case
* for Windows bitmaps. You can also be clever and use this parameter
* to skip lines, 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 an image buffer that will receive the YUV image.
* Use #tjBufSizeYUV() to determine the appropriate size for this buffer
* based on the image width, height, and level of chrominance
* subsampling.
* @param subsamp the level of chrominance subsampling to be used when
* generating the YUV image (see @ref TJSAMP
* "Chrominance subsampling options".)
* @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 #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjEncodeYUV2(tjhandle handle,
unsigned char *srcBuf, int width, int pitch, int height, int pixelFormat,
unsigned char *dstBuf, int subsamp, int flags);
/**
* Create a TurboJPEG decompressor instance.
*
* @return a handle to the newly-created instance, or NULL if an error
* occurred (see #tjGetErrorStr().)
*/
DLLEXPORT tjhandle DLLCALL tjInitDecompress(void);
/**
* Retrieve information about a JPEG image without decompressing it.
*
* @param handle a handle to a TurboJPEG decompressor or transformer instance
* @param jpegBuf pointer to a buffer containing a JPEG image
* @param jpegSize size of the JPEG image (in bytes)
* @param width pointer to an integer variable that will receive the width (in
* pixels) of the JPEG image
* @param height pointer to an integer variable that will receive the height
* (in pixels) of the JPEG image
* @param jpegSubsamp pointer to an integer variable that will receive the
* level of chrominance subsampling used when compressing the JPEG image
* (see @ref TJSAMP "Chrominance subsampling options".)
*
* @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjDecompressHeader2(tjhandle handle,
unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height,
int *jpegSubsamp);
/**
* Returns a list of fractional scaling factors that the JPEG decompressor in
* this implementation of TurboJPEG 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 #tjGetErrorStr().)
*/
DLLEXPORT tjscalingfactor* DLLCALL tjGetScalingFactors(int *numscalingfactors);
/**
* Decompress a JPEG image to an RGB or grayscale image.
*
* @param handle a handle to a TurboJPEG decompressor or transformer instance
* @param jpegBuf pointer to a buffer containing the JPEG image to decompress
* @param jpegSize size of the JPEG image (in bytes)
* @param dstBuf pointer to an image buffer that will receive the decompressed
* image. This buffer should normally be <tt>pitch * scaledHeight</tt>
* bytes in size, where <tt>scaledHeight</tt> can be determined by
* calling #TJSCALED() with the JPEG image height and one of the scaling
* factors returned by #tjGetScalingFactors(). The <tt>dstBuf</tt>
* 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
* <tt>width</tt> is set to 0, then only the height will be considered
* when determining the scaled image size.
* @param pitch bytes per line of the destination image. Normally, this is
* <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt> if the decompressed
* image is unpadded, else <tt>#TJPAD(scaledWidth *
* #tjPixelSize[pixelFormat])</tt> if each line of the decompressed
* image is padded to the nearest 32-bit boundary, as is the case for
* Windows bitmaps. (NOTE: <tt>scaledWidth</tt> 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 lines, 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 <tt>height</tt> 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_BOTTOMUP
* "flags".
*
* @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjDecompress2(tjhandle handle,
unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
int width, int pitch, int height, int pixelFormat, int flags);
/**
* Decompress a JPEG image to a YUV planar image. This function performs JPEG
* decompression but leaves out the color conversion step, so a planar YUV
* image is generated instead of an RGB image. The padding of the planes in
* this image is the same as in the images generated by #tjEncodeYUV2(). Note
* that, if the width or height of the image is not an even multiple of the MCU
* block size (see #tjMCUWidth and #tjMCUHeight), then an intermediate buffer
* copy will be performed within TurboJPEG.
* <p>
* NOTE: Technically, the JPEG format uses the YCbCr colorspace, 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.
*
* @param handle a handle to a TurboJPEG decompressor or transformer instance
* @param jpegBuf pointer to a buffer containing the JPEG image to decompress
* @param jpegSize size of the JPEG image (in bytes)
* @param dstBuf pointer to an image buffer that will receive the YUV image.
* Use #tjBufSizeYUV() to determine the appropriate size for this buffer
* based on the image width, height, and level of subsampling.
* @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 #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjDecompressToYUV(tjhandle handle,
unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
int flags);
/**
* Create a new TurboJPEG transformer instance.
*
* @return a handle to the newly-created instance, or NULL if an error
* occurred (see #tjGetErrorStr().)
*/
DLLEXPORT tjhandle DLLCALL tjInitTransform(void);
/**
* Losslessly transform a JPEG image into another JPEG image. Lossless
* transforms work by moving the raw 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 buffer containing the JPEG image to transform
* @param jpegSize size of the JPEG image (in bytes)
* @param n the number of transformed JPEG images to generate
* @param dstBufs pointer to an array of n image buffers. <tt>dstBufs[i]</tt>
* will receive a JPEG image that has been transformed using the
* parameters in <tt>transforms[i]</tt>. 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 <tt>dstBufs[i]</tt> 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. This should ensure that the buffer never has to be
* re-allocated (setting #TJFLAG_NOREALLOC guarantees this.)
* .
* If you choose option 1, <tt>dstSizes[i]</tt> should be set to
* the size of your pre-allocated buffer. In any case, unless you have
* set #TJFLAG_NOREALLOC, you should always check <tt>dstBufs[i]</tt>
* 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 <tt>dstBufs[i]</tt> points to a pre-allocated buffer, then
* <tt>dstSizes[i]</tt> should be set to the size of the buffer. Upon
* return, <tt>dstSizes[i]</tt> will contain the size of the 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 output image.
* @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 #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjTransform(tjhandle handle, 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 #tjGetErrorStr().)
*/
DLLEXPORT int DLLCALL tjDestroy(tjhandle handle);
/**
* Allocate an image buffer for use with TurboJPEG. You should always use
* this function to allocate the JPEG destination buffer(s) for #tjCompress2()
* and #tjTransform() 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* DLLCALL tjAlloc(int bytes);
/**
* Free an image buffer previously allocated by TurboJPEG. You should always
* use this function to free JPEG destination buffer(s) that were automatically
* (re)allocated by #tjCompress2() or #tjTransform() or that were manually
* allocated using #tjAlloc().
*
* @param buffer address of the buffer to free
*
* @sa tjAlloc()
*/
DLLEXPORT void DLLCALL tjFree(unsigned char *buffer);
/**
* Returns a descriptive error message explaining why the last command failed.
*
* @return a descriptive error message explaining why the last command failed.
*/
DLLEXPORT char* DLLCALL tjGetErrorStr(void);
/* Backward compatibility functions and macros (nothing to see here) */
#define NUMSUBOPT TJ_NUMSAMP
#define TJ_444 TJSAMP_444
#define TJ_422 TJSAMP_422
#define TJ_420 TJSAMP_420
#define TJ_411 TJSAMP_420
#define TJ_GRAYSCALE TJSAMP_GRAY
#define TJ_BGR 1
#define TJ_BOTTOMUP TJFLAG_BOTTOMUP
#define TJ_FORCEMMX TJFLAG_FORCEMMX
#define TJ_FORCESSE TJFLAG_FORCESSE
#define TJ_FORCESSE2 TJFLAG_FORCESSE2
#define TJ_ALPHAFIRST 64
#define TJ_FORCESSE3 TJFLAG_FORCESSE3
#define TJ_FASTUPSAMPLE TJFLAG_FASTUPSAMPLE
#define TJ_YUV 512
DLLEXPORT unsigned long DLLCALL TJBUFSIZE(int width, int height);
DLLEXPORT unsigned long DLLCALL TJBUFSIZEYUV(int width, int height,
int jpegSubsamp);
DLLEXPORT int DLLCALL 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 DLLCALL tjEncodeYUV(tjhandle handle,
unsigned char *srcBuf, int width, int pitch, int height, int pixelSize,
unsigned char *dstBuf, int subsamp, int flags);
DLLEXPORT int DLLCALL tjDecompressHeader(tjhandle handle,
unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height);
DLLEXPORT int DLLCALL tjDecompress(tjhandle handle,
unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
int width, int pitch, int height, int pixelSize, int flags);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#endif