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29 #ifndef __TURBOJPEG_H__
30 #define __TURBOJPEG_H__
32 #if defined(_WIN32) && defined(DLLDEFINE)
33 #define DLLEXPORT __declspec(dllexport)
41 * @addtogroup TurboJPEG
42 * TurboJPEG API. This API provides an interface for generating, decoding, and
43 * transforming planar YUV and JPEG images in memory.
46 * YUV Image Format Notes
47 * ----------------------
48 * Technically, the JPEG format uses the YCbCr colorspace (which is technically
49 * not a colorspace but a color transform), but per the convention of the
50 * digital video community, the TurboJPEG API uses "YUV" to refer to an image
51 * format consisting of Y, Cb, and Cr image planes.
53 * Each plane is simply a 2D array of bytes, each byte representing the value
54 * of one of the components (Y, Cb, or Cr) at a particular location in the
55 * image. The width and height of each plane are determined by the image
56 * width, height, and level of chrominance subsampling. The luminance plane
57 * width is the image width padded to the nearest multiple of the horizontal
58 * subsampling factor (2 in the case of 4:2:0 and 4:2:2, 4 in the case of
59 * 4:1:1, 1 in the case of 4:4:4 or grayscale.) Similarly, the luminance plane
60 * height is the image height padded to the nearest multiple of the vertical
61 * subsampling factor (2 in the case of 4:2:0 or 4:4:0, 1 in the case of 4:4:4
62 * or grayscale.) This is irrespective of any additional padding that may be
63 * specified as an argument to the various YUV functions. The chrominance
64 * plane width is equal to the luminance plane width divided by the horizontal
65 * subsampling factor, and the chrominance plane height is equal to the
66 * luminance plane height divided by the vertical subsampling factor.
68 * For example, if the source image is 35 x 35 pixels and 4:2:2 subsampling is
69 * used, then the luminance plane would be 36 x 35 bytes, and each of the
70 * chrominance planes would be 18 x 35 bytes. If you specify a line padding of
71 * 4 bytes on top of this, then the luminance plane would be 36 x 35 bytes, and
72 * each of the chrominance planes would be 20 x 35 bytes.
79 * The number of chrominance subsampling options
84 * Chrominance subsampling options.
85 * When pixels are converted from RGB to YCbCr (see #TJCS_YCbCr) or from CMYK
86 * to YCCK (see #TJCS_YCCK) as part of the JPEG compression process, some of
87 * the Cb and Cr (chrominance) components can be discarded or averaged together
88 * to produce a smaller image with little perceptible loss of image clarity
89 * (the human eye is more sensitive to small changes in brightness than to
90 * small changes in color.) This is called "chrominance subsampling".
95 * 4:4:4 chrominance subsampling (no chrominance subsampling). The JPEG or
96 * YUV image will contain one chrominance component for every pixel in the
101 * 4:2:2 chrominance subsampling. The JPEG or YUV image will contain one
102 * chrominance component for every 2x1 block of pixels in the source image.
106 * 4:2:0 chrominance subsampling. The JPEG or YUV image will contain one
107 * chrominance component for every 2x2 block of pixels in the source image.
111 * Grayscale. The JPEG or YUV image will contain no chrominance components.
115 * 4:4:0 chrominance subsampling. The JPEG or YUV image will contain one
116 * chrominance component for every 1x2 block of pixels in the source image.
118 * @note 4:4:0 subsampling is not fully accelerated in libjpeg-turbo.
122 * 4:1:1 chrominance subsampling. The JPEG or YUV image will contain one
123 * chrominance component for every 4x1 block of pixels in the source image.
124 * JPEG images compressed with 4:1:1 subsampling will be almost exactly the
125 * same size as those compressed with 4:2:0 subsampling, and in the
126 * aggregate, both subsampling methods produce approximately the same
127 * perceptual quality. However, 4:1:1 is better able to reproduce sharp
128 * horizontal features.
130 * @note 4:1:1 subsampling is not fully accelerated in libjpeg-turbo.
136 * MCU block width (in pixels) for a given level of chrominance subsampling.
138 * - 8x8 for no subsampling or grayscale
144 static const int tjMCUWidth[TJ_NUMSAMP] = {8, 16, 16, 8, 8, 32};
147 * MCU block height (in pixels) for a given level of chrominance subsampling.
149 * - 8x8 for no subsampling or grayscale
155 static const int tjMCUHeight[TJ_NUMSAMP] = {8, 8, 16, 8, 16, 8};
159 * The number of pixel formats
169 * RGB pixel format. The red, green, and blue components in the image are
170 * stored in 3-byte pixels in the order R, G, B from lowest to highest byte
171 * address within each pixel.
175 * BGR pixel format. The red, green, and blue components in the image are
176 * stored in 3-byte pixels in the order B, G, R from lowest to highest byte
177 * address within each pixel.
181 * RGBX pixel format. The red, green, and blue components in the image are
182 * stored in 4-byte pixels in the order R, G, B from lowest to highest byte
183 * address within each pixel. The X component is ignored when compressing
184 * and undefined when decompressing.
188 * BGRX pixel format. The red, green, and blue components in the image are
189 * stored in 4-byte pixels in the order B, G, R from lowest to highest byte
190 * address within each pixel. The X component is ignored when compressing
191 * and undefined when decompressing.
195 * XBGR pixel format. The red, green, and blue components in the image are
196 * stored in 4-byte pixels in the order R, G, B from highest to lowest byte
197 * address within each pixel. The X component is ignored when compressing
198 * and undefined when decompressing.
202 * XRGB pixel format. The red, green, and blue components in the image are
203 * stored in 4-byte pixels in the order B, G, R from highest to lowest byte
204 * address within each pixel. The X component is ignored when compressing
205 * and undefined when decompressing.
209 * Grayscale pixel format. Each 1-byte pixel represents a luminance
210 * (brightness) level from 0 to 255.
214 * RGBA pixel format. This is the same as @ref TJPF_RGBX, except that when
215 * decompressing, the X component is guaranteed to be 0xFF, which can be
216 * interpreted as an opaque alpha channel.
220 * BGRA pixel format. This is the same as @ref TJPF_BGRX, except that when
221 * decompressing, the X component is guaranteed to be 0xFF, which can be
222 * interpreted as an opaque alpha channel.
226 * ABGR pixel format. This is the same as @ref TJPF_XBGR, except that when
227 * decompressing, the X component is guaranteed to be 0xFF, which can be
228 * interpreted as an opaque alpha channel.
232 * ARGB pixel format. This is the same as @ref TJPF_XRGB, except that when
233 * decompressing, the X component is guaranteed to be 0xFF, which can be
234 * interpreted as an opaque alpha channel.
238 * CMYK pixel format. Unlike RGB, which is an additive color model used
239 * primarily for display, CMYK (Cyan/Magenta/Yellow/Key) is a subtractive
240 * color model used primarily for printing. In the CMYK color model, the
241 * value of each color component typically corresponds to an amount of cyan,
242 * magenta, yellow, or black ink that is applied to a white background. In
243 * order to convert between CMYK and RGB, it is necessary to use a color
244 * management system (CMS.) A CMS will attempt to map colors within the
245 * printer's gamut to perceptually similar colors in the display's gamut and
246 * vice versa, but the mapping is typically not 1:1 or reversible, nor can it
247 * be defined with a simple formula. Thus, such a conversion is out of scope
248 * for a codec library. However, the TurboJPEG API allows for compressing
249 * CMYK pixels into a YCCK JPEG image (see #TJCS_YCCK) and decompressing YCCK
250 * JPEG images into CMYK pixels.
257 * Red offset (in bytes) for a given pixel format. This specifies the number
258 * of bytes that the red component is offset from the start of the pixel. For
259 * instance, if a pixel of format TJ_BGRX is stored in <tt>char pixel[]</tt>,
260 * then the red component will be <tt>pixel[tjRedOffset[TJ_BGRX]]</tt>.
262 static const int tjRedOffset[TJ_NUMPF] = {0, 2, 0, 2, 3, 1, 0, 0, 2, 3, 1, -1};
264 * Green offset (in bytes) for a given pixel format. This specifies the number
265 * of bytes that the green component is offset from the start of the pixel.
266 * For instance, if a pixel of format TJ_BGRX is stored in
267 * <tt>char pixel[]</tt>, then the green component will be
268 * <tt>pixel[tjGreenOffset[TJ_BGRX]]</tt>.
270 static const int tjGreenOffset[TJ_NUMPF] = {1, 1, 1, 1, 2, 2, 0, 1, 1, 2, 2, -1};
272 * Blue offset (in bytes) for a given pixel format. This specifies the number
273 * of bytes that the Blue component is offset from the start of the pixel. For
274 * instance, if a pixel of format TJ_BGRX is stored in <tt>char pixel[]</tt>,
275 * then the blue component will be <tt>pixel[tjBlueOffset[TJ_BGRX]]</tt>.
277 static const int tjBlueOffset[TJ_NUMPF] = {2, 0, 2, 0, 1, 3, 0, 2, 0, 1, 3, -1};
279 * Pixel size (in bytes) for a given pixel format.
281 static const int tjPixelSize[TJ_NUMPF] = {3, 3, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4};
285 * The number of JPEG colorspaces
295 * RGB colorspace. When compressing the JPEG image, the R, G, and B
296 * components in the source image are reordered into image planes, but no
297 * colorspace conversion or subsampling is performed. RGB JPEG images can be
298 * decompressed to any of the extended RGB pixel formats or grayscale, but
299 * they cannot be decompressed to YUV images.
303 * YCbCr colorspace. YCbCr is not an absolute colorspace but rather a
304 * mathematical transformation of RGB designed solely for storage and
305 * transmission. YCbCr images must be converted to RGB before they can
306 * actually be displayed. In the YCbCr colorspace, the Y (luminance)
307 * component represents the black & white portion of the original image, and
308 * the Cb and Cr (chrominance) components represent the color portion of the
309 * original image. Originally, the analog equivalent of this transformation
310 * allowed the same signal to drive both black & white and color televisions,
311 * but JPEG images use YCbCr primarily because it allows the color data to be
312 * optionally subsampled for the purposes of reducing bandwidth or disk
313 * space. YCbCr is the most common JPEG colorspace, and YCbCr JPEG images
314 * can be compressed from and decompressed to any of the extended RGB pixel
315 * formats or grayscale, or they can be decompressed to YUV planar images.
319 * Grayscale colorspace. The JPEG image retains only the luminance data (Y
320 * component), and any color data from the source image is discarded.
321 * Grayscale JPEG images can be compressed from and decompressed to any of
322 * the extended RGB pixel formats or grayscale, or they can be decompressed
323 * to YUV planar images.
327 * CMYK colorspace. When compressing the JPEG image, the C, M, Y, and K
328 * components in the source image are reordered into image planes, but no
329 * colorspace conversion or subsampling is performed. CMYK JPEG images can
330 * only be decompressed to CMYK pixels.
334 * YCCK colorspace. YCCK (AKA "YCbCrK") is not an absolute colorspace but
335 * rather a mathematical transformation of CMYK designed solely for storage
336 * and transmission. It is to CMYK as YCbCr is to RGB. CMYK pixels can be
337 * reversibly transformed into YCCK, and as with YCbCr, the chrominance
338 * components in the YCCK pixels can be subsampled without incurring major
339 * perceptual loss. YCCK JPEG images can only be compressed from and
340 * decompressed to CMYK pixels.
347 * The uncompressed source/destination image is stored in bottom-up (Windows,
348 * OpenGL) order, not top-down (X11) order.
350 #define TJFLAG_BOTTOMUP 2
352 * When decompressing an image that was compressed using chrominance
353 * subsampling, use the fastest chrominance upsampling algorithm available in
354 * the underlying codec. The default is to use smooth upsampling, which
355 * creates a smooth transition between neighboring chrominance components in
356 * order to reduce upsampling artifacts in the decompressed image.
358 #define TJFLAG_FASTUPSAMPLE 256
360 * Disable buffer (re)allocation. If passed to one of the JPEG compression or
361 * transform functions, this flag will cause those functions to generate an
362 * error if the JPEG image buffer is invalid or too small rather than
363 * attempting to allocate or reallocate that buffer. This reproduces the
364 * behavior of earlier versions of TurboJPEG.
366 #define TJFLAG_NOREALLOC 1024
368 * Use the fastest DCT/IDCT algorithm available in the underlying codec. The
369 * default if this flag is not specified is implementation-specific. For
370 * example, the implementation of TurboJPEG for libjpeg[-turbo] uses the fast
371 * algorithm by default when compressing, because this has been shown to have
372 * only a very slight effect on accuracy, but it uses the accurate algorithm
373 * when decompressing, because this has been shown to have a larger effect.
375 #define TJFLAG_FASTDCT 2048
377 * Use the most accurate DCT/IDCT algorithm available in the underlying codec.
378 * The default if this flag is not specified is implementation-specific. For
379 * example, the implementation of TurboJPEG for libjpeg[-turbo] uses the fast
380 * algorithm by default when compressing, because this has been shown to have
381 * only a very slight effect on accuracy, but it uses the accurate algorithm
382 * when decompressing, because this has been shown to have a larger effect.
384 #define TJFLAG_ACCURATEDCT 4096
388 * The number of transform operations
393 * Transform operations for #tjTransform()
398 * Do not transform the position of the image pixels
402 * Flip (mirror) image horizontally. This transform is imperfect if there
403 * are any partial MCU blocks on the right edge (see #TJXOPT_PERFECT.)
407 * Flip (mirror) image vertically. This transform is imperfect if there are
408 * any partial MCU blocks on the bottom edge (see #TJXOPT_PERFECT.)
412 * Transpose image (flip/mirror along upper left to lower right axis.) This
413 * transform is always perfect.
417 * Transverse transpose image (flip/mirror along upper right to lower left
418 * axis.) This transform is imperfect if there are any partial MCU blocks in
419 * the image (see #TJXOPT_PERFECT.)
423 * Rotate image clockwise by 90 degrees. This transform is imperfect if
424 * there are any partial MCU blocks on the bottom edge (see
429 * Rotate image 180 degrees. This transform is imperfect if there are any
430 * partial MCU blocks in the image (see #TJXOPT_PERFECT.)
434 * Rotate image counter-clockwise by 90 degrees. This transform is imperfect
435 * if there are any partial MCU blocks on the right edge (see
443 * This option will cause #tjTransform() to return an error if the transform is
444 * not perfect. Lossless transforms operate on MCU blocks, whose size depends
445 * on the level of chrominance subsampling used (see #tjMCUWidth
446 * and #tjMCUHeight.) If the image's width or height is not evenly divisible
447 * by the MCU block size, then there will be partial MCU blocks on the right
448 * and/or bottom edges. It is not possible to move these partial MCU blocks to
449 * the top or left of the image, so any transform that would require that is
450 * "imperfect." If this option is not specified, then any partial MCU blocks
451 * that cannot be transformed will be left in place, which will create
452 * odd-looking strips on the right or bottom edge of the image.
454 #define TJXOPT_PERFECT 1
456 * This option will cause #tjTransform() to discard any partial MCU blocks that
457 * cannot be transformed.
459 #define TJXOPT_TRIM 2
461 * This option will enable lossless cropping. See #tjTransform() for more
464 #define TJXOPT_CROP 4
466 * This option will discard the color data in the input image and produce
467 * a grayscale output image.
469 #define TJXOPT_GRAY 8
471 * This option will prevent #tjTransform() from outputting a JPEG image for
472 * this particular transform (this can be used in conjunction with a custom
473 * filter to capture the transformed DCT coefficients without transcoding
476 #define TJXOPT_NOOUTPUT 16
500 * The left boundary of the cropping region. This must be evenly divisible
501 * by the MCU block width (see #tjMCUWidth.)
505 * The upper boundary of the cropping region. This must be evenly divisible
506 * by the MCU block height (see #tjMCUHeight.)
510 * The width of the cropping region. Setting this to 0 is the equivalent of
511 * setting it to the width of the source JPEG image - x.
515 * The height of the cropping region. Setting this to 0 is the equivalent of
516 * setting it to the height of the source JPEG image - y.
524 typedef struct tjtransform
531 * One of the @ref TJXOP "transform operations"
535 * The bitwise OR of one of more of the @ref TJXOPT_CROP "transform options"
539 * Arbitrary data that can be accessed within the body of the callback
544 * A callback function that can be used to modify the DCT coefficients
545 * after they are losslessly transformed but before they are transcoded to a
546 * new JPEG image. This allows for custom filters or other transformations
547 * to be applied in the frequency domain.
549 * @param coeffs pointer to an array of transformed DCT coefficients. (NOTE:
550 * this pointer is not guaranteed to be valid once the callback returns, so
551 * applications wishing to hand off the DCT coefficients to another function
552 * or library should make a copy of them within the body of the callback.)
554 * @param arrayRegion #tjregion structure containing the width and height of
555 * the array pointed to by <tt>coeffs</tt> as well as its offset relative to
556 * the component plane. TurboJPEG implementations may choose to split each
557 * component plane into multiple DCT coefficient arrays and call the callback
558 * function once for each array.
560 * @param planeRegion #tjregion structure containing the width and height of
561 * the component plane to which <tt>coeffs</tt> belongs
563 * @param componentID ID number of the component plane to which
564 * <tt>coeffs</tt> belongs (Y, Cb, and Cr have, respectively, ID's of 0, 1,
565 * and 2 in typical JPEG images.)
567 * @param transformID ID number of the transformed image to which
568 * <tt>coeffs</tt> belongs. This is the same as the index of the transform
569 * in the <tt>transforms</tt> array that was passed to #tjTransform().
571 * @param transform a pointer to a #tjtransform structure that specifies the
572 * parameters and/or cropping region for this transform
574 * @return 0 if the callback was successful, or -1 if an error occurred.
576 int (*customFilter)(short *coeffs, tjregion arrayRegion,
577 tjregion planeRegion, int componentIndex, int transformIndex,
578 struct tjtransform *transform);
582 * TurboJPEG instance handle
584 typedef void* tjhandle;
588 * Pad the given width to the nearest 32-bit boundary
590 #define TJPAD(width) (((width)+3)&(~3))
593 * Compute the scaled value of <tt>dimension</tt> using the given scaling
594 * factor. This macro performs the integer equivalent of <tt>ceil(dimension *
595 * scalingFactor)</tt>.
597 #define TJSCALED(dimension, scalingFactor) ((dimension * scalingFactor.num \
598 + scalingFactor.denom - 1) / scalingFactor.denom)
607 * Create a TurboJPEG compressor instance.
609 * @return a handle to the newly-created instance, or NULL if an error
610 * occurred (see #tjGetErrorStr().)
612 DLLEXPORT tjhandle DLLCALL tjInitCompress(void);
616 * Compress an RGB, grayscale, or CMYK image into a JPEG image.
618 * @param handle a handle to a TurboJPEG compressor or transformer instance
620 * @param srcBuf pointer to an image buffer containing RGB, grayscale, or
621 * CMYK pixels to be compressed
623 * @param width width (in pixels) of the source image
625 * @param pitch bytes per line in the source image. Normally, this should be
626 * <tt>width * #tjPixelSize[pixelFormat]</tt> if the image is unpadded, or
627 * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line of the image
628 * is padded to the nearest 32-bit boundary, as is the case for Windows
629 * bitmaps. You can also be clever and use this parameter to skip lines, etc.
630 * Setting this parameter to 0 is the equivalent of setting it to
631 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
633 * @param height height (in pixels) of the source image
635 * @param pixelFormat pixel format of the source image (see @ref TJPF
638 * @param jpegBuf address of a pointer to an image buffer that will receive the
639 * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer
640 * to accommodate the size of the JPEG image. Thus, you can choose to:
641 * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and
642 * let TurboJPEG grow the buffer as needed,
643 * -# set <tt>*jpegBuf</tt> to NULL to tell TurboJPEG to allocate the buffer
645 * -# pre-allocate the buffer to a "worst case" size determined by calling
646 * #tjBufSize(). This should ensure that the buffer never has to be
647 * re-allocated (setting #TJFLAG_NOREALLOC guarantees that it won't be.)
649 * If you choose option 1, <tt>*jpegSize</tt> should be set to the size of your
650 * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC,
651 * you should always check <tt>*jpegBuf</tt> upon return from this function, as
652 * it may have changed.
654 * @param jpegSize pointer to an unsigned long variable that holds the size of
655 * the JPEG image buffer. If <tt>*jpegBuf</tt> points to a pre-allocated
656 * buffer, then <tt>*jpegSize</tt> should be set to the size of the buffer.
657 * Upon return, <tt>*jpegSize</tt> will contain the size of the JPEG image (in
658 * bytes.) If <tt>*jpegBuf</tt> points to a JPEG image buffer that is being
659 * reused from a previous call to one of the JPEG compression functions, then
660 * <tt>*jpegSize</tt> is ignored.
662 * @param jpegSubsamp the level of chrominance subsampling to be used when
663 * generating the JPEG image (see @ref TJSAMP
664 * "Chrominance subsampling options".)
666 * @param jpegQual the image quality of the generated JPEG image (1 = worst,
669 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
672 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
674 DLLEXPORT int DLLCALL tjCompress2(tjhandle handle, const unsigned char *srcBuf,
675 int width, int pitch, int height, int pixelFormat, unsigned char **jpegBuf,
676 unsigned long *jpegSize, int jpegSubsamp, int jpegQual, int flags);
680 * Compress a YUV planar image into a JPEG image.
682 * @param handle a handle to a TurboJPEG compressor or transformer instance
684 * @param srcBuf pointer to an image buffer containing a YUV planar image to be
685 * compressed. The size of this buffer should match the value returned by
686 * #tjBufSizeYUV2() for the given image width, height, padding, and level of
687 * chrominance subsampling. The Y, U (Cb), and V (Cr) image planes should be
688 * stored sequentially in the source buffer (refer to @ref YUVnotes
689 * "YUV Image Format Notes".)
691 * @param width width (in pixels) of the source image. If the width is not an
692 * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate
693 * buffer copy will be performed within TurboJPEG.
695 * @param pad the line padding used in the source image. For instance, if each
696 * line in each plane of the YUV image is padded to the nearest multiple of 4
697 * bytes, then <tt>pad</tt> should be set to 4.
699 * @param height height (in pixels) of the source image. If the height is not
700 * an even multiple of the MCU block height (see #tjMCUHeight), then an
701 * intermediate buffer copy will be performed within TurboJPEG.
703 * @param subsamp the level of chrominance subsampling used in the source
704 * image (see @ref TJSAMP "Chrominance subsampling options".)
706 * @param jpegBuf address of a pointer to an image buffer that will receive the
707 * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer to
708 * accommodate the size of the JPEG image. Thus, you can choose to:
709 * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and
710 * let TurboJPEG grow the buffer as needed,
711 * -# set <tt>*jpegBuf</tt> to NULL to tell TurboJPEG to allocate the buffer
713 * -# pre-allocate the buffer to a "worst case" size determined by calling
714 * #tjBufSize(). This should ensure that the buffer never has to be
715 * re-allocated (setting #TJFLAG_NOREALLOC guarantees that it won't be.)
717 * If you choose option 1, <tt>*jpegSize</tt> should be set to the size of your
718 * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC,
719 * you should always check <tt>*jpegBuf</tt> upon return from this function, as
720 * it may have changed.
722 * @param jpegSize pointer to an unsigned long variable that holds the size of
723 * the JPEG image buffer. If <tt>*jpegBuf</tt> points to a pre-allocated
724 * buffer, then <tt>*jpegSize</tt> should be set to the size of the buffer.
725 * Upon return, <tt>*jpegSize</tt> will contain the size of the JPEG image (in
726 * bytes.) If <tt>*jpegBuf</tt> points to a JPEG image buffer that is being
727 * reused from a previous call to one of the JPEG compression functions, then
728 * <tt>*jpegSize</tt> is ignored.
730 * @param jpegQual the image quality of the generated JPEG image (1 = worst,
733 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
736 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
738 DLLEXPORT int DLLCALL tjCompressFromYUV(tjhandle handle,
739 const unsigned char *srcBuf, int width, int pad, int height, int subsamp,
740 unsigned char **jpegBuf, unsigned long *jpegSize, int jpegQual, int flags);
744 * Compress a set of Y, U (Cb), and V (Cr) image planes into a JPEG image.
746 * @param handle a handle to a TurboJPEG compressor or transformer instance
748 * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
749 * (or just a Y plane, if compressing a grayscale image) that contain a YUV
750 * image to be compressed. These planes can be contiguous or non-contiguous in
751 * memory. The size of each plane should match the value returned by
752 * #tjPlaneSizeYUV() for the given image width, height, strides, and level of
753 * chrominance subsampling. Refer to @ref YUVnotes "YUV Image Format Notes"
756 * @param width width (in pixels) of the source image. If the width is not an
757 * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate
758 * buffer copy will be performed within TurboJPEG.
760 * @param strides an array of integers, each specifying the number of bytes per
761 * line in the corresponding plane of the YUV source image. Setting the stride
762 * for any plane to 0 is the same as setting it to the plane width (see
763 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
764 * the strides for all planes will be set to their respective plane widths.
765 * You can adjust the strides in order to specify an arbitrary amount of line
766 * padding in each plane or to create a JPEG image from a subregion of a larger
769 * @param height height (in pixels) of the source image. If the height is not
770 * an even multiple of the MCU block height (see #tjMCUHeight), then an
771 * intermediate buffer copy will be performed within TurboJPEG.
773 * @param subsamp the level of chrominance subsampling used in the source
774 * image (see @ref TJSAMP "Chrominance subsampling options".)
776 * @param jpegBuf address of a pointer to an image buffer that will receive the
777 * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer to
778 * accommodate the size of the JPEG image. Thus, you can choose to:
779 * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and
780 * let TurboJPEG grow the buffer as needed,
781 * -# set <tt>*jpegBuf</tt> to NULL to tell TurboJPEG to allocate the buffer
783 * -# pre-allocate the buffer to a "worst case" size determined by calling
784 * #tjBufSize(). This should ensure that the buffer never has to be
785 * re-allocated (setting #TJFLAG_NOREALLOC guarantees that it won't be.)
787 * If you choose option 1, <tt>*jpegSize</tt> should be set to the size of your
788 * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC,
789 * you should always check <tt>*jpegBuf</tt> upon return from this function, as
790 * it may have changed.
792 * @param jpegSize pointer to an unsigned long variable that holds the size of
793 * the JPEG image buffer. If <tt>*jpegBuf</tt> points to a pre-allocated
794 * buffer, then <tt>*jpegSize</tt> should be set to the size of the buffer.
795 * Upon return, <tt>*jpegSize</tt> will contain the size of the JPEG image (in
796 * bytes.) If <tt>*jpegBuf</tt> points to a JPEG image buffer that is being
797 * reused from a previous call to one of the JPEG compression functions, then
798 * <tt>*jpegSize</tt> is ignored.
800 * @param jpegQual the image quality of the generated JPEG image (1 = worst,
803 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
806 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
808 DLLEXPORT int DLLCALL tjCompressFromYUVPlanes(tjhandle handle,
809 const unsigned char **srcPlanes, int width, const int *strides, int height,
810 int subsamp, unsigned char **jpegBuf, unsigned long *jpegSize, int jpegQual,
815 * The maximum size of the buffer (in bytes) required to hold a JPEG image with
816 * the given parameters. The number of bytes returned by this function is
817 * larger than the size of the uncompressed source image. The reason for this
818 * is that the JPEG format uses 16-bit coefficients, and it is thus possible
819 * for a very high-quality JPEG image with very high-frequency content to
820 * expand rather than compress when converted to the JPEG format. Such images
821 * represent a very rare corner case, but since there is no way to predict the
822 * size of a JPEG image prior to compression, the corner case has to be
825 * @param width width (in pixels) of the image
827 * @param height height (in pixels) of the image
829 * @param jpegSubsamp the level of chrominance subsampling to be used when
830 * generating the JPEG image (see @ref TJSAMP
831 * "Chrominance subsampling options".)
833 * @return the maximum size of the buffer (in bytes) required to hold the
834 * image, or -1 if the arguments are out of bounds.
836 DLLEXPORT unsigned long DLLCALL tjBufSize(int width, int height,
841 * The size of the buffer (in bytes) required to hold a YUV planar image with
842 * the given parameters.
844 * @param width width (in pixels) of the image
846 * @param pad the width of each line in each plane of the image is padded to
847 * the nearest multiple of this number of bytes (must be a power of 2.)
849 * @param height height (in pixels) of the image
851 * @param subsamp level of chrominance subsampling in the image (see
852 * @ref TJSAMP "Chrominance subsampling options".)
854 * @return the size of the buffer (in bytes) required to hold the image, or
855 * -1 if the arguments are out of bounds.
857 DLLEXPORT unsigned long DLLCALL tjBufSizeYUV2(int width, int pad, int height,
862 * The size of the buffer (in bytes) required to hold a YUV image plane with
863 * the given parameters.
865 * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
867 * @param width width (in pixels) of the YUV image. NOTE: this is the width of
868 * the whole image, not the plane width.
870 * @param stride bytes per line in the image plane. Setting this to 0 is the
871 * equivalent of setting it to the plane width.
873 * @param height height (in pixels) of the YUV image. NOTE: this is the height
874 * of the whole image, not the plane height.
876 * @param subsamp level of chrominance subsampling in the image (see
877 * @ref TJSAMP "Chrominance subsampling options".)
879 * @return the size of the buffer (in bytes) required to hold the YUV image
880 * plane, or -1 if the arguments are out of bounds.
882 DLLEXPORT unsigned long DLLCALL tjPlaneSizeYUV(int componentID, int width,
883 int stride, int height, int subsamp);
887 * The plane width of a YUV image plane with the given parameters. Refer to
888 * @ref YUVnotes "YUV Image Format Notes" for a description of plane width.
890 * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
892 * @param width width (in pixels) of the YUV image
894 * @param subsamp level of chrominance subsampling in the image (see
895 * @ref TJSAMP "Chrominance subsampling options".)
897 * @return the plane width of a YUV image plane with the given parameters, or
898 * -1 if the arguments are out of bounds.
900 DLLEXPORT int tjPlaneWidth(int componentID, int width, int subsamp);
904 * The plane height of a YUV image plane with the given parameters. Refer to
905 * @ref YUVnotes "YUV Image Format Notes" for a description of plane height.
907 * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
909 * @param height height (in pixels) of the YUV image
911 * @param subsamp level of chrominance subsampling in the image (see
912 * @ref TJSAMP "Chrominance subsampling options".)
914 * @return the plane height of a YUV image plane with the given parameters, or
915 * -1 if the arguments are out of bounds.
917 DLLEXPORT int tjPlaneHeight(int componentID, int height, int subsamp);
921 * Encode an RGB or grayscale image into a YUV planar image. This function
922 * uses the accelerated color conversion routines in the underlying
923 * codec but does not execute any of the other steps in the JPEG compression
926 * @param handle a handle to a TurboJPEG compressor or transformer instance
928 * @param srcBuf pointer to an image buffer containing RGB or grayscale pixels
931 * @param width width (in pixels) of the source image
933 * @param pitch bytes per line in the source image. Normally, this should be
934 * <tt>width * #tjPixelSize[pixelFormat]</tt> if the image is unpadded, or
935 * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line of the image
936 * is padded to the nearest 32-bit boundary, as is the case for Windows
937 * bitmaps. You can also be clever and use this parameter to skip lines, etc.
938 * Setting this parameter to 0 is the equivalent of setting it to
939 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
941 * @param height height (in pixels) of the source image
943 * @param pixelFormat pixel format of the source image (see @ref TJPF
946 * @param dstBuf pointer to an image buffer that will receive the YUV image.
947 * Use #tjBufSizeYUV2() to determine the appropriate size for this buffer based
948 * on the image width, height, padding, and level of chrominance subsampling.
949 * The Y, U (Cb), and V (Cr) image planes will be stored sequentially in the
950 * buffer (refer to @ref YUVnotes "YUV Image Format Notes".)
952 * @param pad the width of each line in each plane of the YUV image will be
953 * padded to the nearest multiple of this number of bytes (must be a power of
954 * 2.) To generate images suitable for X Video, <tt>pad</tt> should be set to
957 * @param subsamp the level of chrominance subsampling to be used when
958 * generating the YUV image (see @ref TJSAMP
959 * "Chrominance subsampling options".) To generate images suitable for X
960 * Video, <tt>subsamp</tt> should be set to @ref TJSAMP_420. This produces an
961 * image compatible with the I420 (AKA "YUV420P") format.
963 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
966 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
968 DLLEXPORT int DLLCALL tjEncodeYUV3(tjhandle handle,
969 const unsigned char *srcBuf, int width, int pitch, int height,
970 int pixelFormat, unsigned char *dstBuf, int pad, int subsamp, int flags);
974 * Encode an RGB or grayscale image into separate Y, U (Cb), and V (Cr) image
975 * planes. This function uses the accelerated color conversion routines in the
976 * underlying codec but does not execute any of the other steps in the JPEG
977 * compression process.
979 * @param handle a handle to a TurboJPEG compressor or transformer instance
981 * @param srcBuf pointer to an image buffer containing RGB or grayscale pixels
984 * @param width width (in pixels) of the source image
986 * @param pitch bytes per line in the source image. Normally, this should be
987 * <tt>width * #tjPixelSize[pixelFormat]</tt> if the image is unpadded, or
988 * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line of the image
989 * is padded to the nearest 32-bit boundary, as is the case for Windows
990 * bitmaps. You can also be clever and use this parameter to skip lines, etc.
991 * Setting this parameter to 0 is the equivalent of setting it to
992 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
994 * @param height height (in pixels) of the source image
996 * @param pixelFormat pixel format of the source image (see @ref TJPF
999 * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
1000 * (or just a Y plane, if generating a grayscale image) that will receive the
1001 * encoded image. These planes can be contiguous or non-contiguous in memory.
1002 * Use #tjPlaneSizeYUV() to determine the appropriate size for each plane based
1003 * on the image width, height, strides, and level of chrominance subsampling.
1004 * Refer to @ref YUVnotes "YUV Image Format Notes" for more details.
1006 * @param strides an array of integers, each specifying the number of bytes per
1007 * line in the corresponding plane of the output image. Setting the stride for
1008 * any plane to 0 is the same as setting it to the plane width (see
1009 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
1010 * the strides for all planes will be set to their respective plane widths.
1011 * You can adjust the strides in order to add an arbitrary amount of line
1012 * padding to each plane or to encode an RGB or grayscale image into a
1013 * subregion of a larger YUV planar image.
1015 * @param subsamp the level of chrominance subsampling to be used when
1016 * generating the YUV image (see @ref TJSAMP
1017 * "Chrominance subsampling options".) To generate images suitable for X
1018 * Video, <tt>subsamp</tt> should be set to @ref TJSAMP_420. This produces an
1019 * image compatible with the I420 (AKA "YUV420P") format.
1021 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1024 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1026 DLLEXPORT int DLLCALL tjEncodeYUVPlanes(tjhandle handle,
1027 const unsigned char *srcBuf, int width, int pitch, int height,
1028 int pixelFormat, unsigned char **dstPlanes, int *strides, int subsamp,
1033 * Create a TurboJPEG decompressor instance.
1035 * @return a handle to the newly-created instance, or NULL if an error
1036 * occurred (see #tjGetErrorStr().)
1038 DLLEXPORT tjhandle DLLCALL tjInitDecompress(void);
1042 * Retrieve information about a JPEG image without decompressing it.
1044 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1046 * @param jpegBuf pointer to a buffer containing a JPEG image
1048 * @param jpegSize size of the JPEG image (in bytes)
1050 * @param width pointer to an integer variable that will receive the width (in
1051 * pixels) of the JPEG image
1053 * @param height pointer to an integer variable that will receive the height
1054 * (in pixels) of the JPEG image
1056 * @param jpegSubsamp pointer to an integer variable that will receive the
1057 * level of chrominance subsampling used when the JPEG image was compressed
1058 * (see @ref TJSAMP "Chrominance subsampling options".)
1060 * @param jpegColorspace pointer to an integer variable that will receive one
1061 * of the JPEG colorspace constants, indicating the colorspace of the JPEG
1062 * image (see @ref TJCS "JPEG colorspaces".)
1064 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1066 DLLEXPORT int DLLCALL tjDecompressHeader3(tjhandle handle,
1067 const unsigned char *jpegBuf, unsigned long jpegSize, int *width,
1068 int *height, int *jpegSubsamp, int *jpegColorspace);
1072 * Returns a list of fractional scaling factors that the JPEG decompressor in
1073 * this implementation of TurboJPEG supports.
1075 * @param numscalingfactors pointer to an integer variable that will receive
1076 * the number of elements in the list
1078 * @return a pointer to a list of fractional scaling factors, or NULL if an
1079 * error is encountered (see #tjGetErrorStr().)
1081 DLLEXPORT tjscalingfactor* DLLCALL tjGetScalingFactors(int *numscalingfactors);
1085 * Decompress a JPEG image to an RGB, grayscale, or CMYK image.
1087 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1089 * @param jpegBuf pointer to a buffer containing the JPEG image to decompress
1091 * @param jpegSize size of the JPEG image (in bytes)
1093 * @param dstBuf pointer to an image buffer that will receive the decompressed
1094 * image. This buffer should normally be <tt>pitch * scaledHeight</tt> bytes
1095 * in size, where <tt>scaledHeight</tt> can be determined by calling
1096 * #TJSCALED() with the JPEG image height and one of the scaling factors
1097 * returned by #tjGetScalingFactors(). The <tt>dstBuf</tt> pointer may also be
1098 * used to decompress into a specific region of a larger buffer.
1100 * @param width desired width (in pixels) of the destination image. If this is
1101 * different than the width of the JPEG image being decompressed, then
1102 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1103 * possible image that will fit within the desired width. If <tt>width</tt> is
1104 * set to 0, then only the height will be considered when determining the
1105 * scaled image size.
1107 * @param pitch bytes per line in the destination image. Normally, this is
1108 * <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt> if the decompressed image
1109 * is unpadded, else <tt>#TJPAD(scaledWidth * #tjPixelSize[pixelFormat])</tt>
1110 * if each line of the decompressed image is padded to the nearest 32-bit
1111 * boundary, as is the case for Windows bitmaps. (NOTE: <tt>scaledWidth</tt>
1112 * can be determined by calling #TJSCALED() with the JPEG image width and one
1113 * of the scaling factors returned by #tjGetScalingFactors().) You can also be
1114 * clever and use the pitch parameter to skip lines, etc. Setting this
1115 * parameter to 0 is the equivalent of setting it to
1116 * <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt>.
1118 * @param height desired height (in pixels) of the destination image. If this
1119 * is different than the height of the JPEG image being decompressed, then
1120 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1121 * possible image that will fit within the desired height. If <tt>height</tt>
1122 * is set to 0, then only the width will be considered when determining the
1123 * scaled image size.
1125 * @param pixelFormat pixel format of the destination image (see @ref
1126 * TJPF "Pixel formats".)
1128 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1131 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1133 DLLEXPORT int DLLCALL tjDecompress2(tjhandle handle,
1134 const unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
1135 int width, int pitch, int height, int pixelFormat, int flags);
1139 * Decompress a JPEG image to a YUV planar image. This function performs JPEG
1140 * decompression but leaves out the color conversion step, so a planar YUV
1141 * image is generated instead of an RGB image.
1143 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1145 * @param jpegBuf pointer to a buffer containing the JPEG image to decompress
1147 * @param jpegSize size of the JPEG image (in bytes)
1149 * @param dstBuf pointer to an image buffer that will receive the YUV image.
1150 * Use #tjBufSizeYUV2() to determine the appropriate size for this buffer based
1151 * on the image width, height, padding, and level of subsampling. The Y,
1152 * U (Cb), and V (Cr) image planes will be stored sequentially in the buffer
1153 * (refer to @ref YUVnotes "YUV Image Format Notes".)
1155 * @param width desired width (in pixels) of the YUV image. If this is
1156 * different than the width of the JPEG image being decompressed, then
1157 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1158 * possible image that will fit within the desired width. If <tt>width</tt> is
1159 * set to 0, then only the height will be considered when determining the
1160 * scaled image size. If the scaled width is not an even multiple of the MCU
1161 * block width (see #tjMCUWidth), then an intermediate buffer copy will be
1162 * performed within TurboJPEG.
1164 * @param pad the width of each line in each plane of the YUV image will be
1165 * padded to the nearest multiple of this number of bytes (must be a power of
1166 * 2.) To generate images suitable for X Video, <tt>pad</tt> should be set to
1169 * @param height desired height (in pixels) of the YUV image. If this is
1170 * different than the height of the JPEG image being decompressed, then
1171 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1172 * possible image that will fit within the desired height. If <tt>height</tt>
1173 * is set to 0, then only the width will be considered when determining the
1174 * scaled image size. If the scaled height is not an even multiple of the MCU
1175 * block height (see #tjMCUHeight), then an intermediate buffer copy will be
1176 * performed within TurboJPEG.
1178 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1181 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1183 DLLEXPORT int DLLCALL tjDecompressToYUV2(tjhandle handle,
1184 const unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
1185 int width, int pad, int height, int flags);
1189 * Decompress a JPEG image into separate Y, U (Cb), and V (Cr) image
1190 * planes. This function performs JPEG decompression but leaves out the color
1191 * conversion step, so a planar YUV image is generated instead of an RGB image.
1193 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1195 * @param jpegBuf pointer to a buffer containing the JPEG image to decompress
1197 * @param jpegSize size of the JPEG image (in bytes)
1199 * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
1200 * (or just a Y plane, if decompressing a grayscale image) that will receive
1201 * the YUV image. These planes can be contiguous or non-contiguous in memory.
1202 * Use #tjPlaneSizeYUV() to determine the appropriate size for each plane based
1203 * on the scaled image width, scaled image height, strides, and level of
1204 * chrominance subsampling. Refer to @ref YUVnotes "YUV Image Format Notes"
1207 * @param width desired width (in pixels) of the YUV image. If this is
1208 * different than the width of the JPEG image being decompressed, then
1209 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1210 * possible image that will fit within the desired width. If <tt>width</tt> is
1211 * set to 0, then only the height will be considered when determining the
1212 * scaled image size. If the scaled width is not an even multiple of the MCU
1213 * block width (see #tjMCUWidth), then an intermediate buffer copy will be
1214 * performed within TurboJPEG.
1216 * @param strides an array of integers, each specifying the number of bytes per
1217 * line in the corresponding plane of the output image. Setting the stride for
1218 * any plane to 0 is the same as setting it to the scaled plane width (see
1219 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
1220 * the strides for all planes will be set to their respective scaled plane
1221 * widths. You can adjust the strides in order to add an arbitrary amount of
1222 * line padding to each plane or to decompress the JPEG image into a subregion
1223 * of a larger YUV planar image.
1225 * @param height desired height (in pixels) of the YUV image. If this is
1226 * different than the height of the JPEG image being decompressed, then
1227 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1228 * possible image that will fit within the desired height. If <tt>height</tt>
1229 * is set to 0, then only the width will be considered when determining the
1230 * scaled image size. If the scaled height is not an even multiple of the MCU
1231 * block height (see #tjMCUHeight), then an intermediate buffer copy will be
1232 * performed within TurboJPEG.
1234 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1237 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1239 DLLEXPORT int DLLCALL tjDecompressToYUVPlanes(tjhandle handle,
1240 const unsigned char *jpegBuf, unsigned long jpegSize,
1241 unsigned char **dstPlanes, int width, int *strides, int height, int flags);
1245 * Decode a YUV planar image into an RGB or grayscale image. This function
1246 * uses the accelerated color conversion routines in the underlying
1247 * codec but does not execute any of the other steps in the JPEG decompression
1250 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1252 * @param srcBuf pointer to an image buffer containing a YUV planar image to be
1253 * decoded. The size of this buffer should match the value returned by
1254 * #tjBufSizeYUV2() for the given image width, height, padding, and level of
1255 * chrominance subsampling. The Y, U (Cb), and V (Cr) image planes should be
1256 * stored sequentially in the source buffer (refer to @ref YUVnotes
1257 * "YUV Image Format Notes".)
1259 * @param pad Use this parameter to specify that the width of each line in each
1260 * plane of the YUV source image is padded to the nearest multiple of this
1261 * number of bytes (must be a power of 2.)
1263 * @param subsamp the level of chrominance subsampling used in the YUV source
1264 * image (see @ref TJSAMP "Chrominance subsampling options".)
1266 * @param dstBuf pointer to an image buffer that will receive the decoded
1267 * image. This buffer should normally be <tt>pitch * height</tt> bytes in
1268 * size, but the <tt>dstBuf</tt> pointer can also be used to decode into a
1269 * specific region of a larger buffer.
1271 * @param width width (in pixels) of the source and destination images
1273 * @param pitch bytes per line in the destination image. Normally, this should
1274 * be <tt>width * #tjPixelSize[pixelFormat]</tt> if the destination image is
1275 * unpadded, or <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line
1276 * of the destination image should be padded to the nearest 32-bit boundary, as
1277 * is the case for Windows bitmaps. You can also be clever and use the pitch
1278 * parameter to skip lines, etc. Setting this parameter to 0 is the equivalent
1279 * of setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>.
1281 * @param height height (in pixels) of the source and destination images
1283 * @param pixelFormat pixel format of the destination image (see @ref TJPF
1286 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1289 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1291 DLLEXPORT int DLLCALL tjDecodeYUV(tjhandle handle, const unsigned char *srcBuf,
1292 int pad, int subsamp, unsigned char *dstBuf, int width, int pitch,
1293 int height, int pixelFormat, int flags);
1297 * Decode a set of Y, U (Cb), and V (Cr) image planes into an RGB or grayscale
1298 * image. This function uses the accelerated color conversion routines in the
1299 * underlying codec but does not execute any of the other steps in the JPEG
1300 * decompression process.
1302 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1304 * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
1305 * (or just a Y plane, if decoding a grayscale image) that contain a YUV image
1306 * to be decoded. These planes can be contiguous or non-contiguous in memory.
1307 * The size of each plane should match the value returned by #tjPlaneSizeYUV()
1308 * for the given image width, height, strides, and level of chrominance
1309 * subsampling. Refer to @ref YUVnotes "YUV Image Format Notes" for more
1312 * @param strides an array of integers, each specifying the number of bytes per
1313 * line in the corresponding plane of the YUV source image. Setting the stride
1314 * for any plane to 0 is the same as setting it to the plane width (see
1315 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
1316 * the strides for all planes will be set to their respective plane widths.
1317 * You can adjust the strides in order to specify an arbitrary amount of line
1318 * padding in each plane or to decode a subregion of a larger YUV planar image.
1320 * @param subsamp the level of chrominance subsampling used in the YUV source
1321 * image (see @ref TJSAMP "Chrominance subsampling options".)
1323 * @param dstBuf pointer to an image buffer that will receive the decoded
1324 * image. This buffer should normally be <tt>pitch * height</tt> bytes in
1325 * size, but the <tt>dstBuf</tt> pointer can also be used to decode into a
1326 * specific region of a larger buffer.
1328 * @param width width (in pixels) of the source and destination images
1330 * @param pitch bytes per line in the destination image. Normally, this should
1331 * be <tt>width * #tjPixelSize[pixelFormat]</tt> if the destination image is
1332 * unpadded, or <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line
1333 * of the destination image should be padded to the nearest 32-bit boundary, as
1334 * is the case for Windows bitmaps. You can also be clever and use the pitch
1335 * parameter to skip lines, etc. Setting this parameter to 0 is the equivalent
1336 * of setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>.
1338 * @param height height (in pixels) of the source and destination images
1340 * @param pixelFormat pixel format of the destination image (see @ref TJPF
1343 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1346 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1348 DLLEXPORT int DLLCALL tjDecodeYUVPlanes(tjhandle handle,
1349 const unsigned char **srcPlanes, const int *strides, int subsamp,
1350 unsigned char *dstBuf, int width, int pitch, int height, int pixelFormat,
1355 * Create a new TurboJPEG transformer instance.
1357 * @return a handle to the newly-created instance, or NULL if an error
1358 * occurred (see #tjGetErrorStr().)
1360 DLLEXPORT tjhandle DLLCALL tjInitTransform(void);
1364 * Losslessly transform a JPEG image into another JPEG image. Lossless
1365 * transforms work by moving the raw DCT coefficients from one JPEG image
1366 * structure to another without altering the values of the coefficients. While
1367 * this is typically faster than decompressing the image, transforming it, and
1368 * re-compressing it, lossless transforms are not free. Each lossless
1369 * transform requires reading and performing Huffman decoding on all of the
1370 * coefficients in the source image, regardless of the size of the destination
1371 * image. Thus, this function provides a means of generating multiple
1372 * transformed images from the same source or applying multiple
1373 * transformations simultaneously, in order to eliminate the need to read the
1374 * source coefficients multiple times.
1376 * @param handle a handle to a TurboJPEG transformer instance
1378 * @param jpegBuf pointer to a buffer containing the JPEG source image to
1381 * @param jpegSize size of the JPEG source image (in bytes)
1383 * @param n the number of transformed JPEG images to generate
1385 * @param dstBufs pointer to an array of n image buffers. <tt>dstBufs[i]</tt>
1386 * will receive a JPEG image that has been transformed using the parameters in
1387 * <tt>transforms[i]</tt>. TurboJPEG has the ability to reallocate the JPEG
1388 * buffer to accommodate the size of the JPEG image. Thus, you can choose to:
1389 * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and
1390 * let TurboJPEG grow the buffer as needed,
1391 * -# set <tt>dstBufs[i]</tt> to NULL to tell TurboJPEG to allocate the buffer
1393 * -# pre-allocate the buffer to a "worst case" size determined by calling
1394 * #tjBufSize() with the transformed or cropped width and height. Under normal
1395 * circumstances, this should ensure that the buffer never has to be
1396 * re-allocated (setting #TJFLAG_NOREALLOC guarantees that it won't be.) Note,
1397 * however, that there are some rare cases (such as transforming images with a
1398 * large amount of embedded EXIF or ICC profile data) in which the output image
1399 * will be larger than the worst-case size, and #TJFLAG_NOREALLOC cannot be
1400 * used in those cases.
1402 * If you choose option 1, <tt>dstSizes[i]</tt> should be set to the size of
1403 * your pre-allocated buffer. In any case, unless you have set
1404 * #TJFLAG_NOREALLOC, you should always check <tt>dstBufs[i]</tt> upon return
1405 * from this function, as it may have changed.
1407 * @param dstSizes pointer to an array of n unsigned long variables that will
1408 * receive the actual sizes (in bytes) of each transformed JPEG image. If
1409 * <tt>dstBufs[i]</tt> points to a pre-allocated buffer, then
1410 * <tt>dstSizes[i]</tt> should be set to the size of the buffer. Upon return,
1411 * <tt>dstSizes[i]</tt> will contain the size of the JPEG image (in bytes.)
1413 * @param transforms pointer to an array of n #tjtransform structures, each of
1414 * which specifies the transform parameters and/or cropping region for the
1415 * corresponding transformed output image.
1417 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1420 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1422 DLLEXPORT int DLLCALL tjTransform(tjhandle handle,
1423 const unsigned char *jpegBuf, unsigned long jpegSize, int n,
1424 unsigned char **dstBufs, unsigned long *dstSizes, tjtransform *transforms,
1429 * Destroy a TurboJPEG compressor, decompressor, or transformer instance.
1431 * @param handle a handle to a TurboJPEG compressor, decompressor or
1432 * transformer instance
1434 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr().)
1436 DLLEXPORT int DLLCALL tjDestroy(tjhandle handle);
1440 * Allocate an image buffer for use with TurboJPEG. You should always use
1441 * this function to allocate the JPEG destination buffer(s) for the compression
1442 * and transform functions unless you are disabling automatic buffer
1443 * (re)allocation (by setting #TJFLAG_NOREALLOC.)
1445 * @param bytes the number of bytes to allocate
1447 * @return a pointer to a newly-allocated buffer with the specified number of
1452 DLLEXPORT unsigned char* DLLCALL tjAlloc(int bytes);
1456 * Free an image buffer previously allocated by TurboJPEG. You should always
1457 * use this function to free JPEG destination buffer(s) that were automatically
1458 * (re)allocated by the compression and transform functions or that were
1459 * manually allocated using #tjAlloc().
1461 * @param buffer address of the buffer to free
1465 DLLEXPORT void DLLCALL tjFree(unsigned char *buffer);
1469 * Returns a descriptive error message explaining why the last command failed.
1471 * @return a descriptive error message explaining why the last command failed.
1473 DLLEXPORT char* DLLCALL tjGetErrorStr(void);
1476 /* Deprecated functions and macros */
1477 #define TJFLAG_FORCEMMX 8
1478 #define TJFLAG_FORCESSE 16
1479 #define TJFLAG_FORCESSE2 32
1480 #define TJFLAG_FORCESSE3 128
1483 /* Backward compatibility functions and macros (nothing to see here) */
1484 #define NUMSUBOPT TJ_NUMSAMP
1485 #define TJ_444 TJSAMP_444
1486 #define TJ_422 TJSAMP_422
1487 #define TJ_420 TJSAMP_420
1488 #define TJ_411 TJSAMP_420
1489 #define TJ_GRAYSCALE TJSAMP_GRAY
1492 #define TJ_BOTTOMUP TJFLAG_BOTTOMUP
1493 #define TJ_FORCEMMX TJFLAG_FORCEMMX
1494 #define TJ_FORCESSE TJFLAG_FORCESSE
1495 #define TJ_FORCESSE2 TJFLAG_FORCESSE2
1496 #define TJ_ALPHAFIRST 64
1497 #define TJ_FORCESSE3 TJFLAG_FORCESSE3
1498 #define TJ_FASTUPSAMPLE TJFLAG_FASTUPSAMPLE
1501 DLLEXPORT unsigned long DLLCALL TJBUFSIZE(int width, int height);
1503 DLLEXPORT unsigned long DLLCALL TJBUFSIZEYUV(int width, int height,
1506 DLLEXPORT unsigned long DLLCALL tjBufSizeYUV(int width, int height,
1509 DLLEXPORT int DLLCALL tjCompress(tjhandle handle, unsigned char *srcBuf,
1510 int width, int pitch, int height, int pixelSize, unsigned char *dstBuf,
1511 unsigned long *compressedSize, int jpegSubsamp, int jpegQual, int flags);
1513 DLLEXPORT int DLLCALL tjEncodeYUV(tjhandle handle,
1514 unsigned char *srcBuf, int width, int pitch, int height, int pixelSize,
1515 unsigned char *dstBuf, int subsamp, int flags);
1517 DLLEXPORT int DLLCALL tjEncodeYUV2(tjhandle handle,
1518 unsigned char *srcBuf, int width, int pitch, int height, int pixelFormat,
1519 unsigned char *dstBuf, int subsamp, int flags);
1521 DLLEXPORT int DLLCALL tjDecompressHeader(tjhandle handle,
1522 unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height);
1524 DLLEXPORT int DLLCALL tjDecompressHeader2(tjhandle handle,
1525 unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height,
1528 DLLEXPORT int DLLCALL tjDecompress(tjhandle handle,
1529 unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
1530 int width, int pitch, int height, int pixelSize, int flags);
1532 DLLEXPORT int DLLCALL tjDecompressToYUV(tjhandle handle,
1533 unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,