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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".
94 * 4:4:4 chrominance subsampling (no chrominance subsampling). The JPEG or
95 * YUV image will contain one chrominance component for every pixel in the
100 * 4:2:2 chrominance subsampling. The JPEG or YUV image will contain one
101 * chrominance component for every 2x1 block of pixels in the source image.
105 * 4:2:0 chrominance subsampling. The JPEG or YUV image will contain one
106 * chrominance component for every 2x2 block of pixels in the source image.
110 * Grayscale. The JPEG or YUV image will contain no chrominance components.
114 * 4:4:0 chrominance subsampling. The JPEG or YUV image will contain one
115 * chrominance component for every 1x2 block of pixels in the source image.
117 * @note 4:4:0 subsampling is not fully accelerated in libjpeg-turbo.
121 * 4:1:1 chrominance subsampling. The JPEG or YUV image will contain one
122 * chrominance component for every 4x1 block of pixels in the source image.
123 * JPEG images compressed with 4:1:1 subsampling will be almost exactly the
124 * same size as those compressed with 4:2:0 subsampling, and in the
125 * aggregate, both subsampling methods produce approximately the same
126 * perceptual quality. However, 4:1:1 is better able to reproduce sharp
127 * horizontal features.
129 * @note 4:1:1 subsampling is not fully accelerated in libjpeg-turbo.
135 * MCU block width (in pixels) for a given level of chrominance subsampling.
137 * - 8x8 for no subsampling or grayscale
143 static const int tjMCUWidth[TJ_NUMSAMP] = { 8, 16, 16, 8, 8, 32 };
146 * MCU block height (in pixels) for a given level of chrominance subsampling.
148 * - 8x8 for no subsampling or grayscale
154 static const int tjMCUHeight[TJ_NUMSAMP] = { 8, 8, 16, 8, 16, 8 };
158 * The number of pixel formats
167 * RGB pixel format. The red, green, and blue components in the image are
168 * stored in 3-byte pixels in the order R, G, B from lowest to highest byte
169 * address within each pixel.
173 * BGR pixel format. The red, green, and blue components in the image are
174 * stored in 3-byte pixels in the order B, G, R from lowest to highest byte
175 * address within each pixel.
179 * RGBX pixel format. The red, green, and blue components in the image are
180 * stored in 4-byte pixels in the order R, G, B from lowest to highest byte
181 * address within each pixel. The X component is ignored when compressing
182 * and undefined when decompressing.
186 * BGRX pixel format. The red, green, and blue components in the image are
187 * stored in 4-byte pixels in the order B, G, R from lowest to highest byte
188 * address within each pixel. The X component is ignored when compressing
189 * and undefined when decompressing.
193 * XBGR pixel format. The red, green, and blue components in the image are
194 * stored in 4-byte pixels in the order R, G, B from highest to lowest byte
195 * address within each pixel. The X component is ignored when compressing
196 * and undefined when decompressing.
200 * XRGB pixel format. The red, green, and blue components in the image are
201 * stored in 4-byte pixels in the order B, G, R from highest to lowest byte
202 * address within each pixel. The X component is ignored when compressing
203 * and undefined when decompressing.
207 * Grayscale pixel format. Each 1-byte pixel represents a luminance
208 * (brightness) level from 0 to 255.
212 * RGBA pixel format. This is the same as @ref TJPF_RGBX, except that when
213 * decompressing, the X component is guaranteed to be 0xFF, which can be
214 * interpreted as an opaque alpha channel.
218 * BGRA pixel format. This is the same as @ref TJPF_BGRX, except that when
219 * decompressing, the X component is guaranteed to be 0xFF, which can be
220 * interpreted as an opaque alpha channel.
224 * ABGR pixel format. This is the same as @ref TJPF_XBGR, except that when
225 * decompressing, the X component is guaranteed to be 0xFF, which can be
226 * interpreted as an opaque alpha channel.
230 * ARGB pixel format. This is the same as @ref TJPF_XRGB, except that when
231 * decompressing, the X component is guaranteed to be 0xFF, which can be
232 * interpreted as an opaque alpha channel.
236 * CMYK pixel format. Unlike RGB, which is an additive color model used
237 * primarily for display, CMYK (Cyan/Magenta/Yellow/Key) is a subtractive
238 * color model used primarily for printing. In the CMYK color model, the
239 * value of each color component typically corresponds to an amount of cyan,
240 * magenta, yellow, or black ink that is applied to a white background. In
241 * order to convert between CMYK and RGB, it is necessary to use a color
242 * management system (CMS.) A CMS will attempt to map colors within the
243 * printer's gamut to perceptually similar colors in the display's gamut and
244 * vice versa, but the mapping is typically not 1:1 or reversible, nor can it
245 * be defined with a simple formula. Thus, such a conversion is out of scope
246 * for a codec library. However, the TurboJPEG API allows for compressing
247 * CMYK pixels into a YCCK JPEG image (see #TJCS_YCCK) and decompressing YCCK
248 * JPEG images into CMYK pixels.
252 * Unknown pixel format. Currently this is only used by #tjLoadImage().
258 * Red offset (in bytes) for a given pixel format. This specifies the number
259 * of bytes that the red component is offset from the start of the pixel. For
260 * instance, if a pixel of format TJ_BGRX is stored in <tt>char pixel[]</tt>,
261 * then the red component will be <tt>pixel[tjRedOffset[TJ_BGRX]]</tt>. This
262 * will be -1 if the pixel format does not have a red component.
264 static const int tjRedOffset[TJ_NUMPF] = {
265 0, 2, 0, 2, 3, 1, -1, 0, 2, 3, 1, -1
268 * Green offset (in bytes) for a given pixel format. This specifies the number
269 * of bytes that the green component is offset from the start of the pixel.
270 * For instance, if a pixel of format TJ_BGRX is stored in
271 * <tt>char pixel[]</tt>, then the green component will be
272 * <tt>pixel[tjGreenOffset[TJ_BGRX]]</tt>. This will be -1 if the pixel format
273 * does not have a green component.
275 static const int tjGreenOffset[TJ_NUMPF] = {
276 1, 1, 1, 1, 2, 2, -1, 1, 1, 2, 2, -1
279 * Blue offset (in bytes) for a given pixel format. This specifies the number
280 * of bytes that the Blue component is offset from the start of the pixel. For
281 * instance, if a pixel of format TJ_BGRX is stored in <tt>char pixel[]</tt>,
282 * then the blue component will be <tt>pixel[tjBlueOffset[TJ_BGRX]]</tt>. This
283 * will be -1 if the pixel format does not have a blue component.
285 static const int tjBlueOffset[TJ_NUMPF] = {
286 2, 0, 2, 0, 1, 3, -1, 2, 0, 1, 3, -1
289 * Alpha offset (in bytes) for a given pixel format. This specifies the number
290 * of bytes that the Alpha component is offset from the start of the pixel.
291 * For instance, if a pixel of format TJ_BGRA is stored in
292 * <tt>char pixel[]</tt>, then the alpha component will be
293 * <tt>pixel[tjAlphaOffset[TJ_BGRA]]</tt>. This will be -1 if the pixel format
294 * does not have an alpha component.
296 static const int tjAlphaOffset[TJ_NUMPF] = {
297 -1, -1, -1, -1, -1, -1, -1, 3, 3, 0, 0, -1
300 * Pixel size (in bytes) for a given pixel format
302 static const int tjPixelSize[TJ_NUMPF] = {
303 3, 3, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4
308 * The number of JPEG colorspaces
317 * RGB colorspace. When compressing the JPEG image, the R, G, and B
318 * components in the source image are reordered into image planes, but no
319 * colorspace conversion or subsampling is performed. RGB JPEG images can be
320 * decompressed to any of the extended RGB pixel formats or grayscale, but
321 * they cannot be decompressed to YUV images.
325 * YCbCr colorspace. YCbCr is not an absolute colorspace but rather a
326 * mathematical transformation of RGB designed solely for storage and
327 * transmission. YCbCr images must be converted to RGB before they can
328 * actually be displayed. In the YCbCr colorspace, the Y (luminance)
329 * component represents the black & white portion of the original image, and
330 * the Cb and Cr (chrominance) components represent the color portion of the
331 * original image. Originally, the analog equivalent of this transformation
332 * allowed the same signal to drive both black & white and color televisions,
333 * but JPEG images use YCbCr primarily because it allows the color data to be
334 * optionally subsampled for the purposes of reducing bandwidth or disk
335 * space. YCbCr is the most common JPEG colorspace, and YCbCr JPEG images
336 * can be compressed from and decompressed to any of the extended RGB pixel
337 * formats or grayscale, or they can be decompressed to YUV planar images.
341 * Grayscale colorspace. The JPEG image retains only the luminance data (Y
342 * component), and any color data from the source image is discarded.
343 * Grayscale JPEG images can be compressed from and decompressed to any of
344 * the extended RGB pixel formats or grayscale, or they can be decompressed
345 * to YUV planar images.
349 * CMYK colorspace. When compressing the JPEG image, the C, M, Y, and K
350 * components in the source image are reordered into image planes, but no
351 * colorspace conversion or subsampling is performed. CMYK JPEG images can
352 * only be decompressed to CMYK pixels.
356 * YCCK colorspace. YCCK (AKA "YCbCrK") is not an absolute colorspace but
357 * rather a mathematical transformation of CMYK designed solely for storage
358 * and transmission. It is to CMYK as YCbCr is to RGB. CMYK pixels can be
359 * reversibly transformed into YCCK, and as with YCbCr, the chrominance
360 * components in the YCCK pixels can be subsampled without incurring major
361 * perceptual loss. YCCK JPEG images can only be compressed from and
362 * decompressed to CMYK pixels.
369 * The uncompressed source/destination image is stored in bottom-up (Windows,
370 * OpenGL) order, not top-down (X11) order.
372 #define TJFLAG_BOTTOMUP 2
374 * When decompressing an image that was compressed using chrominance
375 * subsampling, use the fastest chrominance upsampling algorithm available in
376 * the underlying codec. The default is to use smooth upsampling, which
377 * creates a smooth transition between neighboring chrominance components in
378 * order to reduce upsampling artifacts in the decompressed image.
380 #define TJFLAG_FASTUPSAMPLE 256
382 * Disable buffer (re)allocation. If passed to one of the JPEG compression or
383 * transform functions, this flag will cause those functions to generate an
384 * error if the JPEG image buffer is invalid or too small rather than
385 * attempting to allocate or reallocate that buffer. This reproduces the
386 * behavior of earlier versions of TurboJPEG.
388 #define TJFLAG_NOREALLOC 1024
390 * Use the fastest DCT/IDCT algorithm available in the underlying codec. The
391 * default if this flag is not specified is implementation-specific. For
392 * example, the implementation of TurboJPEG for libjpeg[-turbo] uses the fast
393 * algorithm by default when compressing, because this has been shown to have
394 * only a very slight effect on accuracy, but it uses the accurate algorithm
395 * when decompressing, because this has been shown to have a larger effect.
397 #define TJFLAG_FASTDCT 2048
399 * Use the most accurate DCT/IDCT algorithm available in the underlying codec.
400 * The default if this flag is not specified is implementation-specific. For
401 * example, the implementation of TurboJPEG for libjpeg[-turbo] uses the fast
402 * algorithm by default when compressing, because this has been shown to have
403 * only a very slight effect on accuracy, but it uses the accurate algorithm
404 * when decompressing, because this has been shown to have a larger effect.
406 #define TJFLAG_ACCURATEDCT 4096
408 * Immediately discontinue the current compression/decompression/transform
409 * operation if the underlying codec throws a warning (non-fatal error). The
410 * default behavior is to allow the operation to complete unless a fatal error
413 #define TJFLAG_STOPONWARNING 8192
415 * Use progressive entropy coding in JPEG images generated by the compression
416 * and transform functions. Progressive entropy coding will generally improve
417 * compression relative to baseline entropy coding (the default), but it will
418 * reduce compression and decompression performance considerably.
420 #define TJFLAG_PROGRESSIVE 16384
424 * The number of error codes
433 * The error was non-fatal and recoverable, but the image may still be
438 * The error was fatal and non-recoverable.
445 * The number of transform operations
450 * Transform operations for #tjTransform()
454 * Do not transform the position of the image pixels
458 * Flip (mirror) image horizontally. This transform is imperfect if there
459 * are any partial MCU blocks on the right edge (see #TJXOPT_PERFECT.)
463 * Flip (mirror) image vertically. This transform is imperfect if there are
464 * any partial MCU blocks on the bottom edge (see #TJXOPT_PERFECT.)
468 * Transpose image (flip/mirror along upper left to lower right axis.) This
469 * transform is always perfect.
473 * Transverse transpose image (flip/mirror along upper right to lower left
474 * axis.) This transform is imperfect if there are any partial MCU blocks in
475 * the image (see #TJXOPT_PERFECT.)
479 * Rotate image clockwise by 90 degrees. This transform is imperfect if
480 * there are any partial MCU blocks on the bottom edge (see
485 * Rotate image 180 degrees. This transform is imperfect if there are any
486 * partial MCU blocks in the image (see #TJXOPT_PERFECT.)
490 * Rotate image counter-clockwise by 90 degrees. This transform is imperfect
491 * if there are any partial MCU blocks on the right edge (see
499 * This option will cause #tjTransform() to return an error if the transform is
500 * not perfect. Lossless transforms operate on MCU blocks, whose size depends
501 * on the level of chrominance subsampling used (see #tjMCUWidth
502 * and #tjMCUHeight.) If the image's width or height is not evenly divisible
503 * by the MCU block size, then there will be partial MCU blocks on the right
504 * and/or bottom edges. It is not possible to move these partial MCU blocks to
505 * the top or left of the image, so any transform that would require that is
506 * "imperfect." If this option is not specified, then any partial MCU blocks
507 * that cannot be transformed will be left in place, which will create
508 * odd-looking strips on the right or bottom edge of the image.
510 #define TJXOPT_PERFECT 1
512 * This option will cause #tjTransform() to discard any partial MCU blocks that
513 * cannot be transformed.
515 #define TJXOPT_TRIM 2
517 * This option will enable lossless cropping. See #tjTransform() for more
520 #define TJXOPT_CROP 4
522 * This option will discard the color data in the input image and produce
523 * a grayscale output image.
525 #define TJXOPT_GRAY 8
527 * This option will prevent #tjTransform() from outputting a JPEG image for
528 * this particular transform (this can be used in conjunction with a custom
529 * filter to capture the transformed DCT coefficients without transcoding
532 #define TJXOPT_NOOUTPUT 16
534 * This option will enable progressive entropy coding in the output image
535 * generated by this particular transform. Progressive entropy coding will
536 * generally improve compression relative to baseline entropy coding (the
537 * default), but it will reduce compression and decompression performance
540 #define TJXOPT_PROGRESSIVE 32
542 * This option will prevent #tjTransform() from copying any extra markers
543 * (including EXIF and ICC profile data) from the source image to the output
546 #define TJXOPT_COPYNONE 64
568 * The left boundary of the cropping region. This must be evenly divisible
569 * by the MCU block width (see #tjMCUWidth.)
573 * The upper boundary of the cropping region. This must be evenly divisible
574 * by the MCU block height (see #tjMCUHeight.)
578 * The width of the cropping region. Setting this to 0 is the equivalent of
579 * setting it to the width of the source JPEG image - x.
583 * The height of the cropping region. Setting this to 0 is the equivalent of
584 * setting it to the height of the source JPEG image - y.
592 typedef struct tjtransform {
598 * One of the @ref TJXOP "transform operations"
602 * The bitwise OR of one of more of the @ref TJXOPT_CROP "transform options"
606 * Arbitrary data that can be accessed within the body of the callback
611 * A callback function that can be used to modify the DCT coefficients
612 * after they are losslessly transformed but before they are transcoded to a
613 * new JPEG image. This allows for custom filters or other transformations
614 * to be applied in the frequency domain.
616 * @param coeffs pointer to an array of transformed DCT coefficients. (NOTE:
617 * this pointer is not guaranteed to be valid once the callback returns, so
618 * applications wishing to hand off the DCT coefficients to another function
619 * or library should make a copy of them within the body of the callback.)
621 * @param arrayRegion #tjregion structure containing the width and height of
622 * the array pointed to by <tt>coeffs</tt> as well as its offset relative to
623 * the component plane. TurboJPEG implementations may choose to split each
624 * component plane into multiple DCT coefficient arrays and call the callback
625 * function once for each array.
627 * @param planeRegion #tjregion structure containing the width and height of
628 * the component plane to which <tt>coeffs</tt> belongs
630 * @param componentID ID number of the component plane to which
631 * <tt>coeffs</tt> belongs (Y, Cb, and Cr have, respectively, ID's of 0, 1,
632 * and 2 in typical JPEG images.)
634 * @param transformID ID number of the transformed image to which
635 * <tt>coeffs</tt> belongs. This is the same as the index of the transform
636 * in the <tt>transforms</tt> array that was passed to #tjTransform().
638 * @param transform a pointer to a #tjtransform structure that specifies the
639 * parameters and/or cropping region for this transform
641 * @return 0 if the callback was successful, or -1 if an error occurred.
643 int (*customFilter) (short *coeffs, tjregion arrayRegion,
644 tjregion planeRegion, int componentIndex,
645 int transformIndex, struct tjtransform *transform);
649 * TurboJPEG instance handle
651 typedef void *tjhandle;
655 * Pad the given width to the nearest 32-bit boundary
657 #define TJPAD(width) (((width) + 3) & (~3))
660 * Compute the scaled value of <tt>dimension</tt> using the given scaling
661 * factor. This macro performs the integer equivalent of <tt>ceil(dimension *
662 * scalingFactor)</tt>.
664 #define TJSCALED(dimension, scalingFactor) \
665 ((dimension * scalingFactor.num + scalingFactor.denom - 1) / \
675 * Create a TurboJPEG compressor instance.
677 * @return a handle to the newly-created instance, or NULL if an error
678 * occurred (see #tjGetErrorStr2().)
680 DLLEXPORT tjhandle tjInitCompress(void);
684 * Compress an RGB, grayscale, or CMYK image into a JPEG image.
686 * @param handle a handle to a TurboJPEG compressor or transformer instance
688 * @param srcBuf pointer to an image buffer containing RGB, grayscale, or
689 * CMYK pixels to be compressed
691 * @param width width (in pixels) of the source image
693 * @param pitch bytes per line in the source image. Normally, this should be
694 * <tt>width * #tjPixelSize[pixelFormat]</tt> if the image is unpadded, or
695 * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line of the image
696 * is padded to the nearest 32-bit boundary, as is the case for Windows
697 * bitmaps. You can also be clever and use this parameter to skip lines, etc.
698 * Setting this parameter to 0 is the equivalent of setting it to
699 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
701 * @param height height (in pixels) of the source image
703 * @param pixelFormat pixel format of the source image (see @ref TJPF
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
708 * to 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 jpegSubsamp the level of chrominance subsampling to be used when
731 * generating the JPEG image (see @ref TJSAMP
732 * "Chrominance subsampling options".)
734 * @param jpegQual the image quality of the generated JPEG image (1 = worst,
737 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
740 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
741 * and #tjGetErrorCode().)
743 DLLEXPORT int tjCompress2(tjhandle handle, const unsigned char *srcBuf,
744 int width, int pitch, int height, int pixelFormat,
745 unsigned char **jpegBuf, unsigned long *jpegSize,
746 int jpegSubsamp, int jpegQual, int flags);
750 * Compress a YUV planar image into a JPEG image.
752 * @param handle a handle to a TurboJPEG compressor or transformer instance
754 * @param srcBuf pointer to an image buffer containing a YUV planar image to be
755 * compressed. The size of this buffer should match the value returned by
756 * #tjBufSizeYUV2() for the given image width, height, padding, and level of
757 * chrominance subsampling. The Y, U (Cb), and V (Cr) image planes should be
758 * stored sequentially in the source buffer (refer to @ref YUVnotes
759 * "YUV Image Format Notes".)
761 * @param width width (in pixels) of the source image. If the width is not an
762 * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate
763 * buffer copy will be performed within TurboJPEG.
765 * @param pad the line padding used in the source image. For instance, if each
766 * line in each plane of the YUV image is padded to the nearest multiple of 4
767 * bytes, then <tt>pad</tt> should be set to 4.
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 #tjGetErrorStr2()
807 * and #tjGetErrorCode().)
809 DLLEXPORT int tjCompressFromYUV(tjhandle handle, const unsigned char *srcBuf,
810 int width, int pad, int height, int subsamp,
811 unsigned char **jpegBuf,
812 unsigned long *jpegSize, int jpegQual,
817 * Compress a set of Y, U (Cb), and V (Cr) image planes into a JPEG image.
819 * @param handle a handle to a TurboJPEG compressor or transformer instance
821 * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
822 * (or just a Y plane, if compressing a grayscale image) that contain a YUV
823 * image to be compressed. These planes can be contiguous or non-contiguous in
824 * memory. The size of each plane should match the value returned by
825 * #tjPlaneSizeYUV() for the given image width, height, strides, and level of
826 * chrominance subsampling. Refer to @ref YUVnotes "YUV Image Format Notes"
829 * @param width width (in pixels) of the source image. If the width is not an
830 * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate
831 * buffer copy will be performed within TurboJPEG.
833 * @param strides an array of integers, each specifying the number of bytes per
834 * line in the corresponding plane of the YUV source image. Setting the stride
835 * for any plane to 0 is the same as setting it to the plane width (see
836 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
837 * the strides for all planes will be set to their respective plane widths.
838 * You can adjust the strides in order to specify an arbitrary amount of line
839 * padding in each plane or to create a JPEG image from a subregion of a larger
842 * @param height height (in pixels) of the source image. If the height is not
843 * an even multiple of the MCU block height (see #tjMCUHeight), then an
844 * intermediate buffer copy will be performed within TurboJPEG.
846 * @param subsamp the level of chrominance subsampling used in the source
847 * image (see @ref TJSAMP "Chrominance subsampling options".)
849 * @param jpegBuf address of a pointer to an image buffer that will receive the
850 * JPEG image. TurboJPEG has the ability to reallocate the JPEG buffer to
851 * accommodate the size of the JPEG image. Thus, you can choose to:
852 * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and
853 * let TurboJPEG grow the buffer as needed,
854 * -# set <tt>*jpegBuf</tt> to NULL to tell TurboJPEG to allocate the buffer
856 * -# pre-allocate the buffer to a "worst case" size determined by calling
857 * #tjBufSize(). This should ensure that the buffer never has to be
858 * re-allocated (setting #TJFLAG_NOREALLOC guarantees that it won't be.)
860 * If you choose option 1, <tt>*jpegSize</tt> should be set to the size of your
861 * pre-allocated buffer. In any case, unless you have set #TJFLAG_NOREALLOC,
862 * you should always check <tt>*jpegBuf</tt> upon return from this function, as
863 * it may have changed.
865 * @param jpegSize pointer to an unsigned long variable that holds the size of
866 * the JPEG image buffer. If <tt>*jpegBuf</tt> points to a pre-allocated
867 * buffer, then <tt>*jpegSize</tt> should be set to the size of the buffer.
868 * Upon return, <tt>*jpegSize</tt> will contain the size of the JPEG image (in
869 * bytes.) If <tt>*jpegBuf</tt> points to a JPEG image buffer that is being
870 * reused from a previous call to one of the JPEG compression functions, then
871 * <tt>*jpegSize</tt> is ignored.
873 * @param jpegQual the image quality of the generated JPEG image (1 = worst,
876 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
879 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
880 * and #tjGetErrorCode().)
882 DLLEXPORT int tjCompressFromYUVPlanes(tjhandle handle,
883 const unsigned char **srcPlanes,
884 int width, const int *strides,
885 int height, int subsamp,
886 unsigned char **jpegBuf,
887 unsigned long *jpegSize, int jpegQual,
892 * The maximum size of the buffer (in bytes) required to hold a JPEG image with
893 * the given parameters. The number of bytes returned by this function is
894 * larger than the size of the uncompressed source image. The reason for this
895 * is that the JPEG format uses 16-bit coefficients, and it is thus possible
896 * for a very high-quality JPEG image with very high-frequency content to
897 * expand rather than compress when converted to the JPEG format. Such images
898 * represent a very rare corner case, but since there is no way to predict the
899 * size of a JPEG image prior to compression, the corner case has to be
902 * @param width width (in pixels) of the image
904 * @param height height (in pixels) of the image
906 * @param jpegSubsamp the level of chrominance subsampling to be used when
907 * generating the JPEG image (see @ref TJSAMP
908 * "Chrominance subsampling options".)
910 * @return the maximum size of the buffer (in bytes) required to hold the
911 * image, or -1 if the arguments are out of bounds.
913 DLLEXPORT unsigned long tjBufSize(int width, int height, int jpegSubsamp);
917 * The size of the buffer (in bytes) required to hold a YUV planar image with
918 * the given parameters.
920 * @param width width (in pixels) of the image
922 * @param pad the width of each line in each plane of the image is padded to
923 * the nearest multiple of this number of bytes (must be a power of 2.)
925 * @param height height (in pixels) of the image
927 * @param subsamp level of chrominance subsampling in the image (see
928 * @ref TJSAMP "Chrominance subsampling options".)
930 * @return the size of the buffer (in bytes) required to hold the image, or
931 * -1 if the arguments are out of bounds.
933 DLLEXPORT unsigned long tjBufSizeYUV2(int width, int pad, int height,
938 * The size of the buffer (in bytes) required to hold a YUV image plane with
939 * the given parameters.
941 * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
943 * @param width width (in pixels) of the YUV image. NOTE: this is the width of
944 * the whole image, not the plane width.
946 * @param stride bytes per line in the image plane. Setting this to 0 is the
947 * equivalent of setting it to the plane width.
949 * @param height height (in pixels) of the YUV image. NOTE: this is the height
950 * of the whole image, not the plane height.
952 * @param subsamp level of chrominance subsampling in the image (see
953 * @ref TJSAMP "Chrominance subsampling options".)
955 * @return the size of the buffer (in bytes) required to hold the YUV image
956 * plane, or -1 if the arguments are out of bounds.
958 DLLEXPORT unsigned long tjPlaneSizeYUV(int componentID, int width, int stride,
959 int height, int subsamp);
963 * The plane width of a YUV image plane with the given parameters. Refer to
964 * @ref YUVnotes "YUV Image Format Notes" for a description of plane width.
966 * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
968 * @param width width (in pixels) of the YUV image
970 * @param subsamp level of chrominance subsampling in the image (see
971 * @ref TJSAMP "Chrominance subsampling options".)
973 * @return the plane width of a YUV image plane with the given parameters, or
974 * -1 if the arguments are out of bounds.
976 DLLEXPORT int tjPlaneWidth(int componentID, int width, int subsamp);
980 * The plane height of a YUV image plane with the given parameters. Refer to
981 * @ref YUVnotes "YUV Image Format Notes" for a description of plane height.
983 * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
985 * @param height height (in pixels) of the YUV image
987 * @param subsamp level of chrominance subsampling in the image (see
988 * @ref TJSAMP "Chrominance subsampling options".)
990 * @return the plane height of a YUV image plane with the given parameters, or
991 * -1 if the arguments are out of bounds.
993 DLLEXPORT int tjPlaneHeight(int componentID, int height, int subsamp);
997 * Encode an RGB or grayscale image into a YUV planar image. This function
998 * uses the accelerated color conversion routines in the underlying
999 * codec but does not execute any of the other steps in the JPEG compression
1002 * @param handle a handle to a TurboJPEG compressor or transformer instance
1004 * @param srcBuf pointer to an image buffer containing RGB or grayscale pixels
1007 * @param width width (in pixels) of the source image
1009 * @param pitch bytes per line in the source image. Normally, this should be
1010 * <tt>width * #tjPixelSize[pixelFormat]</tt> if the image is unpadded, or
1011 * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line of the image
1012 * is padded to the nearest 32-bit boundary, as is the case for Windows
1013 * bitmaps. You can also be clever and use this parameter to skip lines, etc.
1014 * Setting this parameter to 0 is the equivalent of setting it to
1015 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
1017 * @param height height (in pixels) of the source image
1019 * @param pixelFormat pixel format of the source image (see @ref TJPF
1022 * @param dstBuf pointer to an image buffer that will receive the YUV image.
1023 * Use #tjBufSizeYUV2() to determine the appropriate size for this buffer based
1024 * on the image width, height, padding, and level of chrominance subsampling.
1025 * The Y, U (Cb), and V (Cr) image planes will be stored sequentially in the
1026 * buffer (refer to @ref YUVnotes "YUV Image Format Notes".)
1028 * @param pad the width of each line in each plane of the YUV image will be
1029 * padded to the nearest multiple of this number of bytes (must be a power of
1030 * 2.) To generate images suitable for X Video, <tt>pad</tt> should be set to
1033 * @param subsamp the level of chrominance subsampling to be used when
1034 * generating the YUV image (see @ref TJSAMP
1035 * "Chrominance subsampling options".) To generate images suitable for X
1036 * Video, <tt>subsamp</tt> should be set to @ref TJSAMP_420. This produces an
1037 * image compatible with the I420 (AKA "YUV420P") format.
1039 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1042 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1043 * and #tjGetErrorCode().)
1045 DLLEXPORT int tjEncodeYUV3(tjhandle handle, const unsigned char *srcBuf,
1046 int width, int pitch, int height, int pixelFormat,
1047 unsigned char *dstBuf, int pad, int subsamp,
1052 * Encode an RGB or grayscale image into separate Y, U (Cb), and V (Cr) image
1053 * planes. This function uses the accelerated color conversion routines in the
1054 * underlying codec but does not execute any of the other steps in the JPEG
1055 * compression process.
1057 * @param handle a handle to a TurboJPEG compressor or transformer instance
1059 * @param srcBuf pointer to an image buffer containing RGB or grayscale pixels
1062 * @param width width (in pixels) of the source image
1064 * @param pitch bytes per line in the source image. Normally, this should be
1065 * <tt>width * #tjPixelSize[pixelFormat]</tt> if the image is unpadded, or
1066 * <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line of the image
1067 * is padded to the nearest 32-bit boundary, as is the case for Windows
1068 * bitmaps. You can also be clever and use this parameter to skip lines, etc.
1069 * Setting this parameter to 0 is the equivalent of setting it to
1070 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
1072 * @param height height (in pixels) of the source image
1074 * @param pixelFormat pixel format of the source image (see @ref TJPF
1077 * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
1078 * (or just a Y plane, if generating a grayscale image) that will receive the
1079 * encoded image. These planes can be contiguous or non-contiguous in memory.
1080 * Use #tjPlaneSizeYUV() to determine the appropriate size for each plane based
1081 * on the image width, height, strides, and level of chrominance subsampling.
1082 * Refer to @ref YUVnotes "YUV Image Format Notes" for more details.
1084 * @param strides an array of integers, each specifying the number of bytes per
1085 * line in the corresponding plane of the output image. Setting the stride for
1086 * any plane to 0 is the same as setting it to the plane width (see
1087 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
1088 * the strides for all planes will be set to their respective plane widths.
1089 * You can adjust the strides in order to add an arbitrary amount of line
1090 * padding to each plane or to encode an RGB or grayscale image into a
1091 * subregion of a larger YUV planar image.
1093 * @param subsamp the level of chrominance subsampling to be used when
1094 * generating the YUV image (see @ref TJSAMP
1095 * "Chrominance subsampling options".) To generate images suitable for X
1096 * Video, <tt>subsamp</tt> should be set to @ref TJSAMP_420. This produces an
1097 * image compatible with the I420 (AKA "YUV420P") format.
1099 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1102 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1103 * and #tjGetErrorCode().)
1105 DLLEXPORT int tjEncodeYUVPlanes(tjhandle handle, const unsigned char *srcBuf,
1106 int width, int pitch, int height,
1107 int pixelFormat, unsigned char **dstPlanes,
1108 int *strides, int subsamp, int flags);
1112 * Create a TurboJPEG decompressor instance.
1114 * @return a handle to the newly-created instance, or NULL if an error
1115 * occurred (see #tjGetErrorStr2().)
1117 DLLEXPORT tjhandle tjInitDecompress(void);
1121 * Retrieve information about a JPEG image without decompressing it.
1123 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1125 * @param jpegBuf pointer to a buffer containing a JPEG image
1127 * @param jpegSize size of the JPEG image (in bytes)
1129 * @param width pointer to an integer variable that will receive the width (in
1130 * pixels) of the JPEG image
1132 * @param height pointer to an integer variable that will receive the height
1133 * (in pixels) of the JPEG image
1135 * @param jpegSubsamp pointer to an integer variable that will receive the
1136 * level of chrominance subsampling used when the JPEG image was compressed
1137 * (see @ref TJSAMP "Chrominance subsampling options".)
1139 * @param jpegColorspace pointer to an integer variable that will receive one
1140 * of the JPEG colorspace constants, indicating the colorspace of the JPEG
1141 * image (see @ref TJCS "JPEG colorspaces".)
1143 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1144 * and #tjGetErrorCode().)
1146 DLLEXPORT int tjDecompressHeader3(tjhandle handle,
1147 const unsigned char *jpegBuf,
1148 unsigned long jpegSize, int *width,
1149 int *height, int *jpegSubsamp,
1150 int *jpegColorspace);
1154 * Returns a list of fractional scaling factors that the JPEG decompressor in
1155 * this implementation of TurboJPEG supports.
1157 * @param numscalingfactors pointer to an integer variable that will receive
1158 * the number of elements in the list
1160 * @return a pointer to a list of fractional scaling factors, or NULL if an
1161 * error is encountered (see #tjGetErrorStr2().)
1163 DLLEXPORT tjscalingfactor *tjGetScalingFactors(int *numscalingfactors);
1167 * Decompress a JPEG image to an RGB, grayscale, or CMYK image.
1169 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1171 * @param jpegBuf pointer to a buffer containing the JPEG image to decompress
1173 * @param jpegSize size of the JPEG image (in bytes)
1175 * @param dstBuf pointer to an image buffer that will receive the decompressed
1176 * image. This buffer should normally be <tt>pitch * scaledHeight</tt> bytes
1177 * in size, where <tt>scaledHeight</tt> can be determined by calling
1178 * #TJSCALED() with the JPEG image height and one of the scaling factors
1179 * returned by #tjGetScalingFactors(). The <tt>dstBuf</tt> pointer may also be
1180 * used to decompress into a specific region of a larger buffer.
1182 * @param width desired width (in pixels) of the destination image. If this is
1183 * different than the width of the JPEG image being decompressed, then
1184 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1185 * possible image that will fit within the desired width. If <tt>width</tt> is
1186 * set to 0, then only the height will be considered when determining the
1187 * scaled image size.
1189 * @param pitch bytes per line in the destination image. Normally, this is
1190 * <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt> if the decompressed image
1191 * is unpadded, else <tt>#TJPAD(scaledWidth * #tjPixelSize[pixelFormat])</tt>
1192 * if each line of the decompressed image is padded to the nearest 32-bit
1193 * boundary, as is the case for Windows bitmaps. (NOTE: <tt>scaledWidth</tt>
1194 * can be determined by calling #TJSCALED() with the JPEG image width and one
1195 * of the scaling factors returned by #tjGetScalingFactors().) You can also be
1196 * clever and use the pitch parameter to skip lines, etc. Setting this
1197 * parameter to 0 is the equivalent of setting it to
1198 * <tt>scaledWidth * #tjPixelSize[pixelFormat]</tt>.
1200 * @param height desired height (in pixels) of the destination image. If this
1201 * is different than the height of the JPEG image being decompressed, then
1202 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1203 * possible image that will fit within the desired height. If <tt>height</tt>
1204 * is set to 0, then only the width will be considered when determining the
1205 * scaled image size.
1207 * @param pixelFormat pixel format of the destination image (see @ref
1208 * TJPF "Pixel formats".)
1210 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1213 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1214 * and #tjGetErrorCode().)
1216 DLLEXPORT int tjDecompress2(tjhandle handle, const unsigned char *jpegBuf,
1217 unsigned long jpegSize, unsigned char *dstBuf,
1218 int width, int pitch, int height, int pixelFormat,
1223 * Decompress a JPEG image to a YUV planar image. This function performs JPEG
1224 * decompression but leaves out the color conversion step, so a planar YUV
1225 * image is generated instead of an RGB image.
1227 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1229 * @param jpegBuf pointer to a buffer containing the JPEG image to decompress
1231 * @param jpegSize size of the JPEG image (in bytes)
1233 * @param dstBuf pointer to an image buffer that will receive the YUV image.
1234 * Use #tjBufSizeYUV2() to determine the appropriate size for this buffer based
1235 * on the image width, height, padding, and level of subsampling. The Y,
1236 * U (Cb), and V (Cr) image planes will be stored sequentially in the buffer
1237 * (refer to @ref YUVnotes "YUV Image Format Notes".)
1239 * @param width desired width (in pixels) of the YUV image. If this is
1240 * different than the width of the JPEG image being decompressed, then
1241 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1242 * possible image that will fit within the desired width. If <tt>width</tt> is
1243 * set to 0, then only the height will be considered when determining the
1244 * scaled image size. If the scaled width is not an even multiple of the MCU
1245 * block width (see #tjMCUWidth), then an intermediate buffer copy will be
1246 * performed within TurboJPEG.
1248 * @param pad the width of each line in each plane of the YUV image will be
1249 * padded to the nearest multiple of this number of bytes (must be a power of
1250 * 2.) To generate images suitable for X Video, <tt>pad</tt> should be set to
1253 * @param height desired height (in pixels) of the YUV image. If this is
1254 * different than the height of the JPEG image being decompressed, then
1255 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1256 * possible image that will fit within the desired height. If <tt>height</tt>
1257 * is set to 0, then only the width will be considered when determining the
1258 * scaled image size. If the scaled height is not an even multiple of the MCU
1259 * block height (see #tjMCUHeight), then an intermediate buffer copy will be
1260 * performed within TurboJPEG.
1262 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1265 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1266 * and #tjGetErrorCode().)
1268 DLLEXPORT int tjDecompressToYUV2(tjhandle handle, const unsigned char *jpegBuf,
1269 unsigned long jpegSize, unsigned char *dstBuf,
1270 int width, int pad, int height, int flags);
1274 * Decompress a JPEG image into separate Y, U (Cb), and V (Cr) image
1275 * planes. This function performs JPEG decompression but leaves out the color
1276 * conversion step, so a planar YUV image is generated instead of an RGB image.
1278 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1280 * @param jpegBuf pointer to a buffer containing the JPEG image to decompress
1282 * @param jpegSize size of the JPEG image (in bytes)
1284 * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
1285 * (or just a Y plane, if decompressing a grayscale image) that will receive
1286 * the YUV image. These planes can be contiguous or non-contiguous in memory.
1287 * Use #tjPlaneSizeYUV() to determine the appropriate size for each plane based
1288 * on the scaled image width, scaled image height, strides, and level of
1289 * chrominance subsampling. Refer to @ref YUVnotes "YUV Image Format Notes"
1292 * @param width desired width (in pixels) of the YUV image. If this is
1293 * different than the width of the JPEG image being decompressed, then
1294 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1295 * possible image that will fit within the desired width. If <tt>width</tt> is
1296 * set to 0, then only the height will be considered when determining the
1297 * scaled image size. If the scaled width is not an even multiple of the MCU
1298 * block width (see #tjMCUWidth), then an intermediate buffer copy will be
1299 * performed within TurboJPEG.
1301 * @param strides an array of integers, each specifying the number of bytes per
1302 * line in the corresponding plane of the output image. Setting the stride for
1303 * any plane to 0 is the same as setting it to the scaled plane width (see
1304 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
1305 * the strides for all planes will be set to their respective scaled plane
1306 * widths. You can adjust the strides in order to add an arbitrary amount of
1307 * line padding to each plane or to decompress the JPEG image into a subregion
1308 * of a larger YUV planar image.
1310 * @param height desired height (in pixels) of the YUV image. If this is
1311 * different than the height of the JPEG image being decompressed, then
1312 * TurboJPEG will use scaling in the JPEG decompressor to generate the largest
1313 * possible image that will fit within the desired height. If <tt>height</tt>
1314 * is set to 0, then only the width will be considered when determining the
1315 * scaled image size. If the scaled height is not an even multiple of the MCU
1316 * block height (see #tjMCUHeight), then an intermediate buffer copy will be
1317 * performed within TurboJPEG.
1319 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1322 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1323 * and #tjGetErrorCode().)
1325 DLLEXPORT int tjDecompressToYUVPlanes(tjhandle handle,
1326 const unsigned char *jpegBuf,
1327 unsigned long jpegSize,
1328 unsigned char **dstPlanes, int width,
1329 int *strides, int height, int flags);
1333 * Decode a YUV planar image into an RGB or grayscale image. This function
1334 * uses the accelerated color conversion routines in the underlying
1335 * codec but does not execute any of the other steps in the JPEG decompression
1338 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1340 * @param srcBuf pointer to an image buffer containing a YUV planar image to be
1341 * decoded. The size of this buffer should match the value returned by
1342 * #tjBufSizeYUV2() for the given image width, height, padding, and level of
1343 * chrominance subsampling. The Y, U (Cb), and V (Cr) image planes should be
1344 * stored sequentially in the source buffer (refer to @ref YUVnotes
1345 * "YUV Image Format Notes".)
1347 * @param pad Use this parameter to specify that the width of each line in each
1348 * plane of the YUV source image is padded to the nearest multiple of this
1349 * number of bytes (must be a power of 2.)
1351 * @param subsamp the level of chrominance subsampling used in the YUV source
1352 * image (see @ref TJSAMP "Chrominance subsampling options".)
1354 * @param dstBuf pointer to an image buffer that will receive the decoded
1355 * image. This buffer should normally be <tt>pitch * height</tt> bytes in
1356 * size, but the <tt>dstBuf</tt> pointer can also be used to decode into a
1357 * specific region of a larger buffer.
1359 * @param width width (in pixels) of the source and destination images
1361 * @param pitch bytes per line in the destination image. Normally, this should
1362 * be <tt>width * #tjPixelSize[pixelFormat]</tt> if the destination image is
1363 * unpadded, or <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line
1364 * of the destination image should be padded to the nearest 32-bit boundary, as
1365 * is the case for Windows bitmaps. You can also be clever and use the pitch
1366 * parameter to skip lines, etc. Setting this parameter to 0 is the equivalent
1367 * of setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>.
1369 * @param height height (in pixels) of the source and destination images
1371 * @param pixelFormat pixel format of the destination image (see @ref TJPF
1374 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1377 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1378 * and #tjGetErrorCode().)
1380 DLLEXPORT int tjDecodeYUV(tjhandle handle, const unsigned char *srcBuf,
1381 int pad, int subsamp, unsigned char *dstBuf,
1382 int width, int pitch, int height, int pixelFormat,
1387 * Decode a set of Y, U (Cb), and V (Cr) image planes into an RGB or grayscale
1388 * image. This function uses the accelerated color conversion routines in the
1389 * underlying codec but does not execute any of the other steps in the JPEG
1390 * decompression process.
1392 * @param handle a handle to a TurboJPEG decompressor or transformer instance
1394 * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
1395 * (or just a Y plane, if decoding a grayscale image) that contain a YUV image
1396 * to be decoded. These planes can be contiguous or non-contiguous in memory.
1397 * The size of each plane should match the value returned by #tjPlaneSizeYUV()
1398 * for the given image width, height, strides, and level of chrominance
1399 * subsampling. Refer to @ref YUVnotes "YUV Image Format Notes" for more
1402 * @param strides an array of integers, each specifying the number of bytes per
1403 * line in the corresponding plane of the YUV source image. Setting the stride
1404 * for any plane to 0 is the same as setting it to the plane width (see
1405 * @ref YUVnotes "YUV Image Format Notes".) If <tt>strides</tt> is NULL, then
1406 * the strides for all planes will be set to their respective plane widths.
1407 * You can adjust the strides in order to specify an arbitrary amount of line
1408 * padding in each plane or to decode a subregion of a larger YUV planar image.
1410 * @param subsamp the level of chrominance subsampling used in the YUV source
1411 * image (see @ref TJSAMP "Chrominance subsampling options".)
1413 * @param dstBuf pointer to an image buffer that will receive the decoded
1414 * image. This buffer should normally be <tt>pitch * height</tt> bytes in
1415 * size, but the <tt>dstBuf</tt> pointer can also be used to decode into a
1416 * specific region of a larger buffer.
1418 * @param width width (in pixels) of the source and destination images
1420 * @param pitch bytes per line in the destination image. Normally, this should
1421 * be <tt>width * #tjPixelSize[pixelFormat]</tt> if the destination image is
1422 * unpadded, or <tt>#TJPAD(width * #tjPixelSize[pixelFormat])</tt> if each line
1423 * of the destination image should be padded to the nearest 32-bit boundary, as
1424 * is the case for Windows bitmaps. You can also be clever and use the pitch
1425 * parameter to skip lines, etc. Setting this parameter to 0 is the equivalent
1426 * of setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>.
1428 * @param height height (in pixels) of the source and destination images
1430 * @param pixelFormat pixel format of the destination image (see @ref TJPF
1433 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1436 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1437 * and #tjGetErrorCode().)
1439 DLLEXPORT int tjDecodeYUVPlanes(tjhandle handle,
1440 const unsigned char **srcPlanes,
1441 const int *strides, int subsamp,
1442 unsigned char *dstBuf, int width, int pitch,
1443 int height, int pixelFormat, int flags);
1447 * Create a new TurboJPEG transformer instance.
1449 * @return a handle to the newly-created instance, or NULL if an error
1450 * occurred (see #tjGetErrorStr2().)
1452 DLLEXPORT tjhandle tjInitTransform(void);
1456 * Losslessly transform a JPEG image into another JPEG image. Lossless
1457 * transforms work by moving the raw DCT coefficients from one JPEG image
1458 * structure to another without altering the values of the coefficients. While
1459 * this is typically faster than decompressing the image, transforming it, and
1460 * re-compressing it, lossless transforms are not free. Each lossless
1461 * transform requires reading and performing Huffman decoding on all of the
1462 * coefficients in the source image, regardless of the size of the destination
1463 * image. Thus, this function provides a means of generating multiple
1464 * transformed images from the same source or applying multiple
1465 * transformations simultaneously, in order to eliminate the need to read the
1466 * source coefficients multiple times.
1468 * @param handle a handle to a TurboJPEG transformer instance
1470 * @param jpegBuf pointer to a buffer containing the JPEG source image to
1473 * @param jpegSize size of the JPEG source image (in bytes)
1475 * @param n the number of transformed JPEG images to generate
1477 * @param dstBufs pointer to an array of n image buffers. <tt>dstBufs[i]</tt>
1478 * will receive a JPEG image that has been transformed using the parameters in
1479 * <tt>transforms[i]</tt>. TurboJPEG has the ability to reallocate the JPEG
1480 * buffer to accommodate the size of the JPEG image. Thus, you can choose to:
1481 * -# pre-allocate the JPEG buffer with an arbitrary size using #tjAlloc() and
1482 * let TurboJPEG grow the buffer as needed,
1483 * -# set <tt>dstBufs[i]</tt> to NULL to tell TurboJPEG to allocate the buffer
1485 * -# pre-allocate the buffer to a "worst case" size determined by calling
1486 * #tjBufSize() with the transformed or cropped width and height. Under normal
1487 * circumstances, this should ensure that the buffer never has to be
1488 * re-allocated (setting #TJFLAG_NOREALLOC guarantees that it won't be.) Note,
1489 * however, that there are some rare cases (such as transforming images with a
1490 * large amount of embedded EXIF or ICC profile data) in which the output image
1491 * will be larger than the worst-case size, and #TJFLAG_NOREALLOC cannot be
1492 * used in those cases.
1494 * If you choose option 1, <tt>dstSizes[i]</tt> should be set to the size of
1495 * your pre-allocated buffer. In any case, unless you have set
1496 * #TJFLAG_NOREALLOC, you should always check <tt>dstBufs[i]</tt> upon return
1497 * from this function, as it may have changed.
1499 * @param dstSizes pointer to an array of n unsigned long variables that will
1500 * receive the actual sizes (in bytes) of each transformed JPEG image. If
1501 * <tt>dstBufs[i]</tt> points to a pre-allocated buffer, then
1502 * <tt>dstSizes[i]</tt> should be set to the size of the buffer. Upon return,
1503 * <tt>dstSizes[i]</tt> will contain the size of the JPEG image (in bytes.)
1505 * @param transforms pointer to an array of n #tjtransform structures, each of
1506 * which specifies the transform parameters and/or cropping region for the
1507 * corresponding transformed output image.
1509 * @param flags the bitwise OR of one or more of the @ref TJFLAG_ACCURATEDCT
1512 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2()
1513 * and #tjGetErrorCode().)
1515 DLLEXPORT int tjTransform(tjhandle handle, const unsigned char *jpegBuf,
1516 unsigned long jpegSize, int n,
1517 unsigned char **dstBufs, unsigned long *dstSizes,
1518 tjtransform *transforms, int flags);
1522 * Destroy a TurboJPEG compressor, decompressor, or transformer instance.
1524 * @param handle a handle to a TurboJPEG compressor, decompressor or
1525 * transformer instance
1527 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2().)
1529 DLLEXPORT int tjDestroy(tjhandle handle);
1533 * Allocate an image buffer for use with TurboJPEG. You should always use
1534 * this function to allocate the JPEG destination buffer(s) for the compression
1535 * and transform functions unless you are disabling automatic buffer
1536 * (re)allocation (by setting #TJFLAG_NOREALLOC.)
1538 * @param bytes the number of bytes to allocate
1540 * @return a pointer to a newly-allocated buffer with the specified number of
1545 DLLEXPORT unsigned char *tjAlloc(int bytes);
1549 * Load an uncompressed image from disk into memory.
1551 * @param filename name of a file containing an uncompressed image in Windows
1552 * BMP or PBMPLUS (PPM/PGM) format
1554 * @param width pointer to an integer variable that will receive the width (in
1555 * pixels) of the uncompressed image
1557 * @param align row alignment of the image buffer to be returned (must be a
1558 * power of 2.) For instance, setting this parameter to 4 will cause all rows
1559 * in the image buffer to be padded to the nearest 32-bit boundary, and setting
1560 * this parameter to 1 will cause all rows in the image buffer to be unpadded.
1562 * @param height pointer to an integer variable that will receive the height
1563 * (in pixels) of the uncompressed image
1565 * @param pixelFormat pointer to an integer variable that specifies or will
1566 * receive the pixel format of the uncompressed image buffer. The behavior of
1567 * #tjLoadImage() will vary depending on the value of <tt>*pixelFormat</tt>
1568 * passed to the function:
1569 * - @ref TJPF_UNKNOWN : The uncompressed image buffer returned by the function
1570 * will use the most optimal pixel format for the file type, and
1571 * <tt>*pixelFormat</tt> will contain the ID of this pixel format upon
1572 * successful return from the function.
1573 * - @ref TJPF_GRAY : Only PGM files and 8-bit BMP files with a grayscale
1574 * colormap can be loaded.
1575 * - @ref TJPF_CMYK : The RGB or grayscale pixels stored in the file will be
1576 * converted using a quick & dirty algorithm that is suitable only for testing
1577 * purposes (proper conversion between CMYK and other formats requires a color
1578 * management system.)
1579 * - Other @ref TJPF "pixel formats" : The uncompressed image buffer will use
1580 * the specified pixel format, and pixel format conversion will be performed if
1583 * @param flags the bitwise OR of one or more of the @ref TJFLAG_BOTTOMUP
1586 * @return a pointer to a newly-allocated buffer containing the uncompressed
1587 * image, converted to the chosen pixel format and with the chosen row
1588 * alignment, or NULL if an error occurred (see #tjGetErrorStr2().) This
1589 * buffer should be freed using #tjFree().
1591 DLLEXPORT unsigned char *tjLoadImage(const char *filename, int *width,
1592 int align, int *height, int *pixelFormat,
1597 * Save an uncompressed image from memory to disk.
1599 * @param filename name of a file to which to save the uncompressed image.
1600 * The image will be stored in Windows BMP or PBMPLUS (PPM/PGM) format,
1601 * depending on the file extension.
1603 * @param buffer pointer to an image buffer containing RGB, grayscale, or
1604 * CMYK pixels to be saved
1606 * @param width width (in pixels) of the uncompressed image
1608 * @param pitch bytes per line in the image buffer. Setting this parameter to
1609 * 0 is the equivalent of setting it to
1610 * <tt>width * #tjPixelSize[pixelFormat]</tt>.
1612 * @param height height (in pixels) of the uncompressed image
1614 * @param pixelFormat pixel format of the image buffer (see @ref TJPF
1615 * "Pixel formats".) If this parameter is set to @ref TJPF_GRAY, then the
1616 * image will be stored in PGM or 8-bit (indexed color) BMP format. Otherwise,
1617 * the image will be stored in PPM or 24-bit BMP format. If this parameter
1618 * is set to @ref TJPF_CMYK, then the CMYK pixels will be converted to RGB
1619 * using a quick & dirty algorithm that is suitable only for testing (proper
1620 * conversion between CMYK and other formats requires a color management
1623 * @param flags the bitwise OR of one or more of the @ref TJFLAG_BOTTOMUP
1626 * @return 0 if successful, or -1 if an error occurred (see #tjGetErrorStr2().)
1628 DLLEXPORT int tjSaveImage(const char *filename, unsigned char *buffer,
1629 int width, int pitch, int height, int pixelFormat,
1634 * Free an image buffer previously allocated by TurboJPEG. You should always
1635 * use this function to free JPEG destination buffer(s) that were automatically
1636 * (re)allocated by the compression and transform functions or that were
1637 * manually allocated using #tjAlloc().
1639 * @param buffer address of the buffer to free. If the address is NULL, then
1640 * this function has no effect.
1644 DLLEXPORT void tjFree(unsigned char *buffer);
1648 * Returns a descriptive error message explaining why the last command failed.
1650 * @param handle a handle to a TurboJPEG compressor, decompressor, or
1651 * transformer instance, or NULL if the error was generated by a global
1652 * function (but note that retrieving the error message for a global function
1653 * is thread-safe only on platforms that support thread-local storage.)
1655 * @return a descriptive error message explaining why the last command failed.
1657 DLLEXPORT char *tjGetErrorStr2(tjhandle handle);
1661 * Returns a code indicating the severity of the last error. See
1662 * @ref TJERR "Error codes".
1664 * @param handle a handle to a TurboJPEG compressor, decompressor or
1665 * transformer instance
1667 * @return a code indicating the severity of the last error. See
1668 * @ref TJERR "Error codes".
1670 DLLEXPORT int tjGetErrorCode(tjhandle handle);
1673 /* Deprecated functions and macros */
1674 #define TJFLAG_FORCEMMX 8
1675 #define TJFLAG_FORCESSE 16
1676 #define TJFLAG_FORCESSE2 32
1677 #define TJFLAG_FORCESSE3 128
1680 /* Backward compatibility functions and macros (nothing to see here) */
1681 #define NUMSUBOPT TJ_NUMSAMP
1682 #define TJ_444 TJSAMP_444
1683 #define TJ_422 TJSAMP_422
1684 #define TJ_420 TJSAMP_420
1685 #define TJ_411 TJSAMP_420
1686 #define TJ_GRAYSCALE TJSAMP_GRAY
1689 #define TJ_BOTTOMUP TJFLAG_BOTTOMUP
1690 #define TJ_FORCEMMX TJFLAG_FORCEMMX
1691 #define TJ_FORCESSE TJFLAG_FORCESSE
1692 #define TJ_FORCESSE2 TJFLAG_FORCESSE2
1693 #define TJ_ALPHAFIRST 64
1694 #define TJ_FORCESSE3 TJFLAG_FORCESSE3
1695 #define TJ_FASTUPSAMPLE TJFLAG_FASTUPSAMPLE
1698 DLLEXPORT unsigned long TJBUFSIZE(int width, int height);
1700 DLLEXPORT unsigned long TJBUFSIZEYUV(int width, int height, int jpegSubsamp);
1702 DLLEXPORT unsigned long tjBufSizeYUV(int width, int height, int subsamp);
1704 DLLEXPORT int tjCompress(tjhandle handle, unsigned char *srcBuf, int width,
1705 int pitch, int height, int pixelSize,
1706 unsigned char *dstBuf, unsigned long *compressedSize,
1707 int jpegSubsamp, int jpegQual, int flags);
1709 DLLEXPORT int tjEncodeYUV(tjhandle handle, unsigned char *srcBuf, int width,
1710 int pitch, int height, int pixelSize,
1711 unsigned char *dstBuf, int subsamp, int flags);
1713 DLLEXPORT int tjEncodeYUV2(tjhandle handle, unsigned char *srcBuf, int width,
1714 int pitch, int height, int pixelFormat,
1715 unsigned char *dstBuf, int subsamp, int flags);
1717 DLLEXPORT int tjDecompressHeader(tjhandle handle, unsigned char *jpegBuf,
1718 unsigned long jpegSize, int *width,
1721 DLLEXPORT int tjDecompressHeader2(tjhandle handle, unsigned char *jpegBuf,
1722 unsigned long jpegSize, int *width,
1723 int *height, int *jpegSubsamp);
1725 DLLEXPORT int tjDecompress(tjhandle handle, unsigned char *jpegBuf,
1726 unsigned long jpegSize, unsigned char *dstBuf,
1727 int width, int pitch, int height, int pixelSize,
1730 DLLEXPORT int tjDecompressToYUV(tjhandle handle, unsigned char *jpegBuf,
1731 unsigned long jpegSize, unsigned char *dstBuf,
1734 DLLEXPORT char *tjGetErrorStr(void);