From 3e87c8b0a4a80cd5dbea4bdce4cdb32c45f04775 Mon Sep 17 00:00:00 2001 From: DRC Date: Sat, 19 Feb 2011 16:42:14 +0000 Subject: [PATCH] Wordsmithing git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.1.x@410 632fc199-4ca6-4c93-a231-07263d6284db --- turbojpeg.h | 50 +++++++++++++++++++++++++------------------------- 1 file changed, 25 insertions(+), 25 deletions(-) diff --git a/turbojpeg.h b/turbojpeg.h index 51bb7bb..d3ba499 100644 --- a/turbojpeg.h +++ b/turbojpeg.h @@ -111,40 +111,40 @@ DLLEXPORT tjhandle DLLCALL tjInitCompress(void); [INPUT] j = instance handle previously returned from a call to tjInitCompress() - [INPUT] srcbuf = pointer to user-allocated image buffer containing pixels in - RGB(A) or BGR(A) form + [INPUT] srcbuf = pointer to user-allocated image buffer containing RGB or + grayscale pixels to be compressed [INPUT] width = width (in pixels) of the source image [INPUT] pitch = bytes per line of the source image (width*pixelsize if the bitmap is unpadded, else TJPAD(width*pixelsize) if each line of the bitmap is padded to the nearest 32-bit boundary, such as is the case for Windows bitmaps. You can also be clever and use this parameter to skip lines, etc. Setting this parameter to 0 is the equivalent of setting it to - width*pixelsize; + width*pixelsize. [INPUT] height = height (in pixels) of the source image [INPUT] pixelsize = size (in bytes) of each pixel in the source image - RGBA and BGRA: 4, RGB and BGR: 3, Grayscale: 1 + RGBX/BGRX/XRGB/XBGR: 4, RGB/BGR: 3, Grayscale: 1 [INPUT] dstbuf = pointer to user-allocated image buffer which will receive - the JPEG image. Use the macro TJBUFSIZE(width, height) to determine + the JPEG image. Use the TJBUFSIZE(width, height) function to determine the appropriate size for this buffer based on the image width and height. [OUTPUT] size = pointer to unsigned long which receives the size (in bytes) of the compressed image [INPUT] jpegsubsamp = Specifies either 4:2:0, 4:2:2, or 4:4:4 subsampling. - When the image is converted from the RGB to YCbCr colorspace as part of the - JPEG compression process, every other Cb and Cr (chrominance) pixel can be - discarded to produce a smaller image with little perceptible loss of - image clarity (the human eye is more sensitive to small changes in + When the image is converted from the RGB to YCbCr colorspace as part of + the JPEG compression process, every other Cb and Cr (chrominance) pixel + can be discarded to produce a smaller image with little perceptible loss + of image clarity (the human eye is more sensitive to small changes in brightness than small changes in color.) TJ_420: 4:2:0 subsampling. Discards every other Cb, Cr pixel in both - horizontal and vertical directions. + horizontal and vertical directions TJ_422: 4:2:2 subsampling. Discards every other Cb, Cr pixel only in - the horizontal direction. - TJ_444: no subsampling. + the horizontal direction + TJ_444: no subsampling TJ_GRAYSCALE: Generate grayscale JPEG image - [INPUT] jpegqual = JPEG quality (an integer between 0 and 100 inclusive.) + [INPUT] jpegqual = JPEG quality (an integer between 0 and 100 inclusive) [INPUT] flags = the bitwise OR of one or more of the flags described in the - "Flags" section above. + "Flags" section above RETURNS: 0 on success, -1 on error */ @@ -172,7 +172,7 @@ DLLEXPORT tjhandle DLLCALL tjInitDecompress(void); /* int tjDecompressHeader2(tjhandle j, unsigned char *srcbuf, unsigned long size, - int *width, int *height, int *jpegsub) + int *width, int *height, int *jpegsubsamp) [INPUT] j = instance handle previously returned from a call to tjInitDecompress() @@ -181,14 +181,14 @@ DLLEXPORT tjhandle DLLCALL tjInitDecompress(void); [INPUT] size = size of the JPEG image buffer (in bytes) [OUTPUT] width = width (in pixels) of the JPEG image [OUTPUT] height = height (in pixels) of the JPEG image - [OUTPUT] jpegsub = type of chrominance subsampling used when compressing the - JPEG image + [OUTPUT] jpegsubsamp = type of chrominance subsampling used when compressing + the JPEG image RETURNS: 0 on success, -1 on error */ DLLEXPORT int DLLCALL tjDecompressHeader2(tjhandle j, unsigned char *srcbuf, unsigned long size, - int *width, int *height, int *jpegsub); + int *width, int *height, int *jpegsubsamp); /* Legacy version of the above function @@ -214,15 +214,15 @@ DLLEXPORT int DLLCALL tjDecompressHeader(tjhandle j, bytes in size, although this pointer may also be used to decompress into a specific region of a larger buffer. [INPUT] width = width (in pixels) of the destination image - [INPUT] pitch = bytes per line of the destination image (width*pixelsize if the - bitmap is unpadded, else TJPAD(width*pixelsize) if each line of the bitmap - is padded to the nearest 32-bit boundary, such as is the case for Windows - bitmaps. You can also be clever and use this parameter to skip lines, - etc. Setting this parameter to 0 is the equivalent of setting it to - width*pixelsize. + [INPUT] pitch = bytes per line of the destination image (width*pixelsize if + the bitmap is unpadded, else TJPAD(width*pixelsize) if each line of the + bitmap is padded to the nearest 32-bit boundary, such as is the case for + Windows bitmaps. You can also be clever and use this parameter to skip + lines, etc. Setting this parameter to 0 is the equivalent of setting it + to width*pixelsize. [INPUT] height = height (in pixels) of the destination image [INPUT] pixelsize = size (in bytes) of each pixel in the destination image - RGBA/RGBx and BGRA/BGRx: 4, RGB and BGR: 3, Grayscale: 1 + RGBX/BGRX/XRGB/XBGR: 4, RGB/BGR: 3, Grayscale: 1 [INPUT] flags = the bitwise OR of one or more of the flags described in the "Flags" section above. -- 2.40.0