#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "allheaders.h"
#include <setjmp.h>
#include "jpeglib.h"
#define DEBUG_INFO 0 |
l_int32 extractJpegDataFromArray | ( | const void * | data, | |
l_int32 | nbytes, | |||
l_int32 * | pw, | |||
l_int32 * | ph, | |||
l_int32 * | pbps, | |||
l_int32 * | pspp | |||
) |
Input: data (binary data consisting of the entire jpeg file) nbytes (size of binary data) &w (<optional return>=""> image width) &h (<optional return>=""> image height) &bps (<optional return>=""> bits/sample; should be 8) &spp (<optional return>=""> samples/pixel; should be 1, 3 or 4) Return: 0 if OK, 1 on error
l_int32 extractJpegDataFromFile | ( | const char * | filein, | |
l_uint8 ** | pdata, | |||
l_int32 * | pnbytes, | |||
l_int32 * | pw, | |||
l_int32 * | ph, | |||
l_int32 * | pbps, | |||
l_int32 * | pspp | |||
) |
Input: filein &data (<return> binary data consisting of the entire jpeg file) &nbytes (<return> size of binary data) &w (<optional return>=""> image width) &h (<optional return>=""> image height) &bps (<optional return>=""> bits/sample; should be 8) &spp (<optional return>=""> samples/pixel; should be 1 or 3) Return: 0 if OK, 1 on error
static boolean jpeg_comment_callback | ( | j_decompress_ptr | cinfo | ) | [static] |
static void jpeg_error_do_not_exit | ( | j_common_ptr | cinfo | ) | [static] |
static l_uint8 jpeg_getc | ( | j_decompress_ptr | cinfo | ) | [static] |
static l_int32 locateJpegImageParameters | ( | l_uint8 * | inarray, | |
l_int32 | size, | |||
l_int32 * | pindex | |||
) | [static] |
Input: filename colormap flag (0 means return RGB image if color; 1 means create colormap and return 8 bpp palette image if color) reduction (scaling factor: 1, 2, 4 or 8) &pnwarn (<optional return>=""> number of warnings about corrupted data) Return: pix, or null on error
Images reduced by factors of 2, 4 or 8 can be returned significantly faster than full resolution images.
The jpeg library will return warnings (or exit) if the jpeg data is bad. Use this function if you want the jpeg library to create an 8 bpp palette image, or to tell if the jpeg data has been corrupted. For corrupt jpeg data, there are two possible outcomes: (1) a damaged pix will be returned, along with a nonzero number of warnings, or (2) for sufficiently serious problems, the library will attempt to exit (caught by our error handler) and no pix will be returned.
PIX* pixReadMemJpeg | ( | const l_uint8 * | cdata, | |
size_t | size, | |||
l_int32 | cmflag, | |||
l_int32 | reduction, | |||
l_int32 * | pnwarn, | |||
l_int32 | hint | |||
) |
PIX* pixReadStreamJpeg | ( | FILE * | fp, | |
l_int32 | cmflag, | |||
l_int32 | reduction, | |||
l_int32 * | pnwarn, | |||
l_int32 | hint | |||
) |
Input: stream colormap flag (0 means return RGB image if color; 1 means create colormap and return 8 bpp palette image if color) reduction (scaling factor: 1, 2, 4 or 8) &pnwarn (<optional return>=""> number of warnings) hint: a bitwise OR of L_HINT_* values Return: pix, or null on error
Usage: see pixReadJpeg()
Input: filename pix quality (1 - 100; 75 is default) progressive (0 for baseline sequential; 1 for progressive) Return: 0 if OK; 1 on error
l_int32 pixWriteMemJpeg | ( | l_uint8 ** | pdata, | |
size_t * | psize, | |||
PIX * | pix, | |||
l_int32 | quality, | |||
l_int32 | progressive | |||
) |
Input: stream pix (8 or 32 bpp) quality (1 - 100; 75 is default value; 0 is also default) progressive (0 for baseline sequential; 1 for progressive) Return: 0 if OK, 1 on error
Notes: (1) Under the covers, the library transforms rgb to a luminence-chromaticity triple, each component of which is also 8 bits, and compresses that. It uses 2 Huffman tables, a higher resolution one (with more quantization levels) for luminosity and a lower resolution one for the chromas. (2) Progressive encoding gives better compression, at the expense of slower encoding and decoding. (3) There are three possibilities: * Grayscale image, no colormap: compress as 8 bpp image. * rgb full color image: copy each line into the color line buffer, and compress as three 8 bpp images. * 8 bpp colormapped image: convert each line to three 8 bpp line images in the color line buffer, and compress as three 8 bpp images. (4) The only valid pixel depths in leptonica are 1, 2, 4, 8, 16 and 32 bpp. However, it is possible, and in some cases desirable, to write out a jpeg file using an rgb pix that has 24 bpp. This can be created by appending the raster data for a 24 bpp image (with proper scanline padding) directly to a 24 bpp pix that was created without a data array. See note in pixWriteStreamPng() for an example.
jmp_buf jpeg_jmpbuf [static] |