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Diffstat (limited to 'cairo_jpg.c')
| -rw-r--r-- | cairo_jpg.c | 623 |
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diff --git a/cairo_jpg.c b/cairo_jpg.c new file mode 100644 index 0000000..90759be --- /dev/null +++ b/cairo_jpg.c @@ -0,0 +1,623 @@ +/* Copyright 2018 Bernhard R. Fischer, 4096R/8E24F29D <bf@abenteuerland.at> + * + * This file is part of Cairo_JPG. + * + * Cairo_JPG is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * Cairo_JPG is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with Cairo_JPG. If not, see <https://www.gnu.org/licenses/>. + */ + +/*! \file cairo_jpg.c + * This file contains two functions for reading and writing JPEG files from + * and to Cairo image surfaces. It uses the functions from the libjpeg. + * Most of the code is directly derived from the online example at + * http://libjpeg-turbo.virtualgl.org/Documentation/Documentation + * + * All prototypes are defined in cairo_jpg.h All functions and their parameters + * and return values are described below directly at the functions. You may + * also have a look at the preprocessor macros defined below. + * + * To compile this code you need to have installed the packages libcairo2-dev + * and libjpeg-dev. Compile with the following to create an object file to link + * with your code: + * gcc -std=c99 -Wall -c `pkg-config cairo libjpeg --cflags --libs` cairo_jpg.c + * Use the following command to include the main() function and create an + * executable for testing of this code: + * gcc -std=c99 -Wall -o cairo_jpg -DCAIRO_JPEG_MAIN `pkg-config cairo libjpeg --cflags --libs` cairo_jpg.c + * + * @author Bernhard R. Fischer, 4096R/8E24F29D bf@abenteuerland.at + * @version 2020/01/18 + * @license LGPL3. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <cairo.h> +#include <jpeglib.h> + +#include "cairo_jpg.h" + +/*! Macro to activate main() function. This is only used for testing. Comment + * it out (#undef) if you link this file to your own program. + */ +//#define CAIRO_JPEG_MAIN +// +/*! Define this to use an alternate implementation of + * cairo_image_surface_create_from_jpeg() which fstat(3)s the file before + * reading (see below). For huge files this /may/ be slightly faster. + */ +#undef CAIRO_JPEG_USE_FSTAT + +/*! This is the read block size for the stream reader + * cairo_image_surface_create_from_jpeg_stream(). + */ +#ifdef USE_CAIRO_READ_FUNC_LEN_T +#define CAIRO_JPEG_IO_BLOCK_SIZE 4096 +#else +/*! Block size has to be one if cairo_read_func_t is in use because of the lack + * to detect EOF (truncated reads). + */ +#define CAIRO_JPEG_IO_BLOCK_SIZE 1 +/*! In case of original cairo_read_func_t is used fstat() should be used for + * performance reasons (see CAIRO_JPEG_USE_FSTAT above). + */ +#define CAIRO_JPEG_USE_FSTAT +#endif + +/*! Define this to test jpeg creation with non-image surfaces. This is only for + * testing and is to be used together with CAIRO_JPEG_MAIN. + */ +#undef CAIRO_JPEG_TEST_SIMILAR +#if defined(CAIRO_JPEG_TEST_SIMILAR) && defined(CAIRO_JPEG_MAIN) +#include <cairo-pdf.h> +#endif + + +#ifndef LIBJPEG_TURBO_VERSION +/*! This function makes a covnersion for "odd" pixel sizes which typically is a + * conversion from a 3-byte to a 4-byte (or more) pixel size or vice versa. + * The conversion is done from the source buffer src to the destination buffer + * dst. The caller MUST ensure that src and dst have the correct memory size. + * This is dw * num for dst and sw * num for src. src and dst may point to the + * same memory address. + * @param dst Pointer to destination buffer. + * @param dw Pixel width (in bytes) of pixels in destination buffer, dw >= 3. + * @param src Pointer to source buffer. + * @param sw Pixel width (in bytes) of pixels in source buffer, sw >= 3. + * @param num Number of pixels to convert, num >= 1; + */ +static void pix_conv(unsigned char *dst, int dw, const unsigned char *src, int sw, int num) +{ + int si, di; + + // safety check + if (dw < 3 || sw < 3 || dst == NULL || src == NULL) + return; + + num--; + for (si = num * sw, di = num * dw; si >= 0; si -= sw, di -= dw) + { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + dst[di + 2] = src[si ]; + dst[di + 1] = src[si + 1]; + dst[di + 0] = src[si + 2]; +#else + // FIXME: This is untested, it may be wrong. + dst[di - 3] = src[si - 3]; + dst[di - 2] = src[si - 2]; + dst[di - 1] = src[si - 1]; +#endif + } +} +#endif + + +/*! This function creates a JPEG file in memory from a Cairo image surface. + * @param sfc Pointer to a Cairo surface. It should be an image surface of + * either CAIRO_FORMAT_ARGB32 or CAIRO_FORMAT_RGB24. Other formats are + * converted to CAIRO_FORMAT_RGB24 before compression. + * Please note that this may give unexpected results because JPEG does not + * support transparency. Thus, default background color is used to replace + * transparent regions. The default background color is black if not specified + * explicitly. Thus converting e.g. PDF surfaces without having any specific + * background color set will apear with black background and not white as you + * might expect. In such cases it is suggested to manually convert the surface + * to RGB24 before calling this function. + * @param data Pointer to a memory pointer. This parameter receives a pointer + * to the memory area where the final JPEG data is found in memory. This + * function reserves the memory properly and it has to be freed by the caller + * with free(3). + * @param len Pointer to a variable of type size_t which will receive the final + * lenght of the memory buffer. + * @param quality Compression quality, 0-100. + * @return On success the function returns CAIRO_STATUS_SUCCESS. In case of + * error CAIRO_STATUS_INVALID_FORMAT is returned. + */ +cairo_status_t cairo_image_surface_write_to_jpeg_mem(cairo_surface_t *sfc, unsigned char **data, size_t *len, int quality) +{ + struct jpeg_compress_struct cinfo; + struct jpeg_error_mgr jerr; + JSAMPROW row_pointer[1]; + cairo_surface_t *other = NULL; + + // check valid input format (must be IMAGE_SURFACE && (ARGB32 || RGB24)) + if (cairo_surface_get_type(sfc) != CAIRO_SURFACE_TYPE_IMAGE || + (cairo_image_surface_get_format(sfc) != CAIRO_FORMAT_ARGB32 && + cairo_image_surface_get_format(sfc) != CAIRO_FORMAT_RGB24)) + { + // create a similar surface with a proper format if supplied input format + // does not fulfill the requirements + double x1, y1, x2, y2; + other = sfc; + cairo_t *ctx = cairo_create(other); + // get extents of original surface + cairo_clip_extents(ctx, &x1, &y1, &x2, &y2); + cairo_destroy(ctx); + + // create new image surface + sfc = cairo_surface_create_similar_image(other, CAIRO_FORMAT_RGB24, x2 - x1, y2 - y1); + if (cairo_surface_status(sfc) != CAIRO_STATUS_SUCCESS) + return CAIRO_STATUS_INVALID_FORMAT; + + // paint original surface to new surface + ctx = cairo_create(sfc); + cairo_set_source_surface(ctx, other, 0, 0); + cairo_paint(ctx); + cairo_destroy(ctx); + } + + // finish queued drawing operations + cairo_surface_flush(sfc); + + // init jpeg compression structures + cinfo.err = jpeg_std_error(&jerr); + jpeg_create_compress(&cinfo); + + // set compression parameters + jpeg_mem_dest(&cinfo, data, len); + cinfo.image_width = cairo_image_surface_get_width(sfc); + cinfo.image_height = cairo_image_surface_get_height(sfc); +#ifdef LIBJPEG_TURBO_VERSION +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + //cinfo.in_color_space = JCS_EXT_BGRX; + cinfo.in_color_space = cairo_image_surface_get_format(sfc) == CAIRO_FORMAT_ARGB32 ? JCS_EXT_BGRA : JCS_EXT_BGRX; +#else + //cinfo.in_color_space = JCS_EXT_XRGB; + cinfo.in_color_space = cairo_image_surface_get_format(sfc) == CAIRO_FORMAT_ARGB32 ? JCS_EXT_ARGB : JCS_EXT_XRGB; +#endif + cinfo.input_components = 4; +#else + cinfo.in_color_space = JCS_RGB; + cinfo.input_components = 3; +#endif + jpeg_set_defaults(&cinfo); + jpeg_set_quality(&cinfo, quality, TRUE); + + // start compressor + jpeg_start_compress(&cinfo, TRUE); + + // loop over all lines and compress + while (cinfo.next_scanline < cinfo.image_height) + { +#ifdef LIBJPEG_TURBO_VERSION + row_pointer[0] = cairo_image_surface_get_data(sfc) + (cinfo.next_scanline + * cairo_image_surface_get_stride(sfc)); +#else + unsigned char row_buf[3 * cinfo.image_width]; + pix_conv(row_buf, 3, cairo_image_surface_get_data(sfc) + + (cinfo.next_scanline * cairo_image_surface_get_stride(sfc)), 4, cinfo.image_width); + row_pointer[0] = row_buf; +#endif + (void) jpeg_write_scanlines(&cinfo, row_pointer, 1); + } + + // finalize and close everything + jpeg_finish_compress(&cinfo); + jpeg_destroy_compress(&cinfo); + + // destroy temporary image surface (if available) + if (other != NULL) + cairo_surface_destroy(sfc); + + return CAIRO_STATUS_SUCCESS; +} + + +/*! This is the internal write function which is called by + * cairo_image_surface_write_to_jpeg(). It is not exported. + */ +static cairo_status_t cj_write(void *closure, const unsigned char *data, unsigned int length) +{ + return write((intptr_t) closure, data, length) < length ? + CAIRO_STATUS_WRITE_ERROR : CAIRO_STATUS_SUCCESS; +} + + +/*! This function writes JPEG file data from a Cairo image surface by using the + * user-supplied stream writer function write_func(). + * @param sfc Pointer to a Cairo *image* surface. Its format must either be + * CAIRO_FORMAT_ARGB32 or CAIRO_FORMAT_RGB24. Other formats are not supported + * by this function, yet. + * @param write_func Function pointer to a function which is actually writing + * the data. + * @param closure Pointer to user-supplied variable which is directly passed to + * write_func(). + * @param quality Compression quality, 0-100. + * @return This function calles cairo_image_surface_write_to_jpeg_mem() and + * returns its return value. + */ +cairo_status_t cairo_image_surface_write_to_jpeg_stream(cairo_surface_t *sfc, cairo_write_func_t write_func, void *closure, int quality) +{ + cairo_status_t e; + unsigned char *data = NULL; + size_t len = 0; + + // create JPEG data in memory from surface + if ((e = cairo_image_surface_write_to_jpeg_mem(sfc, &data, &len, quality)) != CAIRO_STATUS_SUCCESS) + return e; + + // write whole memory block with stream function + e = write_func(closure, data, len); + + // free JPEG memory again and return the return value + free(data); + return e; + +} + + +/*! This function creates a JPEG file from a Cairo image surface. + * @param sfc Pointer to a Cairo *image* surface. Its format must either be + * CAIRO_FORMAT_ARGB32 or CAIRO_FORMAT_RGB24. Other formats are not supported + * by this function, yet. + * @param filename Pointer to the filename. + * @param quality Compression quality, 0-100. + * @return In case of success CAIRO_STATUS_SUCCESS is returned. If an error + * occured while opening/creating the file CAIRO_STATUS_DEVICE_ERROR is + * returned. The error can be tracked down by inspecting errno(3). The function + * internally calles cairo_image_surface_write_to_jpeg_stream() and returnes + * its return value respectively (see there). + */ +cairo_status_t cairo_image_surface_write_to_jpeg(cairo_surface_t *sfc, const char *filename, int quality) +{ + cairo_status_t e; + int outfile; + + // Open/create new file + if ((outfile = open(filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)) == -1) + return CAIRO_STATUS_DEVICE_ERROR; + + // write surface to file + e = cairo_image_surface_write_to_jpeg_stream(sfc, cj_write, (void*)(intptr_t) outfile, quality); + + // close file again and return + close(outfile); + return e; +} + + + +/*! This function decompresses a JPEG image from a memory buffer and creates a + * Cairo image surface. + * @param data Pointer to JPEG data (i.e. the full contents of a JPEG file read + * into this buffer). + * @param len Length of buffer in bytes. + * @return Returns a pointer to a cairo_surface_t structure. It should be + * checked with cairo_surface_status() for errors. + */ +cairo_surface_t *cairo_image_surface_create_from_jpeg_mem(void *data, size_t len) +{ + struct jpeg_decompress_struct cinfo; + struct jpeg_error_mgr jerr; + JSAMPROW row_pointer[1]; + cairo_surface_t *sfc; + + // initialize jpeg decompression structures + cinfo.err = jpeg_std_error(&jerr); + jpeg_create_decompress(&cinfo); + jpeg_mem_src(&cinfo, data, len); + (void) jpeg_read_header(&cinfo, TRUE); + +#ifdef LIBJPEG_TURBO_VERSION +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + cinfo.out_color_space = JCS_EXT_BGRA; +#else + cinfo.out_color_space = JCS_EXT_ARGB; +#endif +#else + cinfo.out_color_space = JCS_RGB; +#endif + + // start decompressor + (void) jpeg_start_decompress(&cinfo); + + // create Cairo image surface + sfc = cairo_image_surface_create(CAIRO_FORMAT_RGB24, cinfo.output_width, cinfo.output_height); + if (cairo_surface_status(sfc) != CAIRO_STATUS_SUCCESS) + { + jpeg_destroy_decompress(&cinfo); + return sfc; + } + + // loop over all scanlines and fill Cairo image surface + while (cinfo.output_scanline < cinfo.output_height) + { + unsigned char *row_address = cairo_image_surface_get_data(sfc) + + (cinfo.output_scanline * cairo_image_surface_get_stride(sfc)); + row_pointer[0] = row_address; + (void) jpeg_read_scanlines(&cinfo, row_pointer, 1); +#ifndef LIBJPEG_TURBO_VERSION + pix_conv(row_address, 4, row_address, 3, cinfo.output_width); +#endif + } + + // finish and close everything + cairo_surface_mark_dirty(sfc); + (void) jpeg_finish_decompress(&cinfo); + jpeg_destroy_decompress(&cinfo); + + // set jpeg mime data + cairo_surface_set_mime_data(sfc, CAIRO_MIME_TYPE_JPEG, data, len, free, data); + + return sfc; +} + + +/*! This function reads a JPEG image from a stream and creates a Cairo image + * surface. + * @param read_func Pointer to function which reads data. + * @param closure Pointer which is passed to read_func(). + * @return Returns a pointer to a cairo_surface_t structure. It should be + * checked with cairo_surface_status() for errors. + * @note If the surface returned is invalid you can use errno(3) to determine + * further reasons. Errno is set according to realloc(3). If you + * intend to check errno you shall set it to 0 before calling this function + * because it modifies errno only in case of an error. + */ +#ifdef USE_CAIRO_READ_FUNC_LEN_T +cairo_surface_t *cairo_image_surface_create_from_jpeg_stream(cairo_read_func_len_t read_func, void *closure) +#else +cairo_surface_t *cairo_image_surface_create_from_jpeg_stream(cairo_read_func_t read_func, void *closure) +#endif +{ + cairo_surface_t *sfc; + void *data, *tmp; + ssize_t len, rlen; + int eof = 0; + + // read all data into memory buffer in blocks of CAIRO_JPEG_IO_BLOCK_SIZE + for (len = 0, data = NULL; !eof; len += rlen) + { + // grow memory buffer and check for error + if ((tmp = realloc(data, len + CAIRO_JPEG_IO_BLOCK_SIZE)) == NULL) + break; + data = tmp; + + // read bytes into buffer and check for error + rlen = read_func(closure, data + len, CAIRO_JPEG_IO_BLOCK_SIZE); +#ifdef USE_CAIRO_READ_FUNC_LEN_T + // check for error + if (rlen == -1) + break; + + // check if EOF occured + if (rlen < CAIRO_JPEG_IO_BLOCK_SIZE) + eof++; +#else + // check for error + if (rlen == CAIRO_STATUS_READ_ERROR) + eof++; +#endif + } + + // check for error in read loop + if (!eof) + { + free(data); + return cairo_image_surface_create(CAIRO_FORMAT_INVALID, 0, 0); + } + + // call jpeg decompression and return surface + sfc = cairo_image_surface_create_from_jpeg_mem(data, len); + if (cairo_surface_status(sfc) != CAIRO_STATUS_SUCCESS) + free(data); + + return sfc; +} + + +#ifdef CAIRO_JPEG_USE_FSTAT +/*! This function reads an JPEG image from a file an creates a Cairo image + * surface. Internally the filesize is determined with fstat(2) and then the + * whole data is read at once. + * @param filename Pointer to filename of JPEG file. + * @return Returns a pointer to a cairo_surface_t structure. It should be + * checked with cairo_surface_status() for errors. + * @note If the returned surface is invalid you can use errno to determine + * further reasons. Errno is set according to fopen(3) and malloc(3). If you + * intend to check errno you shall set it to 0 before calling this function + * because it does not modify errno itself. + */ +cairo_surface_t *cairo_image_surface_create_from_jpeg(const char *filename) +{ + void *data; + int infile; + struct stat stat; + + // open input file + if ((infile = open(filename, O_RDONLY)) == -1) + return cairo_image_surface_create(CAIRO_FORMAT_INVALID, 0, 0); + + // get stat structure for file size + if (fstat(infile, &stat) == -1) + return cairo_image_surface_create(CAIRO_FORMAT_INVALID, 0, 0); + + // allocate memory + if ((data = malloc(stat.st_size)) == NULL) + return cairo_image_surface_create(CAIRO_FORMAT_INVALID, 0, 0); + + // read data + if (read(infile, data, stat.st_size) < stat.st_size) + return cairo_image_surface_create(CAIRO_FORMAT_INVALID, 0, 0); + + close(infile); + + return cairo_image_surface_create_from_jpeg_mem(data, stat.st_size); +} + +#else + + +/*! This is the read function which is called by + * cairo_image_surface_create_from_jpeg_stream() (non-fstat-version below). It + * is not exported. + */ +#ifdef USE_CAIRO_READ_FUNC_LEN_T +static ssize_t cj_read(void *closure, unsigned char *data, unsigned int length) +{ + return read((intptr_t) closure, data, length); +} +#else +static cairo_status_t cj_read(void *closure, unsigned char *data, unsigned int length) +{ + return read((intptr_t) closure, data, length) < length ? CAIRO_STATUS_READ_ERROR : CAIRO_STATUS_SUCCESS; +} +#endif + + +/*! This function reads an JPEG image from a file an creates a Cairo image + * surface. Internally the function calls + * cairo_image_surface_create_from_jpeg_stream() to actually read the data. + * @param filename Pointer to filename of JPEG file. + * @return Returns a pointer to a cairo_surface_t structure. It should be + * checked with cairo_surface_status() for errors. + * @note If the returned surface is invalid you can use errno to determine + * further reasons. Errno is set according to fopen(3) and malloc(3). If you + * intend to check errno you shall set it to 0 before calling this function + * because it does not modify errno itself. + */ +cairo_surface_t *cairo_image_surface_create_from_jpeg(const char *filename) +{ + cairo_surface_t *sfc; + int infile; + + // open input file + if ((infile = open(filename, O_RDONLY)) == -1) + return cairo_image_surface_create(CAIRO_FORMAT_INVALID, 0, 0); + + // call stream loading function + sfc = cairo_image_surface_create_from_jpeg_stream(cj_read, (void*)(intptr_t) infile); + close(infile); + + return sfc; +} + +#endif + + +#ifdef CAIRO_JPEG_MAIN +#include <string.h> +#include <strings.h> + +int strrcasecmp(const char *s1, const char *s2) +{ + int off = (int) strlen(s1) - (int) strlen(s2); // typecast size_t to int because size_t typically is unsigned + return strcasecmp(s1 + (off < 0 ? 0 : off), s2); +} + +/*! Main routine, only for testing. #undef CAIRO_JPEG_MAIN or simply delete + * this part if you link this file to your own program. + */ +int main(int argc, char **argv) +{ + cairo_surface_t *sfc; + +#ifndef CAIRO_JPEG_TEST_SIMILAR + if (argc < 3) + { + fprintf(stderr, "usage: %s <infile> <outfile>\n", argv[0]); + return 1; + } + + // test input file type and read file + if (!strrcasecmp(argv[1], ".png")) + { + // read PNG file + sfc = cairo_image_surface_create_from_png(argv[1]); + } + else if (!strrcasecmp(argv[1], ".jpg")) + { + // read JPEG file + sfc = cairo_image_surface_create_from_jpeg(argv[1]); + } + else + { + fprintf(stderr, "source file is neither JPG nor PNG\n"); + return 1; + } + + // check surface status + if (cairo_surface_status(sfc) != CAIRO_STATUS_SUCCESS) + { + fprintf(stderr, "error loading image: %s", cairo_status_to_string(cairo_surface_status(sfc))); + return 2; + } + + // test output file type and write file + if (!strrcasecmp(argv[2], ".png")) + { + // write PNG file + cairo_surface_write_to_png(sfc, argv[2]); + } + else if (!strrcasecmp(argv[2], ".jpg")) + { + // write JPEG file + cairo_image_surface_write_to_jpeg(sfc, argv[2], 90); + } + else + { + fprintf(stderr, "destination file is neither JPG nor PNG\n"); + return 1; + } + + cairo_surface_destroy(sfc); + +#else + sfc = cairo_pdf_surface_create("xyz.pdf", 595.276, 841.890); + + cairo_t *ctx = cairo_create(sfc); + cairo_set_source_rgb(ctx, 1, 1, 1); + cairo_paint(ctx); + cairo_move_to(ctx, 100, 100); + cairo_set_source_rgb(ctx, 1, 0, 0); + cairo_set_line_width(ctx, 3); + cairo_line_to(ctx, 400, 400); + cairo_stroke(ctx); + cairo_destroy(ctx); + + cairo_image_surface_write_to_jpeg(sfc, "xyz.jpg", 90); + cairo_surface_destroy(sfc); +#endif + + return 0; +} + +#endif + |