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+/* 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
+