image laoder

1 files changed, 58 insertions, 0 deletions

diff --git a/image.c b/image.c
new file mode 100644
index 0000000..62e3da1
--- /dev/null
+++ b/image.c
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <endian.h>
+
+#include <jpeglib.h>
+#include <jerror.h>
+#include <cairo.h>
+
+#include "image.h"
+
+cairo_surface_t *load_jpeg(const char* filename)
+{
+    struct jpeg_decompress_struct info;
+    struct jpeg_error_mgr err;
+    cairo_surface_t *surface;
+    uint8_t *rowptr[1];
+    FILE* file;
+
+    file = fopen(filename, "rb");
+    if (!file) {
+        fprintf(stderr, "open %s: %s\n", filename, strerror(errno));
+        exit(1);
+    }
+
+    info.err = jpeg_std_error(&err);
+    jpeg_create_decompress(&info);
+
+    jpeg_stdio_src(&info, file);
+    jpeg_read_header(&info, TRUE);
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+    info.out_color_space = JCS_EXT_BGRX;
+#else
+    info.out_color_space = JCS_EXT_XRGB;
+#endif
+    jpeg_start_decompress(&info);
+
+    surface = cairo_image_surface_create(CAIRO_FORMAT_RGB24, /* 32bpp, native endian */
+                                         info.output_width,
+                                         info.output_height);
+    if (cairo_surface_status(surface) != CAIRO_STATUS_SUCCESS) {
+        fprintf(stderr, "cairo_image_surface_create failed\n");
+        exit(1);
+    }
+
+    while (info.output_scanline < info.output_height) {
+        rowptr[0] = (uint8_t *)cairo_image_surface_get_data(surface) +
+            cairo_image_surface_get_stride(surface) * info.output_scanline;
+        jpeg_read_scanlines(&info, rowptr, 1);
+    }
+    jpeg_finish_decompress(&info);
+
+    fclose(file);
+    return surface;
+}