+
+#include "main.h"
+#include "image-load.h"
+#include "image_load_jpeg.h"
+
+#include <setjmp.h>
+#include <jpeglib.h>
+#include <jerror.h>
+
+typedef struct _ImageLoaderJpeg ImageLoaderJpeg;
+struct _ImageLoaderJpeg {
+ ImageLoaderBackendCbAreaUpdated area_updated_cb;
+ ImageLoaderBackendCbSize size_cb;
+ ImageLoaderBackendCbAreaPrepared area_prepared_cb;
+
+ gpointer data;
+
+ GdkPixbuf *pixbuf;
+ guint requested_width;
+ guint requested_height;
+
+ gboolean abort;
+
+};
+
+/* error handler data */
+struct error_handler_data {
+ struct jpeg_error_mgr pub;
+ sigjmp_buf setjmp_buffer;
+ GError **error;
+};
+
+/* explode gray image data from jpeg library into rgb components in pixbuf */
+static void
+explode_gray_into_buf (struct jpeg_decompress_struct *cinfo,
+ guchar **lines)
+{
+ gint i, j;
+ guint w;
+
+ g_return_if_fail (cinfo != NULL);
+ g_return_if_fail (cinfo->output_components == 1);
+ g_return_if_fail (cinfo->out_color_space == JCS_GRAYSCALE);
+
+ /* Expand grey->colour. Expand from the end of the
+ * memory down, so we can use the same buffer.
+ */
+ w = cinfo->output_width;
+ for (i = cinfo->rec_outbuf_height - 1; i >= 0; i--) {
+ guchar *from, *to;
+
+ from = lines[i] + w - 1;
+ to = lines[i] + (w - 1) * 3;
+ for (j = w - 1; j >= 0; j--) {
+ to[0] = from[0];
+ to[1] = from[0];
+ to[2] = from[0];
+ to -= 3;
+ from--;
+ }
+ }
+}
+
+
+static void
+convert_cmyk_to_rgb (struct jpeg_decompress_struct *cinfo,
+ guchar **lines)
+{
+ gint i, j;
+
+ g_return_if_fail (cinfo != NULL);
+ g_return_if_fail (cinfo->output_components == 4);
+ g_return_if_fail (cinfo->out_color_space == JCS_CMYK);
+
+ for (i = cinfo->rec_outbuf_height - 1; i >= 0; i--) {
+ guchar *p;
+
+ p = lines[i];
+ for (j = 0; j < cinfo->output_width; j++) {
+ int c, m, y, k;
+ c = p[0];
+ m = p[1];
+ y = p[2];
+ k = p[3];
+ if (cinfo->saw_Adobe_marker) {
+ p[0] = k*c / 255;
+ p[1] = k*m / 255;
+ p[2] = k*y / 255;
+ }
+ else {
+ p[0] = (255 - k)*(255 - c) / 255;
+ p[1] = (255 - k)*(255 - m) / 255;
+ p[2] = (255 - k)*(255 - y) / 255;
+ }
+ p[3] = 255;
+ p += 4;
+ }
+ }
+}
+
+
+static gpointer image_loader_jpeg_new(ImageLoaderBackendCbAreaUpdated area_updated_cb, ImageLoaderBackendCbSize size_cb, ImageLoaderBackendCbAreaPrepared area_prepared_cb, gpointer data)
+{
+ ImageLoaderJpeg *loader = g_new0(ImageLoaderJpeg, 1);
+
+ loader->area_updated_cb = area_updated_cb;
+ loader->size_cb = size_cb;
+ loader->area_prepared_cb = area_prepared_cb;
+ loader->data = data;
+ return (gpointer) loader;
+}
+
+static void
+fatal_error_handler (j_common_ptr cinfo)
+{
+ struct error_handler_data *errmgr;
+ char buffer[JMSG_LENGTH_MAX];
+
+ errmgr = (struct error_handler_data *) cinfo->err;
+
+ /* Create the message */
+ (* cinfo->err->format_message) (cinfo, buffer);
+
+ /* broken check for *error == NULL for robustness against
+ * crappy JPEG library
+ */
+ if (errmgr->error && *errmgr->error == NULL) {
+ g_set_error (errmgr->error,
+ GDK_PIXBUF_ERROR,
+ cinfo->err->msg_code == JERR_OUT_OF_MEMORY
+ ? GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY
+ : GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+ _("Error interpreting JPEG image file (%s)"),
+ buffer);
+ }
+
+ siglongjmp (errmgr->setjmp_buffer, 1);
+
+ g_assert_not_reached ();
+}
+
+static void
+output_message_handler (j_common_ptr cinfo)
+{
+ /* This method keeps libjpeg from dumping crap to stderr */
+
+ /* do nothing */
+}
+
+static gboolean image_loader_jpeg_load (gpointer loader, const guchar *buf, gsize count, GError **error)
+{
+ ImageLoaderJpeg *lj = (ImageLoaderJpeg *) loader;
+ struct jpeg_decompress_struct cinfo;
+ guchar *dptr;
+ guint rowstride;
+
+ struct error_handler_data jerr;
+// stdio_src_ptr src;
+
+ /* setup error handler */
+ cinfo.err = jpeg_std_error (&jerr.pub);
+ jerr.pub.error_exit = fatal_error_handler;
+ jerr.pub.output_message = output_message_handler;
+
+ jerr.error = error;
+
+
+ if (setjmp(jerr.setjmp_buffer))
+ {
+ /* If we get here, the JPEG code has signaled an error.
+ * We need to clean up the JPEG object, close the input file, and return.
+ */
+ jpeg_destroy_decompress(&cinfo);
+ return FALSE;
+ }
+
+ jpeg_create_decompress(&cinfo);
+
+ jpeg_mem_src(&cinfo, (unsigned char *)buf, count);
+
+
+ jpeg_read_header(&cinfo, TRUE);
+
+ lj->requested_width = cinfo.image_width;
+ lj->requested_height = cinfo.image_height;
+ lj->size_cb(loader, cinfo.image_width, cinfo.image_height, lj->data);
+
+ cinfo.scale_num = 1;
+ for (cinfo.scale_denom = 2; cinfo.scale_denom <= 8; cinfo.scale_denom *= 2) {
+ jpeg_calc_output_dimensions(&cinfo);
+ if (cinfo.output_width < lj->requested_width || cinfo.output_height < lj->requested_height) {
+ cinfo.scale_denom /= 2;
+ break;
+ }
+ }
+ jpeg_calc_output_dimensions(&cinfo);
+
+ jpeg_start_decompress(&cinfo);
+
+ lj->pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB,
+ cinfo.out_color_components == 4 ? TRUE : FALSE,
+ 8, cinfo.output_width, cinfo.output_height);
+
+ lj->area_prepared_cb(loader, lj->data);
+ rowstride = gdk_pixbuf_get_rowstride(lj->pixbuf);
+ dptr = gdk_pixbuf_get_pixels(lj->pixbuf);
+
+ if (!lj->pixbuf)
+ {
+ jpeg_destroy_decompress (&cinfo);
+ return 0;
+ }
+
+ while (cinfo.output_scanline < cinfo.output_height && !lj->abort)
+ {
+ guchar *lines[4];
+ guchar **lptr;
+ gint i;
+ guint scanline = cinfo.output_scanline;
+
+ lptr = lines;
+ for (i = 0; i < cinfo.rec_outbuf_height; i++)
+ {
+ *lptr++ = dptr;
+ dptr += rowstride;
+ }
+
+ jpeg_read_scanlines (&cinfo, lines, cinfo.rec_outbuf_height);
+
+ switch (cinfo.out_color_space)
+ {
+ case JCS_GRAYSCALE:
+ explode_gray_into_buf (&cinfo, lines);
+ break;
+ case JCS_RGB:
+ /* do nothing */
+ break;
+ case JCS_CMYK:
+ convert_cmyk_to_rgb (&cinfo, lines);
+ break;
+ default:
+ break;
+ }
+ lj->area_updated_cb(loader, 0, scanline, cinfo.output_width, cinfo.rec_outbuf_height, lj->data);
+ }
+
+ jpeg_finish_decompress(&cinfo);
+ jpeg_destroy_decompress(&cinfo);
+ return TRUE;
+}
+
+static void image_loader_jpeg_set_size(gpointer loader, int width, int height)
+{
+ ImageLoaderJpeg *lj = (ImageLoaderJpeg *) loader;
+ lj->requested_width = width;
+ lj->requested_height = height;
+}
+
+static GdkPixbuf* image_loader_jpeg_get_pixbuf(gpointer loader)
+{
+ ImageLoaderJpeg *lj = (ImageLoaderJpeg *) loader;
+ return lj->pixbuf;
+}
+
+static gchar* image_loader_jpeg_get_format_name(gpointer loader)
+{
+ return g_strdup("jpeg");
+}
+static gchar** image_loader_jpeg_get_format_mime_types(gpointer loader)
+{
+ static gchar *mime[] = {"image/jpeg", NULL};
+ return g_strdupv(mime);
+}
+
+static gboolean image_loader_jpeg_close(gpointer loader, GError **error)
+{
+ return TRUE;
+}
+
+static void image_loader_jpeg_abort(gpointer loader)
+{
+ ImageLoaderJpeg *lj = (ImageLoaderJpeg *) loader;
+ lj->abort = TRUE;
+}
+
+static void image_loader_jpeg_free(gpointer loader)
+{
+ ImageLoaderJpeg *lj = (ImageLoaderJpeg *) loader;
+ if (lj->pixbuf) g_object_unref(lj->pixbuf);
+ g_free(lj);
+}
+
+
+void image_loader_backend_set_jpeg(ImageLoaderBackend *funcs)
+{
+ funcs->loader_new = image_loader_jpeg_new;
+ funcs->set_size = image_loader_jpeg_set_size;
+ funcs->load = image_loader_jpeg_load;
+ funcs->write = NULL;
+ funcs->get_pixbuf = image_loader_jpeg_get_pixbuf;
+ funcs->close = image_loader_jpeg_close;
+ funcs->abort = image_loader_jpeg_abort;
+ funcs->free = image_loader_jpeg_free;
+
+ funcs->get_format_name = image_loader_jpeg_get_format_name;
+ funcs->get_format_mime_types = image_loader_jpeg_get_format_mime_types;
+}
+
+
+