[gthumb] raw: added ability to read bitmap thumbnails

[Paolo Bacchilega <paobac src gnome org>]

commit 7aed8b360104e935fccb063bba195672d86cb587
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Mon Jun 24 11:06:28 2013 +0200

    raw: added ability to read bitmap thumbnails

 extensions/raw_files/main.c |   65 +++++++++++++++++++++++++++++++++++++++---
 1 files changed, 60 insertions(+), 5 deletions(-)
---
diff --git a/extensions/raw_files/main.c b/extensions/raw_files/main.c
index 58b1414..e26e7dc 100644
--- a/extensions/raw_files/main.c
+++ b/extensions/raw_files/main.c
@@ -67,6 +67,8 @@ _libraw_read_jpeg_thumbnail (libraw_data_t  *raw_data,
        GInputStream       *istream;
        GthImage           *image;
 
+       g_return_val_if_fail (raw_data->thumbnail.tformat == LIBRAW_THUMBNAIL_JPEG, NULL);
+
        loader_func = gth_main_get_image_loader_func ("image/jpeg", GTH_IMAGE_FORMAT_CAIRO_SURFACE);
        if (loader_func == NULL)
                return NULL;
@@ -91,11 +93,56 @@ _libraw_read_jpeg_thumbnail (libraw_data_t  *raw_data,
 
 
 static cairo_surface_t *
+_cairo_surface_create_from_ppm (int     width,
+                               int     height,
+                               guchar *buffer,
+                               gsize   buffer_size)
+{
+       cairo_surface_t *surface;
+       int              stride;
+       guchar          *buffer_p;
+       int              r, c;
+       guchar          *row;
+       guchar          *column;
+       guint32          pixel;
+
+       surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
+       stride = cairo_image_surface_get_stride (surface);
+
+       cairo_surface_flush (surface);
+
+       buffer_p = buffer;
+       row = cairo_image_surface_get_data (surface);
+       for (r = 0; r < height; r++) {
+               column = row;
+               for (c = 0; c < width; c++) {
+                       pixel = CAIRO_RGBA_TO_UINT32 (buffer_p[0], buffer_p[1], buffer_p[2], 0xff);
+                       memcpy (column, &pixel, sizeof (guint32));
+
+                       column += 4;
+                       buffer_p += 3;
+               }
+               row += stride;
+       }
+
+       cairo_surface_mark_dirty (surface);
+
+       return NULL;
+}
+
+
+static GthImage *
 _libraw_read_bitmap_thumbnail (libraw_data_t *raw_data)
 {
        GthImage        *image = NULL;
        cairo_surface_t *surface = NULL;
 
+       g_return_val_if_fail (raw_data->thumbnail.tformat == LIBRAW_THUMBNAIL_BITMAP, NULL);
+
+       surface = _cairo_surface_create_from_ppm (raw_data->thumbnail.twidth,
+                                                 raw_data->thumbnail.theight,
+                                                 (guchar *) raw_data->thumbnail.thumb,
+                                                 raw_data->thumbnail.tlength);
        if (surface != NULL) {
                image = gth_image_new_for_surface (surface);
                cairo_surface_destroy (surface);
@@ -129,6 +176,16 @@ _libraw_get_tranform (libraw_data_t *raw_data)
 }
 
 
+static void
+swap_int (int *a,
+         int *b)
+{
+       int tmp = *a;
+       *a = *b;
+       *b = tmp;
+}
+
+
 static GthImage *
 _cairo_image_surface_create_from_raw (GInputStream  *istream,
                                      GthFileData   *file_data,
@@ -169,18 +226,16 @@ _cairo_image_surface_create_from_raw (GInputStream  *istream,
 
        width = raw_data->sizes.iwidth;
        height = raw_data->sizes.iheight;
+
        switch (raw_data->sizes.flip) {
        case 5: /* 270 degrees */
        case 6: /* 90 degrees */
-       {
-               int tmp = width;
-               width = height;
-               height = tmp;
+               swap_int (&width, &height);
                break;
-       }
        default:
                break;
        }
+
        if (original_width)
                *original_width = width;
        if (original_height)