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-rw-r--r--demo.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/demo.c b/demo.c
index f69babe..9bbaedf 100644
--- a/demo.c
+++ b/demo.c
@@ -72,3 +72,81 @@ struct device *device_open(int argc, char **argv)
return device;
}
+cairo_surface_t *
+_cairo_image_surface_create_from_pixbuf(const GdkPixbuf *pixbuf)
+{
+ gint width = gdk_pixbuf_get_width (pixbuf);
+ gint height = gdk_pixbuf_get_height (pixbuf);
+ guchar *gdk_pixels = gdk_pixbuf_get_pixels (pixbuf);
+ int gdk_rowstride = gdk_pixbuf_get_rowstride (pixbuf);
+ int n_channels = gdk_pixbuf_get_n_channels (pixbuf);
+ int cairo_stride;
+ guchar *cairo_pixels;
+ cairo_format_t format;
+ cairo_surface_t *surface;
+ int j;
+
+ if (n_channels == 3)
+ format = CAIRO_FORMAT_RGB24;
+ else
+ format = CAIRO_FORMAT_ARGB32;
+
+ surface = cairo_image_surface_create(format, width, height);
+ if (cairo_surface_status(surface))
+ return surface;
+
+ cairo_stride = cairo_image_surface_get_stride (surface);
+ cairo_pixels = cairo_image_surface_get_data(surface);
+
+ for (j = height; j; j--) {
+ guchar *p = gdk_pixels;
+ guchar *q = cairo_pixels;
+
+ if (n_channels == 3) {
+ guchar *end = p + 3 * width;
+
+ while (p < end) {
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+ q[0] = p[2];
+ q[1] = p[1];
+ q[2] = p[0];
+#else
+ q[1] = p[0];
+ q[2] = p[1];
+ q[3] = p[2];
+#endif
+ p += 3;
+ q += 4;
+ }
+ } else {
+ guchar *end = p + 4 * width;
+ guint t1,t2,t3;
+
+#define MULT(d,c,a,t) G_STMT_START { t = c * a + 0x7f; d = ((t >> 8) + t) >> 8; } G_STMT_END
+
+ while (p < end) {
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+ MULT(q[0], p[2], p[3], t1);
+ MULT(q[1], p[1], p[3], t2);
+ MULT(q[2], p[0], p[3], t3);
+ q[3] = p[3];
+#else
+ q[0] = p[3];
+ MULT(q[1], p[0], p[3], t1);
+ MULT(q[2], p[1], p[3], t2);
+ MULT(q[3], p[2], p[3], t3);
+#endif
+
+ p += 4;
+ q += 4;
+ }
+#undef MULT
+ }
+
+ gdk_pixels += gdk_rowstride;
+ cairo_pixels += cairo_stride;
+ }
+
+ return surface;
+}
+