Add some code for transparent frame backgrounds without Cairo

* src/image.c (svg_load_image): Fix build without native image
transforms.

* src/xfns.c (set_up_x_back_buffer):
(tear_down_x_back_buffer): Free XR picture if present.

* src/xftfont.c (xftfont_get_xft_draw): Fix formatting issue.

* src/xterm.c (x_xr_ensure_picture): New function.
(FRAME_CR_CONTEXT, FRAME_CR_CONTEXT):
(FRAME_CR_SURFACE_DESIRED_WIDTH)
(FRAME_CR_SURFACE_DESIRED_HEIGHT): Move to separate USE_CAIRO
block so the ext data code can be used on builds with XRender as
well.

(x_xr_apply_ext_clip):
(x_xr_reset_ext_clip): New functions.
(x_set_clip_rectangles):
(x_reset_clip_rectangles): Set ext data on XRender as well.
(x_term_init): Look for a picture format appropriate for our
purposes.
(x_clear_area): Use XRenderFillRectangle to draw backgrounds if
available.
(x_xrender_color_from_gc_foreground):
(x_xrender_color_from_gc_background): New functions.

* src/xterm.h (FRAME_X_PICTURE):
(FRAME_X_PICTURE_FORMAT)
(FRAME_CHECK_XR_VERSION): New macros.

(struct x_gc_ext_data): Define on XRender as well.
(struct x_display_info): Define ext_codes when using XRender and
add new field `pict_format'.
(struct x_output): New field `picture'.

1 files changed, 36 insertions, 2 deletions

diff --git a/src/xterm.h b/src/xterm.h
index a4ad57eddaa..33887be52b0 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -54,6 +54,10 @@ typedef Widget xt_or_gtk_widget;
 #define GTK_CHECK_VERSION(i, j, k) false
 #endif
 
+#ifdef HAVE_XRENDER
+#include <X11/extensions/Xrender.h>
+#endif
+
 #ifdef USE_GTK
 /* Some definitions to reduce conditionals.  */
 typedef GtkWidget *xt_or_gtk_widget;
@@ -148,7 +152,7 @@ struct x_bitmap_record
   int height, width, depth;
 };
 
-#ifdef USE_CAIRO
+#if defined USE_CAIRO || defined HAVE_XRENDER
 struct x_gc_ext_data
 {
 #define MAX_CLIP_RECTS 2
@@ -158,7 +162,9 @@ struct x_gc_ext_data
   /* Clipping rectangles.  */
   XRectangle clip_rects[MAX_CLIP_RECTS];
 };
+#endif
 
+#ifdef USE_CAIRO
 extern cairo_pattern_t *x_bitmap_stipple (struct frame *, Pixmap);
 #endif
 
@@ -239,6 +245,11 @@ struct x_display_info
   /* The Visual being used for this display.  */
   Visual *visual;
 
+#ifdef HAVE_XRENDER
+  /* The picture format for this display.  */
+  XRenderPictFormat *pict_format;
+#endif
+
   /* The colormap being used.  */
   Colormap cmap;
 
@@ -509,7 +520,7 @@ struct x_display_info
   int xrandr_minor_version;
 #endif
 
-#ifdef USE_CAIRO
+#if defined USE_CAIRO || defined HAVE_XRENDER
   XExtCodes *ext_codes;
 #endif
 
@@ -616,6 +627,13 @@ struct x_output
      window's back buffer.  */
   Drawable draw_desc;
 
+#ifdef HAVE_XRENDER
+  /* The Xrender picture that corresponds to this drawable.  None
+     means no picture format was found, or the Xrender extension is
+     not present.  */
+  Picture picture;
+#endif
+
   /* Flag that indicates whether we've modified the back buffer and
      need to publish our modifications to the front buffer at a
      convenient time.  */
@@ -933,6 +951,17 @@ extern void x_mark_frame_dirty (struct frame *f);
 /* This is the Visual which frame F is on.  */
 #define FRAME_X_VISUAL(f) FRAME_DISPLAY_INFO (f)->visual
 
+#ifdef HAVE_XRENDER
+#define FRAME_X_PICTURE_FORMAT(f) FRAME_DISPLAY_INFO (f)->pict_format
+#define FRAME_X_PICTURE(f) ((f)->output_data.x->picture)
+#define FRAME_CHECK_XR_VERSION(f, major, minor)			\
+  (FRAME_DISPLAY_INFO (f)->xrender_supported_p			\
+   && ((FRAME_DISPLAY_INFO (f)->xrender_major == (major)	\
+	&& FRAME_DISPLAY_INFO (f)->xrender_minor >= (minor))	\
+       || (FRAME_DISPLAY_INFO (f)->xrender_major > (major))))
+#endif
+
+
 /* This is the Colormap which frame F uses.  */
 #define FRAME_X_COLORMAP(f) FRAME_DISPLAY_INFO (f)->cmap
 
@@ -1212,6 +1241,11 @@ extern void x_cr_draw_frame (cairo_t *, struct frame *);
 extern Lisp_Object x_cr_export_frames (Lisp_Object, cairo_surface_type_t);
 #endif
 
+#ifdef HAVE_XRENDER
+extern void x_xrender_color_from_gc_foreground (struct frame *, GC, XRenderColor *);
+extern void x_xrender_color_from_gc_background (struct frame *, GC, XRenderColor *);
+#endif
+
 INLINE int
 x_display_pixel_height (struct x_display_info *dpyinfo)
 {