master d6d73224a2: Make fringe bitmaps respect alpha-background

[Po Lu]

branch: master
commit d6d73224a21506b0ba31fd03bd99c5535ce3bb9c
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Make fringe bitmaps respect alpha-background
    
    * src/xterm.c (x_draw_fringe_bitmap): Respect alpha-background
    on non-overlay fringe bitmaps.
    * src/xterm.h (struct x_display_info): New field `alpha_mask'.
---
 src/xterm.c | 13 ++++++++++++-
 src/xterm.h |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/xterm.c b/src/xterm.c
index 5bcb77bbeb..2fc336f72a 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -2032,6 +2032,7 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row 
*row, struct draw_fring
       Pixmap pixmap, clipmask = None;
       int depth = FRAME_DISPLAY_INFO (f)->n_planes;
       XGCValues gcv;
+      unsigned long background = face->background;
 #ifdef HAVE_XRENDER
       Picture picture = None;
       XRenderPictureAttributes attrs;
@@ -2044,6 +2045,14 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row 
*row, struct draw_fring
       else
        bits = (char *) p->bits + p->dh;
 
+      if (FRAME_DISPLAY_INFO (f)->alpha_bits)
+       {
+         background = (background & ~FRAME_DISPLAY_INFO (f)->alpha_mask);
+         background |= (((unsigned long) (f->alpha_background * 0xffff)
+                         >> (16 - FRAME_DISPLAY_INFO (f)->alpha_bits))
+                        << FRAME_DISPLAY_INFO (f)->alpha_offset);
+       }
+
       /* Draw the bitmap.  I believe these small pixmaps can be cached
         by the server.  */
       pixmap = XCreatePixmapFromBitmapData (display, drawable, bits, p->wd, 
p->h,
@@ -2051,7 +2060,7 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row 
*row, struct draw_fring
                                             ? (p->overlay_p ? face->background
                                                : 
f->output_data.x->cursor_pixel)
                                             : face->foreground),
-                                           face->background, depth);
+                                           background, depth);
 
 #ifdef HAVE_XRENDER
       if (FRAME_X_PICTURE_FORMAT (f)
@@ -15574,6 +15583,7 @@ x_term_init (Lisp_Object display_name, char 
*xrm_option, char *resource_name)
          if (channel_mask)
            get_bits_and_offset (channel_mask, &dpyinfo->alpha_bits,
                                 &dpyinfo->alpha_offset);
+         dpyinfo->alpha_mask = channel_mask;
        }
       else
 #endif
@@ -15594,6 +15604,7 @@ x_term_init (Lisp_Object display_name, char 
*xrm_option, char *resource_name)
              if (alpha_mask)
                get_bits_and_offset (alpha_mask, &dpyinfo->alpha_bits,
                                     &dpyinfo->alpha_offset);
+             dpyinfo->alpha_mask = alpha_mask;
            }
        }
     }
diff --git a/src/xterm.h b/src/xterm.h
index c8c491a7d3..02270d6936 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -462,6 +462,7 @@ struct x_display_info
   /* Bits and shifts to use to compose pixel values on TrueColor visuals.  */
   int red_bits, blue_bits, green_bits, alpha_bits;
   int red_offset, blue_offset, green_offset, alpha_offset;
+  unsigned long alpha_mask;
 
   /* The type of window manager we have.  If we move FRAME_OUTER_WINDOW
      to x/y 0/0, some window managers (type A) puts the window manager