From: Po Lu <luangruo@yahoo.com>
Date: Sat, 9 Apr 2022 00:41:00 +0000 (+0800)
Subject: Fix subpixel AA with alpha-background on Cairo on X
X-Git-Tag: emacs-29.0.90~1931^2~694
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=bb7623b9bee14bf428accc5b8cc88fa34fd9c9a2;p=emacs.git

Fix subpixel AA with alpha-background on Cairo on X

* xterm.c (x_set_cr_source_with_gc_foreground)
(x_set_cr_source_with_gc_background): Set operator back to OVER
if alpha-background isn't to be respected.
---

diff --git a/src/xterm.c b/src/xterm.c
index dc06df246c4..da671731863 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -4240,8 +4240,11 @@ x_set_cr_source_with_gc_foreground (struct frame *f, GC gc,
       cairo_set_operator (FRAME_CR_CONTEXT (f), CAIRO_OPERATOR_SOURCE);
     }
   else
-    cairo_set_source_rgb (FRAME_CR_CONTEXT (f), color.red / 65535.0,
-                          color.green / 65535.0, color.blue / 65535.0);
+    {
+      cairo_set_source_rgb (FRAME_CR_CONTEXT (f), color.red / 65535.0,
+			    color.green / 65535.0, color.blue / 65535.0);
+      cairo_set_operator (FRAME_CR_CONTEXT (f), CAIRO_OPERATOR_OVER);
+    }
 }
 
 void
@@ -4269,8 +4272,11 @@ x_set_cr_source_with_gc_background (struct frame *f, GC gc,
       cairo_set_operator (FRAME_CR_CONTEXT (f), CAIRO_OPERATOR_SOURCE);
     }
   else
-    cairo_set_source_rgb (FRAME_CR_CONTEXT (f), color.red / 65535.0,
-                          color.green / 65535.0, color.blue / 65535.0);
+    {
+      cairo_set_source_rgb (FRAME_CR_CONTEXT (f), color.red / 65535.0,
+			    color.green / 65535.0, color.blue / 65535.0);
+      cairo_set_operator (FRAME_CR_CONTEXT (f), CAIRO_OPERATOR_OVER);
+    }
 }
 
 static const cairo_user_data_key_t xlib_surface_key, saved_drawable_key;