[gimp/gimp-2-10] Issue #6210: Subpixel font rendering system settings should only…

[Jehan <jehanp src gnome org>]

commit a08055f1a18886fdacaf0cba5887b7ff2f687732
Author: Adam Fontenot <adam m fontenot gmail com>
Date:   Tue Jan 19 13:47:27 2021 +0100

    Issue #6210: Subpixel font rendering system settings should only…
    
    … apply to GIMP GUI not text layer rendering in image.
    
    Reviewer note: this is the theoretical fix, but it won't work right now
    because Cairo explicitly bypasses grayscale antialiasing when system set
    subpixel one. Still let's push this first patch, but the issue will be
    actually fixed when Cairo will merge my MR too:
    https://gitlab.freedesktop.org/cairo/cairo/-/merge_requests/114
    
    (cherry picked from commit 00bbeabaf4d8a434bd64371303ee982fb5403ab6)

 app/text/gimptextlayout.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/text/gimptextlayout.c b/app/text/gimptextlayout.c
index 47beed7705..56c670ea0b 100644
--- a/app/text/gimptextlayout.c
+++ b/app/text/gimptextlayout.c
@@ -701,7 +701,7 @@ gimp_text_get_font_options (GimpText *text)
   cairo_font_options_t *options = cairo_font_options_create ();
 
   cairo_font_options_set_antialias (options, (text->antialias ?
-                                              CAIRO_ANTIALIAS_DEFAULT :
+                                              CAIRO_ANTIALIAS_GRAY :
                                               CAIRO_ANTIALIAS_NONE));
 
   switch (text->hint_style)