ft,fc,xlib: LCD filtering patch.

This adds internal API to retrieve the LCD filtering parameters from
fontconfig, or as set on the Screen, and feed them to FreeType when
rendering the glyph.

References:
  Bug 10301 - LCD filtering patch
  https://bugs.freedesktop.org/show_bug.cgi?id=10301

Tested-by: Brandon Wright <bearoso@gmail.com>
Forward-ported-by: Robert Hooker <sarvatt@gmail.cm>

ickle: The API is clearly not ready for public consumption, the enum are
poorly named, however this stands by itself as enabling system wide
properties.

1 files changed, 50 insertions, 1 deletions

diff --git a/src/cairo-font-options.c b/src/cairo-font-options.c
index 0348d28fb..971f7d50d 100644
--- a/src/cairo-font-options.c
+++ b/src/cairo-font-options.c
@@ -40,6 +40,7 @@
 static const cairo_font_options_t _cairo_font_options_nil = {
     CAIRO_ANTIALIAS_DEFAULT,
     CAIRO_SUBPIXEL_ORDER_DEFAULT,
+    CAIRO_LCD_FILTER_DEFAULT,
     CAIRO_HINT_STYLE_DEFAULT,
     CAIRO_HINT_METRICS_DEFAULT
 };
@@ -55,6 +56,7 @@ _cairo_font_options_init_default (cairo_font_options_t *options)
 {
     options->antialias = CAIRO_ANTIALIAS_DEFAULT;
     options->subpixel_order = CAIRO_SUBPIXEL_ORDER_DEFAULT;
+    options->lcd_filter = CAIRO_LCD_FILTER_DEFAULT;
     options->hint_style = CAIRO_HINT_STYLE_DEFAULT;
     options->hint_metrics = CAIRO_HINT_METRICS_DEFAULT;
 }
@@ -65,6 +67,7 @@ _cairo_font_options_init_copy (cairo_font_options_t		*options,
 {
     options->antialias = other->antialias;
     options->subpixel_order = other->subpixel_order;
+    options->lcd_filter = other->lcd_filter;
     options->hint_style = other->hint_style;
     options->hint_metrics = other->hint_metrics;
 }
@@ -190,6 +193,8 @@ cairo_font_options_merge (cairo_font_options_t       *options,
 	options->antialias = other->antialias;
     if (other->subpixel_order != CAIRO_SUBPIXEL_ORDER_DEFAULT)
 	options->subpixel_order = other->subpixel_order;
+    if (other->lcd_filter != CAIRO_LCD_FILTER_DEFAULT)
+	options->lcd_filter = other->lcd_filter;
     if (other->hint_style != CAIRO_HINT_STYLE_DEFAULT)
 	options->hint_style = other->hint_style;
     if (other->hint_metrics != CAIRO_HINT_METRICS_DEFAULT)
@@ -222,6 +227,7 @@ cairo_font_options_equal (const cairo_font_options_t *options,
 
     return (options->antialias == other->antialias &&
 	    options->subpixel_order == other->subpixel_order &&
+	    options->lcd_filter == other->lcd_filter &&
 	    options->hint_style == other->hint_style &&
 	    options->hint_metrics == other->hint_metrics);
 }
@@ -247,7 +253,8 @@ cairo_font_options_hash (const cairo_font_options_t *options)
 
     return ((options->antialias) |
 	    (options->subpixel_order << 4) |
-	    (options->hint_style << 8) |
+	    (options->lcd_filter << 8) |
+	    (options->hint_style << 12) |
 	    (options->hint_metrics << 16));
 }
 slim_hidden_def (cairo_font_options_hash);
@@ -329,6 +336,48 @@ cairo_font_options_get_subpixel_order (const cairo_font_options_t *options)
 }
 
 /**
+ * _cairo_font_options_set_lcd_filter:
+ * @options: a #cairo_font_options_t
+ * @lcd_filter: the new LCD filter
+ *
+ * Sets the LCD filter for the font options object. The LCD filter
+ * specifies how pixels are filtered when rendered with an antialiasing
+ * mode of %CAIRO_ANTIALIAS_SUBPIXEL. See the documentation for
+ * #cairo_lcd_filter_t for full details.
+ *
+ * Since: 1.8
+ **/
+void
+_cairo_font_options_set_lcd_filter (cairo_font_options_t *options,
+				    cairo_lcd_filter_t    lcd_filter)
+{
+    if (cairo_font_options_status (options))
+	return;
+
+    options->lcd_filter = lcd_filter;
+}
+
+/**
+ * _cairo_font_options_get_lcd_filter:
+ * @options: a #cairo_font_options_t
+ *
+ * Gets the LCD filter for the font options object.
+ * See the documentation for #cairo_lcd_filter_t for full details.
+ *
+ * Return value: the LCD filter for the font options object
+ *
+ * Since: 1.8
+ **/
+cairo_lcd_filter_t
+_cairo_font_options_get_lcd_filter (const cairo_font_options_t *options)
+{
+    if (cairo_font_options_status ((cairo_font_options_t *) options))
+	return CAIRO_LCD_FILTER_DEFAULT;
+
+    return options->lcd_filter;
+}
+
+/**
  * cairo_font_options_set_hint_style:
  * @options: a #cairo_font_options_t
  * @hint_style: the new hint style