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, 25 insertions, 0 deletions

diff --git a/src/cairo-types-private.h b/src/cairo-types-private.h
index 8b5a94b43..49fc7092a 100644
--- a/src/cairo-types-private.h
+++ b/src/cairo-types-private.h
@@ -129,9 +129,34 @@ struct _cairo_array {
     cairo_bool_t is_snapshot;
 };
 
+/**
+ * cairo_lcd_filter_t:
+ * @CAIRO_LCD_FILTER_DEFAULT: Use the default LCD filter for
+ *   font backend and target device
+ * @CAIRO_LCD_FILTER_NONE: Do not perform LCD filtering
+ * @CAIRO_LCD_FILTER_INTRA_PIXEL: Intra-pixel filter
+ * @CAIRO_LCD_FILTER_FIR3: FIR filter with a 3x3 kernel
+ * @CAIRO_LCD_FILTER_FIR5: FIR filter with a 5x5 kernel
+ *
+ * The LCD filter specifies the low-pass filter applied to LCD-optimized
+ * bitmaps generated with an antialiasing mode of %CAIRO_ANTIALIAS_SUBPIXEL.
+ *
+ * Note: This API was temporarily made available in the public
+ * interface during the 1.7.x development series, but was made private
+ * before 1.8.
+ **/
+typedef enum _cairo_lcd_filter {
+    CAIRO_LCD_FILTER_DEFAULT,
+    CAIRO_LCD_FILTER_NONE,
+    CAIRO_LCD_FILTER_INTRA_PIXEL,
+    CAIRO_LCD_FILTER_FIR3,
+    CAIRO_LCD_FILTER_FIR5
+} cairo_lcd_filter_t;
+
 struct _cairo_font_options {
     cairo_antialias_t antialias;
     cairo_subpixel_order_t subpixel_order;
+    cairo_lcd_filter_t lcd_filter;
     cairo_hint_style_t hint_style;
     cairo_hint_metrics_t hint_metrics;
 };