--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/include/freetype/ftlcdfil.h Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,213 @@
+/***************************************************************************/
+/* */
+/* ftlcdfil.h */
+/* */
+/* FreeType API for color filtering of subpixel bitmap glyphs */
+/* (specification). */
+/* */
+/* Copyright 2006, 2007, 2008, 2010 by */
+/* David Turner, Robert Wilhelm, and Werner Lemberg. */
+/* */
+/* This file is part of the FreeType project, and may only be used, */
+/* modified, and distributed under the terms of the FreeType project */
+/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
+/* this file you indicate that you have read the license and */
+/* understand and accept it fully. */
+/* */
+/***************************************************************************/
+
+
+#ifndef __FT_LCD_FILTER_H__
+#define __FT_LCD_FILTER_H__
+
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
+#ifdef FREETYPE_H
+#error "freetype.h of FreeType 1 has been loaded!"
+#error "Please fix the directory search order for header files"
+#error "so that freetype.h of FreeType 2 is found first."
+#endif
+
+
+FT_BEGIN_HEADER
+
+ /***************************************************************************
+ *
+ * @section:
+ * lcd_filtering
+ *
+ * @title:
+ * LCD Filtering
+ *
+ * @abstract:
+ * Reduce color fringes of LCD-optimized bitmaps.
+ *
+ * @description:
+ * The @FT_Library_SetLcdFilter API can be used to specify a low-pass
+ * filter which is then applied to LCD-optimized bitmaps generated
+ * through @FT_Render_Glyph. This is useful to reduce color fringes
+ * which would occur with unfiltered rendering.
+ *
+ * Note that no filter is active by default, and that this function is
+ * *not* implemented in default builds of the library. You need to
+ * #define FT_CONFIG_OPTION_SUBPIXEL_RENDERING in your `ftoption.h' file
+ * in order to activate it.
+ */
+
+
+ /****************************************************************************
+ *
+ * @enum:
+ * FT_LcdFilter
+ *
+ * @description:
+ * A list of values to identify various types of LCD filters.
+ *
+ * @values:
+ * FT_LCD_FILTER_NONE ::
+ * Do not perform filtering. When used with subpixel rendering, this
+ * results in sometimes severe color fringes.
+ *
+ * FT_LCD_FILTER_DEFAULT ::
+ * The default filter reduces color fringes considerably, at the cost
+ * of a slight blurriness in the output.
+ *
+ * FT_LCD_FILTER_LIGHT ::
+ * The light filter is a variant that produces less blurriness at the
+ * cost of slightly more color fringes than the default one. It might
+ * be better, depending on taste, your monitor, or your personal vision.
+ *
+ * FT_LCD_FILTER_LEGACY ::
+ * This filter corresponds to the original libXft color filter. It
+ * provides high contrast output but can exhibit really bad color
+ * fringes if glyphs are not extremely well hinted to the pixel grid.
+ * In other words, it only works well if the TrueType bytecode
+ * interpreter is enabled *and* high-quality hinted fonts are used.
+ *
+ * This filter is only provided for comparison purposes, and might be
+ * disabled or stay unsupported in the future.
+ *
+ * @since:
+ * 2.3.0
+ */
+ typedef enum FT_LcdFilter_
+ {
+ FT_LCD_FILTER_NONE = 0,
+ FT_LCD_FILTER_DEFAULT = 1,
+ FT_LCD_FILTER_LIGHT = 2,
+ FT_LCD_FILTER_LEGACY = 16,
+
+ FT_LCD_FILTER_MAX /* do not remove */
+
+ } FT_LcdFilter;
+
+
+ /**************************************************************************
+ *
+ * @func:
+ * FT_Library_SetLcdFilter
+ *
+ * @description:
+ * This function is used to apply color filtering to LCD decimated
+ * bitmaps, like the ones used when calling @FT_Render_Glyph with
+ * @FT_RENDER_MODE_LCD or @FT_RENDER_MODE_LCD_V.
+ *
+ * @input:
+ * library ::
+ * A handle to the target library instance.
+ *
+ * filter ::
+ * The filter type.
+ *
+ * You can use @FT_LCD_FILTER_NONE here to disable this feature, or
+ * @FT_LCD_FILTER_DEFAULT to use a default filter that should work
+ * well on most LCD screens.
+ *
+ * @return:
+ * FreeType error code. 0~means success.
+ *
+ * @note:
+ * This feature is always disabled by default. Clients must make an
+ * explicit call to this function with a `filter' value other than
+ * @FT_LCD_FILTER_NONE in order to enable it.
+ *
+ * Due to *PATENTS* covering subpixel rendering, this function doesn't
+ * do anything except returning `FT_Err_Unimplemented_Feature' if the
+ * configuration macro FT_CONFIG_OPTION_SUBPIXEL_RENDERING is not
+ * defined in your build of the library, which should correspond to all
+ * default builds of FreeType.
+ *
+ * The filter affects glyph bitmaps rendered through @FT_Render_Glyph,
+ * @FT_Outline_Get_Bitmap, @FT_Load_Glyph, and @FT_Load_Char.
+ *
+ * It does _not_ affect the output of @FT_Outline_Render and
+ * @FT_Outline_Get_Bitmap.
+ *
+ * If this feature is activated, the dimensions of LCD glyph bitmaps are
+ * either larger or taller than the dimensions of the corresponding
+ * outline with regards to the pixel grid. For example, for
+ * @FT_RENDER_MODE_LCD, the filter adds up to 3~pixels to the left, and
+ * up to 3~pixels to the right.
+ *
+ * The bitmap offset values are adjusted correctly, so clients shouldn't
+ * need to modify their layout and glyph positioning code when enabling
+ * the filter.
+ *
+ * @since:
+ * 2.3.0
+ */
+ FT_EXPORT( FT_Error )
+ FT_Library_SetLcdFilter( FT_Library library,
+ FT_LcdFilter filter );
+
+
+ /**************************************************************************
+ *
+ * @func:
+ * FT_Library_SetLcdFilterWeights
+ *
+ * @description:
+ * Use this function to override the filter weights selected by
+ * @FT_Library_SetLcdFilter. By default, FreeType uses the quintuple
+ * (0x00, 0x55, 0x56, 0x55, 0x00) for FT_LCD_FILTER_LIGHT, and (0x10,
+ * 0x40, 0x70, 0x40, 0x10) for FT_LCD_FILTER_DEFAULT and
+ * FT_LCD_FILTER_LEGACY.
+ *
+ * @input:
+ * library ::
+ * A handle to the target library instance.
+ *
+ * weights ::
+ * A pointer to an array; the function copies the first five bytes and
+ * uses them to specify the filter weights.
+ *
+ * @return:
+ * FreeType error code. 0~means success.
+ *
+ * @note:
+ * Due to *PATENTS* covering subpixel rendering, this function doesn't
+ * do anything except returning `FT_Err_Unimplemented_Feature' if the
+ * configuration macro FT_CONFIG_OPTION_SUBPIXEL_RENDERING is not
+ * defined in your build of the library, which should correspond to all
+ * default builds of FreeType.
+ *
+ * This function must be called after @FT_Library_SetLcdFilter to have
+ * any effect.
+ *
+ * @since:
+ * 2.4.0
+ */
+ FT_EXPORT( FT_Error )
+ FT_Library_SetLcdFilterWeights( FT_Library library,
+ unsigned char *weights );
+
+ /* */
+
+
+FT_END_HEADER
+
+#endif /* __FT_LCD_FILTER_H__ */
+
+
+/* END */