From 4cfa8fc5be7142a3cca1ba1afc95a7a5b0716a16 Mon Sep 17 00:00:00 2001 From: Dave Arnold Date: Thu, 10 Oct 2013 13:36:49 -0700 Subject: [PATCH] Comment on no-stem-darkening & darkening-parameters --- include/freetype/ftcffdrv.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/include/freetype/ftcffdrv.h b/include/freetype/ftcffdrv.h index 7f885e861..e4d039d02 100644 --- a/include/freetype/ftcffdrv.h +++ b/include/freetype/ftcffdrv.h @@ -173,8 +173,9 @@ FT_BEGIN_HEADER * * @description: * By default, the Adobe CFF engine darkens stems at smaller sizes, - * regardless of hinting, to enhance contrast. Setting this property, - * stem darkening gets switched off. + * regardless of hinting, to enhance contrast. This feature requires + * a rendering system with proper gamma correction. Setting this + * property, stem darkening gets switched off. * * Note that stem darkening is never applied if @FT_LOAD_NO_SCALE is set. * @@ -231,9 +232,10 @@ FT_BEGIN_HEADER * * The x~values give the stem width, and the y~values the darkening * amount. The unit is 1000th of pixels. All coordinate values must be - * positive; the x~values must be monotonically increasing, and the - * y~values smaller than or equal to 500 (corresponding to half a - * pixel). + * positive; the x~values must be monotonically increasing; the + * y~values must be monotonically decreasing and smaller than or + * equal to 500 (corresponding to half a pixel); the slope of each + * linear piece must be shallower than -1 (e.g., -.4). * * @note: * This property can be used with @FT_Property_Get also.