From 4f18d457e2c3a0ead780919521193b0b43ef9e59 Mon Sep 17 00:00:00 2001 From: Werner Lemberg Date: Sun, 7 Oct 2012 22:36:46 +0200 Subject: [PATCH] Improve documentation regarding vertical layout. --- include/freetype/freetype.h | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/include/freetype/freetype.h b/include/freetype/freetype.h index af020efb4..d2419fb6f 100644 --- a/include/freetype/freetype.h +++ b/include/freetype/freetype.h @@ -1109,8 +1109,8 @@ FT_BEGIN_HEADER * FT_HAS_VERTICAL( face ) * * @description: - * A macro that returns true whenever a face object contains vertical - * metrics. + * A macro that returns true whenever a face object contains real + * vertical metrics (and not only synthesized ones). * */ #define FT_HAS_VERTICAL( face ) \ @@ -2456,8 +2456,14 @@ FT_BEGIN_HEADER * @FT_LOAD_NO_SCALE always sets this flag. * * FT_LOAD_VERTICAL_LAYOUT :: - * Load the glyph for vertical text layout. _Don't_ use it as it is - * problematic currently. + * Load the glyph for vertical text layout. In particular, the + * `advance' value in the @FT_GlyphSlotRec structure is set to the + * `vertAdvance' value of the `metrics' field. + * + * In case @FT_HAS_VERTICAL doesn't return true, you shouldn't use + * this flag currently. Reason is that in this case vertical metrics + * get synthesized, and those values are not always consistent across + * various font formats. * * FT_LOAD_FORCE_AUTOHINT :: * Indicates that the auto-hinter is preferred over the font's native