ref: 4f18d457e2c3a0ead780919521193b0b43ef9e59
parent: be81ec22ccdecb5bf80dd9528223e443e8c03359
author: Werner Lemberg <[email protected]>
date: Sun Oct 7 18:36:46 EDT 2012
Improve documentation regarding vertical layout.
--- a/include/freetype/freetype.h
+++ b/include/freetype/freetype.h
@@ -1109,8 +1109,8 @@
* 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_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