+
+ IV.1 Can I use FreeType to draw text on a pixmap with arbitratry depth ?
+
+
+ No directly, as FreeType is a font library, not a general purpose
+ graphics library or text rendering service. However, note that the
+ anti-aliased renderer allows you to convert a vectorial glyph outline
+ into a list of "spans" (i.e. horizontal pixel segments with same coverage)
+ that can be rendered through user-provided callbacks.
+
+ By providing the appropriate span callback, you can render anti-aliased
+ text to any kind of surface. You can also use any color or fill
+ pattern/image if you want to. This process is called
+ direct rendering. For more information, please read the
+ documentation contained in the following files:
+
+
+
+ <freetype/ftimage.h> contains the definition
+ of the FT_Raster_Params type used with direct rendering.
+
+ <freetype/ftoutln.h> contains the definition
+ of the FT_Outline_Render function that can be used to
+ convert vectorial outlines to span lists.
+
+
+ Here's some code that uses them:
+
+
+ FT_Raster_Params params;
+ FT_Outline outline;
+
+ .. load vectorial glyph in "outline"
+
+ params.flags = ft_raster_flag_aa | ft_raster_flag_direct;
+ params.gray_spans = (FT_Raster_Span_Func)your_own_span_function_here;
+ params.user = your_own_data_pointer;
+
+ error = FT_Outline_Render( library, &outline, ¶ms );
+
+
+ Note that direct rendering is not available with monochrome
+ output, as the current renderer uses a two-pass algorithm to generate
+ glyphs with correct drop-out control.
+
+
+
+
+ IV.2 How can I set the color of text rendered by FreeType ?
+
+
+ Basically, you can't do that, because FreeType is simply a font
+ library. In general, you'll need to use your favorite graphics library
+ to draw the FreeType glyphs with the appropriate color.
+
+ Note that for anti-aliased glyphs, you can "set the color" by using
+ direct rendering as described in this
+ answer
+
+
+
+
+
+ IV.3 I set the pixel size to 8x8, but the resulting glyphs are larger
+ (or smaller) than that. Why ??
+
+
+ A lot of people have a hard time understanding this topic, because
+ they think of glyphs as fixed-width/height "cells", like those of
+ fonts used in terminals/consoles. This assumption is simply not valid
+ with most "modern" font formats, even bitmapped-based ones like
+ PCF or BDF.
+
+ Be aware that the character size that is set either through
+ FT_Set_Char_Size or FT_Set_Pixel_Sizes isn't directly
+ related to the dimension of the glyph bitmaps generated.
+
+ Rather, the character size is indeed the size of
+ an abstract square, called the EM, used by typographers
+ to design fonts. Scaling two distinct fonts to the same character size, be
+ it expressed in points or pixels, will generally result in bitmaps with
+ distinct dimensions !
+
+ Note that historically, the EM corresponded to the width of a capital
+ "M" in Latin typefaces. However, later improvements in typography led to
+ the designs that greatly detract from this rule. Today, it is not possible
+ to connect the EM size to a specific font "feature" in a reliable way.
+
+
+
+