• David Turner's avatar
    David Turner authored
        A lot of internal modifications have been performed lately on the
        source in order to provide the following enhancements:
          - more generic module support:
            The FT_Module type is now defined to represent a handle to a given
            module. The file <freetype/ftmodule.h> contains the FT_Module_Class
            definition, as well as the module-loading public API
            The FT_Driver type is still defined, and still represents a pointer
            to a font driver. Note that FT_Add_Driver is replaced by FT_Add_Module,
            FT_Get_Driver by FT_Get_Module, etc..
          - support for generic glyph image types:
            The FT_Renderer type is a pointer to a module used to perform various
            operations on glyph image.
            Each renderer is capable of handling images in a single format
            (e.g. ft_glyph_format_outline). Its functions are used to:
               - transform an glyph image
               - render a glyph image into a bitmap
               - return the control box (dimensions) of a given glyph image
            The scan converters "ftraster.c" and "ftgrays.c" have been moved
            to the new directory "src/renderer", and are used to provide two
            default renderer modules.
            One corresponds to the "standard" scan-converter, the other to the
            "smooth" one.
            The current renderer can be set through the new function
            The old raster-related function FT_Set_Raster, FT_Get_Raster and
            FT_Set_Raster_Mode have now disappeared, in favor of the new:
            see the file <freetype/ftrender.h> for more details..
            These changes were necessary to properly support different scalable
            formats in the future, like bi-color glyphs, etc..
          - glyph loader object:
            A new internal object, called a 'glyph loader' has been introduced
            in the base layer. It is used by all scalable format font drivers
            to load glyphs and composites.
            This object has been created to reduce the code size of each driver,
            as each one of them basically re-implemented its functionality.
            See <freetype/internal/ftobjs.h> and the FT_GlyphLoader type for
            more information..
          - FT_GlyphSlot had new fields:
            In order to support extended features (see below), the FT_GlyphSlot
            structure has a few new fields:
               linearHoriAdvance:  this field gives the linearly scaled (i.e.
                                   scaled but unhinted) advance width for the glyph,
                                   expressed as a 16.16 fixed pixel value. This
                                   is useful to perform WYSIWYG text.
               linearVertAdvance:  this field gives the linearly scaled advance
                                   height for the glyph (relevant in vertical glyph
                                   layouts only). This is useful to perform
                                   WYSIWYG text.
            Note that the two above field replace the removed "metrics2" field
            in the glyph slot.
               advance:   this field is a vector that gives the transformed
                          advance for the glyph. By default, it corresponds
                          to the advance width, unless FT_LOAD_VERTICAL_LAYOUT
                          was specified when calling FT_Load_Glyph or FT_Load_Char
               bitmap_left: this field gives the distance in integer pixels from
                            the current pen position to the left-most pixel of
                            a glyph image WHEN IT IS A BITMAP. It is only valid
                            when the "format" field is set to
                            "ft_glyph_format_bitmap", for example, after calling
                            the new function FT_Render_Glyph.
               bitmap_top:  this field gives the distance in integer pixels from
                            the current pen position (located on the baseline) to
                            the top-most pixel of the glyph image WHEN IT IS A
                            BITMAP. Positive values correspond to upwards Y.
               loader:  this is a new private field for the glyph slot. Client
                        applications should not touch it..
          - support for transforms and direct rendering in FT_Load_Glyph:
            Most of the functionality found in <freetype/ftglyph.h> has been
            moved to the core library. Hence, the following:
              - a transform can be specified for a face through FT_Set_Transform.
                this transform is applied by FT_Load_Glyph to scalable glyph images
                (i.e. NOT TO BITMAPS) before the function returns, unless the
                bit flag FT_LOAD_IGNORE_TRANSFORM was set in the load flags..
              - once a glyph image has been loaded, it can be directly converted to
                a bitmap by using the new FT_Render_Glyph function. Note that this
                function takes the glyph image from the glyph slot, and converts
                it to a bitmap whose properties are returned in "face.glyph.bitmap",
                "face.glyph.bitmap_left" and "face.glyph.bitmap_top". The original
                native image might be lost after the conversion.
              - when using the new bit flag FT_LOAD_RENDER, the FT_Load_Glyph
                and FT_Load_Char functions will call FT_Render_Glyph automatically
                when needed.