fcft_glyph_rasterize - Man Page

rasterize a glyph for a wide character

Synopsis

#include <fcft/fcft.h>

const struct fcft_glyph *fcft_glyph_rasterize(

struct fcft_font *font, wchar_t wc, enum fcft_subpixel subpixel);

Description

fcft_glyph_rasterize() rasterizes the wide character wc using the primary font, or one of the fallback fonts, in font.

wc is first searched for in the primary font. If not found, the fallback fonts are searched (in the order they were specified in fcft_from_name(3)). If not found in any of the fallback fonts, the FontConfig fallback list for the primary font is searched.

subpixel allows you to specify which subpixel mode to use. It is one of:

  enum fcft_subpixel {
      FCFT_SUBPIXEL_DEFAULT,
      FCFT_SUBPIXEL_NONE,
      FCFT_SUBPIXEL_HORIZONTAL_RGB,
      FCFT_SUBPIXEL_HORIZONTAL_BGR,
      FCFT_SUBPIXEL_VERTICAL_RGB,
      FCFT_SUBPIXEL_VERTICAL_BGR,
  };

If FCFT_SUBPIXEL_DEFAULT is specified, the subpixel mode configured in FontConfig is used. If FCFT_SUBPIXEL_NONE is specified, grayscale antialiasing will be used. For all other values, the specified mode is used.

Note that if antialiasing has been disabled (in FontConfig, either globally, or specifically for the current font), then subpixel is ignored.

The intention is to enable programs to use per-monitor subpixel modes. Incidentally, enum fcft_subpixel matches enum wl_output_subpixel, the enum used in Wayland.

Note: you probably do not want anything by FCFT_SUBPIXEL_NONE if blending with a transparent background.

Return Value

On error, NULL is returned.

On success, a pointer to a rasterized glyph is returned. The glyph is cached in fcft, making subsequent calls with the same arguments very fast (i.e. there is no need for programs to cache glyphs by themselves).

The glyph object is managed by font. There is no need to explicitly free it; it is freed when font is destroyed (with fcft_destroy(3)).

  struct fcft_glyph {
      wchar_t wc;
      int cols;

    pixman_image_t *pix;

    int x;
    int y;
    int width;
    int height;

    struct {
        int x;
        int y;
    } advance;
};

wc is the same wc from the fcft_glyph_rasterize() call.

cols is the number of "columns" the glyph occupies (effectively, wcwidth(wc)).

pix is the rasterized glyph. Its format depends on a number of factors, but will be one of PIXMAN_a1, PIXMAN_a8, PIXMAN_x8r8g8b8, PIXMAN_a8r8g8b8. Use pixman_image_get_format() to find out which one it is.

PIXMAN_a1 corresponds to FT_PIXEL_MODE_MONO. I.e. the glyph is an un-antialiased bitmask. Use as a mask when blending.

PIXMAN_a8 corresponds to FT_PIXEL_MODE_GRAY. I.e. the glyph is a grayscale antialiased bitmask. use as a mask when blending.

PIXMAN_x8r8g8b8 corresponds to either FT_PIXEL_MODE_LCD or FT_PIXEL_MODE_LCD_V. pixman_image_set_component_alpha() has been called by fcft for you. Use as a mask when blending.

PIXMAN_a8r8g8b8 corresponds to FT_PIXEL_MODE_BGRA. I.e. the glyph is a plain RGBA image. Use as source when blending.

x is the glyph's horizontal offset, in pixels. Add this to the current pen position when blending.

y is the glyph's vertical offset, in pixels. Add this to the current pen position when blending.

width is the glyph's width, in pixels. Use as 'width' argument when blending.

height is the glyph's height, in pixels. Use as 'height' argument when blending.

advance is the glyph's 'advance', in pixels. Add this to the pen position after blending; x for a horizontal layout and y for a vertical layout.

Example

See fcft_from_name(3)

See Also

fcft_destroy(3), fcft_kerning(3)

Referenced By

fcft_destroy(3), fcft_from_name(3), fcft_grapheme_rasterize(3), fcft_precompose(3), fcft_set_scaling_filter(3).

2021-03-08 2.3.2 fcft