1239 lines
38 KiB
C
1239 lines
38 KiB
C
/****************************************************************************
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*
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* ftimage.h
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*
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* FreeType glyph image formats and default raster interface
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* (specification).
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*
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* Copyright (C) 1996-2020 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* This file is part of the FreeType project, and may only be used,
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* modified, and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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*/
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/**************************************************************************
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*
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* Note: A 'raster' is simply a scan-line converter, used to render
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* FT_Outlines into FT_Bitmaps.
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*
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*/
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#ifndef FTIMAGE_H_
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#define FTIMAGE_H_
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/* STANDALONE_ is from ftgrays.c */
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#ifndef STANDALONE_
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#include <ft2build.h>
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#endif
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FT_BEGIN_HEADER
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/**************************************************************************
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*
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* @section:
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* basic_types
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*
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*/
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/**************************************************************************
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*
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* @type:
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* FT_Pos
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*
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* @description:
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* The type FT_Pos is used to store vectorial coordinates. Depending on
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* the context, these can represent distances in integer font units, or
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* 16.16, or 26.6 fixed-point pixel coordinates.
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*/
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typedef signed long FT_Pos;
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/**************************************************************************
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*
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* @struct:
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* FT_Vector
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*
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* @description:
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* A simple structure used to store a 2D vector; coordinates are of the
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* FT_Pos type.
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*
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* @fields:
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* x ::
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* The horizontal coordinate.
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* y ::
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* The vertical coordinate.
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*/
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typedef struct FT_Vector_
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{
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FT_Pos x;
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FT_Pos y;
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} FT_Vector;
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/**************************************************************************
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*
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* @struct:
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* FT_BBox
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*
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* @description:
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* A structure used to hold an outline's bounding box, i.e., the
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* coordinates of its extrema in the horizontal and vertical directions.
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*
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* @fields:
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* xMin ::
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* The horizontal minimum (left-most).
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*
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* yMin ::
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* The vertical minimum (bottom-most).
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*
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* xMax ::
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* The horizontal maximum (right-most).
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*
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* yMax ::
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* The vertical maximum (top-most).
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*
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* @note:
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* The bounding box is specified with the coordinates of the lower left
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* and the upper right corner. In PostScript, those values are often
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* called (llx,lly) and (urx,ury), respectively.
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*
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* If `yMin` is negative, this value gives the glyph's descender.
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* Otherwise, the glyph doesn't descend below the baseline. Similarly,
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* if `ymax` is positive, this value gives the glyph's ascender.
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*
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* `xMin` gives the horizontal distance from the glyph's origin to the
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* left edge of the glyph's bounding box. If `xMin` is negative, the
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* glyph extends to the left of the origin.
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*/
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typedef struct FT_BBox_
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{
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FT_Pos xMin, yMin;
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FT_Pos xMax, yMax;
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} FT_BBox;
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/**************************************************************************
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*
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* @enum:
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* FT_Pixel_Mode
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*
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* @description:
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* An enumeration type used to describe the format of pixels in a given
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* bitmap. Note that additional formats may be added in the future.
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*
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* @values:
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* FT_PIXEL_MODE_NONE ::
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* Value~0 is reserved.
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*
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* FT_PIXEL_MODE_MONO ::
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* A monochrome bitmap, using 1~bit per pixel. Note that pixels are
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* stored in most-significant order (MSB), which means that the
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* left-most pixel in a byte has value 128.
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*
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* FT_PIXEL_MODE_GRAY ::
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* An 8-bit bitmap, generally used to represent anti-aliased glyph
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* images. Each pixel is stored in one byte. Note that the number of
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* 'gray' levels is stored in the `num_grays` field of the @FT_Bitmap
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* structure (it generally is 256).
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*
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* FT_PIXEL_MODE_GRAY2 ::
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* A 2-bit per pixel bitmap, used to represent embedded anti-aliased
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* bitmaps in font files according to the OpenType specification. We
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* haven't found a single font using this format, however.
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*
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* FT_PIXEL_MODE_GRAY4 ::
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* A 4-bit per pixel bitmap, representing embedded anti-aliased bitmaps
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* in font files according to the OpenType specification. We haven't
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* found a single font using this format, however.
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*
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* FT_PIXEL_MODE_LCD ::
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* An 8-bit bitmap, representing RGB or BGR decimated glyph images used
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* for display on LCD displays; the bitmap is three times wider than
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* the original glyph image. See also @FT_RENDER_MODE_LCD.
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*
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* FT_PIXEL_MODE_LCD_V ::
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* An 8-bit bitmap, representing RGB or BGR decimated glyph images used
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* for display on rotated LCD displays; the bitmap is three times
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* taller than the original glyph image. See also
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* @FT_RENDER_MODE_LCD_V.
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*
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* FT_PIXEL_MODE_BGRA ::
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* [Since 2.5] An image with four 8-bit channels per pixel,
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* representing a color image (such as emoticons) with alpha channel.
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* For each pixel, the format is BGRA, which means, the blue channel
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* comes first in memory. The color channels are pre-multiplied and in
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* the sRGB colorspace. For example, full red at half-translucent
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* opacity will be represented as '00,00,80,80', not '00,00,FF,80'.
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* See also @FT_LOAD_COLOR.
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*/
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typedef enum FT_Pixel_Mode_
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{
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FT_PIXEL_MODE_NONE = 0,
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FT_PIXEL_MODE_MONO,
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FT_PIXEL_MODE_GRAY,
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FT_PIXEL_MODE_GRAY2,
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FT_PIXEL_MODE_GRAY4,
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FT_PIXEL_MODE_LCD,
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FT_PIXEL_MODE_LCD_V,
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FT_PIXEL_MODE_BGRA,
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FT_PIXEL_MODE_MAX /* do not remove */
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} FT_Pixel_Mode;
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/* these constants are deprecated; use the corresponding `FT_Pixel_Mode` */
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/* values instead. */
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#define ft_pixel_mode_none FT_PIXEL_MODE_NONE
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#define ft_pixel_mode_mono FT_PIXEL_MODE_MONO
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#define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY
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#define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2
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#define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4
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/**************************************************************************
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*
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* @struct:
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* FT_Bitmap
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*
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* @description:
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* A structure used to describe a bitmap or pixmap to the raster. Note
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* that we now manage pixmaps of various depths through the `pixel_mode`
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* field.
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*
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* @fields:
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* rows ::
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* The number of bitmap rows.
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*
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* width ::
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* The number of pixels in bitmap row.
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*
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* pitch ::
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* The pitch's absolute value is the number of bytes taken by one
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* bitmap row, including padding. However, the pitch is positive when
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* the bitmap has a 'down' flow, and negative when it has an 'up' flow.
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* In all cases, the pitch is an offset to add to a bitmap pointer in
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* order to go down one row.
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*
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* Note that 'padding' means the alignment of a bitmap to a byte
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* border, and FreeType functions normally align to the smallest
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* possible integer value.
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*
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* For the B/W rasterizer, `pitch` is always an even number.
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*
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* To change the pitch of a bitmap (say, to make it a multiple of 4),
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* use @FT_Bitmap_Convert. Alternatively, you might use callback
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* functions to directly render to the application's surface; see the
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* file `example2.cpp` in the tutorial for a demonstration.
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*
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* buffer ::
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* A typeless pointer to the bitmap buffer. This value should be
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* aligned on 32-bit boundaries in most cases.
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*
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* num_grays ::
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* This field is only used with @FT_PIXEL_MODE_GRAY; it gives the
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* number of gray levels used in the bitmap.
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*
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* pixel_mode ::
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* The pixel mode, i.e., how pixel bits are stored. See @FT_Pixel_Mode
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* for possible values.
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*
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* palette_mode ::
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* This field is intended for paletted pixel modes; it indicates how
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* the palette is stored. Not used currently.
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*
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* palette ::
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* A typeless pointer to the bitmap palette; this field is intended for
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* paletted pixel modes. Not used currently.
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*/
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typedef struct FT_Bitmap_
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{
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unsigned int rows;
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unsigned int width;
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int pitch;
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unsigned char* buffer;
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unsigned short num_grays;
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unsigned char pixel_mode;
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unsigned char palette_mode;
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void* palette;
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} FT_Bitmap;
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/**************************************************************************
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*
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* @section:
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* outline_processing
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*
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*/
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/**************************************************************************
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*
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* @struct:
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* FT_Outline
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*
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* @description:
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* This structure is used to describe an outline to the scan-line
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* converter.
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*
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* @fields:
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* n_contours ::
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* The number of contours in the outline.
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*
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* n_points ::
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* The number of points in the outline.
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*
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* points ::
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* A pointer to an array of `n_points` @FT_Vector elements, giving the
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* outline's point coordinates.
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*
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* tags ::
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* A pointer to an array of `n_points` chars, giving each outline
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* point's type.
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*
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* If bit~0 is unset, the point is 'off' the curve, i.e., a Bezier
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* control point, while it is 'on' if set.
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*
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* Bit~1 is meaningful for 'off' points only. If set, it indicates a
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* third-order Bezier arc control point; and a second-order control
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* point if unset.
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*
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* If bit~2 is set, bits 5-7 contain the drop-out mode (as defined in
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* the OpenType specification; the value is the same as the argument to
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* the 'SCANMODE' instruction).
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*
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* Bits 3 and~4 are reserved for internal purposes.
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*
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* contours ::
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* An array of `n_contours` shorts, giving the end point of each
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* contour within the outline. For example, the first contour is
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* defined by the points '0' to `contours[0]`, the second one is
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* defined by the points `contours[0]+1` to `contours[1]`, etc.
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*
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* flags ::
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* A set of bit flags used to characterize the outline and give hints
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* to the scan-converter and hinter on how to convert/grid-fit it. See
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* @FT_OUTLINE_XXX.
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*
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* @note:
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* The B/W rasterizer only checks bit~2 in the `tags` array for the first
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* point of each contour. The drop-out mode as given with
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* @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and
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* @FT_OUTLINE_INCLUDE_STUBS in `flags` is then overridden.
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*/
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typedef struct FT_Outline_
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{
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short n_contours; /* number of contours in glyph */
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short n_points; /* number of points in the glyph */
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FT_Vector* points; /* the outline's points */
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char* tags; /* the points flags */
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short* contours; /* the contour end points */
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int flags; /* outline masks */
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} FT_Outline;
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/* */
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/* Following limits must be consistent with */
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/* FT_Outline.{n_contours,n_points} */
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#define FT_OUTLINE_CONTOURS_MAX SHRT_MAX
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#define FT_OUTLINE_POINTS_MAX SHRT_MAX
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/**************************************************************************
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*
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* @enum:
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* FT_OUTLINE_XXX
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*
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* @description:
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* A list of bit-field constants used for the flags in an outline's
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* `flags` field.
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*
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* @values:
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* FT_OUTLINE_NONE ::
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* Value~0 is reserved.
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*
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* FT_OUTLINE_OWNER ::
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* If set, this flag indicates that the outline's field arrays (i.e.,
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* `points`, `flags`, and `contours`) are 'owned' by the outline
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* object, and should thus be freed when it is destroyed.
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*
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* FT_OUTLINE_EVEN_ODD_FILL ::
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* By default, outlines are filled using the non-zero winding rule. If
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* set to 1, the outline will be filled using the even-odd fill rule
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* (only works with the smooth rasterizer).
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*
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* FT_OUTLINE_REVERSE_FILL ::
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* By default, outside contours of an outline are oriented in
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* clock-wise direction, as defined in the TrueType specification.
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* This flag is set if the outline uses the opposite direction
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* (typically for Type~1 fonts). This flag is ignored by the scan
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* converter.
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*
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* FT_OUTLINE_IGNORE_DROPOUTS ::
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* By default, the scan converter will try to detect drop-outs in an
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* outline and correct the glyph bitmap to ensure consistent shape
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* continuity. If set, this flag hints the scan-line converter to
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* ignore such cases. See below for more information.
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*
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* FT_OUTLINE_SMART_DROPOUTS ::
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* Select smart dropout control. If unset, use simple dropout control.
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* Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more
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* information.
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*
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* FT_OUTLINE_INCLUDE_STUBS ::
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* If set, turn pixels on for 'stubs', otherwise exclude them. Ignored
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* if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more
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* information.
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*
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* FT_OUTLINE_HIGH_PRECISION ::
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* This flag indicates that the scan-line converter should try to
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* convert this outline to bitmaps with the highest possible quality.
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* It is typically set for small character sizes. Note that this is
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* only a hint that might be completely ignored by a given
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* scan-converter.
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*
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* FT_OUTLINE_SINGLE_PASS ::
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* This flag is set to force a given scan-converter to only use a
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* single pass over the outline to render a bitmap glyph image.
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* Normally, it is set for very large character sizes. It is only a
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* hint that might be completely ignored by a given scan-converter.
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*
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* @note:
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* The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and
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* @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth rasterizer.
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*
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* There exists a second mechanism to pass the drop-out mode to the B/W
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* rasterizer; see the `tags` field in @FT_Outline.
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*
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* Please refer to the description of the 'SCANTYPE' instruction in the
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* OpenType specification (in file `ttinst1.doc`) how simple drop-outs,
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* smart drop-outs, and stubs are defined.
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*/
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#define FT_OUTLINE_NONE 0x0
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#define FT_OUTLINE_OWNER 0x1
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#define FT_OUTLINE_EVEN_ODD_FILL 0x2
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#define FT_OUTLINE_REVERSE_FILL 0x4
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#define FT_OUTLINE_IGNORE_DROPOUTS 0x8
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#define FT_OUTLINE_SMART_DROPOUTS 0x10
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#define FT_OUTLINE_INCLUDE_STUBS 0x20
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#define FT_OUTLINE_HIGH_PRECISION 0x100
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#define FT_OUTLINE_SINGLE_PASS 0x200
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/* these constants are deprecated; use the corresponding */
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/* `FT_OUTLINE_XXX` values instead */
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#define ft_outline_none FT_OUTLINE_NONE
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#define ft_outline_owner FT_OUTLINE_OWNER
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#define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL
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#define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL
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#define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS
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#define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION
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#define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS
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/* */
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#define FT_CURVE_TAG( flag ) ( flag & 0x03 )
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/* see the `tags` field in `FT_Outline` for a description of the values */
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#define FT_CURVE_TAG_ON 0x01
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#define FT_CURVE_TAG_CONIC 0x00
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#define FT_CURVE_TAG_CUBIC 0x02
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#define FT_CURVE_TAG_HAS_SCANMODE 0x04
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#define FT_CURVE_TAG_TOUCH_X 0x08 /* reserved for TrueType hinter */
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#define FT_CURVE_TAG_TOUCH_Y 0x10 /* reserved for TrueType hinter */
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#define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \
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FT_CURVE_TAG_TOUCH_Y )
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/* values 0x20, 0x40, and 0x80 are reserved */
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|
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|
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/* these constants are deprecated; use the corresponding */
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/* `FT_CURVE_TAG_XXX` values instead */
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#define FT_Curve_Tag_On FT_CURVE_TAG_ON
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#define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC
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#define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC
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#define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X
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#define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y
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/**************************************************************************
|
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*
|
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* @functype:
|
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* FT_Outline_MoveToFunc
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*
|
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* @description:
|
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* A function pointer type used to describe the signature of a 'move to'
|
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* function during outline walking/decomposition.
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*
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* A 'move to' is emitted to start a new contour in an outline.
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*
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* @input:
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* to ::
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* A pointer to the target point of the 'move to'.
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*
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* user ::
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* A typeless pointer, which is passed from the caller of the
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* decomposition function.
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*
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* @return:
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* Error code. 0~means success.
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*/
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typedef int
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(*FT_Outline_MoveToFunc)( const FT_Vector* to,
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void* user );
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#define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc
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/**************************************************************************
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*
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* @functype:
|
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* FT_Outline_LineToFunc
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*
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* @description:
|
|
* A function pointer type used to describe the signature of a 'line to'
|
|
* function during outline walking/decomposition.
|
|
*
|
|
* A 'line to' is emitted to indicate a segment in the outline.
|
|
*
|
|
* @input:
|
|
* to ::
|
|
* A pointer to the target point of the 'line to'.
|
|
*
|
|
* user ::
|
|
* A typeless pointer, which is passed from the caller of the
|
|
* decomposition function.
|
|
*
|
|
* @return:
|
|
* Error code. 0~means success.
|
|
*/
|
|
typedef int
|
|
(*FT_Outline_LineToFunc)( const FT_Vector* to,
|
|
void* user );
|
|
|
|
#define FT_Outline_LineTo_Func FT_Outline_LineToFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Outline_ConicToFunc
|
|
*
|
|
* @description:
|
|
* A function pointer type used to describe the signature of a 'conic to'
|
|
* function during outline walking or decomposition.
|
|
*
|
|
* A 'conic to' is emitted to indicate a second-order Bezier arc in the
|
|
* outline.
|
|
*
|
|
* @input:
|
|
* control ::
|
|
* An intermediate control point between the last position and the new
|
|
* target in `to`.
|
|
*
|
|
* to ::
|
|
* A pointer to the target end point of the conic arc.
|
|
*
|
|
* user ::
|
|
* A typeless pointer, which is passed from the caller of the
|
|
* decomposition function.
|
|
*
|
|
* @return:
|
|
* Error code. 0~means success.
|
|
*/
|
|
typedef int
|
|
(*FT_Outline_ConicToFunc)( const FT_Vector* control,
|
|
const FT_Vector* to,
|
|
void* user );
|
|
|
|
#define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Outline_CubicToFunc
|
|
*
|
|
* @description:
|
|
* A function pointer type used to describe the signature of a 'cubic to'
|
|
* function during outline walking or decomposition.
|
|
*
|
|
* A 'cubic to' is emitted to indicate a third-order Bezier arc.
|
|
*
|
|
* @input:
|
|
* control1 ::
|
|
* A pointer to the first Bezier control point.
|
|
*
|
|
* control2 ::
|
|
* A pointer to the second Bezier control point.
|
|
*
|
|
* to ::
|
|
* A pointer to the target end point.
|
|
*
|
|
* user ::
|
|
* A typeless pointer, which is passed from the caller of the
|
|
* decomposition function.
|
|
*
|
|
* @return:
|
|
* Error code. 0~means success.
|
|
*/
|
|
typedef int
|
|
(*FT_Outline_CubicToFunc)( const FT_Vector* control1,
|
|
const FT_Vector* control2,
|
|
const FT_Vector* to,
|
|
void* user );
|
|
|
|
#define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @struct:
|
|
* FT_Outline_Funcs
|
|
*
|
|
* @description:
|
|
* A structure to hold various function pointers used during outline
|
|
* decomposition in order to emit segments, conic, and cubic Beziers.
|
|
*
|
|
* @fields:
|
|
* move_to ::
|
|
* The 'move to' emitter.
|
|
*
|
|
* line_to ::
|
|
* The segment emitter.
|
|
*
|
|
* conic_to ::
|
|
* The second-order Bezier arc emitter.
|
|
*
|
|
* cubic_to ::
|
|
* The third-order Bezier arc emitter.
|
|
*
|
|
* shift ::
|
|
* The shift that is applied to coordinates before they are sent to the
|
|
* emitter.
|
|
*
|
|
* delta ::
|
|
* The delta that is applied to coordinates before they are sent to the
|
|
* emitter, but after the shift.
|
|
*
|
|
* @note:
|
|
* The point coordinates sent to the emitters are the transformed version
|
|
* of the original coordinates (this is important for high accuracy
|
|
* during scan-conversion). The transformation is simple:
|
|
*
|
|
* ```
|
|
* x' = (x << shift) - delta
|
|
* y' = (y << shift) - delta
|
|
* ```
|
|
*
|
|
* Set the values of `shift` and `delta` to~0 to get the original point
|
|
* coordinates.
|
|
*/
|
|
typedef struct FT_Outline_Funcs_
|
|
{
|
|
FT_Outline_MoveToFunc move_to;
|
|
FT_Outline_LineToFunc line_to;
|
|
FT_Outline_ConicToFunc conic_to;
|
|
FT_Outline_CubicToFunc cubic_to;
|
|
|
|
int shift;
|
|
FT_Pos delta;
|
|
|
|
} FT_Outline_Funcs;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @section:
|
|
* basic_types
|
|
*
|
|
*/
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @macro:
|
|
* FT_IMAGE_TAG
|
|
*
|
|
* @description:
|
|
* This macro converts four-letter tags to an unsigned long type.
|
|
*
|
|
* @note:
|
|
* Since many 16-bit compilers don't like 32-bit enumerations, you should
|
|
* redefine this macro in case of problems to something like this:
|
|
*
|
|
* ```
|
|
* #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value
|
|
* ```
|
|
*
|
|
* to get a simple enumeration without assigning special numbers.
|
|
*/
|
|
#ifndef FT_IMAGE_TAG
|
|
#define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \
|
|
value = ( ( (unsigned long)_x1 << 24 ) | \
|
|
( (unsigned long)_x2 << 16 ) | \
|
|
( (unsigned long)_x3 << 8 ) | \
|
|
(unsigned long)_x4 )
|
|
#endif /* FT_IMAGE_TAG */
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @enum:
|
|
* FT_Glyph_Format
|
|
*
|
|
* @description:
|
|
* An enumeration type used to describe the format of a given glyph
|
|
* image. Note that this version of FreeType only supports two image
|
|
* formats, even though future font drivers will be able to register
|
|
* their own format.
|
|
*
|
|
* @values:
|
|
* FT_GLYPH_FORMAT_NONE ::
|
|
* The value~0 is reserved.
|
|
*
|
|
* FT_GLYPH_FORMAT_COMPOSITE ::
|
|
* The glyph image is a composite of several other images. This format
|
|
* is _only_ used with @FT_LOAD_NO_RECURSE, and is used to report
|
|
* compound glyphs (like accented characters).
|
|
*
|
|
* FT_GLYPH_FORMAT_BITMAP ::
|
|
* The glyph image is a bitmap, and can be described as an @FT_Bitmap.
|
|
* You generally need to access the `bitmap` field of the
|
|
* @FT_GlyphSlotRec structure to read it.
|
|
*
|
|
* FT_GLYPH_FORMAT_OUTLINE ::
|
|
* The glyph image is a vectorial outline made of line segments and
|
|
* Bezier arcs; it can be described as an @FT_Outline; you generally
|
|
* want to access the `outline` field of the @FT_GlyphSlotRec structure
|
|
* to read it.
|
|
*
|
|
* FT_GLYPH_FORMAT_PLOTTER ::
|
|
* The glyph image is a vectorial path with no inside and outside
|
|
* contours. Some Type~1 fonts, like those in the Hershey family,
|
|
* contain glyphs in this format. These are described as @FT_Outline,
|
|
* but FreeType isn't currently capable of rendering them correctly.
|
|
*/
|
|
typedef enum FT_Glyph_Format_
|
|
{
|
|
FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ),
|
|
|
|
FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
|
|
FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's' ),
|
|
FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l' ),
|
|
FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't' )
|
|
|
|
} FT_Glyph_Format;
|
|
|
|
|
|
/* these constants are deprecated; use the corresponding */
|
|
/* `FT_Glyph_Format` values instead. */
|
|
#define ft_glyph_format_none FT_GLYPH_FORMAT_NONE
|
|
#define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE
|
|
#define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP
|
|
#define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE
|
|
#define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER
|
|
|
|
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/***** *****/
|
|
/***** R A S T E R D E F I N I T I O N S *****/
|
|
/***** *****/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* A raster is a scan converter, in charge of rendering an outline into a
|
|
* bitmap. This section contains the public API for rasters.
|
|
*
|
|
* Note that in FreeType 2, all rasters are now encapsulated within
|
|
* specific modules called 'renderers'. See `ftrender.h` for more details
|
|
* on renderers.
|
|
*
|
|
*/
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @section:
|
|
* raster
|
|
*
|
|
* @title:
|
|
* Scanline Converter
|
|
*
|
|
* @abstract:
|
|
* How vectorial outlines are converted into bitmaps and pixmaps.
|
|
*
|
|
* @description:
|
|
* This section contains technical definitions.
|
|
*
|
|
* @order:
|
|
* FT_Raster
|
|
* FT_Span
|
|
* FT_SpanFunc
|
|
*
|
|
* FT_Raster_Params
|
|
* FT_RASTER_FLAG_XXX
|
|
*
|
|
* FT_Raster_NewFunc
|
|
* FT_Raster_DoneFunc
|
|
* FT_Raster_ResetFunc
|
|
* FT_Raster_SetModeFunc
|
|
* FT_Raster_RenderFunc
|
|
* FT_Raster_Funcs
|
|
*
|
|
*/
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @type:
|
|
* FT_Raster
|
|
*
|
|
* @description:
|
|
* An opaque handle (pointer) to a raster object. Each object can be
|
|
* used independently to convert an outline into a bitmap or pixmap.
|
|
*/
|
|
typedef struct FT_RasterRec_* FT_Raster;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @struct:
|
|
* FT_Span
|
|
*
|
|
* @description:
|
|
* A structure used to model a single span of gray pixels when rendering
|
|
* an anti-aliased bitmap.
|
|
*
|
|
* @fields:
|
|
* x ::
|
|
* The span's horizontal start position.
|
|
*
|
|
* len ::
|
|
* The span's length in pixels.
|
|
*
|
|
* coverage ::
|
|
* The span color/coverage, ranging from 0 (background) to 255
|
|
* (foreground).
|
|
*
|
|
* @note:
|
|
* This structure is used by the span drawing callback type named
|
|
* @FT_SpanFunc that takes the y~coordinate of the span as a parameter.
|
|
*
|
|
* The coverage value is always between 0 and 255. If you want less gray
|
|
* values, the callback function has to reduce them.
|
|
*/
|
|
typedef struct FT_Span_
|
|
{
|
|
short x;
|
|
unsigned short len;
|
|
unsigned char coverage;
|
|
|
|
} FT_Span;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_SpanFunc
|
|
*
|
|
* @description:
|
|
* A function used as a call-back by the anti-aliased renderer in order
|
|
* to let client applications draw themselves the gray pixel spans on
|
|
* each scan line.
|
|
*
|
|
* @input:
|
|
* y ::
|
|
* The scanline's upward y~coordinate.
|
|
*
|
|
* count ::
|
|
* The number of spans to draw on this scanline.
|
|
*
|
|
* spans ::
|
|
* A table of `count` spans to draw on the scanline.
|
|
*
|
|
* user ::
|
|
* User-supplied data that is passed to the callback.
|
|
*
|
|
* @note:
|
|
* This callback allows client applications to directly render the gray
|
|
* spans of the anti-aliased bitmap to any kind of surfaces.
|
|
*
|
|
* This can be used to write anti-aliased outlines directly to a given
|
|
* background bitmap, and even perform translucency.
|
|
*/
|
|
typedef void
|
|
(*FT_SpanFunc)( int y,
|
|
int count,
|
|
const FT_Span* spans,
|
|
void* user );
|
|
|
|
#define FT_Raster_Span_Func FT_SpanFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_BitTest_Func
|
|
*
|
|
* @description:
|
|
* Deprecated, unimplemented.
|
|
*/
|
|
typedef int
|
|
(*FT_Raster_BitTest_Func)( int y,
|
|
int x,
|
|
void* user );
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_BitSet_Func
|
|
*
|
|
* @description:
|
|
* Deprecated, unimplemented.
|
|
*/
|
|
typedef void
|
|
(*FT_Raster_BitSet_Func)( int y,
|
|
int x,
|
|
void* user );
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @enum:
|
|
* FT_RASTER_FLAG_XXX
|
|
*
|
|
* @description:
|
|
* A list of bit flag constants as used in the `flags` field of a
|
|
* @FT_Raster_Params structure.
|
|
*
|
|
* @values:
|
|
* FT_RASTER_FLAG_DEFAULT ::
|
|
* This value is 0.
|
|
*
|
|
* FT_RASTER_FLAG_AA ::
|
|
* This flag is set to indicate that an anti-aliased glyph image should
|
|
* be generated. Otherwise, it will be monochrome (1-bit).
|
|
*
|
|
* FT_RASTER_FLAG_DIRECT ::
|
|
* This flag is set to indicate direct rendering. In this mode, client
|
|
* applications must provide their own span callback. This lets them
|
|
* directly draw or compose over an existing bitmap. If this bit is
|
|
* _not_ set, the target pixmap's buffer _must_ be zeroed before
|
|
* rendering and the output will be clipped to its size.
|
|
*
|
|
* Direct rendering is only possible with anti-aliased glyphs.
|
|
*
|
|
* FT_RASTER_FLAG_CLIP ::
|
|
* This flag is only used in direct rendering mode. If set, the output
|
|
* will be clipped to a box specified in the `clip_box` field of the
|
|
* @FT_Raster_Params structure. Otherwise, the `clip_box` is
|
|
* effectively set to the bounding box and all spans are generated.
|
|
*/
|
|
#define FT_RASTER_FLAG_DEFAULT 0x0
|
|
#define FT_RASTER_FLAG_AA 0x1
|
|
#define FT_RASTER_FLAG_DIRECT 0x2
|
|
#define FT_RASTER_FLAG_CLIP 0x4
|
|
|
|
/* these constants are deprecated; use the corresponding */
|
|
/* `FT_RASTER_FLAG_XXX` values instead */
|
|
#define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT
|
|
#define ft_raster_flag_aa FT_RASTER_FLAG_AA
|
|
#define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT
|
|
#define ft_raster_flag_clip FT_RASTER_FLAG_CLIP
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @struct:
|
|
* FT_Raster_Params
|
|
*
|
|
* @description:
|
|
* A structure to hold the parameters used by a raster's render function,
|
|
* passed as an argument to @FT_Outline_Render.
|
|
*
|
|
* @fields:
|
|
* target ::
|
|
* The target bitmap.
|
|
*
|
|
* source ::
|
|
* A pointer to the source glyph image (e.g., an @FT_Outline).
|
|
*
|
|
* flags ::
|
|
* The rendering flags.
|
|
*
|
|
* gray_spans ::
|
|
* The gray span drawing callback.
|
|
*
|
|
* black_spans ::
|
|
* Unused.
|
|
*
|
|
* bit_test ::
|
|
* Unused.
|
|
*
|
|
* bit_set ::
|
|
* Unused.
|
|
*
|
|
* user ::
|
|
* User-supplied data that is passed to each drawing callback.
|
|
*
|
|
* clip_box ::
|
|
* An optional clipping box. It is only used in direct rendering mode.
|
|
* Note that coordinates here should be expressed in _integer_ pixels
|
|
* (and not in 26.6 fixed-point units).
|
|
*
|
|
* @note:
|
|
* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA bit
|
|
* flag is set in the `flags` field, otherwise a monochrome bitmap is
|
|
* generated.
|
|
*
|
|
* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags`, the raster
|
|
* will call the `gray_spans` callback to draw gray pixel spans. This
|
|
* allows direct composition over a pre-existing bitmap through
|
|
* user-provided callbacks to perform the span drawing and composition.
|
|
* Not supported by the monochrome rasterizer.
|
|
*/
|
|
typedef struct FT_Raster_Params_
|
|
{
|
|
const FT_Bitmap* target;
|
|
const void* source;
|
|
int flags;
|
|
FT_SpanFunc gray_spans;
|
|
FT_SpanFunc black_spans; /* unused */
|
|
FT_Raster_BitTest_Func bit_test; /* unused */
|
|
FT_Raster_BitSet_Func bit_set; /* unused */
|
|
void* user;
|
|
FT_BBox clip_box;
|
|
|
|
} FT_Raster_Params;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_NewFunc
|
|
*
|
|
* @description:
|
|
* A function used to create a new raster object.
|
|
*
|
|
* @input:
|
|
* memory ::
|
|
* A handle to the memory allocator.
|
|
*
|
|
* @output:
|
|
* raster ::
|
|
* A handle to the new raster object.
|
|
*
|
|
* @return:
|
|
* Error code. 0~means success.
|
|
*
|
|
* @note:
|
|
* The `memory` parameter is a typeless pointer in order to avoid
|
|
* un-wanted dependencies on the rest of the FreeType code. In practice,
|
|
* it is an @FT_Memory object, i.e., a handle to the standard FreeType
|
|
* memory allocator. However, this field can be completely ignored by a
|
|
* given raster implementation.
|
|
*/
|
|
typedef int
|
|
(*FT_Raster_NewFunc)( void* memory,
|
|
FT_Raster* raster );
|
|
|
|
#define FT_Raster_New_Func FT_Raster_NewFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_DoneFunc
|
|
*
|
|
* @description:
|
|
* A function used to destroy a given raster object.
|
|
*
|
|
* @input:
|
|
* raster ::
|
|
* A handle to the raster object.
|
|
*/
|
|
typedef void
|
|
(*FT_Raster_DoneFunc)( FT_Raster raster );
|
|
|
|
#define FT_Raster_Done_Func FT_Raster_DoneFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_ResetFunc
|
|
*
|
|
* @description:
|
|
* FreeType used to provide an area of memory called the 'render pool'
|
|
* available to all registered rasterizers. This was not thread safe,
|
|
* however, and now FreeType never allocates this pool.
|
|
*
|
|
* This function is called after a new raster object is created.
|
|
*
|
|
* @input:
|
|
* raster ::
|
|
* A handle to the new raster object.
|
|
*
|
|
* pool_base ::
|
|
* Previously, the address in memory of the render pool. Set this to
|
|
* `NULL`.
|
|
*
|
|
* pool_size ::
|
|
* Previously, the size in bytes of the render pool. Set this to 0.
|
|
*
|
|
* @note:
|
|
* Rasterizers should rely on dynamic or stack allocation if they want to
|
|
* (a handle to the memory allocator is passed to the rasterizer
|
|
* constructor).
|
|
*/
|
|
typedef void
|
|
(*FT_Raster_ResetFunc)( FT_Raster raster,
|
|
unsigned char* pool_base,
|
|
unsigned long pool_size );
|
|
|
|
#define FT_Raster_Reset_Func FT_Raster_ResetFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_SetModeFunc
|
|
*
|
|
* @description:
|
|
* This function is a generic facility to change modes or attributes in a
|
|
* given raster. This can be used for debugging purposes, or simply to
|
|
* allow implementation-specific 'features' in a given raster module.
|
|
*
|
|
* @input:
|
|
* raster ::
|
|
* A handle to the new raster object.
|
|
*
|
|
* mode ::
|
|
* A 4-byte tag used to name the mode or property.
|
|
*
|
|
* args ::
|
|
* A pointer to the new mode/property to use.
|
|
*/
|
|
typedef int
|
|
(*FT_Raster_SetModeFunc)( FT_Raster raster,
|
|
unsigned long mode,
|
|
void* args );
|
|
|
|
#define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FT_Raster_RenderFunc
|
|
*
|
|
* @description:
|
|
* Invoke a given raster to scan-convert a given glyph image into a
|
|
* target bitmap.
|
|
*
|
|
* @input:
|
|
* raster ::
|
|
* A handle to the raster object.
|
|
*
|
|
* params ::
|
|
* A pointer to an @FT_Raster_Params structure used to store the
|
|
* rendering parameters.
|
|
*
|
|
* @return:
|
|
* Error code. 0~means success.
|
|
*
|
|
* @note:
|
|
* The exact format of the source image depends on the raster's glyph
|
|
* format defined in its @FT_Raster_Funcs structure. It can be an
|
|
* @FT_Outline or anything else in order to support a large array of
|
|
* glyph formats.
|
|
*
|
|
* Note also that the render function can fail and return a
|
|
* `FT_Err_Unimplemented_Feature` error code if the raster used does not
|
|
* support direct composition.
|
|
*/
|
|
typedef int
|
|
(*FT_Raster_RenderFunc)( FT_Raster raster,
|
|
const FT_Raster_Params* params );
|
|
|
|
#define FT_Raster_Render_Func FT_Raster_RenderFunc
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @struct:
|
|
* FT_Raster_Funcs
|
|
*
|
|
* @description:
|
|
* A structure used to describe a given raster class to the library.
|
|
*
|
|
* @fields:
|
|
* glyph_format ::
|
|
* The supported glyph format for this raster.
|
|
*
|
|
* raster_new ::
|
|
* The raster constructor.
|
|
*
|
|
* raster_reset ::
|
|
* Used to reset the render pool within the raster.
|
|
*
|
|
* raster_render ::
|
|
* A function to render a glyph into a given bitmap.
|
|
*
|
|
* raster_done ::
|
|
* The raster destructor.
|
|
*/
|
|
typedef struct FT_Raster_Funcs_
|
|
{
|
|
FT_Glyph_Format glyph_format;
|
|
|
|
FT_Raster_NewFunc raster_new;
|
|
FT_Raster_ResetFunc raster_reset;
|
|
FT_Raster_SetModeFunc raster_set_mode;
|
|
FT_Raster_RenderFunc raster_render;
|
|
FT_Raster_DoneFunc raster_done;
|
|
|
|
} FT_Raster_Funcs;
|
|
|
|
/* */
|
|
|
|
|
|
FT_END_HEADER
|
|
|
|
#endif /* FTIMAGE_H_ */
|
|
|
|
|
|
/* END */
|
|
|
|
|
|
/* Local Variables: */
|
|
/* coding: utf-8 */
|
|
/* End: */
|