1
/***************************************************************************/
5
/* FreeType glyph image formats and default raster interface */
8
/* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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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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/* 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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/* _STANDALONE_ is from ftgrays.c */
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/* The type FT_Pos is used to store vectorial coordinates. Depending */
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/* on the context, these can represent distances in integer font */
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/* units, or 16.16, or 26.6 fixed float pixel coordinates. */
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typedef signed long FT_Pos;
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/*************************************************************************/
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/* A simple structure used to store a 2D vector; coordinates are of */
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/* the FT_Pos type. */
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/* x :: The horizontal coordinate. */
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/* y :: The vertical coordinate. */
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typedef struct FT_Vector_
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/*************************************************************************/
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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 */
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/* xMin :: The horizontal minimum (left-most). */
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/* yMin :: The vertical minimum (bottom-most). */
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/* xMax :: The horizontal maximum (right-most). */
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/* yMax :: The vertical maximum (top-most). */
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/* The bounding box is specified with the coordinates of the lower */
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/* left and the upper right corner. In PostScript, those values are */
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/* often called (llx,lly) and (urx,ury), respectively. */
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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. */
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/* Similarly, if `ymax' is positive, this value gives the glyph's */
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/* `xMin' gives the horizontal distance from the glyph's origin to */
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/* the left edge of the glyph's bounding box. If `xMin' is negative, */
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/* the glyph extends to the left of the origin. */
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typedef struct FT_BBox_
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/*************************************************************************/
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/* An enumeration type used to describe the format of pixels in a */
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/* given bitmap. Note that additional formats may be added in the */
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/* FT_PIXEL_MODE_NONE :: */
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/* Value~0 is reserved. */
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/* FT_PIXEL_MODE_MONO :: */
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/* A monochrome bitmap, using 1~bit per pixel. Note that pixels */
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/* are stored in most-significant order (MSB), which means that */
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/* the left-most pixel in a byte has value 128. */
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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 */
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/* of `gray' levels is stored in the `num_grays' field of the */
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/* @FT_Bitmap structure (it generally is 256). */
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/* FT_PIXEL_MODE_GRAY2 :: */
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/* A 2-bit per pixel bitmap, used to represent embedded */
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/* anti-aliased bitmaps in font files according to the OpenType */
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/* specification. We haven't found a single font using this */
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/* format, however. */
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/* FT_PIXEL_MODE_GRAY4 :: */
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/* A 4-bit per pixel bitmap, representing embedded anti-aliased */
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/* bitmaps in font files according to the OpenType specification. */
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/* We haven't found a single font using this format, however. */
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/* FT_PIXEL_MODE_LCD :: */
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/* An 8-bit bitmap, representing RGB or BGR decimated glyph images */
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/* used for display on LCD displays; the bitmap is three times */
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/* wider than the original glyph image. See also */
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/* @FT_RENDER_MODE_LCD. */
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/* FT_PIXEL_MODE_LCD_V :: */
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/* An 8-bit bitmap, representing RGB or BGR decimated glyph images */
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/* used for display on rotated LCD displays; the bitmap is three */
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/* times taller than the original glyph image. See also */
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/* @FT_RENDER_MODE_LCD_V. */
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typedef enum FT_Pixel_Mode_
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FT_PIXEL_MODE_NONE = 0,
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FT_PIXEL_MODE_MAX /* do not remove */
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/*************************************************************************/
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/* ft_pixel_mode_xxx */
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/* A list of deprecated constants. Use the corresponding */
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/* @FT_Pixel_Mode values instead. */
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/* ft_pixel_mode_none :: See @FT_PIXEL_MODE_NONE. */
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/* ft_pixel_mode_mono :: See @FT_PIXEL_MODE_MONO. */
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/* ft_pixel_mode_grays :: See @FT_PIXEL_MODE_GRAY. */
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/* ft_pixel_mode_pal2 :: See @FT_PIXEL_MODE_GRAY2. */
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/* ft_pixel_mode_pal4 :: See @FT_PIXEL_MODE_GRAY4. */
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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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/* FT_Palette_Mode */
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/* THIS TYPE IS DEPRECATED. DO NOT USE IT! */
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/* An enumeration type to describe the format of a bitmap palette, */
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/* used with ft_pixel_mode_pal4 and ft_pixel_mode_pal8. */
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/* ft_palette_mode_rgb :: The palette is an array of 3-byte RGB */
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/* ft_palette_mode_rgba :: The palette is an array of 4-byte RGBA */
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/* As ft_pixel_mode_pal2, pal4 and pal8 are currently unused by */
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/* FreeType, these types are not handled by the library itself. */
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typedef enum FT_Palette_Mode_
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ft_palette_mode_rgb = 0,
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ft_palette_mode_rgba,
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ft_palette_mode_max /* do not remove */
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/*************************************************************************/
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/* A structure used to describe a bitmap or pixmap to the raster. */
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/* Note that we now manage pixmaps of various depths through the */
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/* `pixel_mode' field. */
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/* rows :: The number of bitmap rows. */
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/* width :: The number of pixels in bitmap row. */
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/* pitch :: The pitch's absolute value is the number of bytes */
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/* taken by one bitmap row, including padding. */
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/* However, the pitch is positive when the bitmap has */
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/* a `down' flow, and negative when it has an `up' */
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/* flow. In all cases, the pitch is an offset to add */
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/* to a bitmap pointer in order to go down one row. */
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/* Note that `padding' means the alignment of a */
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/* bitmap to a byte border, and FreeType functions */
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/* normally align to the smallest possible integer */
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/* For the B/W rasterizer, `pitch' is always an even */
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/* To change the pitch of a bitmap (say, to make it a */
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/* multiple of 4), use @FT_Bitmap_Convert. */
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/* Alternatively, you might use callback functions to */
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/* directly render to the application's surface; see */
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/* the file `example2.cpp' in the tutorial for a */
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/* buffer :: A typeless pointer to the bitmap buffer. This */
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/* value should be aligned on 32-bit boundaries in */
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/* num_grays :: This field is only used with */
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/* @FT_PIXEL_MODE_GRAY; it gives the number of gray */
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/* levels used in the bitmap. */
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/* pixel_mode :: The pixel mode, i.e., how pixel bits are stored. */
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/* See @FT_Pixel_Mode for possible values. */
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/* palette_mode :: This field is intended for paletted pixel modes; */
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/* it indicates how the palette is stored. Not */
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/* used currently. */
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/* palette :: A typeless pointer to the bitmap palette; this */
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/* field is intended for paletted pixel modes. Not */
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/* used currently. */
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/* For now, the only pixel modes supported by FreeType are mono and */
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/* grays. However, drivers might be added in the future to support */
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/* more `colorful' options. */
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typedef struct FT_Bitmap_
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unsigned char* buffer;
324
/*************************************************************************/
327
/* outline_processing */
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/*************************************************************************/
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/*************************************************************************/
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/* This structure is used to describe an outline to the scan-line */
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/* n_contours :: The number of contours in the outline. */
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/* n_points :: The number of points in the outline. */
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/* points :: A pointer to an array of `n_points' @FT_Vector */
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/* elements, giving the outline's point coordinates. */
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/* tags :: A pointer to an array of `n_points' chars, giving */
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/* each outline point's type. */
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/* If bit~0 is unset, the point is `off' the curve, */
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/* i.e., a Bézier control point, while it is `on' if */
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/* Bit~1 is meaningful for `off' points only. If set, */
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/* it indicates a third-order Bézier arc control point; */
358
/* and a second-order control point if unset. */
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/* If bit~2 is set, bits 5-7 contain the drop-out mode */
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/* (as defined in the OpenType specification; the value */
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/* is the same as the argument to the SCANMODE */
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/* Bits 3 and~4 are reserved for internal purposes. */
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/* contours :: An array of `n_contours' shorts, giving the end */
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/* point of each contour within the outline. For */
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/* example, the first contour is defined by the points */
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/* `0' to `contours[0]', the second one is defined by */
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/* the points `contours[0]+1' to `contours[1]', etc. */
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/* flags :: A set of bit flags used to characterize the outline */
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/* and give hints to the scan-converter and hinter on */
375
/* how to convert/grid-fit it. See @FT_OUTLINE_FLAGS. */
378
/* The B/W rasterizer only checks bit~2 in the `tags' array for the */
379
/* first 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. */
383
typedef struct FT_Outline_
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short n_contours; /* number of contours in glyph */
386
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 */
390
short* contours; /* the contour end points */
392
int flags; /* outline masks */
396
/* Following limits must be consistent with */
397
/* FT_Outline.{n_contours,n_points} */
398
#define FT_OUTLINE_CONTOURS_MAX SHRT_MAX
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#define FT_OUTLINE_POINTS_MAX SHRT_MAX
402
/*************************************************************************/
405
/* FT_OUTLINE_FLAGS */
408
/* A list of bit-field constants use for the flags in an outline's */
412
/* FT_OUTLINE_NONE :: */
413
/* Value~0 is reserved. */
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/* FT_OUTLINE_OWNER :: */
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/* If set, this flag indicates that the outline's field arrays */
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/* (i.e., `points', `flags', and `contours') are `owned' by the */
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/* outline object, and should thus be freed when it is destroyed. */
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/* FT_OUTLINE_EVEN_ODD_FILL :: */
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/* By default, outlines are filled using the non-zero winding rule. */
422
/* If set to 1, the outline will be filled using the even-odd fill */
423
/* rule (only works with the smooth rasterizer). */
425
/* FT_OUTLINE_REVERSE_FILL :: */
426
/* By default, outside contours of an outline are oriented in */
427
/* clock-wise direction, as defined in the TrueType specification. */
428
/* This flag is set if the outline uses the opposite direction */
429
/* (typically for Type~1 fonts). This flag is ignored by the scan */
432
/* FT_OUTLINE_IGNORE_DROPOUTS :: */
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/* By default, the scan converter will try to detect drop-outs in */
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/* an outline and correct the glyph bitmap to ensure consistent */
435
/* shape continuity. If set, this flag hints the scan-line */
436
/* converter to ignore such cases. See below for more information. */
438
/* FT_OUTLINE_SMART_DROPOUTS :: */
439
/* Select smart dropout control. If unset, use simple dropout */
440
/* control. Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See */
441
/* below for more information. */
443
/* FT_OUTLINE_INCLUDE_STUBS :: */
444
/* If set, turn pixels on for `stubs', otherwise exclude them. */
445
/* Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for */
446
/* more information. */
448
/* 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 */
451
/* quality. It is typically set for small character sizes. Note */
452
/* that this is only a hint that might be completely ignored by a */
453
/* given scan-converter. */
455
/* FT_OUTLINE_SINGLE_PASS :: */
456
/* This flag is set to force a given scan-converter to only use a */
457
/* single pass over the outline to render a bitmap glyph image. */
458
/* Normally, it is set for very large character sizes. It is only */
459
/* a hint that might be completely ignored by a given */
460
/* scan-converter. */
463
/* The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */
464
/* and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth */
467
/* There exists a second mechanism to pass the drop-out mode to the */
468
/* B/W rasterizer; see the `tags' field in @FT_Outline. */
470
/* Please refer to the description of the `SCANTYPE' instruction in */
471
/* the OpenType specification (in file `ttinst1.doc') how simple */
472
/* drop-outs, smart drop-outs, and stubs are defined. */
474
#define FT_OUTLINE_NONE 0x0
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#define FT_OUTLINE_OWNER 0x1
476
#define FT_OUTLINE_EVEN_ODD_FILL 0x2
477
#define FT_OUTLINE_REVERSE_FILL 0x4
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#define FT_OUTLINE_IGNORE_DROPOUTS 0x8
479
#define FT_OUTLINE_SMART_DROPOUTS 0x10
480
#define FT_OUTLINE_INCLUDE_STUBS 0x20
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#define FT_OUTLINE_HIGH_PRECISION 0x100
483
#define FT_OUTLINE_SINGLE_PASS 0x200
486
/*************************************************************************
492
* These constants are deprecated. Please use the corresponding
493
* @FT_OUTLINE_FLAGS values.
496
* ft_outline_none :: See @FT_OUTLINE_NONE.
497
* ft_outline_owner :: See @FT_OUTLINE_OWNER.
498
* ft_outline_even_odd_fill :: See @FT_OUTLINE_EVEN_ODD_FILL.
499
* ft_outline_reverse_fill :: See @FT_OUTLINE_REVERSE_FILL.
500
* ft_outline_ignore_dropouts :: See @FT_OUTLINE_IGNORE_DROPOUTS.
501
* ft_outline_high_precision :: See @FT_OUTLINE_HIGH_PRECISION.
502
* ft_outline_single_pass :: See @FT_OUTLINE_SINGLE_PASS.
504
#define ft_outline_none FT_OUTLINE_NONE
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#define ft_outline_owner FT_OUTLINE_OWNER
506
#define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL
507
#define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL
508
#define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS
509
#define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION
510
#define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS
514
#define FT_CURVE_TAG( flag ) ( flag & 3 )
516
#define FT_CURVE_TAG_ON 1
517
#define FT_CURVE_TAG_CONIC 0
518
#define FT_CURVE_TAG_CUBIC 2
520
#define FT_CURVE_TAG_HAS_SCANMODE 4
522
#define FT_CURVE_TAG_TOUCH_X 8 /* reserved for the TrueType hinter */
523
#define FT_CURVE_TAG_TOUCH_Y 16 /* reserved for the TrueType hinter */
525
#define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \
526
FT_CURVE_TAG_TOUCH_Y )
528
#define FT_Curve_Tag_On FT_CURVE_TAG_ON
529
#define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC
530
#define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC
531
#define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X
532
#define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y
535
/*************************************************************************/
538
/* FT_Outline_MoveToFunc */
541
/* A function pointer type used to describe the signature of a `move */
542
/* to' function during outline walking/decomposition. */
544
/* A `move to' is emitted to start a new contour in an outline. */
547
/* to :: A pointer to the target point of the `move to'. */
549
/* user :: A typeless pointer which is passed from the caller of the */
550
/* decomposition function. */
553
/* Error code. 0~means success. */
556
(*FT_Outline_MoveToFunc)( const FT_Vector* to,
559
#define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc
562
/*************************************************************************/
565
/* FT_Outline_LineToFunc */
568
/* A function pointer type used to describe the signature of a `line */
569
/* to' function during outline walking/decomposition. */
571
/* A `line to' is emitted to indicate a segment in the outline. */
574
/* to :: A pointer to the target point of the `line to'. */
576
/* user :: A typeless pointer which is passed from the caller of the */
577
/* decomposition function. */
580
/* Error code. 0~means success. */
583
(*FT_Outline_LineToFunc)( const FT_Vector* to,
586
#define FT_Outline_LineTo_Func FT_Outline_LineToFunc
589
/*************************************************************************/
592
/* FT_Outline_ConicToFunc */
595
/* A function pointer type used to describe the signature of a `conic */
596
/* to' function during outline walking or decomposition. */
598
/* A `conic to' is emitted to indicate a second-order Bézier arc in */
602
/* control :: An intermediate control point between the last position */
603
/* and the new target in `to'. */
605
/* to :: A pointer to the target end point of the conic arc. */
607
/* user :: A typeless pointer which is passed from the caller of */
608
/* the decomposition function. */
611
/* Error code. 0~means success. */
614
(*FT_Outline_ConicToFunc)( const FT_Vector* control,
618
#define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc
621
/*************************************************************************/
624
/* FT_Outline_CubicToFunc */
627
/* A function pointer type used to describe the signature of a `cubic */
628
/* to' function during outline walking or decomposition. */
630
/* A `cubic to' is emitted to indicate a third-order Bézier arc. */
633
/* control1 :: A pointer to the first Bézier control point. */
635
/* control2 :: A pointer to the second Bézier control point. */
637
/* to :: A pointer to the target end point. */
639
/* user :: A typeless pointer which is passed from the caller of */
640
/* the decomposition function. */
643
/* Error code. 0~means success. */
646
(*FT_Outline_CubicToFunc)( const FT_Vector* control1,
647
const FT_Vector* control2,
651
#define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc
654
/*************************************************************************/
657
/* FT_Outline_Funcs */
660
/* A structure to hold various function pointers used during outline */
661
/* decomposition in order to emit segments, conic, and cubic Béziers. */
664
/* move_to :: The `move to' emitter. */
666
/* line_to :: The segment emitter. */
668
/* conic_to :: The second-order Bézier arc emitter. */
670
/* cubic_to :: The third-order Bézier arc emitter. */
672
/* shift :: The shift that is applied to coordinates before they */
673
/* are sent to the emitter. */
675
/* delta :: The delta that is applied to coordinates before they */
676
/* are sent to the emitter, but after the shift. */
679
/* The point coordinates sent to the emitters are the transformed */
680
/* version of the original coordinates (this is important for high */
681
/* accuracy during scan-conversion). The transformation is simple: */
684
/* x' = (x << shift) - delta */
685
/* y' = (x << shift) - delta */
688
/* Set the values of `shift' and `delta' to~0 to get the original */
689
/* point coordinates. */
691
typedef struct FT_Outline_Funcs_
693
FT_Outline_MoveToFunc move_to;
694
FT_Outline_LineToFunc line_to;
695
FT_Outline_ConicToFunc conic_to;
696
FT_Outline_CubicToFunc cubic_to;
704
/*************************************************************************/
709
/*************************************************************************/
712
/*************************************************************************/
718
/* This macro converts four-letter tags to an unsigned long type. */
721
/* Since many 16-bit compilers don't like 32-bit enumerations, you */
722
/* should redefine this macro in case of problems to something like */
726
/* #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value */
729
/* to get a simple enumeration without assigning special numbers. */
732
#define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \
733
value = ( ( (unsigned long)_x1 << 24 ) | \
734
( (unsigned long)_x2 << 16 ) | \
735
( (unsigned long)_x3 << 8 ) | \
737
#endif /* FT_IMAGE_TAG */
740
/*************************************************************************/
743
/* FT_Glyph_Format */
746
/* An enumeration type used to describe the format of a given glyph */
747
/* image. Note that this version of FreeType only supports two image */
748
/* formats, even though future font drivers will be able to register */
749
/* their own format. */
752
/* FT_GLYPH_FORMAT_NONE :: */
753
/* The value~0 is reserved. */
755
/* FT_GLYPH_FORMAT_COMPOSITE :: */
756
/* The glyph image is a composite of several other images. This */
757
/* format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to */
758
/* report compound glyphs (like accented characters). */
760
/* FT_GLYPH_FORMAT_BITMAP :: */
761
/* The glyph image is a bitmap, and can be described as an */
762
/* @FT_Bitmap. You generally need to access the `bitmap' field of */
763
/* the @FT_GlyphSlotRec structure to read it. */
765
/* FT_GLYPH_FORMAT_OUTLINE :: */
766
/* The glyph image is a vectorial outline made of line segments */
767
/* and Bézier arcs; it can be described as an @FT_Outline; you */
768
/* generally want to access the `outline' field of the */
769
/* @FT_GlyphSlotRec structure to read it. */
771
/* FT_GLYPH_FORMAT_PLOTTER :: */
772
/* The glyph image is a vectorial path with no inside and outside */
773
/* contours. Some Type~1 fonts, like those in the Hershey family, */
774
/* contain glyphs in this format. These are described as */
775
/* @FT_Outline, but FreeType isn't currently capable of rendering */
776
/* them correctly. */
778
typedef enum FT_Glyph_Format_
780
FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ),
782
FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
783
FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's' ),
784
FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l' ),
785
FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't' )
790
/*************************************************************************/
793
/* ft_glyph_format_xxx */
796
/* A list of deprecated constants. Use the corresponding */
797
/* @FT_Glyph_Format values instead. */
800
/* ft_glyph_format_none :: See @FT_GLYPH_FORMAT_NONE. */
801
/* ft_glyph_format_composite :: See @FT_GLYPH_FORMAT_COMPOSITE. */
802
/* ft_glyph_format_bitmap :: See @FT_GLYPH_FORMAT_BITMAP. */
803
/* ft_glyph_format_outline :: See @FT_GLYPH_FORMAT_OUTLINE. */
804
/* ft_glyph_format_plotter :: See @FT_GLYPH_FORMAT_PLOTTER. */
806
#define ft_glyph_format_none FT_GLYPH_FORMAT_NONE
807
#define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE
808
#define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP
809
#define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE
810
#define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER
813
/*************************************************************************/
814
/*************************************************************************/
815
/*************************************************************************/
817
/***** R A S T E R D E F I N I T I O N S *****/
819
/*************************************************************************/
820
/*************************************************************************/
821
/*************************************************************************/
824
/*************************************************************************/
826
/* A raster is a scan converter, in charge of rendering an outline into */
827
/* a a bitmap. This section contains the public API for rasters. */
829
/* Note that in FreeType 2, all rasters are now encapsulated within */
830
/* specific modules called `renderers'. See `freetype/ftrender.h' for */
831
/* more details on renderers. */
833
/*************************************************************************/
836
/*************************************************************************/
842
/* Scanline Converter */
845
/* How vectorial outlines are converted into bitmaps and pixmaps. */
848
/* This section contains technical definitions. */
850
/*************************************************************************/
853
/*************************************************************************/
859
/* A handle (pointer) to a raster object. Each object can be used */
860
/* independently to convert an outline into a bitmap or pixmap. */
862
typedef struct FT_RasterRec_* FT_Raster;
865
/*************************************************************************/
871
/* A structure used to model a single span of gray (or black) pixels */
872
/* when rendering a monochrome or anti-aliased bitmap. */
875
/* x :: The span's horizontal start position. */
877
/* len :: The span's length in pixels. */
879
/* coverage :: The span color/coverage, ranging from 0 (background) */
880
/* to 255 (foreground). Only used for anti-aliased */
884
/* This structure is used by the span drawing callback type named */
885
/* @FT_SpanFunc which takes the y~coordinate of the span as a */
888
/* The coverage value is always between 0 and 255. If you want less */
889
/* gray values, the callback function has to reduce them. */
891
typedef struct FT_Span_
895
unsigned char coverage;
900
/*************************************************************************/
906
/* A function used as a call-back by the anti-aliased renderer in */
907
/* order to let client applications draw themselves the gray pixel */
908
/* spans on each scan line. */
911
/* y :: The scanline's y~coordinate. */
913
/* count :: The number of spans to draw on this scanline. */
915
/* spans :: A table of `count' spans to draw on the scanline. */
917
/* user :: User-supplied data that is passed to the callback. */
920
/* This callback allows client applications to directly render the */
921
/* gray spans of the anti-aliased bitmap to any kind of surfaces. */
923
/* This can be used to write anti-aliased outlines directly to a */
924
/* given background bitmap, and even perform translucency. */
926
/* Note that the `count' field cannot be greater than a fixed value */
927
/* defined by the `FT_MAX_GRAY_SPANS' configuration macro in */
928
/* `ftoption.h'. By default, this value is set to~32, which means */
929
/* that if there are more than 32~spans on a given scanline, the */
930
/* callback is called several times with the same `y' parameter in */
931
/* order to draw all callbacks. */
933
/* Otherwise, the callback is only called once per scan-line, and */
934
/* only for those scanlines that do have `gray' pixels on them. */
937
(*FT_SpanFunc)( int y,
939
const FT_Span* spans,
942
#define FT_Raster_Span_Func FT_SpanFunc
945
/*************************************************************************/
948
/* FT_Raster_BitTest_Func */
951
/* THIS TYPE IS DEPRECATED. DO NOT USE IT. */
953
/* A function used as a call-back by the monochrome scan-converter */
954
/* to test whether a given target pixel is already set to the drawing */
955
/* `color'. These tests are crucial to implement drop-out control */
956
/* per-se the TrueType spec. */
959
/* y :: The pixel's y~coordinate. */
961
/* x :: The pixel's x~coordinate. */
963
/* user :: User-supplied data that is passed to the callback. */
966
/* 1~if the pixel is `set', 0~otherwise. */
969
(*FT_Raster_BitTest_Func)( int y,
974
/*************************************************************************/
977
/* FT_Raster_BitSet_Func */
980
/* THIS TYPE IS DEPRECATED. DO NOT USE IT. */
982
/* A function used as a call-back by the monochrome scan-converter */
983
/* to set an individual target pixel. This is crucial to implement */
984
/* drop-out control according to the TrueType specification. */
987
/* y :: The pixel's y~coordinate. */
989
/* x :: The pixel's x~coordinate. */
991
/* user :: User-supplied data that is passed to the callback. */
994
/* 1~if the pixel is `set', 0~otherwise. */
997
(*FT_Raster_BitSet_Func)( int y,
1002
/*************************************************************************/
1005
/* FT_RASTER_FLAG_XXX */
1008
/* A list of bit flag constants as used in the `flags' field of a */
1009
/* @FT_Raster_Params structure. */
1012
/* FT_RASTER_FLAG_DEFAULT :: This value is 0. */
1014
/* FT_RASTER_FLAG_AA :: This flag is set to indicate that an */
1015
/* anti-aliased glyph image should be */
1016
/* generated. Otherwise, it will be */
1017
/* monochrome (1-bit). */
1019
/* FT_RASTER_FLAG_DIRECT :: This flag is set to indicate direct */
1020
/* rendering. In this mode, client */
1021
/* applications must provide their own span */
1022
/* callback. This lets them directly */
1023
/* draw or compose over an existing bitmap. */
1024
/* If this bit is not set, the target */
1025
/* pixmap's buffer _must_ be zeroed before */
1028
/* Note that for now, direct rendering is */
1029
/* only possible with anti-aliased glyphs. */
1031
/* FT_RASTER_FLAG_CLIP :: This flag is only used in direct */
1032
/* rendering mode. If set, the output will */
1033
/* be clipped to a box specified in the */
1034
/* `clip_box' field of the */
1035
/* @FT_Raster_Params structure. */
1037
/* Note that by default, the glyph bitmap */
1038
/* is clipped to the target pixmap, except */
1039
/* in direct rendering mode where all spans */
1040
/* are generated if no clipping box is set. */
1042
#define FT_RASTER_FLAG_DEFAULT 0x0
1043
#define FT_RASTER_FLAG_AA 0x1
1044
#define FT_RASTER_FLAG_DIRECT 0x2
1045
#define FT_RASTER_FLAG_CLIP 0x4
1048
#define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT
1049
#define ft_raster_flag_aa FT_RASTER_FLAG_AA
1050
#define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT
1051
#define ft_raster_flag_clip FT_RASTER_FLAG_CLIP
1054
/*************************************************************************/
1057
/* FT_Raster_Params */
1060
/* A structure to hold the arguments used by a raster's render */
1064
/* target :: The target bitmap. */
1066
/* source :: A pointer to the source glyph image (e.g., an */
1069
/* flags :: The rendering flags. */
1071
/* gray_spans :: The gray span drawing callback. */
1073
/* black_spans :: The black span drawing callback. UNIMPLEMENTED! */
1075
/* bit_test :: The bit test callback. UNIMPLEMENTED! */
1077
/* bit_set :: The bit set callback. UNIMPLEMENTED! */
1079
/* user :: User-supplied data that is passed to each drawing */
1082
/* clip_box :: An optional clipping box. It is only used in */
1083
/* direct rendering mode. Note that coordinates here */
1084
/* should be expressed in _integer_ pixels (and not in */
1085
/* 26.6 fixed-point units). */
1088
/* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA */
1089
/* bit flag is set in the `flags' field, otherwise a monochrome */
1090
/* bitmap is generated. */
1092
/* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */
1093
/* raster will call the `gray_spans' callback to draw gray pixel */
1094
/* spans, in the case of an aa glyph bitmap, it will call */
1095
/* `black_spans', and `bit_test' and `bit_set' in the case of a */
1096
/* monochrome bitmap. This allows direct composition over a */
1097
/* pre-existing bitmap through user-provided callbacks to perform the */
1098
/* span drawing/composition. */
1100
/* Note that the `bit_test' and `bit_set' callbacks are required when */
1101
/* rendering a monochrome bitmap, as they are crucial to implement */
1102
/* correct drop-out control as defined in the TrueType specification. */
1104
typedef struct FT_Raster_Params_
1106
const FT_Bitmap* target;
1109
FT_SpanFunc gray_spans;
1110
FT_SpanFunc black_spans; /* doesn't work! */
1111
FT_Raster_BitTest_Func bit_test; /* doesn't work! */
1112
FT_Raster_BitSet_Func bit_set; /* doesn't work! */
1119
/*************************************************************************/
1122
/* FT_Raster_NewFunc */
1125
/* A function used to create a new raster object. */
1128
/* memory :: A handle to the memory allocator. */
1131
/* raster :: A handle to the new raster object. */
1134
/* Error code. 0~means success. */
1137
/* The `memory' parameter is a typeless pointer in order to avoid */
1138
/* un-wanted dependencies on the rest of the FreeType code. In */
1139
/* practice, it is an @FT_Memory object, i.e., a handle to the */
1140
/* standard FreeType memory allocator. However, this field can be */
1141
/* completely ignored by a given raster implementation. */
1144
(*FT_Raster_NewFunc)( void* memory,
1145
FT_Raster* raster );
1147
#define FT_Raster_New_Func FT_Raster_NewFunc
1150
/*************************************************************************/
1153
/* FT_Raster_DoneFunc */
1156
/* A function used to destroy a given raster object. */
1159
/* raster :: A handle to the raster object. */
1162
(*FT_Raster_DoneFunc)( FT_Raster raster );
1164
#define FT_Raster_Done_Func FT_Raster_DoneFunc
1167
/*************************************************************************/
1170
/* FT_Raster_ResetFunc */
1173
/* FreeType provides an area of memory called the `render pool', */
1174
/* available to all registered rasters. This pool can be freely used */
1175
/* during a given scan-conversion but is shared by all rasters. Its */
1176
/* content is thus transient. */
1178
/* This function is called each time the render pool changes, or just */
1179
/* after a new raster object is created. */
1182
/* raster :: A handle to the new raster object. */
1184
/* pool_base :: The address in memory of the render pool. */
1186
/* pool_size :: The size in bytes of the render pool. */
1189
/* Rasters can ignore the render pool and rely on dynamic memory */
1190
/* allocation if they want to (a handle to the memory allocator is */
1191
/* passed to the raster constructor). However, this is not */
1192
/* recommended for efficiency purposes. */
1195
(*FT_Raster_ResetFunc)( FT_Raster raster,
1196
unsigned char* pool_base,
1197
unsigned long pool_size );
1199
#define FT_Raster_Reset_Func FT_Raster_ResetFunc
1202
/*************************************************************************/
1205
/* FT_Raster_SetModeFunc */
1208
/* This function is a generic facility to change modes or attributes */
1209
/* in a given raster. This can be used for debugging purposes, or */
1210
/* simply to allow implementation-specific `features' in a given */
1211
/* raster module. */
1214
/* raster :: A handle to the new raster object. */
1216
/* mode :: A 4-byte tag used to name the mode or property. */
1218
/* args :: A pointer to the new mode/property to use. */
1221
(*FT_Raster_SetModeFunc)( FT_Raster raster,
1225
#define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc
1228
/*************************************************************************/
1231
/* FT_Raster_RenderFunc */
1234
/* Invoke a given raster to scan-convert a given glyph image into a */
1235
/* target bitmap. */
1238
/* raster :: A handle to the raster object. */
1240
/* params :: A pointer to an @FT_Raster_Params structure used to */
1241
/* store the rendering parameters. */
1244
/* Error code. 0~means success. */
1247
/* The exact format of the source image depends on the raster's glyph */
1248
/* format defined in its @FT_Raster_Funcs structure. It can be an */
1249
/* @FT_Outline or anything else in order to support a large array of */
1250
/* glyph formats. */
1252
/* Note also that the render function can fail and return a */
1253
/* `FT_Err_Unimplemented_Feature' error code if the raster used does */
1254
/* not support direct composition. */
1256
/* XXX: For now, the standard raster doesn't support direct */
1257
/* composition but this should change for the final release (see */
1258
/* the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c' */
1259
/* for examples of distinct implementations which support direct */
1263
(*FT_Raster_RenderFunc)( FT_Raster raster,
1264
const FT_Raster_Params* params );
1266
#define FT_Raster_Render_Func FT_Raster_RenderFunc
1269
/*************************************************************************/
1272
/* FT_Raster_Funcs */
1275
/* A structure used to describe a given raster class to the library. */
1278
/* glyph_format :: The supported glyph format for this raster. */
1280
/* raster_new :: The raster constructor. */
1282
/* raster_reset :: Used to reset the render pool within the raster. */
1284
/* raster_render :: A function to render a glyph into a given bitmap. */
1286
/* raster_done :: The raster destructor. */
1288
typedef struct FT_Raster_Funcs_
1290
FT_Glyph_Format glyph_format;
1291
FT_Raster_NewFunc raster_new;
1292
FT_Raster_ResetFunc raster_reset;
1293
FT_Raster_SetModeFunc raster_set_mode;
1294
FT_Raster_RenderFunc raster_render;
1295
FT_Raster_DoneFunc raster_done;
1305
#endif /* __FTIMAGE_H__ */
1311
/* Local Variables: */
added
removed
misc/libfreetype/include/freetype/ftimage.h
