/***************************************************************************/ /* */ /* ftimage.h */ /* */ /* FreeType glyph image formats and default raster interface */ /* (specification). */ /* */ /* Copyright 1996-2010, 2013 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ /* modified, and distributed under the terms of the FreeType project */ /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ /* this file you indicate that you have read the license and */ /* understand and accept it fully. */ /* */ /***************************************************************************/ #ifndef PLUTOVG_FT_RASTER_H #define PLUTOVG_FT_RASTER_H #include "plutovg-ft-types.h" /*************************************************************************/ /* */ /* */ /* FT_BBox */ /* */ /* */ /* A structure used to hold an outline's bounding box, i.e., the */ /* coordinates of its extrema in the horizontal and vertical */ /* directions. */ /* */ /* */ /* xMin :: The horizontal minimum (left-most). */ /* */ /* yMin :: The vertical minimum (bottom-most). */ /* */ /* xMax :: The horizontal maximum (right-most). */ /* */ /* yMax :: The vertical maximum (top-most). */ /* */ /* */ /* The bounding box is specified with the coordinates of the lower */ /* left and the upper right corner. In PostScript, those values are */ /* often called (llx,lly) and (urx,ury), respectively. */ /* */ /* If `yMin' is negative, this value gives the glyph's descender. */ /* Otherwise, the glyph doesn't descend below the baseline. */ /* Similarly, if `ymax' is positive, this value gives the glyph's */ /* ascender. */ /* */ /* `xMin' gives the horizontal distance from the glyph's origin to */ /* the left edge of the glyph's bounding box. If `xMin' is negative, */ /* the glyph extends to the left of the origin. */ /* */ typedef struct PVG_FT_BBox_ { PVG_FT_Pos xMin, yMin; PVG_FT_Pos xMax, yMax; } PVG_FT_BBox; /*************************************************************************/ /* */ /* */ /* PVG_FT_Outline */ /* */ /* */ /* This structure is used to describe an outline to the scan-line */ /* converter. */ /* */ /* */ /* n_contours :: The number of contours in the outline. */ /* */ /* n_points :: The number of points in the outline. */ /* */ /* points :: A pointer to an array of `n_points' @PVG_FT_Vector */ /* elements, giving the outline's point coordinates. */ /* */ /* tags :: A pointer to an array of `n_points' chars, giving */ /* each outline point's type. */ /* */ /* If bit~0 is unset, the point is `off' the curve, */ /* i.e., a Bézier control point, while it is `on' if */ /* set. */ /* */ /* Bit~1 is meaningful for `off' points only. If set, */ /* it indicates a third-order Bézier arc control point; */ /* and a second-order control point if unset. */ /* */ /* If bit~2 is set, bits 5-7 contain the drop-out mode */ /* (as defined in the OpenType specification; the value */ /* is the same as the argument to the SCANMODE */ /* instruction). */ /* */ /* Bits 3 and~4 are reserved for internal purposes. */ /* */ /* contours :: An array of `n_contours' shorts, giving the end */ /* point of each contour within the outline. For */ /* example, the first contour is defined by the points */ /* `0' to `contours[0]', the second one is defined by */ /* the points `contours[0]+1' to `contours[1]', etc. */ /* */ /* flags :: A set of bit flags used to characterize the outline */ /* and give hints to the scan-converter and hinter on */ /* how to convert/grid-fit it. See @PVG_FT_OUTLINE_FLAGS.*/ /* */ typedef struct PVG_FT_Outline_ { int n_contours; /* number of contours in glyph */ int n_points; /* number of points in the glyph */ PVG_FT_Vector* points; /* the outline's points */ char* tags; /* the points flags */ int* contours; /* the contour end points */ char* contours_flag; /* the contour open flags */ int flags; /* outline masks */ } PVG_FT_Outline; /*************************************************************************/ /* */ /* */ /* PVG_FT_OUTLINE_FLAGS */ /* */ /* */ /* A list of bit-field constants use for the flags in an outline's */ /* `flags' field. */ /* */ /* */ /* PVG_FT_OUTLINE_NONE :: */ /* Value~0 is reserved. */ /* */ /* PVG_FT_OUTLINE_OWNER :: */ /* If set, this flag indicates that the outline's field arrays */ /* (i.e., `points', `flags', and `contours') are `owned' by the */ /* outline object, and should thus be freed when it is destroyed. */ /* */ /* PVG_FT_OUTLINE_EVEN_ODD_FILL :: */ /* By default, outlines are filled using the non-zero winding rule. */ /* If set to 1, the outline will be filled using the even-odd fill */ /* rule (only works with the smooth rasterizer). */ /* */ /* PVG_FT_OUTLINE_REVERSE_FILL :: */ /* By default, outside contours of an outline are oriented in */ /* clock-wise direction, as defined in the TrueType specification. */ /* This flag is set if the outline uses the opposite direction */ /* (typically for Type~1 fonts). This flag is ignored by the scan */ /* converter. */ /* */ /* */ /* */ /* There exists a second mechanism to pass the drop-out mode to the */ /* B/W rasterizer; see the `tags' field in @PVG_FT_Outline. */ /* */ /* Please refer to the description of the `SCANTYPE' instruction in */ /* the OpenType specification (in file `ttinst1.doc') how simple */ /* drop-outs, smart drop-outs, and stubs are defined. */ /* */ #define PVG_FT_OUTLINE_NONE 0x0 #define PVG_FT_OUTLINE_OWNER 0x1 #define PVG_FT_OUTLINE_EVEN_ODD_FILL 0x2 #define PVG_FT_OUTLINE_REVERSE_FILL 0x4 /* */ #define PVG_FT_CURVE_TAG( flag ) ( flag & 3 ) #define PVG_FT_CURVE_TAG_ON 1 #define PVG_FT_CURVE_TAG_CONIC 0 #define PVG_FT_CURVE_TAG_CUBIC 2 #define PVG_FT_Curve_Tag_On PVG_FT_CURVE_TAG_ON #define PVG_FT_Curve_Tag_Conic PVG_FT_CURVE_TAG_CONIC #define PVG_FT_Curve_Tag_Cubic PVG_FT_CURVE_TAG_CUBIC /*************************************************************************/ /* */ /* */ /* PVG_FT_Outline_Check */ /* */ /* */ /* Check the contents of an outline descriptor. */ /* */ /* */ /* outline :: A handle to a source outline. */ /* */ /* */ /* FreeType error code. 0~means success. */ /* */ PVG_FT_Error PVG_FT_Outline_Check( PVG_FT_Outline* outline ); /*************************************************************************/ /* */ /* */ /* PVG_FT_Outline_Get_CBox */ /* */ /* */ /* Return an outline's `control box'. The control box encloses all */ /* the outline's points, including Bézier control points. Though it */ /* coincides with the exact bounding box for most glyphs, it can be */ /* slightly larger in some situations (like when rotating an outline */ /* that contains Bézier outside arcs). */ /* */ /* Computing the control box is very fast, while getting the bounding */ /* box can take much more time as it needs to walk over all segments */ /* and arcs in the outline. To get the latter, you can use the */ /* `ftbbox' component, which is dedicated to this single task. */ /* */ /* */ /* outline :: A pointer to the source outline descriptor. */ /* */ /* */ /* acbox :: The outline's control box. */ /* */ /* */ /* See @PVG_FT_Glyph_Get_CBox for a discussion of tricky fonts. */ /* */ void PVG_FT_Outline_Get_CBox( const PVG_FT_Outline* outline, PVG_FT_BBox *acbox ); /*************************************************************************/ /* */ /* */ /* PVG_FT_Span */ /* */ /* */ /* A structure used to model a single span of gray (or black) pixels */ /* when rendering a monochrome or anti-aliased bitmap. */ /* */ /* */ /* 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). Only used for anti-aliased */ /* rendering. */ /* */ /* */ /* This structure is used by the span drawing callback type named */ /* @PVG_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 PVG_FT_Span_ { int x; int len; int y; unsigned char coverage; } PVG_FT_Span; /*************************************************************************/ /* */ /* */ /* PVG_FT_SpanFunc */ /* */ /* */ /* 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. */ /* */ /* */ /* y :: The scanline's 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. */ /* */ /* */ /* 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. */ /* */ /* Note that the `count' field cannot be greater than a fixed value */ /* defined by the `PVG_FT_MAX_GRAY_SPANS' configuration macro in */ /* `ftoption.h'. By default, this value is set to~32, which means */ /* that if there are more than 32~spans on a given scanline, the */ /* callback is called several times with the same `y' parameter in */ /* order to draw all callbacks. */ /* */ /* Otherwise, the callback is only called once per scan-line, and */ /* only for those scanlines that do have `gray' pixels on them. */ /* */ typedef void (*PVG_FT_SpanFunc)( int count, const PVG_FT_Span* spans, void* user ); #define PVG_FT_Raster_Span_Func PVG_FT_SpanFunc /*************************************************************************/ /* */ /* */ /* PVG_FT_RASTER_FLAG_XXX */ /* */ /* */ /* A list of bit flag constants as used in the `flags' field of a */ /* @PVG_FT_Raster_Params structure. */ /* */ /* */ /* PVG_FT_RASTER_FLAG_DEFAULT :: This value is 0. */ /* */ /* PVG_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). */ /* */ /* PVG_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. */ /* */ /* Note that for now, direct rendering is */ /* only possible with anti-aliased glyphs. */ /* */ /* PVG_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 */ /* @PVG_FT_Raster_Params structure. */ /* */ /* Note that by default, the glyph bitmap */ /* is clipped to the target pixmap, except */ /* in direct rendering mode where all spans */ /* are generated if no clipping box is set. */ /* */ #define PVG_FT_RASTER_FLAG_DEFAULT 0x0 #define PVG_FT_RASTER_FLAG_AA 0x1 #define PVG_FT_RASTER_FLAG_DIRECT 0x2 #define PVG_FT_RASTER_FLAG_CLIP 0x4 /*************************************************************************/ /* */ /* */ /* PVG_FT_Raster_Params */ /* */ /* */ /* A structure to hold the arguments used by a raster's render */ /* function. */ /* */ /* */ /* target :: The target bitmap. */ /* */ /* source :: A pointer to the source glyph image (e.g., an */ /* @PVG_FT_Outline). */ /* */ /* flags :: The rendering flags. */ /* */ /* gray_spans :: The gray span drawing callback. */ /* */ /* black_spans :: The black span drawing callback. UNIMPLEMENTED! */ /* */ /* bit_test :: The bit test callback. UNIMPLEMENTED! */ /* */ /* bit_set :: The bit set callback. UNIMPLEMENTED! */ /* */ /* 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). */ /* */ /* */ /* An anti-aliased glyph bitmap is drawn if the @PVG_FT_RASTER_FLAG_AA */ /* bit flag is set in the `flags' field, otherwise a monochrome */ /* bitmap is generated. */ /* */ /* If the @PVG_FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */ /* raster will call the `gray_spans' callback to draw gray pixel */ /* spans, in the case of an aa glyph bitmap, it will call */ /* `black_spans', and `bit_test' and `bit_set' in the case of a */ /* monochrome bitmap. This allows direct composition over a */ /* pre-existing bitmap through user-provided callbacks to perform the */ /* span drawing/composition. */ /* */ /* Note that the `bit_test' and `bit_set' callbacks are required when */ /* rendering a monochrome bitmap, as they are crucial to implement */ /* correct drop-out control as defined in the TrueType specification. */ /* */ typedef struct PVG_FT_Raster_Params_ { const void* source; int flags; PVG_FT_SpanFunc gray_spans; void* user; PVG_FT_BBox clip_box; } PVG_FT_Raster_Params; void PVG_FT_Raster_Render(const PVG_FT_Raster_Params *params); #endif // PLUTOVG_FT_RASTER_H