| /**************************************************************************** |
| * |
| * ftimage.h |
| * |
| * FreeType glyph image formats and default raster interface |
| * (specification). |
| * |
| * Copyright (C) 1996-2022 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. |
| * |
| */ |
| |
| /************************************************************************** |
| * |
| * Note: A 'raster' is simply a scan-line converter, used to render |
| * FT_Outlines into FT_Bitmaps. |
| * |
| */ |
| |
| |
| #ifndef FTIMAGE_H_ |
| #define FTIMAGE_H_ |
| |
| |
| FT_BEGIN_HEADER |
| |
| |
| /************************************************************************** |
| * |
| * @section: |
| * basic_types |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @type: |
| * FT_Pos |
| * |
| * @description: |
| * The type FT_Pos is used to store vectorial coordinates. Depending on |
| * the context, these can represent distances in integer font units, or |
| * 16.16, or 26.6 fixed-point pixel coordinates. |
| */ |
| typedef signed long FT_Pos; |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_Vector |
| * |
| * @description: |
| * A simple structure used to store a 2D vector; coordinates are of the |
| * FT_Pos type. |
| * |
| * @fields: |
| * x :: |
| * The horizontal coordinate. |
| * y :: |
| * The vertical coordinate. |
| */ |
| typedef struct FT_Vector_ |
| { |
| FT_Pos x; |
| FT_Pos y; |
| |
| } FT_Vector; |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_BBox |
| * |
| * @description: |
| * A structure used to hold an outline's bounding box, i.e., the |
| * coordinates of its extrema in the horizontal and vertical directions. |
| * |
| * @fields: |
| * xMin :: |
| * The horizontal minimum (left-most). |
| * |
| * yMin :: |
| * The vertical minimum (bottom-most). |
| * |
| * xMax :: |
| * The horizontal maximum (right-most). |
| * |
| * yMax :: |
| * The vertical maximum (top-most). |
| * |
| * @note: |
| * 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 FT_BBox_ |
| { |
| FT_Pos xMin, yMin; |
| FT_Pos xMax, yMax; |
| |
| } FT_BBox; |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * FT_Pixel_Mode |
| * |
| * @description: |
| * An enumeration type used to describe the format of pixels in a given |
| * bitmap. Note that additional formats may be added in the future. |
| * |
| * @values: |
| * FT_PIXEL_MODE_NONE :: |
| * Value~0 is reserved. |
| * |
| * FT_PIXEL_MODE_MONO :: |
| * A monochrome bitmap, using 1~bit per pixel. Note that pixels are |
| * stored in most-significant order (MSB), which means that the |
| * left-most pixel in a byte has value 128. |
| * |
| * FT_PIXEL_MODE_GRAY :: |
| * An 8-bit bitmap, generally used to represent anti-aliased glyph |
| * images. Each pixel is stored in one byte. Note that the number of |
| * 'gray' levels is stored in the `num_grays` field of the @FT_Bitmap |
| * structure (it generally is 256). |
| * |
| * FT_PIXEL_MODE_GRAY2 :: |
| * A 2-bit per pixel bitmap, used to represent embedded anti-aliased |
| * bitmaps in font files according to the OpenType specification. We |
| * haven't found a single font using this format, however. |
| * |
| * FT_PIXEL_MODE_GRAY4 :: |
| * A 4-bit per pixel bitmap, representing embedded anti-aliased bitmaps |
| * in font files according to the OpenType specification. We haven't |
| * found a single font using this format, however. |
| * |
| * FT_PIXEL_MODE_LCD :: |
| * An 8-bit bitmap, representing RGB or BGR decimated glyph images used |
| * for display on LCD displays; the bitmap is three times wider than |
| * the original glyph image. See also @FT_RENDER_MODE_LCD. |
| * |
| * FT_PIXEL_MODE_LCD_V :: |
| * An 8-bit bitmap, representing RGB or BGR decimated glyph images used |
| * for display on rotated LCD displays; the bitmap is three times |
| * taller than the original glyph image. See also |
| * @FT_RENDER_MODE_LCD_V. |
| * |
| * FT_PIXEL_MODE_BGRA :: |
| * [Since 2.5] An image with four 8-bit channels per pixel, |
| * representing a color image (such as emoticons) with alpha channel. |
| * For each pixel, the format is BGRA, which means, the blue channel |
| * comes first in memory. The color channels are pre-multiplied and in |
| * the sRGB colorspace. For example, full red at half-translucent |
| * opacity will be represented as '00,00,80,80', not '00,00,FF,80'. |
| * See also @FT_LOAD_COLOR. |
| */ |
| typedef enum FT_Pixel_Mode_ |
| { |
| FT_PIXEL_MODE_NONE = 0, |
| FT_PIXEL_MODE_MONO, |
| FT_PIXEL_MODE_GRAY, |
| FT_PIXEL_MODE_GRAY2, |
| FT_PIXEL_MODE_GRAY4, |
| FT_PIXEL_MODE_LCD, |
| FT_PIXEL_MODE_LCD_V, |
| FT_PIXEL_MODE_BGRA, |
| |
| FT_PIXEL_MODE_MAX /* do not remove */ |
| |
| } FT_Pixel_Mode; |
| |
| |
| /* these constants are deprecated; use the corresponding `FT_Pixel_Mode` */ |
| /* values instead. */ |
| #define ft_pixel_mode_none FT_PIXEL_MODE_NONE |
| #define ft_pixel_mode_mono FT_PIXEL_MODE_MONO |
| #define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY |
| #define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2 |
| #define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4 |
| |
| /* */ |
| |
| /* For debugging, the @FT_Pixel_Mode enumeration must stay in sync */ |
| /* with the `pixel_modes` array in file `ftobjs.c`. */ |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_Bitmap |
| * |
| * @description: |
| * A structure used to describe a bitmap or pixmap to the raster. Note |
| * that we now manage pixmaps of various depths through the `pixel_mode` |
| * field. |
| * |
| * @fields: |
| * rows :: |
| * The number of bitmap rows. |
| * |
| * width :: |
| * The number of pixels in bitmap row. |
| * |
| * pitch :: |
| * The pitch's absolute value is the number of bytes taken by one |
| * bitmap row, including padding. However, the pitch is positive when |
| * the bitmap has a 'down' flow, and negative when it has an 'up' flow. |
| * In all cases, the pitch is an offset to add to a bitmap pointer in |
| * order to go down one row. |
| * |
| * Note that 'padding' means the alignment of a bitmap to a byte |
| * border, and FreeType functions normally align to the smallest |
| * possible integer value. |
| * |
| * For the B/W rasterizer, `pitch` is always an even number. |
| * |
| * To change the pitch of a bitmap (say, to make it a multiple of 4), |
| * use @FT_Bitmap_Convert. Alternatively, you might use callback |
| * functions to directly render to the application's surface; see the |
| * file `example2.cpp` in the tutorial for a demonstration. |
| * |
| * buffer :: |
| * A typeless pointer to the bitmap buffer. This value should be |
| * aligned on 32-bit boundaries in most cases. |
| * |
| * num_grays :: |
| * This field is only used with @FT_PIXEL_MODE_GRAY; it gives the |
| * number of gray levels used in the bitmap. |
| * |
| * pixel_mode :: |
| * The pixel mode, i.e., how pixel bits are stored. See @FT_Pixel_Mode |
| * for possible values. |
| * |
| * palette_mode :: |
| * This field is intended for paletted pixel modes; it indicates how |
| * the palette is stored. Not used currently. |
| * |
| * palette :: |
| * A typeless pointer to the bitmap palette; this field is intended for |
| * paletted pixel modes. Not used currently. |
| */ |
| typedef struct FT_Bitmap_ |
| { |
| unsigned int rows; |
| unsigned int width; |
| int pitch; |
| unsigned char* buffer; |
| unsigned short num_grays; |
| unsigned char pixel_mode; |
| unsigned char palette_mode; |
| void* palette; |
| |
| } FT_Bitmap; |
| |
| |
| /************************************************************************** |
| * |
| * @section: |
| * outline_processing |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_Outline |
| * |
| * @description: |
| * This structure is used to describe an outline to the scan-line |
| * converter. |
| * |
| * @fields: |
| * 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` @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 Bezier |
| * control point, while it is 'on' if set. |
| * |
| * Bit~1 is meaningful for 'off' points only. If set, it indicates a |
| * third-order Bezier 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 |
| * @FT_OUTLINE_XXX. |
| * |
| * @note: |
| * The B/W rasterizer only checks bit~2 in the `tags` array for the first |
| * point of each contour. The drop-out mode as given with |
| * @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and |
| * @FT_OUTLINE_INCLUDE_STUBS in `flags` is then overridden. |
| */ |
| typedef struct FT_Outline_ |
| { |
| short n_contours; /* number of contours in glyph */ |
| short n_points; /* number of points in the glyph */ |
| |
| FT_Vector* points; /* the outline's points */ |
| char* tags; /* the points flags */ |
| short* contours; /* the contour end points */ |
| |
| int flags; /* outline masks */ |
| |
| } FT_Outline; |
| |
| /* */ |
| |
| /* Following limits must be consistent with */ |
| /* FT_Outline.{n_contours,n_points} */ |
| #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX |
| #define FT_OUTLINE_POINTS_MAX SHRT_MAX |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * FT_OUTLINE_XXX |
| * |
| * @description: |
| * A list of bit-field constants used for the flags in an outline's |
| * `flags` field. |
| * |
| * @values: |
| * FT_OUTLINE_NONE :: |
| * Value~0 is reserved. |
| * |
| * 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. |
| * |
| * 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). |
| * |
| * 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. |
| * |
| * FT_OUTLINE_IGNORE_DROPOUTS :: |
| * By default, the scan converter will try to detect drop-outs in an |
| * outline and correct the glyph bitmap to ensure consistent shape |
| * continuity. If set, this flag hints the scan-line converter to |
| * ignore such cases. See below for more information. |
| * |
| * FT_OUTLINE_SMART_DROPOUTS :: |
| * Select smart dropout control. If unset, use simple dropout control. |
| * Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more |
| * information. |
| * |
| * FT_OUTLINE_INCLUDE_STUBS :: |
| * If set, turn pixels on for 'stubs', otherwise exclude them. Ignored |
| * if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more |
| * information. |
| * |
| * FT_OUTLINE_OVERLAP :: |
| * [Since 2.10.3] This flag indicates that this outline contains |
| * overlapping contours and the anti-aliased renderer should perform |
| * oversampling to mitigate possible artifacts. This flag should _not_ |
| * be set for well designed glyphs without overlaps because it quadruples |
| * the rendering time. |
| * |
| * FT_OUTLINE_HIGH_PRECISION :: |
| * This flag indicates that the scan-line converter should try to |
| * convert this outline to bitmaps with the highest possible quality. |
| * It is typically set for small character sizes. Note that this is |
| * only a hint that might be completely ignored by a given |
| * scan-converter. |
| * |
| * FT_OUTLINE_SINGLE_PASS :: |
| * This flag is set to force a given scan-converter to only use a |
| * single pass over the outline to render a bitmap glyph image. |
| * Normally, it is set for very large character sizes. It is only a |
| * hint that might be completely ignored by a given scan-converter. |
| * |
| * @note: |
| * The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and |
| * @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth rasterizer. |
| * |
| * There exists a second mechanism to pass the drop-out mode to the B/W |
| * rasterizer; see the `tags` field in @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 FT_OUTLINE_NONE 0x0 |
| #define FT_OUTLINE_OWNER 0x1 |
| #define FT_OUTLINE_EVEN_ODD_FILL 0x2 |
| #define FT_OUTLINE_REVERSE_FILL 0x4 |
| #define FT_OUTLINE_IGNORE_DROPOUTS 0x8 |
| #define FT_OUTLINE_SMART_DROPOUTS 0x10 |
| #define FT_OUTLINE_INCLUDE_STUBS 0x20 |
| #define FT_OUTLINE_OVERLAP 0x40 |
| |
| #define FT_OUTLINE_HIGH_PRECISION 0x100 |
| #define FT_OUTLINE_SINGLE_PASS 0x200 |
| |
| |
| /* these constants are deprecated; use the corresponding */ |
| /* `FT_OUTLINE_XXX` values instead */ |
| #define ft_outline_none FT_OUTLINE_NONE |
| #define ft_outline_owner FT_OUTLINE_OWNER |
| #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL |
| #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL |
| #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS |
| #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION |
| #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS |
| |
| /* */ |
| |
| #define FT_CURVE_TAG( flag ) ( flag & 0x03 ) |
| |
| /* see the `tags` field in `FT_Outline` for a description of the values */ |
| #define FT_CURVE_TAG_ON 0x01 |
| #define FT_CURVE_TAG_CONIC 0x00 |
| #define FT_CURVE_TAG_CUBIC 0x02 |
| |
| #define FT_CURVE_TAG_HAS_SCANMODE 0x04 |
| |
| #define FT_CURVE_TAG_TOUCH_X 0x08 /* reserved for TrueType hinter */ |
| #define FT_CURVE_TAG_TOUCH_Y 0x10 /* reserved for TrueType hinter */ |
| |
| #define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \ |
| FT_CURVE_TAG_TOUCH_Y ) |
| /* values 0x20, 0x40, and 0x80 are reserved */ |
| |
| |
| /* these constants are deprecated; use the corresponding */ |
| /* `FT_CURVE_TAG_XXX` values instead */ |
| #define FT_Curve_Tag_On FT_CURVE_TAG_ON |
| #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC |
| #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC |
| #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X |
| #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y |
| |
| |
| /************************************************************************** |
| * |
| * @functype: |
| * FT_Outline_MoveToFunc |
| * |
| * @description: |
| * A function pointer type used to describe the signature of a 'move to' |
| * function during outline walking/decomposition. |
| * |
| * A 'move to' is emitted to start a new contour in an outline. |
| * |
| * @input: |
| * to :: |
| * A pointer to the target point of the 'move 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_MoveToFunc)( const FT_Vector* to, |
| void* user ); |
| |
| #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc |
| |
| |
| /************************************************************************** |
| * |
| * @functype: |
| * FT_Outline_LineToFunc |
| * |
| * @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 = ( ( FT_STATIC_BYTE_CAST( unsigned long, _x1 ) << 24 ) | \ |
| ( FT_STATIC_BYTE_CAST( unsigned long, _x2 ) << 16 ) | \ |
| ( FT_STATIC_BYTE_CAST( unsigned long, _x3 ) << 8 ) | \ |
| FT_STATIC_BYTE_CAST( 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. |
| * |
| * FT_GLYPH_FORMAT_SVG :: |
| * [Since 2.12] The glyph is represented by an SVG document in the |
| * 'SVG~' table. |
| */ |
| 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_IMAGE_TAG( FT_GLYPH_FORMAT_SVG, 'S', 'V', 'G', ' ' ) |
| |
| } 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 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| |
| |
| /************************************************************************** |
| * |
| * @section: |
| * raster |
| * |
| * @title: |
| * Scanline Converter |
| * |
| * @abstract: |
| * How vectorial outlines are converted into bitmaps and pixmaps. |
| * |
| * @description: |
| * A raster or a rasterizer is a scan converter in charge of producing a |
| * pixel coverage bitmap that can be used as an alpha channel when |
| * compositing a glyph with a background. FreeType comes with two |
| * rasterizers: bilevel `raster1` and anti-aliased `smooth` are two |
| * separate modules. They are usually called from the high-level |
| * @FT_Load_Glyph or @FT_Render_Glyph functions and produce the entire |
| * coverage bitmap at once, while staying largely invisible to users. |
| * |
| * Instead of working with complete coverage bitmaps, it is also possible |
| * to intercept consecutive pixel runs on the same scanline with the same |
| * coverage, called _spans_, and process them individually. Only the |
| * `smooth` rasterizer permits this when calling @FT_Outline_Render with |
| * @FT_Raster_Params as described below. |
| * |
| * Working with either complete bitmaps or spans it is important to think |
| * of them as colorless coverage objects suitable as alpha channels to |
| * blend arbitrary colors with a background. For best results, it is |
| * recommended to use gamma correction, too. |
| * |
| * This section also describes the public API needed to set up alternative |
| * @FT_Renderer modules. |
| * |
| * @order: |
| * FT_Span |
| * FT_SpanFunc |
| * FT_Raster_Params |
| * FT_RASTER_FLAG_XXX |
| * |
| * FT_Raster |
| * FT_Raster_NewFunc |
| * FT_Raster_DoneFunc |
| * FT_Raster_ResetFunc |
| * FT_Raster_SetModeFunc |
| * FT_Raster_RenderFunc |
| * FT_Raster_Funcs |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_Span |
| * |
| * @description: |
| * A structure to model a single span of consecutive 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 anti-aliased rasterizer produces coverage values from 0 to 255, |
| * this is, from completely transparent to completely opaque. |
| */ |
| 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 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 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 using alpha compositing. It can also be used for |
| * oversampling and averaging. |
| */ |
| 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. |
| * |
| * FT_RASTER_FLAG_SDF :: |
| * This flag is set to indicate that a signed distance field glyph |
| * image should be generated. This is only used while rendering with |
| * the @FT_RENDER_MODE_SDF render mode. |
| */ |
| #define FT_RASTER_FLAG_DEFAULT 0x0 |
| #define FT_RASTER_FLAG_AA 0x1 |
| #define FT_RASTER_FLAG_DIRECT 0x2 |
| #define FT_RASTER_FLAG_CLIP 0x4 |
| #define FT_RASTER_FLAG_SDF 0x8 |
| |
| /* 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 span clipping box expressed in _integer_ pixels |
| * (not in 26.6 fixed-point units). |
| * |
| * @note: |
| * The @FT_RASTER_FLAG_AA bit flag must be set in the `flags` to |
| * generate an anti-aliased glyph bitmap, otherwise a monochrome bitmap |
| * is generated. The `target` should have appropriate pixel mode and its |
| * dimensions define the clipping region. |
| * |
| * If both @FT_RASTER_FLAG_AA and @FT_RASTER_FLAG_DIRECT bit flags |
| * are set in `flags`, the raster calls an @FT_SpanFunc callback |
| * `gray_spans` with `user` data as an argument ignoring `target`. This |
| * allows direct composition over a pre-existing user surface to perform |
| * the span drawing and composition. To optionally clip the spans, set |
| * the @FT_RASTER_FLAG_CLIP flag and `clip_box`. The monochrome raster |
| * does not support the direct mode. |
| * |
| * The gray-level rasterizer always uses 256 gray levels. If you want |
| * fewer gray levels, you have to use @FT_RASTER_FLAG_DIRECT and reduce |
| * the levels in the callback function. |
| */ |
| 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; |
| |
| |
| /************************************************************************** |
| * |
| * @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. |
| * |
| * @note: |
| * In FreeType 2, all rasters are now encapsulated within specific |
| * @FT_Renderer modules and only used in their context. |
| * |
| */ |
| typedef struct FT_RasterRec_* FT_Raster; |
| |
| |
| /************************************************************************** |
| * |
| * @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: */ |
