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Diffstat (limited to 'modules/freetype2/include/freetype/ftoutln.h')
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diff --git a/modules/freetype2/include/freetype/ftoutln.h b/modules/freetype2/include/freetype/ftoutln.h new file mode 100644 index 0000000000..54434b25f6 --- /dev/null +++ b/modules/freetype2/include/freetype/ftoutln.h @@ -0,0 +1,588 @@ +/**************************************************************************** + * + * ftoutln.h + * + * Support for the FT_Outline type used to store glyph shapes of + * most scalable font formats (specification). + * + * Copyright (C) 1996-2023 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 FTOUTLN_H_ +#define FTOUTLN_H_ + + +#include <freetype/freetype.h> + +#ifdef FREETYPE_H +#error "freetype.h of FreeType 1 has been loaded!" +#error "Please fix the directory search order for header files" +#error "so that freetype.h of FreeType 2 is found first." +#endif + + +FT_BEGIN_HEADER + + + /************************************************************************** + * + * @section: + * outline_processing + * + * @title: + * Outline Processing + * + * @abstract: + * Functions to create, transform, and render vectorial glyph images. + * + * @description: + * This section contains routines used to create and destroy scalable + * glyph images known as 'outlines'. These can also be measured, + * transformed, and converted into bitmaps and pixmaps. + * + * @order: + * FT_Outline + * FT_Outline_New + * FT_Outline_Done + * FT_Outline_Copy + * FT_Outline_Translate + * FT_Outline_Transform + * FT_Outline_Embolden + * FT_Outline_EmboldenXY + * FT_Outline_Reverse + * FT_Outline_Check + * + * FT_Outline_Get_CBox + * FT_Outline_Get_BBox + * + * FT_Outline_Get_Bitmap + * FT_Outline_Render + * FT_Outline_Decompose + * FT_Outline_Funcs + * FT_Outline_MoveToFunc + * FT_Outline_LineToFunc + * FT_Outline_ConicToFunc + * FT_Outline_CubicToFunc + * + * FT_Orientation + * FT_Outline_Get_Orientation + * + * FT_OUTLINE_XXX + * + */ + + + /************************************************************************** + * + * @function: + * FT_Outline_Decompose + * + * @description: + * Walk over an outline's structure to decompose it into individual + * segments and Bezier arcs. This function also emits 'move to' + * operations to indicate the start of new contours in the outline. + * + * @input: + * outline :: + * A pointer to the source target. + * + * func_interface :: + * A table of 'emitters', i.e., function pointers called during + * decomposition to indicate path operations. + * + * @inout: + * user :: + * A typeless pointer that is passed to each emitter during the + * decomposition. It can be used to store the state during the + * decomposition. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * Degenerate contours, segments, and Bezier arcs may be reported. In + * most cases, it is best to filter these out before using the outline + * for stroking or other path modification purposes (which may cause + * degenerate segments to become non-degenrate and visible, like when + * stroke caps are used or the path is otherwise outset). Some glyph + * outlines may contain deliberate degenerate single points for mark + * attachement. + * + * Similarly, the function returns success for an empty outline also + * (doing nothing, this is, not calling any emitter); if necessary, you + * should filter this out, too. + */ + FT_EXPORT( FT_Error ) + FT_Outline_Decompose( FT_Outline* outline, + const FT_Outline_Funcs* func_interface, + void* user ); + + + /************************************************************************** + * + * @function: + * FT_Outline_New + * + * @description: + * Create a new outline of a given size. + * + * @input: + * library :: + * A handle to the library object from where the outline is allocated. + * Note however that the new outline will **not** necessarily be + * **freed**, when destroying the library, by @FT_Done_FreeType. + * + * numPoints :: + * The maximum number of points within the outline. Must be smaller + * than or equal to 0xFFFF (65535). + * + * numContours :: + * The maximum number of contours within the outline. This value must + * be in the range 0 to `numPoints`. + * + * @output: + * anoutline :: + * A handle to the new outline. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * The reason why this function takes a `library` parameter is simply to + * use the library's memory allocator. + */ + FT_EXPORT( FT_Error ) + FT_Outline_New( FT_Library library, + FT_UInt numPoints, + FT_Int numContours, + FT_Outline *anoutline ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Done + * + * @description: + * Destroy an outline created with @FT_Outline_New. + * + * @input: + * library :: + * A handle of the library object used to allocate the outline. + * + * outline :: + * A pointer to the outline object to be discarded. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * If the outline's 'owner' field is not set, only the outline descriptor + * will be released. + */ + FT_EXPORT( FT_Error ) + FT_Outline_Done( FT_Library library, + FT_Outline* outline ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Check + * + * @description: + * Check the contents of an outline descriptor. + * + * @input: + * outline :: + * A handle to a source outline. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * An empty outline, or an outline with a single point only is also + * valid. + */ + FT_EXPORT( FT_Error ) + FT_Outline_Check( FT_Outline* outline ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Get_CBox + * + * @description: + * Return an outline's 'control box'. The control box encloses all the + * outline's points, including Bezier 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 Bezier 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. + * + * @input: + * outline :: + * A pointer to the source outline descriptor. + * + * @output: + * acbox :: + * The outline's control box. + * + * @note: + * See @FT_Glyph_Get_CBox for a discussion of tricky fonts. + */ + FT_EXPORT( void ) + FT_Outline_Get_CBox( const FT_Outline* outline, + FT_BBox *acbox ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Translate + * + * @description: + * Apply a simple translation to the points of an outline. + * + * @inout: + * outline :: + * A pointer to the target outline descriptor. + * + * @input: + * xOffset :: + * The horizontal offset. + * + * yOffset :: + * The vertical offset. + */ + FT_EXPORT( void ) + FT_Outline_Translate( const FT_Outline* outline, + FT_Pos xOffset, + FT_Pos yOffset ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Copy + * + * @description: + * Copy an outline into another one. Both objects must have the same + * sizes (number of points & number of contours) when this function is + * called. + * + * @input: + * source :: + * A handle to the source outline. + * + * @output: + * target :: + * A handle to the target outline. + * + * @return: + * FreeType error code. 0~means success. + */ + FT_EXPORT( FT_Error ) + FT_Outline_Copy( const FT_Outline* source, + FT_Outline *target ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Transform + * + * @description: + * Apply a simple 2x2 matrix to all of an outline's points. Useful for + * applying rotations, slanting, flipping, etc. + * + * @inout: + * outline :: + * A pointer to the target outline descriptor. + * + * @input: + * matrix :: + * A pointer to the transformation matrix. + * + * @note: + * You can use @FT_Outline_Translate if you need to translate the + * outline's points. + */ + FT_EXPORT( void ) + FT_Outline_Transform( const FT_Outline* outline, + const FT_Matrix* matrix ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Embolden + * + * @description: + * Embolden an outline. The new outline will be at most 4~times + * `strength` pixels wider and higher. You may think of the left and + * bottom borders as unchanged. + * + * Negative `strength` values to reduce the outline thickness are + * possible also. + * + * @inout: + * outline :: + * A handle to the target outline. + * + * @input: + * strength :: + * How strong the glyph is emboldened. Expressed in 26.6 pixel format. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * The used algorithm to increase or decrease the thickness of the glyph + * doesn't change the number of points; this means that certain + * situations like acute angles or intersections are sometimes handled + * incorrectly. + * + * If you need 'better' metrics values you should call + * @FT_Outline_Get_CBox or @FT_Outline_Get_BBox. + * + * To get meaningful results, font scaling values must be set with + * functions like @FT_Set_Char_Size before calling FT_Render_Glyph. + * + * @example: + * ``` + * FT_Load_Glyph( face, index, FT_LOAD_DEFAULT ); + * + * if ( face->glyph->format == FT_GLYPH_FORMAT_OUTLINE ) + * FT_Outline_Embolden( &face->glyph->outline, strength ); + * ``` + * + */ + FT_EXPORT( FT_Error ) + FT_Outline_Embolden( FT_Outline* outline, + FT_Pos strength ); + + + /************************************************************************** + * + * @function: + * FT_Outline_EmboldenXY + * + * @description: + * Embolden an outline. The new outline will be `xstrength` pixels wider + * and `ystrength` pixels higher. Otherwise, it is similar to + * @FT_Outline_Embolden, which uses the same strength in both directions. + * + * @since: + * 2.4.10 + */ + FT_EXPORT( FT_Error ) + FT_Outline_EmboldenXY( FT_Outline* outline, + FT_Pos xstrength, + FT_Pos ystrength ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Reverse + * + * @description: + * Reverse the drawing direction of an outline. This is used to ensure + * consistent fill conventions for mirrored glyphs. + * + * @inout: + * outline :: + * A pointer to the target outline descriptor. + * + * @note: + * This function toggles the bit flag @FT_OUTLINE_REVERSE_FILL in the + * outline's `flags` field. + * + * It shouldn't be used by a normal client application, unless it knows + * what it is doing. + */ + FT_EXPORT( void ) + FT_Outline_Reverse( FT_Outline* outline ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Get_Bitmap + * + * @description: + * Render an outline within a bitmap. The outline's image is simply + * OR-ed to the target bitmap. + * + * @input: + * library :: + * A handle to a FreeType library object. + * + * outline :: + * A pointer to the source outline descriptor. + * + * @inout: + * abitmap :: + * A pointer to the target bitmap descriptor. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * This function does **not create** the bitmap, it only renders an + * outline image within the one you pass to it! Consequently, the + * various fields in `abitmap` should be set accordingly. + * + * It will use the raster corresponding to the default glyph format. + * + * The value of the `num_grays` field in `abitmap` is ignored. If you + * select the gray-level rasterizer, and you want less than 256 gray + * levels, you have to use @FT_Outline_Render directly. + */ + FT_EXPORT( FT_Error ) + FT_Outline_Get_Bitmap( FT_Library library, + FT_Outline* outline, + const FT_Bitmap *abitmap ); + + + /************************************************************************** + * + * @function: + * FT_Outline_Render + * + * @description: + * Render an outline within a bitmap using the current scan-convert. + * + * @input: + * library :: + * A handle to a FreeType library object. + * + * outline :: + * A pointer to the source outline descriptor. + * + * @inout: + * params :: + * A pointer to an @FT_Raster_Params structure used to describe the + * rendering operation. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * This advanced function uses @FT_Raster_Params as an argument. + * The field `params.source` will be set to `outline` before the scan + * converter is called, which means that the value you give to it is + * actually ignored. Either `params.target` must point to preallocated + * bitmap, or @FT_RASTER_FLAG_DIRECT must be set in `params.flags` + * allowing FreeType rasterizer to be used for direct composition, + * translucency, etc. See @FT_Raster_Params for more details. + */ + FT_EXPORT( FT_Error ) + FT_Outline_Render( FT_Library library, + FT_Outline* outline, + FT_Raster_Params* params ); + + + /************************************************************************** + * + * @enum: + * FT_Orientation + * + * @description: + * A list of values used to describe an outline's contour orientation. + * + * The TrueType and PostScript specifications use different conventions + * to determine whether outline contours should be filled or unfilled. + * + * @values: + * FT_ORIENTATION_TRUETYPE :: + * According to the TrueType specification, clockwise contours must be + * filled, and counter-clockwise ones must be unfilled. + * + * FT_ORIENTATION_POSTSCRIPT :: + * According to the PostScript specification, counter-clockwise + * contours must be filled, and clockwise ones must be unfilled. + * + * FT_ORIENTATION_FILL_RIGHT :: + * This is identical to @FT_ORIENTATION_TRUETYPE, but is used to + * remember that in TrueType, everything that is to the right of the + * drawing direction of a contour must be filled. + * + * FT_ORIENTATION_FILL_LEFT :: + * This is identical to @FT_ORIENTATION_POSTSCRIPT, but is used to + * remember that in PostScript, everything that is to the left of the + * drawing direction of a contour must be filled. + * + * FT_ORIENTATION_NONE :: + * The orientation cannot be determined. That is, different parts of + * the glyph have different orientation. + * + */ + typedef enum FT_Orientation_ + { + FT_ORIENTATION_TRUETYPE = 0, + FT_ORIENTATION_POSTSCRIPT = 1, + FT_ORIENTATION_FILL_RIGHT = FT_ORIENTATION_TRUETYPE, + FT_ORIENTATION_FILL_LEFT = FT_ORIENTATION_POSTSCRIPT, + FT_ORIENTATION_NONE + + } FT_Orientation; + + + /************************************************************************** + * + * @function: + * FT_Outline_Get_Orientation + * + * @description: + * This function analyzes a glyph outline and tries to compute its fill + * orientation (see @FT_Orientation). This is done by integrating the + * total area covered by the outline. The positive integral corresponds + * to the clockwise orientation and @FT_ORIENTATION_POSTSCRIPT is + * returned. The negative integral corresponds to the counter-clockwise + * orientation and @FT_ORIENTATION_TRUETYPE is returned. + * + * Note that this will return @FT_ORIENTATION_TRUETYPE for empty + * outlines. + * + * @input: + * outline :: + * A handle to the source outline. + * + * @return: + * The orientation. + * + */ + FT_EXPORT( FT_Orientation ) + FT_Outline_Get_Orientation( FT_Outline* outline ); + + + /* */ + + +FT_END_HEADER + +#endif /* FTOUTLN_H_ */ + + +/* END */ + + +/* Local Variables: */ +/* coding: utf-8 */ +/* End: */ |