ref: 2eb8f8862669f50bf11693fb5c4f729a0ddf847f
dir: /src/truetype/ttobjs.h/
/**************************************************************************** * * ttobjs.h * * Objects manager (specification). * * Copyright (C) 1996-2020 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 TTOBJS_H_ #define TTOBJS_H_ #include <freetype/internal/ftobjs.h> #include <freetype/internal/tttypes.h> FT_BEGIN_HEADER /************************************************************************** * * @Type: * TT_Driver * * @Description: * A handle to a TrueType driver object. */ typedef struct TT_DriverRec_* TT_Driver; /************************************************************************** * * @Type: * TT_GlyphSlot * * @Description: * A handle to a TrueType glyph slot object. * * @Note: * This is a direct typedef of FT_GlyphSlot, as there is nothing * specific about the TrueType glyph slot. */ typedef FT_GlyphSlot TT_GlyphSlot; /************************************************************************** * * @Struct: * TT_GraphicsState * * @Description: * The TrueType graphics state used during bytecode interpretation. */ typedef struct TT_GraphicsState_ { FT_UShort rp0; FT_UShort rp1; FT_UShort rp2; FT_UnitVector dualVector; FT_UnitVector projVector; FT_UnitVector freeVector; FT_Long loop; FT_F26Dot6 minimum_distance; FT_Int round_state; FT_Bool auto_flip; FT_F26Dot6 control_value_cutin; FT_F26Dot6 single_width_cutin; FT_F26Dot6 single_width_value; FT_UShort delta_base; FT_UShort delta_shift; FT_Byte instruct_control; /* According to Greg Hitchcock from Microsoft, the `scan_control' */ /* variable as documented in the TrueType specification is a 32-bit */ /* integer; the high-word part holds the SCANTYPE value, the low-word */ /* part the SCANCTRL value. We separate it into two fields. */ FT_Bool scan_control; FT_Int scan_type; FT_UShort gep0; FT_UShort gep1; FT_UShort gep2; } TT_GraphicsState; #ifdef TT_USE_BYTECODE_INTERPRETER FT_LOCAL( void ) tt_glyphzone_done( TT_GlyphZone zone ); FT_LOCAL( FT_Error ) tt_glyphzone_new( FT_Memory memory, FT_UShort maxPoints, FT_Short maxContours, TT_GlyphZone zone ); #endif /* TT_USE_BYTECODE_INTERPRETER */ /************************************************************************** * * EXECUTION SUBTABLES * * These sub-tables relate to instruction execution. * */ #define TT_MAX_CODE_RANGES 3 /************************************************************************** * * There can only be 3 active code ranges at once: * - the Font Program * - the CVT Program * - a glyph's instructions set */ typedef enum TT_CodeRange_Tag_ { tt_coderange_none = 0, tt_coderange_font, tt_coderange_cvt, tt_coderange_glyph } TT_CodeRange_Tag; typedef struct TT_CodeRange_ { FT_Byte* base; FT_Long size; } TT_CodeRange; typedef TT_CodeRange TT_CodeRangeTable[TT_MAX_CODE_RANGES]; /************************************************************************** * * Defines a function/instruction definition record. */ typedef struct TT_DefRecord_ { FT_Int range; /* in which code range is it located? */ FT_Long start; /* where does it start? */ FT_Long end; /* where does it end? */ FT_UInt opc; /* function #, or instruction code */ FT_Bool active; /* is it active? */ FT_Bool inline_delta; /* is function that defines inline delta? */ FT_ULong sph_fdef_flags; /* flags to identify special functions */ } TT_DefRecord, *TT_DefArray; /************************************************************************** * * Subglyph transformation record. */ typedef struct TT_Transform_ { FT_Fixed xx, xy; /* transformation matrix coefficients */ FT_Fixed yx, yy; FT_F26Dot6 ox, oy; /* offsets */ } TT_Transform; /************************************************************************** * * A note regarding non-squared pixels: * * (This text will probably go into some docs at some time; for now, it * is kept here to explain some definitions in the TT_Size_Metrics * record). * * The CVT is a one-dimensional array containing values that control * certain important characteristics in a font, like the height of all * capitals, all lowercase letter, default spacing or stem width/height. * * These values are found in FUnits in the font file, and must be scaled * to pixel coordinates before being used by the CVT and glyph programs. * Unfortunately, when using distinct x and y resolutions (or distinct x * and y pointsizes), there are two possible scalings. * * A first try was to implement a `lazy' scheme where all values were * scaled when first used. However, while some values are always used * in the same direction, some others are used under many different * circumstances and orientations. * * I have found a simpler way to do the same, and it even seems to work * in most of the cases: * * - All CVT values are scaled to the maximum ppem size. * * - When performing a read or write in the CVT, a ratio factor is used * to perform adequate scaling. Example: * * x_ppem = 14 * y_ppem = 10 * * We choose ppem = x_ppem = 14 as the CVT scaling size. All cvt * entries are scaled to it. * * x_ratio = 1.0 * y_ratio = y_ppem/ppem (< 1.0) * * We compute the current ratio like: * * - If projVector is horizontal, * ratio = x_ratio = 1.0 * * - if projVector is vertical, * ratio = y_ratio * * - else, * ratio = sqrt( (proj.x * x_ratio) ^ 2 + (proj.y * y_ratio) ^ 2 ) * * Reading a cvt value returns * ratio * cvt[index] * * Writing a cvt value in pixels: * cvt[index] / ratio * * The current ppem is simply * ratio * ppem * */ /************************************************************************** * * Metrics used by the TrueType size and context objects. */ typedef struct TT_Size_Metrics_ { /* for non-square pixels */ FT_Long x_ratio; FT_Long y_ratio; FT_UShort ppem; /* maximum ppem size */ FT_Long ratio; /* current ratio */ FT_Fixed scale; FT_F26Dot6 compensations[4]; /* device-specific compensations */ FT_Bool valid; FT_Bool rotated; /* `is the glyph rotated?'-flag */ FT_Bool stretched; /* `is the glyph stretched?'-flag */ } TT_Size_Metrics; /************************************************************************** * * TrueType size class. */ typedef struct TT_SizeRec_ { FT_SizeRec root; /* we have our own copy of metrics so that we can modify */ /* it without affecting auto-hinting (when used) */ FT_Size_Metrics* metrics; /* for the current rendering mode */ FT_Size_Metrics hinted_metrics; /* for the hinted rendering mode */ TT_Size_Metrics ttmetrics; FT_ULong strike_index; /* 0xFFFFFFFF to indicate invalid */ #ifdef TT_USE_BYTECODE_INTERPRETER FT_Long point_size; /* for the `MPS' bytecode instruction */ FT_UInt num_function_defs; /* number of function definitions */ FT_UInt max_function_defs; TT_DefArray function_defs; /* table of function definitions */ FT_UInt num_instruction_defs; /* number of ins. definitions */ FT_UInt max_instruction_defs; TT_DefArray instruction_defs; /* table of ins. definitions */ FT_UInt max_func; FT_UInt max_ins; TT_CodeRangeTable codeRangeTable; TT_GraphicsState GS; FT_ULong cvt_size; /* the scaled control value table */ FT_Long* cvt; FT_UShort storage_size; /* The storage area is now part of */ FT_Long* storage; /* the instance */ TT_GlyphZoneRec twilight; /* The instance's twilight zone */ TT_ExecContext context; /* if negative, `fpgm' (resp. `prep'), wasn't executed yet; */ /* otherwise it is the returned error code */ FT_Error bytecode_ready; FT_Error cvt_ready; #endif /* TT_USE_BYTECODE_INTERPRETER */ } TT_SizeRec; /************************************************************************** * * TrueType driver class. */ typedef struct TT_DriverRec_ { FT_DriverRec root; TT_GlyphZoneRec zone; /* glyph loader points zone */ FT_UInt interpreter_version; } TT_DriverRec; /* Note: All of the functions below (except tt_size_reset()) are used */ /* as function pointers in a FT_Driver_ClassRec. Therefore their */ /* parameters are of types FT_Face, FT_Size, etc., rather than TT_Face, */ /* TT_Size, etc., so that the compiler can confirm that the types and */ /* number of parameters are correct. In all cases the FT_xxx types are */ /* cast to their TT_xxx counterparts inside the functions since FreeType */ /* will always use the TT driver to create them. */ /************************************************************************** * * Face functions */ FT_LOCAL( FT_Error ) tt_face_init( FT_Stream stream, FT_Face ttface, /* TT_Face */ FT_Int face_index, FT_Int num_params, FT_Parameter* params ); FT_LOCAL( void ) tt_face_done( FT_Face ttface ); /* TT_Face */ /************************************************************************** * * Size functions */ FT_LOCAL( FT_Error ) tt_size_init( FT_Size ttsize ); /* TT_Size */ FT_LOCAL( void ) tt_size_done( FT_Size ttsize ); /* TT_Size */ #ifdef TT_USE_BYTECODE_INTERPRETER FT_LOCAL( FT_Error ) tt_size_run_fpgm( TT_Size size, FT_Bool pedantic ); FT_LOCAL( FT_Error ) tt_size_run_prep( TT_Size size, FT_Bool pedantic ); FT_LOCAL( FT_Error ) tt_size_ready_bytecode( TT_Size size, FT_Bool pedantic ); #endif /* TT_USE_BYTECODE_INTERPRETER */ FT_LOCAL( FT_Error ) tt_size_reset( TT_Size size, FT_Bool only_height ); /************************************************************************** * * Driver functions */ FT_LOCAL( FT_Error ) tt_driver_init( FT_Module ttdriver ); /* TT_Driver */ FT_LOCAL( void ) tt_driver_done( FT_Module ttdriver ); /* TT_Driver */ /************************************************************************** * * Slot functions */ FT_LOCAL( FT_Error ) tt_slot_init( FT_GlyphSlot slot ); /* auxiliary */ #define IS_HINTED( flags ) ( ( flags & FT_LOAD_NO_HINTING ) == 0 ) FT_END_HEADER #endif /* TTOBJS_H_ */ /* END */