/**************************************************************************** * * pshalgo.c * * PostScript hinting algorithm (body). * * Copyright (C) 2001-2023 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. * */ #include <freetype/internal/ftobjs.h> #include <freetype/internal/ftdebug.h> #include <freetype/internal/ftcalc.h> #include "pshalgo.h" #include "pshnterr.h" #undef FT_COMPONENT #define FT_COMPONENT … #ifdef DEBUG_HINTER PSH_Hint_Table ps_debug_hint_table = NULL; PSH_HintFunc ps_debug_hint_func = NULL; PSH_Glyph ps_debug_glyph = NULL; #endif #define COMPUTE_INFLEXS … /* and similar glyphs */ /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** BASIC HINTS RECORDINGS *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* return true if two stem hints overlap */ static FT_Int psh_hint_overlap( PSH_Hint hint1, PSH_Hint hint2 ) { … } /* destroy hints table */ static void psh_hint_table_done( PSH_Hint_Table table, FT_Memory memory ) { … } /* deactivate all hints in a table */ static void psh_hint_table_deactivate( PSH_Hint_Table table ) { … } /* internal function to record a new hint */ static void psh_hint_table_record( PSH_Hint_Table table, FT_UInt idx ) { … } static void psh_hint_table_record_mask( PSH_Hint_Table table, PS_Mask hint_mask ) { … } /* create hints table */ static FT_Error psh_hint_table_init( PSH_Hint_Table table, PS_Hint_Table hints, PS_Mask_Table hint_masks, PS_Mask_Table counter_masks, FT_Memory memory ) { … } static void psh_hint_table_activate_mask( PSH_Hint_Table table, PS_Mask hint_mask ) { … } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** HINTS GRID-FITTING AND OPTIMIZATION *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ #if 1 static FT_Pos psh_dimension_quantize_len( PSH_Dimension dim, FT_Pos len, FT_Bool do_snapping ) { … } #endif /* 0 */ #ifdef DEBUG_HINTER static void ps_simple_scale( PSH_Hint_Table table, FT_Fixed scale, FT_Fixed delta, FT_Int dimension ) { FT_UInt count; for ( count = 0; count < table->max_hints; count++ ) { PSH_Hint hint = table->hints + count; hint->cur_pos = FT_MulFix( hint->org_pos, scale ) + delta; hint->cur_len = FT_MulFix( hint->org_len, scale ); if ( ps_debug_hint_func ) ps_debug_hint_func( hint, dimension ); } } #endif /* DEBUG_HINTER */ static FT_Fixed psh_hint_snap_stem_side_delta( FT_Fixed pos, FT_Fixed len ) { … } static void psh_hint_align( PSH_Hint hint, PSH_Globals globals, FT_Int dimension, PSH_Glyph glyph ) { … } #if 0 /* not used for now, experimental */ /* * A variant to perform "light" hinting (i.e. FT_RENDER_MODE_LIGHT) * of stems */ static void psh_hint_align_light( PSH_Hint hint, PSH_Globals globals, FT_Int dimension, PSH_Glyph glyph ) { PSH_Dimension dim = &globals->dimension[dimension]; FT_Fixed scale = dim->scale_mult; FT_Fixed delta = dim->scale_delta; if ( !psh_hint_is_fitted( hint ) ) { FT_Pos pos = FT_MulFix( hint->org_pos, scale ) + delta; FT_Pos len = FT_MulFix( hint->org_len, scale ); FT_Pos fit_len; PSH_AlignmentRec align; /* ignore stem alignments when requested through the hint flags */ if ( ( dimension == 0 && !glyph->do_horz_hints ) || ( dimension == 1 && !glyph->do_vert_hints ) ) { hint->cur_pos = pos; hint->cur_len = len; psh_hint_set_fitted( hint ); return; } fit_len = len; hint->cur_len = fit_len; /* check blue zones for horizontal stems */ align.align = PSH_BLUE_ALIGN_NONE; align.align_bot = align.align_top = 0; if ( dimension == 1 ) psh_blues_snap_stem( &globals->blues, ADD_INT( hint->org_pos, hint->org_len ), hint->org_pos, &align ); switch ( align.align ) { case PSH_BLUE_ALIGN_TOP: /* the top of the stem is aligned against a blue zone */ hint->cur_pos = align.align_top - fit_len; break; case PSH_BLUE_ALIGN_BOT: /* the bottom of the stem is aligned against a blue zone */ hint->cur_pos = align.align_bot; break; case PSH_BLUE_ALIGN_TOP | PSH_BLUE_ALIGN_BOT: /* both edges of the stem are aligned against blue zones */ hint->cur_pos = align.align_bot; hint->cur_len = align.align_top - align.align_bot; break; default: { PSH_Hint parent = hint->parent; if ( parent ) { FT_Pos par_org_center, par_cur_center; FT_Pos cur_org_center, cur_delta; /* ensure that parent is already fitted */ if ( !psh_hint_is_fitted( parent ) ) psh_hint_align_light( parent, globals, dimension, glyph ); par_org_center = parent->org_pos + ( parent->org_len / 2 ); par_cur_center = parent->cur_pos + ( parent->cur_len / 2 ); cur_org_center = hint->org_pos + ( hint->org_len / 2 ); cur_delta = FT_MulFix( cur_org_center - par_org_center, scale ); pos = par_cur_center + cur_delta - ( len >> 1 ); } /* Stems less than one pixel wide are easy -- we want to * make them as dark as possible, so they must fall within * one pixel. If the stem is split between two pixels * then snap the edge that is nearer to the pixel boundary * to the pixel boundary. */ if ( len <= 64 ) { if ( ( pos + len + 63 ) / 64 != pos / 64 + 1 ) pos += psh_hint_snap_stem_side_delta ( pos, len ); } /* Position stems other to minimize the amount of mid-grays. * There are, in general, two positions that do this, * illustrated as A) and B) below. * * + + + + * * A) |--------------------------------| * B) |--------------------------------| * C) |--------------------------------| * * Position A) (split the excess stem equally) should be better * for stems of width N + f where f < 0.5. * * Position B) (split the deficiency equally) should be better * for stems of width N + f where f > 0.5. * * It turns out though that minimizing the total number of lit * pixels is also important, so position C), with one edge * aligned with a pixel boundary is actually preferable * to A). There are also more possible positions for C) than * for A) or B), so it involves less distortion of the overall * character shape. */ else /* len > 64 */ { FT_Fixed frac_len = len & 63; FT_Fixed center = pos + ( len >> 1 ); FT_Fixed delta_a, delta_b; if ( ( len / 64 ) & 1 ) { delta_a = FT_PIX_FLOOR( center ) + 32 - center; delta_b = FT_PIX_ROUND( center ) - center; } else { delta_a = FT_PIX_ROUND( center ) - center; delta_b = FT_PIX_FLOOR( center ) + 32 - center; } /* We choose between B) and C) above based on the amount * of fractional stem width; for small amounts, choose * C) always, for large amounts, B) always, and inbetween, * pick whichever one involves less stem movement. */ if ( frac_len < 32 ) { pos += psh_hint_snap_stem_side_delta ( pos, len ); } else if ( frac_len < 48 ) { FT_Fixed side_delta = psh_hint_snap_stem_side_delta ( pos, len ); if ( FT_ABS( side_delta ) < FT_ABS( delta_b ) ) pos += side_delta; else pos += delta_b; } else { pos += delta_b; } } hint->cur_pos = pos; } } /* switch */ psh_hint_set_fitted( hint ); #ifdef DEBUG_HINTER if ( ps_debug_hint_func ) ps_debug_hint_func( hint, dimension ); #endif } } #endif /* 0 */ static void psh_hint_table_align_hints( PSH_Hint_Table table, PSH_Globals globals, FT_Int dimension, PSH_Glyph glyph ) { … } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** POINTS INTERPOLATION ROUTINES *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ #define xxDEBUG_ZONES #ifdef DEBUG_ZONES #include FT_CONFIG_STANDARD_LIBRARY_H static void psh_print_zone( PSH_Zone zone ) { printf( "zone [scale,delta,min,max] = [%.5f,%.2f,%d,%d]\n", zone->scale / 65536.0, zone->delta / 64.0, zone->min, zone->max ); } #endif /* DEBUG_ZONES */ /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** HINTER GLYPH MANAGEMENT *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ #define psh_corner_is_flat … #define psh_corner_orientation … #ifdef COMPUTE_INFLEXS /* compute all inflex points in a given glyph */ static void psh_glyph_compute_inflections( PSH_Glyph glyph ) { … } #endif /* COMPUTE_INFLEXS */ static void psh_glyph_done( PSH_Glyph glyph ) { … } static PSH_Dir psh_compute_dir( FT_Pos dx, FT_Pos dy ) { … } /* load outline point coordinates into hinter glyph */ static void psh_glyph_load_points( PSH_Glyph glyph, FT_Int dimension ) { … } /* save hinted point coordinates back to outline */ static void psh_glyph_save_points( PSH_Glyph glyph, FT_Int dimension ) { … } static FT_Error psh_glyph_init( PSH_Glyph glyph, FT_Outline* outline, PS_Hints ps_hints, PSH_Globals globals ) { … } /* compute all extrema in a glyph for a given dimension */ static void psh_glyph_compute_extrema( PSH_Glyph glyph ) { … } /* the min and max are based on contour orientation and fill rule */ static void psh_hint_table_find_strong_points( PSH_Hint_Table table, PSH_Point point, FT_UInt count, FT_Int threshold, PSH_Dir major_dir ) { … } /* the accepted shift for strong points in fractional pixels */ #define PSH_STRONG_THRESHOLD … /* the maximum shift value in font units tuned to distinguish */ /* between stems and serifs in URW+ font collection */ #define PSH_STRONG_THRESHOLD_MAXIMUM … /* find strong points in a glyph */ static void psh_glyph_find_strong_points( PSH_Glyph glyph, FT_Int dimension ) { … } /* find points in a glyph which are in a blue zone and have `in' or */ /* `out' tangents parallel to the horizontal axis */ static void psh_glyph_find_blue_points( PSH_Blues blues, PSH_Glyph glyph ) { … } /* interpolate strong points with the help of hinted coordinates */ static void psh_glyph_interpolate_strong_points( PSH_Glyph glyph, FT_Int dimension ) { … } #define PSH_MAX_STRONG_INTERNAL … static void psh_glyph_interpolate_normal_points( PSH_Glyph glyph, FT_Int dimension ) { … } /* interpolate other points */ static void psh_glyph_interpolate_other_points( PSH_Glyph glyph, FT_Int dimension ) { … } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** HIGH-LEVEL INTERFACE *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ FT_Error ps_hints_apply( PS_Hints ps_hints, FT_Outline* outline, PSH_Globals globals, FT_Render_Mode hint_mode ) { … } /* END */
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