596 lines
16 KiB
C
596 lines
16 KiB
C
/****************************************************************************
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*
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* ftsmooth.c
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*
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* Anti-aliasing renderer interface (body).
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*
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* Copyright (C) 2000-2021 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* This file is part of the FreeType project, and may only be used,
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* modified, and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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*/
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#include <freetype/internal/ftdebug.h>
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#include <freetype/internal/ftobjs.h>
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#include <freetype/ftoutln.h>
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#include "ftsmooth.h"
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#include "ftgrays.h"
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#include "ftsmerrs.h"
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/* sets render-specific mode */
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static FT_Error
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ft_smooth_set_mode( FT_Renderer render,
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FT_ULong mode_tag,
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FT_Pointer data )
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{
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/* we simply pass it to the raster */
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return render->clazz->raster_class->raster_set_mode( render->raster,
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mode_tag,
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data );
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}
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/* transform a given glyph image */
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static FT_Error
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ft_smooth_transform( FT_Renderer render,
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FT_GlyphSlot slot,
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const FT_Matrix* matrix,
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const FT_Vector* delta )
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{
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FT_Error error = FT_Err_Ok;
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if ( slot->format != render->glyph_format )
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{
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error = FT_THROW( Invalid_Argument );
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goto Exit;
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}
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if ( matrix )
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FT_Outline_Transform( &slot->outline, matrix );
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if ( delta )
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FT_Outline_Translate( &slot->outline, delta->x, delta->y );
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Exit:
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return error;
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}
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/* return the glyph's control box */
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static void
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ft_smooth_get_cbox( FT_Renderer render,
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FT_GlyphSlot slot,
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FT_BBox* cbox )
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{
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FT_ZERO( cbox );
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if ( slot->format == render->glyph_format )
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FT_Outline_Get_CBox( &slot->outline, cbox );
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}
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typedef struct TOrigin_
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{
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unsigned char* origin; /* pixmap origin at the bottom-left */
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int pitch; /* pitch to go down one row */
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} TOrigin;
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#ifndef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
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/* initialize renderer -- init its raster */
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static FT_Error
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ft_smooth_init( FT_Renderer render )
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{
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FT_Vector* sub = render->root.library->lcd_geometry;
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/* set up default subpixel geometry for striped RGB panels. */
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sub[0].x = -21;
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sub[0].y = 0;
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sub[1].x = 0;
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sub[1].y = 0;
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sub[2].x = 21;
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sub[2].y = 0;
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render->clazz->raster_class->raster_reset( render->raster, NULL, 0 );
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return 0;
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}
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/* This function writes every third byte in direct rendering mode */
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static void
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ft_smooth_lcd_spans( int y,
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int count,
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const FT_Span* spans,
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TOrigin* target )
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{
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unsigned char* dst_line = target->origin - y * target->pitch;
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unsigned char* dst;
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unsigned short w;
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for ( ; count--; spans++ )
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for ( dst = dst_line + spans->x * 3, w = spans->len; w--; dst += 3 )
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*dst = spans->coverage;
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}
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static FT_Error
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ft_smooth_raster_lcd( FT_Renderer render,
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FT_Outline* outline,
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FT_Bitmap* bitmap )
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{
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FT_Error error = FT_Err_Ok;
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FT_Vector* sub = render->root.library->lcd_geometry;
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FT_Pos x, y;
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FT_Raster_Params params;
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TOrigin target;
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/* Render 3 separate coverage bitmaps, shifting the outline. */
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/* Set up direct rendering to record them on each third byte. */
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params.source = outline;
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params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT;
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params.gray_spans = (FT_SpanFunc)ft_smooth_lcd_spans;
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params.user = ⌖
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params.clip_box.xMin = 0;
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params.clip_box.yMin = 0;
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params.clip_box.xMax = bitmap->width;
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params.clip_box.yMax = bitmap->rows;
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if ( bitmap->pitch < 0 )
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target.origin = bitmap->buffer;
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else
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target.origin = bitmap->buffer
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+ ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch;
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target.pitch = bitmap->pitch;
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FT_Outline_Translate( outline,
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-sub[0].x,
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-sub[0].y );
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error = render->raster_render( render->raster, ¶ms );
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x = sub[0].x;
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y = sub[0].y;
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if ( error )
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goto Exit;
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target.origin++;
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FT_Outline_Translate( outline,
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sub[0].x - sub[1].x,
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sub[0].y - sub[1].y );
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error = render->raster_render( render->raster, ¶ms );
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x = sub[1].x;
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y = sub[1].y;
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if ( error )
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goto Exit;
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target.origin++;
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FT_Outline_Translate( outline,
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sub[1].x - sub[2].x,
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sub[1].y - sub[2].y );
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error = render->raster_render( render->raster, ¶ms );
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x = sub[2].x;
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y = sub[2].y;
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Exit:
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FT_Outline_Translate( outline, x, y );
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return error;
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}
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static FT_Error
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ft_smooth_raster_lcdv( FT_Renderer render,
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FT_Outline* outline,
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FT_Bitmap* bitmap )
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{
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FT_Error error = FT_Err_Ok;
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int pitch = bitmap->pitch;
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FT_Vector* sub = render->root.library->lcd_geometry;
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FT_Pos x, y;
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FT_Raster_Params params;
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params.target = bitmap;
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params.source = outline;
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params.flags = FT_RASTER_FLAG_AA;
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/* Render 3 separate coverage bitmaps, shifting the outline. */
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/* Notice that the subpixel geometry vectors are rotated. */
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/* Triple the pitch to render on each third row. */
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bitmap->pitch *= 3;
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bitmap->rows /= 3;
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FT_Outline_Translate( outline,
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-sub[0].y,
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sub[0].x );
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error = render->raster_render( render->raster, ¶ms );
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x = sub[0].y;
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y = -sub[0].x;
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if ( error )
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goto Exit;
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bitmap->buffer += pitch;
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FT_Outline_Translate( outline,
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sub[0].y - sub[1].y,
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sub[1].x - sub[0].x );
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error = render->raster_render( render->raster, ¶ms );
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x = sub[1].y;
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y = -sub[1].x;
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bitmap->buffer -= pitch;
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if ( error )
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goto Exit;
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bitmap->buffer += 2 * pitch;
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FT_Outline_Translate( outline,
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sub[1].y - sub[2].y,
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sub[2].x - sub[1].x );
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error = render->raster_render( render->raster, ¶ms );
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x = sub[2].y;
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y = -sub[2].x;
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bitmap->buffer -= 2 * pitch;
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Exit:
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FT_Outline_Translate( outline, x, y );
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bitmap->pitch /= 3;
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bitmap->rows *= 3;
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return error;
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}
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#else /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
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/* initialize renderer -- init its raster */
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static FT_Error
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ft_smooth_init( FT_Renderer render )
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{
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/* set up default LCD filtering */
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FT_Library_SetLcdFilter( render->root.library, FT_LCD_FILTER_DEFAULT );
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render->clazz->raster_class->raster_reset( render->raster, NULL, 0 );
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return 0;
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}
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static FT_Error
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ft_smooth_raster_lcd( FT_Renderer render,
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FT_Outline* outline,
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FT_Bitmap* bitmap )
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{
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FT_Error error = FT_Err_Ok;
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FT_Vector* points = outline->points;
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FT_Vector* points_end = FT_OFFSET( points, outline->n_points );
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FT_Vector* vec;
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FT_Raster_Params params;
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params.target = bitmap;
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params.source = outline;
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params.flags = FT_RASTER_FLAG_AA;
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/* implode outline */
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for ( vec = points; vec < points_end; vec++ )
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vec->x *= 3;
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/* render outline into the bitmap */
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error = render->raster_render( render->raster, ¶ms );
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/* deflate outline */
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for ( vec = points; vec < points_end; vec++ )
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vec->x /= 3;
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return error;
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}
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static FT_Error
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ft_smooth_raster_lcdv( FT_Renderer render,
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FT_Outline* outline,
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FT_Bitmap* bitmap )
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{
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FT_Error error = FT_Err_Ok;
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FT_Vector* points = outline->points;
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FT_Vector* points_end = FT_OFFSET( points, outline->n_points );
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FT_Vector* vec;
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FT_Raster_Params params;
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params.target = bitmap;
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params.source = outline;
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params.flags = FT_RASTER_FLAG_AA;
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/* implode outline */
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for ( vec = points; vec < points_end; vec++ )
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vec->y *= 3;
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/* render outline into the bitmap */
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error = render->raster_render( render->raster, ¶ms );
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/* deflate outline */
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for ( vec = points; vec < points_end; vec++ )
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vec->y /= 3;
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return error;
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}
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#endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
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/* Oversampling scale to be used in rendering overlaps */
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#define SCALE ( 1 << 2 )
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/* This function averages inflated spans in direct rendering mode */
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static void
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ft_smooth_overlap_spans( int y,
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int count,
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const FT_Span* spans,
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TOrigin* target )
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{
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unsigned char* dst = target->origin - ( y / SCALE ) * target->pitch;
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unsigned short x;
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unsigned int cover, sum;
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/* When accumulating the oversampled spans we need to assure that */
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/* fully covered pixels are equal to 255 and do not overflow. */
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/* It is important that the SCALE is a power of 2, each subpixel */
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/* cover can also reach a power of 2 after rounding, and the total */
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/* is clamped to 255 when it adds up to 256. */
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for ( ; count--; spans++ )
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{
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cover = ( spans->coverage + SCALE * SCALE / 2 ) / ( SCALE * SCALE );
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for ( x = 0; x < spans->len; x++ )
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{
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sum = dst[( spans->x + x ) / SCALE] + cover;
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dst[( spans->x + x ) / SCALE] = (unsigned char)( sum - ( sum >> 8 ) );
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}
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}
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}
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static FT_Error
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ft_smooth_raster_overlap( FT_Renderer render,
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FT_Outline* outline,
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FT_Bitmap* bitmap )
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{
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FT_Error error = FT_Err_Ok;
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FT_Vector* points = outline->points;
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FT_Vector* points_end = FT_OFFSET( points, outline->n_points );
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FT_Vector* vec;
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FT_Raster_Params params;
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TOrigin target;
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/* Reject outlines that are too wide for 16-bit FT_Span. */
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/* Other limits are applied upstream with the same error code. */
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if ( bitmap->width * SCALE > 0x7FFF )
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return FT_THROW( Raster_Overflow );
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/* Set up direct rendering to average oversampled spans. */
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params.source = outline;
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params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT;
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params.gray_spans = (FT_SpanFunc)ft_smooth_overlap_spans;
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params.user = ⌖
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params.clip_box.xMin = 0;
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params.clip_box.yMin = 0;
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params.clip_box.xMax = bitmap->width * SCALE;
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params.clip_box.yMax = bitmap->rows * SCALE;
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if ( bitmap->pitch < 0 )
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target.origin = bitmap->buffer;
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else
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target.origin = bitmap->buffer
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+ ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch;
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target.pitch = bitmap->pitch;
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/* inflate outline */
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for ( vec = points; vec < points_end; vec++ )
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{
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vec->x *= SCALE;
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vec->y *= SCALE;
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}
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/* render outline into the bitmap */
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error = render->raster_render( render->raster, ¶ms );
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/* deflate outline */
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for ( vec = points; vec < points_end; vec++ )
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{
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vec->x /= SCALE;
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vec->y /= SCALE;
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}
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return error;
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}
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#undef SCALE
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static FT_Error
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ft_smooth_render( FT_Renderer render,
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FT_GlyphSlot slot,
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FT_Render_Mode mode,
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const FT_Vector* origin )
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{
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FT_Error error = FT_Err_Ok;
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FT_Outline* outline = &slot->outline;
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FT_Bitmap* bitmap = &slot->bitmap;
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FT_Memory memory = render->root.memory;
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FT_Pos x_shift = 0;
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FT_Pos y_shift = 0;
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/* check glyph image format */
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if ( slot->format != render->glyph_format )
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{
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error = FT_THROW( Invalid_Argument );
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goto Exit;
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}
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/* check mode */
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if ( mode != FT_RENDER_MODE_NORMAL &&
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mode != FT_RENDER_MODE_LIGHT &&
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mode != FT_RENDER_MODE_LCD &&
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mode != FT_RENDER_MODE_LCD_V )
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{
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error = FT_THROW( Cannot_Render_Glyph );
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goto Exit;
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}
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/* release old bitmap buffer */
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if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP )
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{
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FT_FREE( bitmap->buffer );
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slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
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}
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if ( ft_glyphslot_preset_bitmap( slot, mode, origin ) )
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{
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error = FT_THROW( Raster_Overflow );
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goto Exit;
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}
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if ( !bitmap->rows || !bitmap->pitch )
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goto Exit;
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/* allocate new one */
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if ( FT_ALLOC_MULT( bitmap->buffer, bitmap->rows, bitmap->pitch ) )
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goto Exit;
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slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
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x_shift = 64 * -slot->bitmap_left;
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y_shift = 64 * -slot->bitmap_top;
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if ( bitmap->pixel_mode == FT_PIXEL_MODE_LCD_V )
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y_shift += 64 * (FT_Int)bitmap->rows / 3;
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else
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y_shift += 64 * (FT_Int)bitmap->rows;
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if ( origin )
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{
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x_shift += origin->x;
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y_shift += origin->y;
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}
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/* translate outline to render it into the bitmap */
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if ( x_shift || y_shift )
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FT_Outline_Translate( outline, x_shift, y_shift );
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if ( mode == FT_RENDER_MODE_NORMAL ||
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mode == FT_RENDER_MODE_LIGHT )
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{
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if ( outline->flags & FT_OUTLINE_OVERLAP )
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error = ft_smooth_raster_overlap( render, outline, bitmap );
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else
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{
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FT_Raster_Params params;
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params.target = bitmap;
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params.source = outline;
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params.flags = FT_RASTER_FLAG_AA;
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error = render->raster_render( render->raster, ¶ms );
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}
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}
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else
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{
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if ( mode == FT_RENDER_MODE_LCD )
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error = ft_smooth_raster_lcd ( render, outline, bitmap );
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else if ( mode == FT_RENDER_MODE_LCD_V )
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error = ft_smooth_raster_lcdv( render, outline, bitmap );
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#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
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/* finally apply filtering */
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{
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FT_Byte* lcd_weights;
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FT_Bitmap_LcdFilterFunc lcd_filter_func;
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/* Per-face LCD filtering takes priority if set up. */
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if ( slot->face && slot->face->internal->lcd_filter_func )
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{
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lcd_weights = slot->face->internal->lcd_weights;
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lcd_filter_func = slot->face->internal->lcd_filter_func;
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}
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else
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{
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lcd_weights = slot->library->lcd_weights;
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lcd_filter_func = slot->library->lcd_filter_func;
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}
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if ( lcd_filter_func )
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lcd_filter_func( bitmap, lcd_weights );
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}
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#endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
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}
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Exit:
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if ( !error )
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{
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/* everything is fine; the glyph is now officially a bitmap */
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slot->format = FT_GLYPH_FORMAT_BITMAP;
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}
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else if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP )
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{
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FT_FREE( bitmap->buffer );
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slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
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}
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if ( x_shift || y_shift )
|
|
FT_Outline_Translate( outline, -x_shift, -y_shift );
|
|
|
|
return error;
|
|
}
|
|
|
|
|
|
FT_DEFINE_RENDERER(
|
|
ft_smooth_renderer_class,
|
|
|
|
FT_MODULE_RENDERER,
|
|
sizeof ( FT_RendererRec ),
|
|
|
|
"smooth",
|
|
0x10000L,
|
|
0x20000L,
|
|
|
|
NULL, /* module specific interface */
|
|
|
|
(FT_Module_Constructor)ft_smooth_init, /* module_init */
|
|
(FT_Module_Destructor) NULL, /* module_done */
|
|
(FT_Module_Requester) NULL, /* get_interface */
|
|
|
|
FT_GLYPH_FORMAT_OUTLINE,
|
|
|
|
(FT_Renderer_RenderFunc) ft_smooth_render, /* render_glyph */
|
|
(FT_Renderer_TransformFunc)ft_smooth_transform, /* transform_glyph */
|
|
(FT_Renderer_GetCBoxFunc) ft_smooth_get_cbox, /* get_glyph_cbox */
|
|
(FT_Renderer_SetModeFunc) ft_smooth_set_mode, /* set_mode */
|
|
|
|
(FT_Raster_Funcs*)&ft_grays_raster /* raster_class */
|
|
)
|
|
|
|
|
|
/* END */
|