Edit
kc3-lang/freetype/src/smooth/ftsmooth.c
Alexei Podtelezhnikov
- src/smooth/ftsmooth.c
-
/**************************************************************************** * * ftsmooth.c * * Anti-aliasing renderer interface (body). * * Copyright (C) 2000-2024 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/ftdebug.h> #include <freetype/internal/ftobjs.h> #include <freetype/ftoutln.h> #include "ftsmooth.h" #include "ftgrays.h" #include "ftsmerrs.h" /* sets render-specific mode */ static FT_Error ft_smooth_set_mode( FT_Renderer render, FT_ULong mode_tag, FT_Pointer data ) { /* we simply pass it to the raster */ return render->clazz->raster_class->raster_set_mode( render->raster, mode_tag, data ); } /* transform a given glyph image */ static FT_Error ft_smooth_transform( FT_Renderer render, FT_GlyphSlot slot, const FT_Matrix* matrix, const FT_Vector* delta ) { FT_Error error = FT_Err_Ok; if ( slot->format != render->glyph_format ) { error = FT_THROW( Invalid_Argument ); goto Exit; } if ( matrix ) FT_Outline_Transform( &slot->outline, matrix ); if ( delta ) FT_Outline_Translate( &slot->outline, delta->x, delta->y ); Exit: return error; } /* return the glyph's control box */ static void ft_smooth_get_cbox( FT_Renderer render, FT_GlyphSlot slot, FT_BBox* cbox ) { FT_ZERO( cbox ); if ( slot->format == render->glyph_format ) FT_Outline_Get_CBox( &slot->outline, cbox ); } typedef struct TOrigin_ { unsigned char* origin; /* pixmap origin at the bottom-left */ int pitch; /* pitch to go down one row */ } TOrigin; #ifndef FT_CONFIG_OPTION_SUBPIXEL_RENDERING /* initialize renderer -- init its raster */ static FT_Error ft_smooth_init( FT_Module module ) /* FT_Renderer */ { FT_Renderer render = (FT_Renderer)module; FT_Vector* sub = render->root.library->lcd_geometry; /* set up default subpixel geometry for striped RGB panels. */ sub[0].x = -21; sub[0].y = 0; sub[1].x = 0; sub[1].y = 0; sub[2].x = 21; sub[2].y = 0; render->clazz->raster_class->raster_reset( render->raster, NULL, 0 ); return 0; } /* This function writes every third byte in direct rendering mode */ static void ft_smooth_lcd_spans( int y, int count, const FT_Span* spans, void* target_ ) /* TOrigin* */ { TOrigin* target = (TOrigin*)target_; unsigned char* dst_line = target->origin - y * target->pitch; unsigned char* dst; unsigned short w; for ( ; count--; spans++ ) for ( dst = dst_line + spans->x * 3, w = spans->len; w--; dst += 3 ) *dst = spans->coverage; } static FT_Error ft_smooth_raster_lcd( FT_Renderer render, FT_Outline* outline, FT_Bitmap* bitmap ) { FT_Error error = FT_Err_Ok; FT_Vector* sub = render->root.library->lcd_geometry; FT_Pos x, y; FT_Raster_Params params; TOrigin target; /* Render 3 separate coverage bitmaps, shifting the outline. */ /* Set up direct rendering to record them on each third byte. */ params.source = outline; params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT; params.gray_spans = ft_smooth_lcd_spans; params.user = ⌖ params.clip_box.xMin = 0; params.clip_box.yMin = 0; params.clip_box.xMax = bitmap->width; params.clip_box.yMax = bitmap->rows; if ( bitmap->pitch < 0 ) target.origin = bitmap->buffer; else target.origin = bitmap->buffer + ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch; target.pitch = bitmap->pitch; FT_Outline_Translate( outline, -sub[0].x, -sub[0].y ); error = render->raster_render( render->raster, ¶ms ); x = sub[0].x; y = sub[0].y; if ( error ) goto Exit; target.origin++; FT_Outline_Translate( outline, sub[0].x - sub[1].x, sub[0].y - sub[1].y ); error = render->raster_render( render->raster, ¶ms ); x = sub[1].x; y = sub[1].y; if ( error ) goto Exit; target.origin++; FT_Outline_Translate( outline, sub[1].x - sub[2].x, sub[1].y - sub[2].y ); error = render->raster_render( render->raster, ¶ms ); x = sub[2].x; y = sub[2].y; Exit: FT_Outline_Translate( outline, x, y ); return error; } static FT_Error ft_smooth_raster_lcdv( FT_Renderer render, FT_Outline* outline, FT_Bitmap* bitmap ) { FT_Error error = FT_Err_Ok; int pitch = bitmap->pitch; FT_Vector* sub = render->root.library->lcd_geometry; FT_Pos x, y; FT_Raster_Params params; params.target = bitmap; params.source = outline; params.flags = FT_RASTER_FLAG_AA; /* Render 3 separate coverage bitmaps, shifting the outline. */ /* Notice that the subpixel geometry vectors are rotated. */ /* Triple the pitch to render on each third row. */ bitmap->pitch *= 3; bitmap->rows /= 3; FT_Outline_Translate( outline, -sub[0].y, sub[0].x ); error = render->raster_render( render->raster, ¶ms ); x = sub[0].y; y = -sub[0].x; if ( error ) goto Exit; bitmap->buffer += pitch; FT_Outline_Translate( outline, sub[0].y - sub[1].y, sub[1].x - sub[0].x ); error = render->raster_render( render->raster, ¶ms ); x = sub[1].y; y = -sub[1].x; bitmap->buffer -= pitch; if ( error ) goto Exit; bitmap->buffer += 2 * pitch; FT_Outline_Translate( outline, sub[1].y - sub[2].y, sub[2].x - sub[1].x ); error = render->raster_render( render->raster, ¶ms ); x = sub[2].y; y = -sub[2].x; bitmap->buffer -= 2 * pitch; Exit: FT_Outline_Translate( outline, x, y ); bitmap->pitch /= 3; bitmap->rows *= 3; return error; } #else /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */ /* initialize renderer -- init its raster */ static FT_Error ft_smooth_init( FT_Module module ) /* FT_Renderer */ { FT_Renderer render = (FT_Renderer)module; /* set up default LCD filtering */ FT_Library_SetLcdFilter( render->root.library, FT_LCD_FILTER_DEFAULT ); render->clazz->raster_class->raster_reset( render->raster, NULL, 0 ); return 0; } static FT_Error ft_smooth_raster_lcd( FT_Renderer render, FT_Outline* outline, FT_Bitmap* bitmap ) { FT_Error error = FT_Err_Ok; FT_Vector* points = outline->points; FT_Vector* points_end = FT_OFFSET( points, outline->n_points ); FT_Vector* vec; FT_Raster_Params params; params.target = bitmap; params.source = outline; params.flags = FT_RASTER_FLAG_AA; /* implode outline */ for ( vec = points; vec < points_end; vec++ ) vec->x *= 3; /* render outline into the bitmap */ error = render->raster_render( render->raster, ¶ms ); /* deflate outline */ for ( vec = points; vec < points_end; vec++ ) vec->x /= 3; return error; } static FT_Error ft_smooth_raster_lcdv( FT_Renderer render, FT_Outline* outline, FT_Bitmap* bitmap ) { FT_Error error = FT_Err_Ok; FT_Vector* points = outline->points; FT_Vector* points_end = FT_OFFSET( points, outline->n_points ); FT_Vector* vec; FT_Raster_Params params; params.target = bitmap; params.source = outline; params.flags = FT_RASTER_FLAG_AA; /* implode outline */ for ( vec = points; vec < points_end; vec++ ) vec->y *= 3; /* render outline into the bitmap */ error = render->raster_render( render->raster, ¶ms ); /* deflate outline */ for ( vec = points; vec < points_end; vec++ ) vec->y /= 3; return error; } #endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */ /* Oversampling scale to be used in rendering overlaps */ #define SCALE ( 1 << 2 ) /* This function averages inflated spans in direct rendering mode */ static void ft_smooth_overlap_spans( int y, int count, const FT_Span* spans, void* target_ ) { TOrigin* target = (TOrigin*)target_; unsigned char* dst = target->origin - ( y / SCALE ) * target->pitch; unsigned short x; unsigned int cover, sum; /* When accumulating the oversampled spans we need to assure that */ /* fully covered pixels are equal to 255 and do not overflow. */ /* It is important that the SCALE is a power of 2, each subpixel */ /* cover can also reach a power of 2 after rounding, and the total */ /* is clamped to 255 when it adds up to 256. */ for ( ; count--; spans++ ) { cover = ( spans->coverage + SCALE * SCALE / 2 ) / ( SCALE * SCALE ); for ( x = 0; x < spans->len; x++ ) { sum = dst[( spans->x + x ) / SCALE] + cover; dst[( spans->x + x ) / SCALE] = (unsigned char)( sum - ( sum >> 8 ) ); } } } static FT_Error ft_smooth_raster_overlap( FT_Renderer render, FT_Outline* outline, FT_Bitmap* bitmap ) { FT_Error error = FT_Err_Ok; FT_Vector* points = outline->points; FT_Vector* points_end = FT_OFFSET( points, outline->n_points ); FT_Vector* vec; FT_Raster_Params params; TOrigin target; /* Reject outlines that are too wide for 16-bit FT_Span. */ /* Other limits are applied upstream with the same error code. */ if ( bitmap->width * SCALE > 0x7FFF ) return FT_THROW( Raster_Overflow ); /* Set up direct rendering to average oversampled spans. */ params.source = outline; params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT; params.gray_spans = ft_smooth_overlap_spans; params.user = ⌖ params.clip_box.xMin = 0; params.clip_box.yMin = 0; params.clip_box.xMax = bitmap->width * SCALE; params.clip_box.yMax = bitmap->rows * SCALE; if ( bitmap->pitch < 0 ) target.origin = bitmap->buffer; else target.origin = bitmap->buffer + ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch; target.pitch = bitmap->pitch; /* inflate outline */ for ( vec = points; vec < points_end; vec++ ) { vec->x *= SCALE; vec->y *= SCALE; } /* render outline into the bitmap */ error = render->raster_render( render->raster, ¶ms ); /* deflate outline */ for ( vec = points; vec < points_end; vec++ ) { vec->x /= SCALE; vec->y /= SCALE; } return error; } #undef SCALE static FT_Error ft_smooth_render( FT_Renderer render, FT_GlyphSlot slot, FT_Render_Mode mode, const FT_Vector* origin ) { FT_Error error = FT_Err_Ok; FT_Outline* outline = &slot->outline; FT_Bitmap* bitmap = &slot->bitmap; FT_Memory memory = render->root.memory; FT_Pos x_shift = 0; FT_Pos y_shift = 0; /* check glyph image format */ if ( slot->format != render->glyph_format ) { error = FT_THROW( Invalid_Argument ); goto Exit; } /* check mode */ if ( mode != FT_RENDER_MODE_NORMAL && mode != FT_RENDER_MODE_LIGHT && mode != FT_RENDER_MODE_LCD && mode != FT_RENDER_MODE_LCD_V ) { error = FT_THROW( Cannot_Render_Glyph ); goto Exit; } /* release old bitmap buffer */ if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP ) { FT_FREE( bitmap->buffer ); slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP; } if ( ft_glyphslot_preset_bitmap( slot, mode, origin ) ) { error = FT_THROW( Raster_Overflow ); goto Exit; } if ( !bitmap->rows || !bitmap->pitch ) goto Exit; /* allocate new one */ if ( FT_ALLOC_MULT( bitmap->buffer, bitmap->rows, bitmap->pitch ) ) goto Exit; slot->internal->flags |= FT_GLYPH_OWN_BITMAP; x_shift = 64 * -slot->bitmap_left; y_shift = 64 * -slot->bitmap_top; if ( bitmap->pixel_mode == FT_PIXEL_MODE_LCD_V ) y_shift += 64 * (FT_Int)bitmap->rows / 3; else y_shift += 64 * (FT_Int)bitmap->rows; if ( origin ) { x_shift += origin->x; y_shift += origin->y; } /* translate outline to render it into the bitmap */ if ( x_shift || y_shift ) FT_Outline_Translate( outline, x_shift, y_shift ); if ( mode == FT_RENDER_MODE_NORMAL || mode == FT_RENDER_MODE_LIGHT ) { if ( outline->flags & FT_OUTLINE_OVERLAP ) error = ft_smooth_raster_overlap( render, outline, bitmap ); else { FT_Raster_Params params; params.target = bitmap; params.source = outline; params.flags = FT_RASTER_FLAG_AA; error = render->raster_render( render->raster, ¶ms ); } } else { if ( mode == FT_RENDER_MODE_LCD ) error = ft_smooth_raster_lcd ( render, outline, bitmap ); else if ( mode == FT_RENDER_MODE_LCD_V ) error = ft_smooth_raster_lcdv( render, outline, bitmap ); #ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING /* finally apply filtering */ { FT_Byte* lcd_weights; FT_Bitmap_LcdFilterFunc lcd_filter_func; /* Per-face LCD filtering takes priority if set up. */ if ( slot->face && slot->face->internal->lcd_filter_func ) { lcd_weights = slot->face->internal->lcd_weights; lcd_filter_func = slot->face->internal->lcd_filter_func; } else { lcd_weights = slot->library->lcd_weights; lcd_filter_func = slot->library->lcd_filter_func; } if ( lcd_filter_func ) lcd_filter_func( bitmap, lcd_weights ); } #endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */ } Exit: if ( !error ) { /* everything is fine; the glyph is now officially a bitmap */ slot->format = FT_GLYPH_FORMAT_BITMAP; } else if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP ) { FT_FREE( bitmap->buffer ); slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP; } 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 */