ref: 587264cfd528f2e8fbb180bc4798ad58d20ceb85
dir: /src/smooth/ftsmooth.c/
/***************************************************************************/
/* */
/* ftsmooth.c */
/* */
/* Anti-aliasing renderer interface (body). */
/* */
/* Copyright 2000-2017 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 <ft2build.h>
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_OBJECTS_H
#include FT_OUTLINE_H
#include "ftsmooth.h"
#include "ftgrays.h"
#include "ftspic.h"
#include "ftsmerrs.h"
/* initialize renderer -- init its raster */
static FT_Error
ft_smooth_init( FT_Renderer render )
{
render->clazz->raster_class->raster_reset( render->raster, NULL, 0 );
return 0;
}
/* 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 );
}
/* convert a slot's glyph image into a bitmap */
static FT_Error
ft_smooth_render_generic( FT_Renderer render,
FT_GlyphSlot slot,
FT_Render_Mode mode,
const FT_Vector* origin,
FT_Render_Mode required_mode )
{
FT_Error error;
FT_Outline* outline = &slot->outline;
FT_Bitmap* bitmap = &slot->bitmap;
FT_Memory memory = render->root.memory;
FT_BBox cbox;
FT_Pos x_shift = 0;
FT_Pos y_shift = 0;
FT_Pos x_left, y_top;
FT_Pos width, height, pitch;
FT_Int hmul = ( mode == FT_RENDER_MODE_LCD );
FT_Int vmul = ( mode == FT_RENDER_MODE_LCD_V );
FT_Raster_Params params;
FT_Bool have_outline_shifted = FALSE;
FT_Bool have_buffer = FALSE;
#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
FT_LcdFiveTapFilter lcd_weights = { 0 };
FT_Bool have_custom_weight = FALSE;
FT_Bitmap_LcdFilterFunc lcd_filter_func = NULL;
if ( slot->face )
{
FT_Char i;
for ( i = 0; i < FT_LCD_FILTER_FIVE_TAPS; i++ )
if ( slot->face->internal->lcd_weights[i] != 0 )
{
have_custom_weight = TRUE;
break;
}
}
/*
* The LCD filter can be set library-wide and per-face. Face overrides
* library. If the face filter weights are all zero (the default), it
* means that the library default should be used.
*/
if ( have_custom_weight )
{
/*
* A per-font filter is set. It always uses the default 5-tap
* in-place FIR filter.
*/
ft_memcpy( lcd_weights,
slot->face->internal->lcd_weights,
FT_LCD_FILTER_FIVE_TAPS );
lcd_filter_func = ft_lcd_filter_fir;
}
else
{
/*
* The face's lcd_weights is {0, 0, 0, 0, 0}, meaning `use library
* default'. If the library is set to use no LCD filtering
* (lcd_filter_func == NULL), `lcd_filter_func' here is also set to
* NULL and the tests further below pass over the filtering process.
*/
ft_memcpy( lcd_weights,
slot->library->lcd_weights,
FT_LCD_FILTER_FIVE_TAPS );
lcd_filter_func = slot->library->lcd_filter_func;
}
#endif /*FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
/* check glyph image format */
if ( slot->format != render->glyph_format )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* check mode */
if ( mode != required_mode )
{
error = FT_THROW( Cannot_Render_Glyph );
goto Exit;
}
if ( origin )
{
x_shift = origin->x;
y_shift = origin->y;
}
/* compute the control box, and grid fit it */
/* taking into account the origin shift */
FT_Outline_Get_CBox( outline, &cbox );
#ifndef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
/* add minimal padding for LCD rendering */
if ( hmul )
{
cbox.xMax += 21;
cbox.xMin -= 21;
}
if ( vmul )
{
cbox.yMax += 21;
cbox.yMin -= 21;
}
#else /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
/* add minimal padding for LCD filter depending on specific weights */
if ( lcd_filter_func )
{
if ( hmul )
{
cbox.xMax += lcd_weights[4] ? 43
: lcd_weights[3] ? 22 : 0;
cbox.xMin -= lcd_weights[0] ? 43
: lcd_weights[1] ? 22 : 0;
}
if ( vmul )
{
cbox.yMax += lcd_weights[4] ? 43
: lcd_weights[3] ? 22 : 0;
cbox.yMin -= lcd_weights[0] ? 43
: lcd_weights[1] ? 22 : 0;
}
}
#endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
cbox.xMin = FT_PIX_FLOOR( cbox.xMin + x_shift );
cbox.yMin = FT_PIX_FLOOR( cbox.yMin + y_shift );
cbox.xMax = FT_PIX_CEIL( cbox.xMax + x_shift );
cbox.yMax = FT_PIX_CEIL( cbox.yMax + y_shift );
x_shift -= cbox.xMin;
y_shift -= cbox.yMin;
x_left = cbox.xMin >> 6;
y_top = cbox.yMax >> 6;
width = (FT_ULong)( cbox.xMax - cbox.xMin ) >> 6;
height = (FT_ULong)( cbox.yMax - cbox.yMin ) >> 6;
pitch = width;
if ( hmul )
{
width *= 3;
pitch = FT_PAD_CEIL( width, 4 );
}
if ( vmul )
height *= 3;
/*
* XXX: on 16bit system, we return an error for huge bitmap
* to prevent an overflow.
*/
if ( x_left > FT_INT_MAX || y_top > FT_INT_MAX ||
x_left < FT_INT_MIN || y_top < FT_INT_MIN )
{
error = FT_THROW( Invalid_Pixel_Size );
goto Exit;
}
/* Required check is (pitch * height < FT_ULONG_MAX), */
/* but we care realistic cases only. Always pitch <= width. */
if ( width > 0x7FFF || height > 0x7FFF )
{
FT_ERROR(( "ft_smooth_render_generic: glyph too large: %u x %u\n",
width, height ));
error = FT_THROW( Raster_Overflow );
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;
}
/* allocate new one */
if ( FT_ALLOC( bitmap->buffer, (FT_ULong)( pitch * height ) ) )
goto Exit;
else
have_buffer = TRUE;
slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
slot->format = FT_GLYPH_FORMAT_BITMAP;
slot->bitmap_left = (FT_Int)x_left;
slot->bitmap_top = (FT_Int)y_top;
bitmap->pixel_mode = FT_PIXEL_MODE_GRAY;
bitmap->num_grays = 256;
bitmap->width = (unsigned int)width;
bitmap->rows = (unsigned int)height;
bitmap->pitch = pitch;
/* translate outline to render it into the bitmap */
if ( x_shift || y_shift )
{
FT_Outline_Translate( outline, x_shift, y_shift );
have_outline_shifted = TRUE;
}
/* set up parameters */
params.target = bitmap;
params.source = outline;
params.flags = FT_RASTER_FLAG_AA;
#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
/* implode outline if needed */
{
FT_Vector* points = outline->points;
FT_Vector* points_end = points + outline->n_points;
FT_Vector* vec;
if ( hmul )
for ( vec = points; vec < points_end; vec++ )
vec->x *= 3;
if ( vmul )
for ( vec = points; vec < points_end; vec++ )
vec->y *= 3;
}
/* render outline into the bitmap */
error = render->raster_render( render->raster, ¶ms );
/* deflate outline if needed */
{
FT_Vector* points = outline->points;
FT_Vector* points_end = points + outline->n_points;
FT_Vector* vec;
if ( hmul )
for ( vec = points; vec < points_end; vec++ )
vec->x /= 3;
if ( vmul )
for ( vec = points; vec < points_end; vec++ )
vec->y /= 3;
}
if ( error )
goto Exit;
if ( lcd_filter_func )
lcd_filter_func( bitmap, mode, lcd_weights );
#else /* !FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
if ( hmul ) /* lcd */
{
FT_Byte* line;
FT_Byte* temp;
FT_Int i, j;
/* Render 3 separate monochrome bitmaps, shifting the outline */
/* by 1/3 pixel. */
width /= 3;
FT_Outline_Translate( outline, 21, 0 );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
FT_Outline_Translate( outline, -21, 0 );
bitmap->buffer += width;
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
FT_Outline_Translate( outline, -21, 0 );
bitmap->buffer += width;
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
FT_Outline_Translate( outline, 21, 0 );
bitmap->buffer -= 2 * width;
/* XXX: Rearrange the bytes according to FT_PIXEL_MODE_LCD. */
/* XXX: It is more efficient to render every third byte above. */
if ( FT_ALLOC( temp, (FT_ULong)pitch ) )
goto Exit;
for ( i = 0; i < height; i++ )
{
line = bitmap->buffer + i * pitch;
for ( j = 0; j < width; j++ )
{
temp[3 * j ] = line[j];
temp[3 * j + 1] = line[j + width];
temp[3 * j + 2] = line[j + width + width];
}
FT_MEM_COPY( line, temp, pitch );
}
FT_FREE( temp );
}
else if ( vmul ) /* lcd_v */
{
/* Render 3 separate monochrome bitmaps, shifting the outline */
/* by 1/3 pixel. Triple the pitch to render on each third row. */
bitmap->pitch *= 3;
bitmap->rows /= 3;
FT_Outline_Translate( outline, 0, 21 );
bitmap->buffer += 2 * pitch;
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
FT_Outline_Translate( outline, 0, -21 );
bitmap->buffer -= pitch;
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
FT_Outline_Translate( outline, 0, -21 );
bitmap->buffer -= pitch;
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
FT_Outline_Translate( outline, 0, 21 );
bitmap->pitch /= 3;
bitmap->rows *= 3;
}
else /* grayscale */
{
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
}
#endif /* !FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
/* everything is fine; don't deallocate buffer */
have_buffer = FALSE;
error = FT_Err_Ok;
Exit:
if ( have_outline_shifted )
FT_Outline_Translate( outline, -x_shift, -y_shift );
if ( have_buffer )
{
FT_FREE( bitmap->buffer );
slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
}
return error;
}
/* convert a slot's glyph image into a bitmap */
static FT_Error
ft_smooth_render( FT_Renderer render,
FT_GlyphSlot slot,
FT_Render_Mode mode,
const FT_Vector* origin )
{
if ( mode == FT_RENDER_MODE_LIGHT )
mode = FT_RENDER_MODE_NORMAL;
return ft_smooth_render_generic( render, slot, mode, origin,
FT_RENDER_MODE_NORMAL );
}
/* convert a slot's glyph image into a horizontal LCD bitmap */
static FT_Error
ft_smooth_render_lcd( FT_Renderer render,
FT_GlyphSlot slot,
FT_Render_Mode mode,
const FT_Vector* origin )
{
FT_Error error;
error = ft_smooth_render_generic( render, slot, mode, origin,
FT_RENDER_MODE_LCD );
if ( !error )
slot->bitmap.pixel_mode = FT_PIXEL_MODE_LCD;
return error;
}
/* convert a slot's glyph image into a vertical LCD bitmap */
static FT_Error
ft_smooth_render_lcd_v( FT_Renderer render,
FT_GlyphSlot slot,
FT_Render_Mode mode,
const FT_Vector* origin )
{
FT_Error error;
error = ft_smooth_render_generic( render, slot, mode, origin,
FT_RENDER_MODE_LCD_V );
if ( !error )
slot->bitmap.pixel_mode = FT_PIXEL_MODE_LCD_V;
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_GET /* raster_class */
)
FT_DEFINE_RENDERER(
ft_smooth_lcd_renderer_class,
FT_MODULE_RENDERER,
sizeof ( FT_RendererRec ),
"smooth-lcd",
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_lcd, /* 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_GET /* raster_class */
)
FT_DEFINE_RENDERER(
ft_smooth_lcdv_renderer_class,
FT_MODULE_RENDERER,
sizeof ( FT_RendererRec ),
"smooth-lcdv",
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_lcd_v, /* 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_GET /* raster_class */
)
/* END */