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* src/autofit/*: important fixes to the auto-fitter. The output 

now seems to be 100% equivalent to the auto-hinter, while being
        about 2% faster (which proves that script-specific algorithm
        selection isn't a performance problem).

        to test it, change "autohint" to "autofit" in
        <freetype/config/ftmodule.h> and recompile.

        a few more testing is needed before making this the official
        auto-hinting module
This commit is contained in:
David Turner 2004-06-04 17:41:59 +00:00
parent 56a4d87cb2
commit e664efaddd
11 changed files with 329 additions and 111 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
ChangeLog
View File

@ -1,3 +1,16 @@
2004-06-04 David Turner <david@freetype.org>
* src/autofit/*: important fixes to the auto-fitter. The output
now seems to be 100% equivalent to the auto-hinter, while being
about 2% faster (which proves that script-specific algorithm
selection isn't a performance problem).
to test it, change "autohint" to "autofit" in
<freetype/config/ftmodule.h> and recompile.
a few more testing is needed before making this the official
auto-hinting module
2004-06-02 Werner Lemberg <wl@gnu.org>
* src/truetype/ttgload.c (compute_glyph_metrics): Fix compiler
@ -24,7 +37,7 @@
2004-05-17 Werner Lemberg <wl@gnu.org>
* src/base/ftbbox.c (BBox_Conic_Check): Fix boundary cases.
* src/base/ftbbox.c (BBox_Conic_Check): Fix boundary cases.
Reported by Mikey Anbary <manbary@vizrt.com>.
2004-05-15 Werner Lemberg <wl@gnu.org>
@ -173,7 +186,7 @@
consistency.
(pcf_cmap_init, pcf_cmap_done, pcf_cmap_char_index,
pcf_cmap_char_next): Don't use PCF_XXX but FT_XXX arguments which
are typecast to the proper PCF_XXX types within the function.
are typecast to the proper PCF_XXX types within the function.
Update code accordingly.
(pcf_cmap_class): Remove casts.
(PCF_Face_Done, PCF_Face_Init, PCF_Set_Pixel_Size): Don't use

96
src/autofit/afangles.c
View File

@ -1,8 +1,57 @@
#include "aftypes.h"
/*
* a python script used to generate the following table
*
import sys, math
units = 256
scale = units/math.pi
comma = ""
print ""
print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units"
r = [-1] + range(32)
for n in r:
if n >= 0:
x = 1.0/(2.0**n) # tangent value
else:
x = 2.0**(-n)
angle = math.atan(x) # arctangent
angle2 = angle*scale # arctangent in FT_Angle units
# determine which integer value for angle gives the best tangent
lo = int(angle2)
hi = lo + 1
tlo = math.tan(lo/scale)
thi = math.tan(hi/scale)
errlo = abs( tlo - x )
errhi = abs( thi - x )
angle2 = hi
if errlo < errhi:
angle2 = lo
if angle2 <= 0:
break
sys.stdout.write( comma + repr( int(angle2) ) )
comma = ", "
*
* end of python script
*/
/* this table was generated for AF_ANGLE_PI = 256 */
#define AF_ANGLE_MAX_ITERS 8
#define AF_TRIG_MAX_ITERS 9
#define AF_TRIG_MAX_ITERS 8
static const FT_Fixed
af_angle_arctan_table[9] =
@ -69,7 +118,7 @@
{
x = -x;
y = -y;
theta = 2 * AF_ANGLE_PI2;
theta = AF_ANGLE_PI;
}
if ( y > 0 )
@ -115,11 +164,13 @@
}
} while ( ++i < AF_TRIG_MAX_ITERS );
#if 0
/* round theta */
if ( theta >= 0 )
theta = FT_PAD_ROUND( theta, 4 );
theta = FT_PAD_ROUND( theta, 2 );
else
theta = - FT_PAD_ROUND( theta, 4 );
theta = - FT_PAD_ROUND( -theta, 2 );
#endif
vec->x = x;
vec->y = theta;
@ -212,3 +263,40 @@
}
}
}
#ifdef TEST
#include <stdio.h>
#include <math.h>
int main( void )
{
int angle;
int dist;
for ( dist = 100; dist < 1000; dist++ )
{
for ( angle = AF_ANGLE_PI; angle < AF_ANGLE_2PI*4; angle++ )
{
double a = (angle*3.1415926535)/(1.0*AF_ANGLE_PI);
int dx, dy, angle1, angle2, delta;
dx = dist * cos(a);
dy = dist * sin(a);
angle1 = ((atan2(dy,dx)*AF_ANGLE_PI)/3.1415926535);
angle2 = af_angle_atan( dx, dy );
delta = (angle2 - angle1) % AF_ANGLE_2PI;
if ( delta < 0 )
delta = -delta;
if ( delta >= 2 )
{
printf( "dist:%4d angle:%4d => (%4d,%4d) angle1:%4d angle2:%4d\n",
dist, angle, dx, dy, angle1, angle2 );
}
}
}
return 0;
}
#endif

13
src/autofit/afdummy.c
View File

@ -3,20 +3,21 @@
static FT_Error
af_dummy_hints_init( AF_GlyphHints hints,
FT_Outline* outline,
AF_ScriptMetrics metrics )
{
return af_glyph_hints_reset( hints,
&metrics->scaler,
metrics,
outline );
af_glyph_hints_rescale( hints,
metrics );
return 0;
}
static FT_Error
af_dummy_hints_apply( AF_GlyphHints hints,
FT_Outline* outline )
{
af_glyph_hints_save( hints, outline );
FT_UNUSED( hints );
FT_UNUSED( outline );
return 0;
}

2
src/autofit/afglobal.c
View File

@ -12,7 +12,7 @@
NULL /* do not remove */
};
#define AF_SCRIPT_LIST_DEFAULT 0 /* index of default script in 'af_script_classes' */
#define AF_SCRIPT_LIST_DEFAULT 1 /* index of default script in 'af_script_classes' */
#define AF_SCRIPT_LIST_NONE 255 /* indicates an uncovered glyph */
/*

39
src/autofit/afhints.c
View File

@ -10,11 +10,11 @@
switch (dir)
{
case AF_DIR_UP: result = "up"; break;
case AF_DIR_DOWN: result = "down"; break;
case AF_DIR_LEFT: result = "left"; break;
case AF_DIR_UP: result = "up"; break;
case AF_DIR_DOWN: result = "down"; break;
case AF_DIR_LEFT: result = "left"; break;
case AF_DIR_RIGHT: result = "right"; break;
default: result = "none";
default: result = "none";
}
return result;
}
@ -111,7 +111,7 @@
for ( edge = edges; edge < limit; edge++ )
{
printf ( " [ %5d | %4d | %5s | %4d | %5d | %c | %5.2f | %5.2f ]\n",
printf ( " [ %5d | %4d | %5s | %4d | %5d | %c | %5.2f | %5.2f ]\n",
edge - edges,
(int)edge->fpos,
af_dir_str( edge->dir ),
@ -314,26 +314,29 @@
FT_LOCAL_DEF( void )
af_glyph_hints_rescale( AF_GlyphHints hints,
AF_ScriptMetrics metrics )
{
hints->metrics = metrics;
}
FT_LOCAL_DEF( FT_Error )
af_glyph_hints_reset( AF_GlyphHints hints,
AF_Scaler scaler,
AF_ScriptMetrics metrics,
FT_Outline* outline )
af_glyph_hints_reload( AF_GlyphHints hints,
FT_Outline* outline )
{
FT_Error error = FT_Err_Ok;
AF_Point points;
FT_UInt old_max, new_max;
FT_Fixed x_scale = scaler->x_scale;
FT_Fixed y_scale = scaler->y_scale;
FT_Pos x_delta = scaler->x_delta;
FT_Pos y_delta = scaler->y_delta;
AF_Scaler scaler = &hints->metrics->scaler;
FT_Fixed x_scale = hints->x_scale;
FT_Fixed y_scale = hints->y_scale;
FT_Pos x_delta = hints->x_delta;
FT_Pos y_delta = hints->y_delta;
FT_Memory memory = hints->memory;
hints->metrics = metrics;
hints->scaler_flags = scaler->flags;
hints->other_flags = 0;
hints->scaler_flags = scaler->flags;
hints->num_points = 0;
hints->num_contours = 0;

10
src/autofit/afhints.h
View File

@ -214,11 +214,13 @@ FT_BEGIN_HEADER
/* recomputes all AF_Point in a AF_GlyphHints from the definitions
* in a source outline
*/
FT_LOCAL( void )
af_glyph_hints_rescale( AF_GlyphHints hints,
AF_ScriptMetrics metrics );
FT_LOCAL( FT_Error )
af_glyph_hints_reset( AF_GlyphHints hints,
AF_Scaler scaler,
AF_ScriptMetrics metrics,
FT_Outline* outline );
af_glyph_hints_reload( AF_GlyphHints hints,
FT_Outline* outline );
FT_LOCAL( void )
af_glyph_hints_save( AF_GlyphHints hints,

154
src/autofit/aflatin.c
View File

@ -25,8 +25,8 @@
FT_Error error;
FT_UInt glyph_index;
AF_Dimension dim;
AF_ScalerRec scaler[1];
AF_ScriptMetricsRec dummy[1];
AF_Scaler scaler = &dummy->scaler;
glyph_index = FT_Get_Char_Index( face, 'o' );
if ( glyph_index == 0 )
@ -36,15 +36,17 @@
if ( error || face->glyph->outline.n_points <= 0 )
goto Exit;
FT_ZERO( dummy );
scaler->x_scale = scaler->y_scale = 0x10000L;
scaler->x_delta = scaler->y_delta = 0;
scaler->face = face;
scaler->render_mode = 0;
scaler->flags = 0;
error = af_glyph_hints_reset( hints, scaler,
(AF_ScriptMetrics) metrics,
&face->glyph->outline );
af_glyph_hints_rescale( hints, dummy );
error = af_glyph_hints_reload( hints, &face->glyph->outline );
if ( error )
goto Exit;
@ -324,6 +326,13 @@
if ( AF_LATIN_IS_TOP_BLUE(bb) )
blue->flags |= AF_LATIN_BLUE_TOP;
/* the following flags is used later to adjust the y and x scales
* in order to optimize the pixel grid alignment of the top of small
* letters.
*/
if ( bb == AF_LATIN_BLUE_SMALL_TOP )
blue->flags |= AF_LATIN_BLUE_ADJUSTMENT;
AF_LOG(( "-- ref = %ld, shoot = %ld\n", *blue_ref, *blue_shoot ));
}
@ -382,8 +391,44 @@
axis->org_scale = scale;
axis->org_delta = delta;
/* XXX: TODO: Correct Y and X scale according to Chester rules
/* correct X and Y scale to optimize the alignment of the top of small
* letters to the pixel grid
*/
{
AF_LatinAxis axis = &metrics->axis[ AF_DIMENSION_VERT ];
AF_LatinBlue blue = NULL;
FT_UInt nn;
for ( nn = 0; nn < axis->blue_count; nn++ )
{
if ( axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT )
{
blue = &axis->blues[nn];
break;
}
}
if ( blue )
{
FT_Pos scaled = FT_MulFix( blue->shoot.org, scaler->y_scale );
FT_Pos fitted = FT_PIX_ROUND( scaled );
if ( scaled != fitted )
{
if ( dim == AF_DIMENSION_HORZ )
{
if ( fitted < scaled )
scale -= scale/50; /* x_scale = x_scale*0.98 */
}
else
{
scale = FT_MulDiv( scale, fitted, scaled );
}
}
}
}
axis->scale = scale;
axis->delta = delta;
@ -417,17 +462,41 @@
AF_LatinBlue blue = & axis->blues[nn];
FT_Pos dist;
blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta;
blue->ref.fit = blue->ref.cur;
blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta;
blue->ref.fit = blue->ref.cur;
blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta;
blue->shoot.fit = blue->shoot.cur;
blue->flags &= ~AF_LATIN_BLUE_ACTIVE;
/* a blue zone is only active when it is less than 3/4 pixels tall
*/
dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale );
if ( dist >= 48 || dist <= -48 )
blue->flags |= ~AF_LATIN_BLUE_ACTIVE;
if ( dist <= 48 && dist >= -48 )
{
FT_Pos delta, delta2;
delta = blue->shoot.org - blue->ref.org;
delta2 = delta;
if ( delta < 0 )
delta2 = -delta2;
delta2 = FT_MulFix( delta2, scale );
if ( delta2 < 32 )
delta2 = 0;
else if ( delta2 < 64 )
delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
else
delta2 = FT_PIX_ROUND( delta2 );
if ( delta < 0 )
delta2 = -delta2;
blue->ref.fit = FT_PIX_ROUND( blue->ref.cur );
blue->shoot.fit = blue->ref.fit + delta2;
blue->flags |= AF_LATIN_BLUE_ACTIVE;
}
}
}
}
@ -437,6 +506,9 @@
af_latin_metrics_scale( AF_LatinMetrics metrics,
AF_Scaler scaler )
{
if ( AF_SCALER_EQUAL_SCALES( scaler, &metrics->root.scaler ) )
return;
af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );
af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );
}
@ -791,6 +863,7 @@
AF_Dimension dim )
{
AF_AxisHints axis = &hints->axis[dim];
AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim];
AF_Edge edges = axis->edges;
AF_Edge edge, edge_limit;
@ -825,7 +898,7 @@
/* */
/*********************************************************************/
edge_distance_threshold = FT_MulFix( hints->edge_distance_threshold,
edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,
scale );
if ( edge_distance_threshold > 64 / 4 )
edge_distance_threshold = 64 / 4;
@ -1138,18 +1211,19 @@
static FT_Error
af_latin_hints_init( AF_GlyphHints hints,
FT_Outline* outline,
AF_LatinMetrics metrics )
{
FT_Error error;
FT_Render_Mode mode;
error = af_glyph_hints_reset( hints, &metrics->root.scaler,
(AF_ScriptMetrics) metrics,
outline );
if (error)
goto Exit;
af_glyph_hints_rescale( hints, (AF_ScriptMetrics)metrics );
/* correct x_scale and y_scale when needed, since they may have
* been modified af_latin_scale_dim above
*/
hints->x_scale = metrics->axis[ AF_DIMENSION_HORZ ].scale;
hints->x_delta = metrics->axis[ AF_DIMENSION_HORZ ].delta;
hints->y_scale = metrics->axis[ AF_DIMENSION_VERT ].scale;
hints->y_delta = metrics->axis[ AF_DIMENSION_VERT ].delta;
/* compute flags depending on render mode, etc...
*/
@ -1176,21 +1250,11 @@
if ( mode == FT_RENDER_MODE_MONO )
hints->other_flags |= AF_LATIN_HINTS_MONO;
/* analyze glyph outline
*/
if ( AF_HINTS_DO_HORIZONTAL(hints) )
af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ );
if ( AF_HINTS_DO_VERTICAL(hints) )
{
af_latin_hints_detect_features( hints, AF_DIMENSION_VERT );
af_latin_hints_compute_blue_edges( hints, metrics );
}
Exit:
return error;
return 0;
}
/***************************************************************************/
/***************************************************************************/
/***** *****/
@ -1738,10 +1802,26 @@
FT_Outline* outline,
AF_LatinMetrics metrics )
{
FT_Error error;
AF_Dimension dim;
FT_UNUSED( metrics );
error = af_glyph_hints_reload( hints, outline );
if ( error )
goto Exit;
/* analyze glyph outline
*/
if ( AF_HINTS_DO_HORIZONTAL(hints) )
af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ );
if ( AF_HINTS_DO_VERTICAL(hints) )
{
af_latin_hints_detect_features( hints, AF_DIMENSION_VERT );
af_latin_hints_compute_blue_edges( hints, metrics );
}
/* grid-fit the outline
*/
for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
{
if ( (dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL(hints)) ||
@ -1755,7 +1835,8 @@
}
af_glyph_hints_save( hints, outline );
return 0;
Exit:
return error;
}
/***************************************************************************/
@ -1768,11 +1849,12 @@
static const AF_Script_UniRangeRec af_latin_uniranges[] =
{
{ 32, 127 }, /* XXX: TODO: Add new Unicode ranges here !! */
{ 32, 127 }, /* XXX: TODO: Add new Unicode ranges here !! */
{ 160, 255 },
{ 0, 0 }
{ 0, 0 }
};
FT_LOCAL_DEF( const AF_ScriptClassRec ) af_latin_script_class =
{
AF_SCRIPT_LATIN,

7
src/autofit/aflatin.h
View File

@ -51,9 +51,10 @@ FT_BEGIN_HEADER
enum
{
AF_LATIN_BLUE_ACTIVE = (1 << 0),
AF_LATIN_BLUE_TOP = (1 << 1),
AF_LATIN_BLUE_ACTIVE = (1 << 0),
AF_LATIN_BLUE_TOP = (1 << 1),
AF_LATIN_BLUE_ADJUSTMENT = (1 << 2), /* used for scale adjustment */
/* optimization */
AF_LATIN_BLUE_FLAG_MAX
};

61
src/autofit/afloader.c
View File

@ -105,16 +105,9 @@
* is needed
*/
if ( loader->transformed )
{
FT_Vector* point = slot->outline.points;
FT_Vector* limit = point + slot->outline.n_points;
for ( ; point < limit; point++ )
{
point->x += loader->trans_delta.x;
point->y += loader->trans_delta.y;
}
}
FT_Outline_Translate( &slot->outline,
loader->trans_delta.x,
loader->trans_delta.y );
/* copy the outline points in the loader's current */
/* extra points which is used to keep original glyph coordinates */
@ -157,16 +150,10 @@
/* now load the slot image into the auto-outline and run the */
/* automatic hinting process */
error = metrics->clazz->script_hints_init( hints,
&gloader->current.outline,
metrics );
if ( error )
goto Exit;
/* apply the hints */
metrics->clazz->script_hints_apply( hints,
&gloader->current.outline,
metrics );
/* we now need to hint the metrics according to the change in */
/* width/positioning that occured during the hinting process */
{
@ -175,20 +162,27 @@
AF_Edge edge1 = axis->edges; /* leftmost edge */
AF_Edge edge2 = edge1 + axis->num_edges - 1; /* rightmost edge */
if ( edge2 > edge1 )
{
old_advance = loader->pp2.x;
old_rsb = old_advance - edge2->opos;
old_lsb = edge1->opos;
new_lsb = edge1->pos;
old_advance = loader->pp2.x;
old_rsb = old_advance - edge2->opos;
old_lsb = edge1->opos;
new_lsb = edge1->pos;
loader->pp1.x = FT_PIX_ROUND( new_lsb - old_lsb );
loader->pp2.x = FT_PIX_ROUND( edge2->pos + old_rsb );
loader->pp1.x = FT_PIX_ROUND( new_lsb - old_lsb );
loader->pp2.x = FT_PIX_ROUND( edge2->pos + old_rsb );
#if 0
/* try to fix certain bad advance computations */
if ( loader->pp2.x + loader->pp1.x == edge2->pos && old_rsb > 4 )
loader->pp2.x += 64;
/* try to fix certain bad advance computations */
if ( loader->pp2.x + loader->pp1.x == edge2->pos && old_rsb > 4 )
loader->pp2.x += 64;
#endif
}
else
{
loader->pp1.x = FT_PIX_ROUND( loader->pp1.x );
loader->pp2.x = FT_PIX_ROUND( loader->pp2.x );
}
}
/* good, we simply add the glyph to our loader's base */
@ -366,7 +360,13 @@
slot->metrics.horiAdvance = FT_MulFix( slot->metrics.horiAdvance,
x_scale );
#else
slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x;
/* for mono-width fonts (like Andale, Courier, etc.) we need */
/* to keep the original rounded advance width */
if ( !FT_IS_FIXED_WIDTH( slot->face ) )
slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x;
else
slot->metrics.horiAdvance = FT_MulFix( slot->metrics.horiAdvance,
metrics->scaler.x_scale );
#endif
slot->metrics.horiAdvance = FT_PIX_ROUND( slot->metrics.horiAdvance );
@ -434,8 +434,13 @@
load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_IGNORE_TRANSFORM;
load_flags &= ~FT_LOAD_RENDER;
error = metrics->clazz->script_hints_init( &loader->hints, metrics );
if ( error )
goto Exit;
error = af_loader_load_g( loader, &scaler, gindex, load_flags, 0 );
}
}
Exit:
return error;
}

26
src/autofit/aftypes.h
View File

@ -1,3 +1,20 @@
/***************************************************************************
*
* FreeType auto-fitter
*
* (c) 2004 David Turner
*
* The auto-fitter is a complete rewrite of the old auto-hinter.
* its main feature is the ability to differentiate between different
* scripts in order to apply language-specific rules.
*
* the code has also been compartimentized into several entities that
* should make algorithmic experimentation easier than with the old
* code.
*
* finally, we get rid of the Catharon license, since this code is
* released under the FreeType one.
*/
#ifndef __AFTYPES_H__
#define __AFTYPES_H__
@ -73,7 +90,7 @@ FT_BEGIN_HEADER
typedef FT_Int AF_Angle;
#define AF_ANGLE_PI 128
#define AF_ANGLE_PI 256
#define AF_ANGLE_2PI (AF_ANGLE_PI*2)
#define AF_ANGLE_PI2 (AF_ANGLE_PI/2)
#define AF_ANGLE_PI4 (AF_ANGLE_PI/4)
@ -164,6 +181,12 @@ FT_BEGIN_HEADER
} AF_ScalerRec, *AF_Scaler;
#define AF_SCALER_EQUAL_SCALES(a,b) \
( (a)->x_scale == (b)->x_scale && \
(a)->y_scale == (b)->y_scale && \
(a)->x_delta == (b)->x_delta && \
(a)->y_delta == (b)->y_delta )
/**************************************************************************/
/**************************************************************************/
@ -228,7 +251,6 @@ FT_BEGIN_HEADER
typedef FT_Error (*AF_Script_InitHintsFunc)( AF_GlyphHints hints,
FT_Outline* outline,
AF_ScriptMetrics metrics );
typedef void (*AF_Script_ApplyHintsFunc)( AF_GlyphHints hints,

15
src/tools/cordic.py
View File

@ -1,7 +1,8 @@
# compute arctangent table for CORDIC computations in fttrigon.c
import sys, math
units = 64*65536.0 # don't change !!
#units = 64*65536.0 # don't change !!
units = 256
scale = units/math.pi
shrink = 1.0
comma = ""
@ -23,7 +24,7 @@ def print_val( n, x ):
errlo = abs( alo - ax )
errhi = abs( ahi - ax )
if ( errlo < errhi ):
hi = lo
@ -44,8 +45,8 @@ for n in r:
x = 1.0/(2.0**n) # tangent value
else:
x = 2.0**(-n)
angle = math.atan(x) # arctangent
angle = math.atan(x) # arctangent
angle2 = angle*scale # arctangent in FT_Angle units
# determine which integer value for angle gives the best tangent
@ -63,12 +64,12 @@ for n in r:
if angle2 <= 0:
break
sys.stdout.write( comma + repr( int(angle2) ) )
comma = ", "
shrink = shrink * math.cos( angle2/scale)
print
print "shrink factor = " + repr( shrink )