rgraves
/
freetype2
forked from minhngoc25a/freetype2
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

* src/sdf/ftsdfrend.c (sdf_generate_bounding_box): Add buffer for signs.

This commit is contained in:
Anuj Verma 2020-07-06 16:18:51 +05:30 committed by anujverma
parent e6576cc0e7
commit c4f64fc0e1
2 changed files with 45 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
[GSoC]ChangeLog
View File

@ -1,3 +1,12 @@
2020-07-06 Anuj Verma <anujv@iitbhilai.ac.in>
* src/sdf/ftsdfrend.c (sdf_generate_bounding_box): Due to
the way we use the bounding box, we need to keep a track
of signed distances of each pixel so later the sign can
be determined properly. The method is certainly faster
then checking all the pixels agains all the edges,
but also require a decent amount of memory to work.
2020-07-06 Anuj Verma <anujv@iitbhilai.ac.in>
[sdf] Precompute the orthogonality.

70
src/sdf/ftsdf.c
View File

@ -2250,9 +2250,10 @@
/* This buffer has the same size in indices as the */
/* bitmap buffer. When we check a pixel position for */
/* shortest distance we keep the sign in this buffer */
/* This way we check find out which pixel is set. */
FT_Char* signs;
/* shortest distance we keep it in this buffer. */
/* This way we check find out which pixel is set, */
/* and also determine the signs properly. */
SDF_Signed_Distance* dists;
if ( !shape || !bitmap )
{
@ -2273,10 +2274,10 @@
rows = bitmap->rows;
buffer = (FT_Short*)bitmap->buffer;
if ( FT_ALLOC_MULT( signs, width, rows ) )
if ( FT_ALLOC_MULT( dists, width, rows * sizeof(*dists) ) )
goto Exit;
FT_MEM_ZERO( signs, width * rows );
FT_MEM_ZERO( dists, width * rows * sizeof(*dists) );
if ( USE_SQUARED_DISTANCES )
sp_sq = FT_INT_16D16( spread * spread );
@ -2307,10 +2308,10 @@
/* get the control box and increase by `spread' */
cbox = get_control_box( *current_edge );
cbox.xMin = ROUND_F26DOT6( cbox.xMin ) / 64 - ( FT_Pos )spread;
cbox.xMax = ROUND_F26DOT6( cbox.xMax ) / 64 + ( FT_Pos )spread;
cbox.yMin = ROUND_F26DOT6( cbox.yMin ) / 64 - ( FT_Pos )spread;
cbox.yMax = ROUND_F26DOT6( cbox.yMax ) / 64 + ( FT_Pos )spread;
cbox.xMin = ( cbox.xMin - 63 ) / 64 - ( FT_Pos )spread;
cbox.xMax = ( cbox.xMax + 63 ) / 64 + ( FT_Pos )spread;
cbox.yMin = ( cbox.yMin - 63 ) / 64 - ( FT_Pos )spread;
cbox.yMax = ( cbox.yMax + 63 ) / 64 + ( FT_Pos )spread;
/* now loop the pixels in the control box. */
for ( y = cbox.yMin; y < cbox.yMax; y++ )
@ -2340,30 +2341,23 @@
grid_point,
&dist ) );
/* clamp the values to spread */
if ( dist.distance > sp_sq )
dist.distance = sp_sq;
/* ignore if the distance is greater than spread */
/* otherwise it creates artifacts due to wrong sign */
if ( dist.distance > sp_sq ) continue;
/* square_root the values and fit in a 6.10 fixed point */
if ( USE_SQUARED_DISTANCES )
dist.distance = square_root( dist.distance );
dist.distance /= 64;
/* [IMPORTANT]: Do corner checking. Unfortunately */
/* this will require more memory usage to keep the */
/* direction of each pixel. */
/* check weather the pixel is set or not */
if ( signs[index] == 0 )
if ( dists[index].sign == 0 )
dists[index] = dist;
else if ( dists[index].distance > dist.distance )
dists[index] = dist;
else if ( FT_ABS(dists[index].distance - dist.distance ) < CORNER_CHECK_EPSILON )
{
buffer[index] = dist.distance;
signs[index] = dist.sign;
}
else if ( dist.distance < buffer[index] )
{
buffer[index] = dist.distance;
signs[index] = dist.sign;
if ( FT_ABS( dists[index].cross ) < FT_ABS( dist.cross ) )
dists[index] = dist;
}
}
}
@ -2386,18 +2380,26 @@
{
index = j * width + i;
if ( signs[index] == 0 )
buffer[index] = (spread * 1024);
/* if the pixel is not set that means it's */
/* shortest distance is more than spread */
if ( dists[index].sign == 0 )
dists[index].distance = FT_INT_16D16( spread );
else
current_sign = signs[index];
current_sign = dists[index].sign;
buffer[index] *= current_sign;
/* clamp the values */
if ( dists[index].distance > FT_INT_16D16( spread ) )
dists[index].distance = FT_INT_16D16( spread );
/* convert from 16.16 to 6.10 */
dists[index].distance /= 64;
buffer[index] = dists[index].distance * current_sign;
}
}
Exit:
FT_FREE( signs );
FT_FREE( dists );
return error;
}
@ -2519,7 +2521,7 @@
FT_CALL( sdf_outline_decompose( outline, shape ) );
FT_CALL( sdf_generate( shape, sdf_params->spread,
FT_CALL( sdf_generate_bounding_box( shape, sdf_params->spread,
sdf_params->root.target ) );
Exit: