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[smooth] Estimate of the rendering pool size. 

The estimate is based on the taxi perimeter with extra space added
for local extrema.

* src/smooth/ftgrays.c (gray_taxi): New function for the perimeter.
(gray_convert_glyph): Updated, banding suppressed.
This commit is contained in:
Alexei Podtelezhnikov 2023-10-09 22:38:16 -04:00
parent 3cb3acf2f8
commit 7bdd4d1a00
1 changed files with 49 additions and 10 deletions
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59
src/smooth/ftgrays.c
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@ -1953,6 +1953,44 @@ typedef ptrdiff_t FT_PtrDist;
}
/*
* The taxicab perimeter of the entire outline is used to estimate
* the necessary memory pool or the job size in general. Clipping
* is ignored because it might hurt the performance.
*/
static long
gray_taxi( RAS_ARG )
{
FT_Outline* outline = &ras.outline;
short c, p, first, last;
FT_Vector d, v;
FT_Pos taxi;
taxi = 0;
last = -1;
for ( c = 0; c < outline->n_contours; c++ )
{
first = last + 1;
last = outline->contours[c];
d = outline->points[last];
for ( p = first; p <= last; p++ )
{
v = outline->points[p];
d.x -= v.x;
d.y -= v.y;
taxi += FT_ABS( d.x ) + FT_ABS( d.y );
d = v;
}
}
return taxi >> 6;
}
static int
gray_convert_glyph( RAS_ARG )
{
@ -1964,7 +2002,8 @@ typedef ptrdiff_t FT_PtrDist;
TCell* buffer;
size_t height = (size_t)( yMax - yMin );
size_t n = FT_MAX_GRAY_POOL / 8;
size_t n;
long size;
TCoord y;
TCoord bands[32]; /* enough to accommodate bisections */
TCoord* band;
@ -1972,11 +2011,18 @@ typedef ptrdiff_t FT_PtrDist;
int continued = 0;
if ( FT_QNEW_ARRAY( buffer, FT_MAX_GRAY_POOL ) )
size = gray_taxi( RAS_VAR ) +
height * sizeof ( PCell ) / sizeof ( TCell ) +
9; /* empirical extra for local extrema */
if ( FT_QNEW_ARRAY( buffer, size ) )
return error;
FT_TRACE7(( "Allocated %ld cells (%ld bytes)\n",
size, size * sizeof ( TCell ) ));
/* Initialize the null cell at the end of the poll. */
ras.cell_null = buffer + FT_MAX_GRAY_POOL - 1;
ras.cell_null = buffer + size - 1;
ras.cell_null->x = CELL_MAX_X_VALUE;
ras.cell_null->area = 0;
ras.cell_null->cover = 0;
@ -1985,13 +2031,6 @@ typedef ptrdiff_t FT_PtrDist;
/* set up vertical bands */
ras.ycells = (PCell*)buffer;
if ( height > n )
{
/* two divisions rounded up */
n = ( height + n - 1 ) / n;
height = ( height + n - 1 ) / n;
}
for ( y = yMin; y < yMax; )
{
ras.min_ey = y;