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Code Issues 4 Releases Wiki Activity

[dense] Add optimization for vertical lines 

* src/dense/ftdense.c: Optimize line drawing when a vertical line is encountered
This commit is contained in:
Anurag Thakur 2022-11-19 13:14:51 +05:30
parent 763f11088e
commit 5d683228e7
1 changed files with 87 additions and 58 deletions
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145
src/dense/ftdense.c
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@ -126,77 +126,106 @@ dense_render_line( dense_worker* worker, FT_Pos tox, FT_Pos toy )
to_y = worker->m_h<<6;
}
int x = from_x;
int y0 = from_y>>6;
int y_limit = (to_y + 0x3f)>>6;
FT20D12* m_a = worker->m_a;
for ( int y = y0; y < y_limit; y++ )
{
int linestart = y * worker->m_w;
FT26D6 dy = FT_MIN( (y + 1)<<6, to_y ) - FT_MAX( y<<6, from_y );
FT26D6 xnext = x + dy * deltax/deltay;
FT26D6 d = dy * dir;
FT26D6 x0, x1;
if ( x < xnext )
{
x0 = x;
x1 = xnext;
}
else
{
x0 = xnext;
x1 = x;
}
int x0i = x0>>6;
if(deltax == 0){
FT26D6 x = from_x;
int x0i = x>>6;
FT26D6 x0floor = x0i<<6;
// y-coordinate of first pixel of line
int y0 = from_y>>6;
int x1i = (x1+0x3f)>>6;
FT26D6 x1ceil = x1i <<6;
// y-coordinate of last pixel of line
int y_limit = (to_y + 0x3f)>>6;
FT20D12* m_a = worker->m_a;
if ( x1i <= x0i + 1 )
for ( int y = y0; y < y_limit; y++ )
{
FT26D6 xmf = ( ( x + xnext )>>1) - x0floor;
m_a[linestart + x0i] += d * ((1<<6) - xmf);
m_a[linestart + ( x0i + 1 )] += d * xmf;
int linestart = y * worker->m_w;
FT26D6 dy = min( (y + 1)<<6, to_y ) - max( y<<6, from_y );
m_a[linestart + x0i] += dir*dy*(64 - x + x0floor);
m_a[linestart + ( x0i + 1 )] += dir*dy*(x-x0floor);
}
else
}
else
{
int x = from_x;
int y0 = from_y>>6;
int y_limit = (to_y + 0x3f)>>6;
FT20D12* m_a = worker->m_a;
for ( int y = y0; y < y_limit; y++ )
{
int linestart = y * worker->m_w;
FT26D6 dy = FT_MIN( (y + 1)<<6, to_y ) - FT_MAX( y<<6, from_y );
FT26D6 xnext = x + dy * deltax/deltay;
FT26D6 d = dy * dir;
FT26D6 oneOverS = x1 - x0;
FT26D6 x0f = x0 - x0floor;
FT26D6 oneMinusX0f = (1<<6) - x0f;
FT26D6 a0 = ((oneMinusX0f * oneMinusX0f) >> 1) / oneOverS;
FT26D6 x1f = x1 - x1ceil + (1<<6);
FT26D6 am = ((x1f * x1f) >> 1) / oneOverS;
m_a[linestart + x0i] += d * a0;
if ( x1i == x0i + 2 )
m_a[linestart + ( x0i + 1 )] += d * ( (1<<6) - a0 - am );
FT26D6 x0, x1;
if ( x < xnext )
{
x0 = x;
x1 = xnext;
}
else
{
FT26D6 a1 = (((1<<6) + (1<<5) - x0f) << 6) / oneOverS;
m_a[linestart + ( x0i + 1 )] += d * ( a1 - a0 );
FT26D6 dTimesS = (d << 12) / oneOverS;
for ( FT26D6 xi = x0i + 2; xi < x1i - 1; xi++ )
m_a[linestart + xi] += dTimesS;
FT26D6 a2 = a1 + (( x1i - x0i - 3 )<<12)/oneOverS;
m_a[linestart + ( x1i - 1 )] += d * ( (1<<6) - a2 - am );
x0 = xnext;
x1 = x;
}
m_a[linestart + x1i] += d * am;
int x0i = x0>>6;
FT26D6 x0floor = x0i<<6;
int x1i = (x1+0x3f)>>6;
FT26D6 x1ceil = x1i <<6;
if ( x1i <= x0i + 1 )
{
FT26D6 xmf = ( ( x + xnext )>>1) - x0floor;
m_a[linestart + x0i] += d * ((1<<6) - xmf);
m_a[linestart + ( x0i + 1 )] += d * xmf;
}
else
{
FT26D6 oneOverS = x1 - x0;
FT26D6 x0f = x0 - x0floor;
FT26D6 oneMinusX0f = (1<<6) - x0f;
FT26D6 a0 = ((oneMinusX0f * oneMinusX0f) >> 1) / oneOverS;
FT26D6 x1f = x1 - x1ceil + (1<<6);
FT26D6 am = ((x1f * x1f) >> 1) / oneOverS;
m_a[linestart + x0i] += d * a0;
if ( x1i == x0i + 2 )
m_a[linestart + ( x0i + 1 )] += d * ( (1<<6) - a0 - am );
else
{
FT26D6 a1 = (((1<<6) + (1<<5) - x0f) << 6) / oneOverS;
m_a[linestart + ( x0i + 1 )] += d * ( a1 - a0 );
FT26D6 dTimesS = (d << 12) / oneOverS;
for ( FT26D6 xi = x0i + 2; xi < x1i - 1; xi++ )
m_a[linestart + xi] += dTimesS;
FT26D6 a2 = a1 + (( x1i - x0i - 3 )<<12)/oneOverS;
m_a[linestart + ( x1i - 1 )] += d * ( (1<<6) - a2 - am );
}
m_a[linestart + x1i] += d * am;
}
x = xnext;
}
x = xnext;
}
}