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authorAnurag Thakur <anurag105csec21@bpitindia.edu.in>2022-11-19 13:14:51 +0530
committerAnurag Thakur <anurag105csec21@bpitindia.edu.in>2022-11-19 13:14:51 +0530
commit5d683228e71eb0584c74affd4461e931cae02774 (patch)
treef1efabe67d45abd34a93128706e62b06ebe41955
parent763f11088e6a0318846902c6c019008ababe3036 (diff)
downloadfreetype2-5d683228e71eb0584c74affd4461e931cae02774.tar.gz
[dense] Add optimization for vertical lines
* src/dense/ftdense.c: Optimize line drawing when a vertical line is encountered
-rw-r--r--src/dense/ftdense.c127
1 files changed, 78 insertions, 49 deletions
diff --git a/src/dense/ftdense.c b/src/dense/ftdense.c
index 1e1eeb4e9..e0b5950b4 100644
--- a/src/dense/ftdense.c
+++ b/src/dense/ftdense.c
@@ -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;
+ if(deltax == 0){
+ FT26D6 x = from_x;
+ int x0i = x>>6;
+ FT26D6 x0floor = x0i<<6;
- 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;
+ // y-coordinate of first pixel of line
+ int y0 = from_y>>6;
- FT26D6 x0, x1;
- if ( x < xnext )
- {
- x0 = x;
- x1 = xnext;
- }
- else
- {
- x0 = xnext;
- x1 = x;
- }
+ // y-coordinate of last pixel of line
+ int y_limit = (to_y + 0x3f)>>6;
+ FT20D12* m_a = worker->m_a;
- int x0i = x0>>6;
- FT26D6 x0floor = x0i<<6;
+ for ( int y = y0; y < y_limit; y++ )
+ {
+ int linestart = y * worker->m_w;
- int x1i = (x1+0x3f)>>6;
- FT26D6 x1ceil = x1i <<6;
+ 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);
- 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
+ }
+ 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 x0, x1;
+ if ( x < xnext )
+ {
+ x0 = x;
+ x1 = xnext;
+ }
+ else
+ {
+ x0 = xnext;
+ x1 = x;
+ }
- FT26D6 oneOverS = x1 - x0;
- FT26D6 x0f = x0 - x0floor;
+ int x0i = x0>>6;
+ FT26D6 x0floor = x0i<<6;
- 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;
+ int x1i = (x1+0x3f)>>6;
+ FT26D6 x1ceil = x1i <<6;
- if ( x1i == x0i + 2 )
- m_a[linestart + ( x0i + 1 )] += d * ( (1<<6) - a0 - am );
+ 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 a1 = (((1<<6) + (1<<5) - x0f) << 6) / oneOverS;
- m_a[linestart + ( x0i + 1 )] += d * ( a1 - a0 );
- FT26D6 dTimesS = (d << 12) / oneOverS;
+ 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;
+ 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 );
+ FT26D6 a2 = a1 + (( x1i - x0i - 3 )<<12)/oneOverS;
+ m_a[linestart + ( x1i - 1 )] += d * ( (1<<6) - a2 - am );
+ }
+ m_a[linestart + x1i] += d * am;
}
- m_a[linestart + x1i] += d * am;
+ x = xnext;
}
- x = xnext;
}
}