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Update qgrayraster.c 

In particular switching the SUBPIXELS macro with FRACT makes the logic
valid for all 24dot8 fixed point values.

Change-Id: I4e58df94f8cf3c557f670c5d3088942e9b8efa6d
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
bb10
Allan Sandfeld Jensen 2020-07-30 13:56:05 +02:00
parent 92ee9bd6b8
commit 9a900dfb07
1 changed files with 77 additions and 79 deletions
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156
src/gui/painting/qgrayraster.c
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@ -216,11 +216,8 @@ typedef ptrdiff_t QT_FT_PtrDist;
#define PIXEL_BITS 8
#define ONE_PIXEL ( 1L << PIXEL_BITS )
#define TRUNC( x ) ( (TCoord)( (x) >> PIXEL_BITS ) )
#define SUBPIXELS( x ) ( (TPos)(x) * ONE_PIXEL )
#define FLOOR( x ) ( (x) & -ONE_PIXEL )
#define CEILING( x ) ( ( (x) + ONE_PIXEL - 1 ) & -ONE_PIXEL )
#define ROUND( x ) ( ( (x) + ONE_PIXEL / 2 ) & -ONE_PIXEL )
#define TRUNC( x ) (TCoord)( (x) >> PIXEL_BITS )
#define FRACT( x ) (TCoord)( (x) & ( ONE_PIXEL - 1 ) )
#if PIXEL_BITS >= 6
#define UPSCALE( x ) ( (x) * ( ONE_PIXEL >> 6 ) )
@ -548,17 +545,13 @@ QT_FT_END_STMNT
TPos x2,
TCoord y2 )
{
TCoord ex1, ex2, fx1, fx2, delta, mod;
int p, first, dx;
TCoord ex1, ex2, fx1, fx2, first, dy, delta, mod;
TPos p, dx;
int incr;
dx = x2 - x1;
ex1 = TRUNC( x1 );
ex2 = TRUNC( x2 );
fx1 = (TCoord)( x1 - SUBPIXELS( ex1 ) );
fx2 = (TCoord)( x2 - SUBPIXELS( ex2 ) );
/* trivial case. Happens often */
if ( y1 == y2 )
@ -567,26 +560,27 @@ QT_FT_END_STMNT
return;
}
fx1 = FRACT( x1 );
fx2 = FRACT( x2 );
/* everything is located in a single cell. That is easy! */
/* */
if ( ex1 == ex2 )
{
delta = y2 - y1;
ras.area += (TArea)( fx1 + fx2 ) * delta;
ras.cover += delta;
return;
}
goto End;
/* ok, we'll have to render a run of adjacent cells on the same */
/* scanline... */
/* */
p = ( ONE_PIXEL - fx1 ) * ( y2 - y1 );
first = ONE_PIXEL;
incr = 1;
dx = x2 - x1;
dy = y2 - y1;
if ( dx < 0 )
if ( dx > 0 )
{
p = fx1 * ( y2 - y1 );
p = ( ONE_PIXEL - fx1 ) * dy;
first = ONE_PIXEL;
incr = 1;
} else {
p = fx1 * dy;
first = 0;
incr = -1;
dx = -dx;
@ -596,42 +590,42 @@ QT_FT_END_STMNT
ras.area += (TArea)( fx1 + first ) * delta;
ras.cover += delta;
ex1 += incr;
y1 += delta;
ex1 += incr;
gray_set_cell( RAS_VAR_ ex1, ey );
y1 += delta;
if ( ex1 != ex2 )
{
TCoord lift, rem;
p = ONE_PIXEL * ( y2 - y1 + delta );
p = ONE_PIXEL * dy;
QT_FT_DIV_MOD( TCoord, p, dx, lift, rem );
mod -= (int)dx;
while ( ex1 != ex2 )
do
{
delta = lift;
mod += rem;
if ( mod >= 0 )
if ( mod >= (TCoord)dx )
{
mod -= (TCoord)dx;
delta++;
}
ras.area += (TArea)ONE_PIXEL * delta;
ras.area += (TArea)( ONE_PIXEL * delta );
ras.cover += delta;
y1 += delta;
ex1 += incr;
gray_set_cell( RAS_VAR_ ex1, ey );
}
} while ( ex1 != ex2 );
}
fx1 = ONE_PIXEL - first;
delta = y2 - y1;
ras.area += (TArea)( fx2 + ONE_PIXEL - first ) * delta;
ras.cover += delta;
End:
dy = y2 - y1;
ras.area += (TArea)( ( fx1 + fx2 ) * dy );
ras.cover += dy;
}
@ -643,25 +637,21 @@ QT_FT_END_STMNT
gray_render_line( RAS_ARG_ TPos to_x,
TPos to_y )
{
TCoord ey1, ey2, fy1, fy2, mod;
TPos dx, dy, x, x2;
int p, first;
int delta, rem, lift, incr;
TCoord ey1, ey2, fy1, fy2, first, delta, mod;
TPos p, dx, dy, x, x2;
int incr;
ey1 = TRUNC( ras.y );
ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
fy1 = (TCoord)( ras.y - SUBPIXELS( ey1 ) );
fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
dx = to_x - ras.x;
dy = to_y - ras.y;
/* perform vertical clipping */
if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
goto End;
fy1 = FRACT( ras.y );
fy2 = FRACT( to_y );
/* everything is on a single scanline */
if ( ey1 == ey2 )
{
@ -669,23 +659,31 @@ QT_FT_END_STMNT
goto End;
}
dx = to_x - ras.x;
dy = to_y - ras.y;
/* vertical line - avoid calling gray_render_scanline */
if ( dx == 0 )
{
TCoord ex = TRUNC( ras.x );
TCoord two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
TCoord two_fx = FRACT( ras.x ) << 1;
TPos area, max_ey1;
first = ONE_PIXEL;
if ( dy < 0 )
if ( dy > 0)
{
first = ONE_PIXEL;
}
else
{
first = 0;
}
delta = (int)( first - fy1 );
delta = first - fy1;
ras.area += (TArea)two_fx * delta;
ras.cover += delta;
delta = (int)( first + first - ONE_PIXEL );
delta = first + first - ONE_PIXEL;
area = (TArea)two_fx * delta;
max_ey1 = ras.count_ey + ras.min_ey;
if (dy < 0) {
@ -738,11 +736,13 @@ QT_FT_END_STMNT
}
/* ok, we have to render several scanlines */
p = ( ONE_PIXEL - fy1 ) * dx;
first = ONE_PIXEL;
incr = 1;
if ( dy < 0 )
if ( dy > 0)
{
p = ( ONE_PIXEL - fy1 ) * dx;
first = ONE_PIXEL;
incr = 1;
}
else
{
p = fy1 * dx;
first = 0;
@ -750,13 +750,9 @@ QT_FT_END_STMNT
dy = -dy;
}
delta = (int)( p / dy );
mod = (int)( p % dy );
if ( mod < 0 )
{
delta--;
mod += (TCoord)dy;
}
/* the fractional part of x-delta is mod/dy. It is essential to */
/* keep track of its accumulation for accurate rendering. */
QT_FT_DIV_MOD( TCoord, p, dy, delta, mod );
x = ras.x + delta;
gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, (TCoord)first );
@ -766,34 +762,36 @@ QT_FT_END_STMNT
if ( ey1 != ey2 )
{
p = ONE_PIXEL * dx;
QT_FT_DIV_MOD( int, p, dy, lift, rem );
mod -= (int)dy;
TCoord lift, rem;
while ( ey1 != ey2 )
p = ONE_PIXEL * dx;
QT_FT_DIV_MOD( TCoord, p, dy, lift, rem );
do
{
delta = lift;
mod += rem;
if ( mod >= 0 )
if ( mod >= (TCoord)dy )
{
mod -= (int)dy;
mod -= (TCoord)dy;
delta++;
}
x2 = x + delta;
gray_render_scanline( RAS_VAR_ ey1, x,
(TCoord)( ONE_PIXEL - first ), x2,
(TCoord)first );
gray_render_scanline( RAS_VAR_ ey1,
x, ONE_PIXEL - first,
x2, first );
x = x2;
ey1 += incr;
gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
}
} while ( ey1 != ey2 );
}
gray_render_scanline( RAS_VAR_ ey1, x,
(TCoord)( ONE_PIXEL - first ), to_x,
fy2 );
gray_render_scanline( RAS_VAR_ ey1,
x, ONE_PIXEL - first,
to_x, fy2 );
End:
ras.x = to_x;
@ -828,8 +826,8 @@ QT_FT_END_STMNT
dx = to_x - ras.x;
dy = to_y - ras.y;
fx1 = ras.x - SUBPIXELS( ex1 );
fy1 = ras.y - SUBPIXELS( ey1 );
fx1 = FRACT( ras.x );
fy1 = FRACT( ras.y );
if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */
;
@ -926,8 +924,8 @@ QT_FT_END_STMNT
} while ( ex1 != ex2 || ey1 != ey2 );
}
fx2 = to_x - SUBPIXELS( ex2 );
fy2 = to_y - SUBPIXELS( ey2 );
fx2 = FRACT( to_x );
fy2 = FRACT( to_y );
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );