#include <string.h>
#include <setjmp.h>
#include <limits.h>
-#define SW_FT_UINT_MAX UINT_MAX
-#define SW_FT_INT_MAX INT_MAX
+#define SW_FT_UINT_MAX UINT_MAX
+#define SW_FT_INT_MAX INT_MAX
+#define SW_FT_ULONG_MAX ULONG_MAX
+#define SW_FT_CHAR_BIT CHAR_BIT
#define ft_memset memset
SW_FT_END_STMNT
#endif /* __arm__ */
+ /* These macros speed up repetitive divisions by replacing them */
+ /* with multiplications and right shifts. */
+#define SW_FT_UDIVPREP( b ) \
+ long b ## _r = (long)( SW_FT_ULONG_MAX >> PIXEL_BITS ) / ( b )
+#define SW_FT_UDIV( a, b ) \
+ ( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \
+ ( sizeof( long ) * SW_FT_CHAR_BIT - PIXEL_BITS ) )
+
/*************************************************************************/
/* */
gray_set_cell( RAS_VAR_ ex, ey );
}
-
/*************************************************************************/
/* */
- /* Render a scanline as one or more cells. */
- /* */
- static void
- gray_render_scanline( RAS_ARG_ TCoord ey,
- TPos x1,
- TCoord y1,
- TPos x2,
- TCoord y2 )
- {
- TCoord ex1, ex2, fx1, fx2, delta, mod;
- long p, first, 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 )
- {
- gray_set_cell( RAS_VAR_ ex2, ey );
- return;
- }
-
- /* 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;
- }
-
- /* 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;
-
- if ( dx < 0 )
- {
- p = fx1 * ( y2 - y1 );
- first = 0;
- incr = -1;
- dx = -dx;
- }
-
- SW_FT_DIV_MOD( TCoord, p, dx, delta, mod );
-
- ras.area += (TArea)(( fx1 + first ) * delta);
- ras.cover += delta;
-
- ex1 += incr;
- gray_set_cell( RAS_VAR_ ex1, ey );
- y1 += delta;
-
- if ( ex1 != ex2 )
- {
- TCoord lift, rem;
-
-
- p = ONE_PIXEL * ( y2 - y1 + delta );
- SW_FT_DIV_MOD( TCoord, p, dx, lift, rem );
-
- mod -= (int)dx;
-
- while ( ex1 != ex2 )
- {
- delta = lift;
- mod += rem;
- if ( mod >= 0 )
- {
- mod -= (TCoord)dx;
- delta++;
- }
-
- ras.area += (TArea)(ONE_PIXEL * delta);
- ras.cover += delta;
- y1 += delta;
- ex1 += incr;
- gray_set_cell( RAS_VAR_ ex1, ey );
- }
- }
-
- delta = y2 - y1;
- ras.area += (TArea)(( fx2 + ONE_PIXEL - first ) * delta);
- ras.cover += delta;
- }
-
-
- /*************************************************************************/
- /* */
- /* Render a given line as a series of scanlines. */
+ /* Render a straight line across multiple cells in any direction. */
/* */
static void
gray_render_line( RAS_ARG_ TPos to_x,
TPos to_y )
{
- TCoord ey1, ey2, fy1, fy2, mod;
- TPos dx, dy, x, x2;
- long p, first;
- int delta, rem, lift, incr;
+ TPos dx, dy, fx1, fy1, fx2, fy2;
+ TCoord ex1, ex2, ey1, ey2;
- ey1 = TRUNC( ras.last_ey );
- ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
- fy1 = (TCoord)( ras.y - ras.last_ey );
- fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
-
- dx = to_x - ras.x;
- dy = to_y - ras.y;
+ ex1 = TRUNC( ras.x );
+ ex2 = TRUNC( to_x );
+ ey1 = TRUNC( ras.y );
+ ey2 = TRUNC( to_y );
/* perform vertical clipping */
- {
- TCoord min, max;
+ if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
+ ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
+ goto End;
+ dx = to_x - ras.x;
+ dy = to_y - ras.y;
- min = ey1;
- max = ey2;
- if ( ey1 > ey2 )
- {
- min = ey2;
- max = ey1;
- }
- if ( min >= ras.max_ey || max < ras.min_ey )
- goto End;
- }
+ fx1 = ras.x - SUBPIXELS( ex1 );
+ fy1 = ras.y - SUBPIXELS( ey1 );
- /* everything is on a single scanline */
- if ( ey1 == ey2 )
+ if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */
+ ;
+ else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */
{
- gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 );
- goto End;
+ ex1 = ex2;
+ gray_set_cell( RAS_VAR_ ex1, ey1 );
}
-
- /* vertical line - avoid calling gray_render_scanline */
- incr = 1;
-
- if ( dx == 0 )
+ else if ( dx == 0 )
{
- TCoord ex = TRUNC( ras.x );
- TCoord two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
- TArea area;
-
-
- first = ONE_PIXEL;
- if ( dy < 0 )
- {
- first = 0;
- incr = -1;
- }
-
- delta = (int)( first - fy1 );
- ras.area += (TArea)two_fx * delta;
- ras.cover += delta;
- ey1 += incr;
-
- gray_set_cell( RAS_VAR_ ex, ey1 );
-
- delta = (int)( first + first - ONE_PIXEL );
- area = (TArea)two_fx * delta;
- while ( ey1 != ey2 )
- {
- ras.area += area;
- ras.cover += delta;
- ey1 += incr;
-
- gray_set_cell( RAS_VAR_ ex, ey1 );
- }
-
- delta = (int)( fy2 - ONE_PIXEL + first );
- ras.area += (TArea)two_fx * delta;
- ras.cover += delta;
-
- goto End;
+ if ( dy > 0 ) /* vertical line up */
+ do
+ {
+ fy2 = ONE_PIXEL;
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * fx1 * 2;
+ fy1 = 0;
+ ey1++;
+ gray_set_cell( RAS_VAR_ ex1, ey1 );
+ } while ( ey1 != ey2 );
+ else /* vertical line down */
+ do
+ {
+ fy2 = 0;
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * fx1 * 2;
+ fy1 = ONE_PIXEL;
+ ey1--;
+ gray_set_cell( RAS_VAR_ ex1, ey1 );
+ } while ( ey1 != ey2 );
}
-
- /* ok, we have to render several scanlines */
- p = ( ONE_PIXEL - fy1 ) * dx;
- first = ONE_PIXEL;
- incr = 1;
-
- if ( dy < 0 )
+ else /* any other line */
{
- p = fy1 * dx;
- first = 0;
- incr = -1;
- dy = -dy;
- }
-
- SW_FT_DIV_MOD( int, p, dy, delta, mod );
-
- x = ras.x + delta;
- gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, (TCoord)first );
+ TArea prod = dx * fy1 - dy * fx1;
+ SW_FT_UDIVPREP( dx );
+ SW_FT_UDIVPREP( dy );
- ey1 += incr;
- gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
-
- if ( ey1 != ey2 )
- {
- p = ONE_PIXEL * dx;
- SW_FT_DIV_MOD( int, p, dy, lift, rem );
- mod -= (int)dy;
- while ( ey1 != ey2 )
+ /* The fundamental value `prod' determines which side and the */
+ /* exact coordinate where the line exits current cell. It is */
+ /* also easily updated when moving from one cell to the next. */
+ do
{
- delta = lift;
- mod += rem;
- if ( mod >= 0 )
+ if ( prod <= 0 &&
+ prod - dx * ONE_PIXEL > 0 ) /* left */
{
- mod -= (int)dy;
- delta++;
+ fx2 = 0;
+ fy2 = (TPos)SW_FT_UDIV( -prod, -dx );
+ prod -= dy * ONE_PIXEL;
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
+ fx1 = ONE_PIXEL;
+ fy1 = fy2;
+ ex1--;
+ }
+ else if ( prod - dx * ONE_PIXEL <= 0 &&
+ prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */
+ {
+ prod -= dx * ONE_PIXEL;
+ fx2 = (TPos)SW_FT_UDIV( -prod, dy );
+ fy2 = ONE_PIXEL;
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
+ fx1 = fx2;
+ fy1 = 0;
+ ey1++;
+ }
+ else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
+ prod + dy * ONE_PIXEL >= 0 ) /* right */
+ {
+ prod += dy * ONE_PIXEL;
+ fx2 = ONE_PIXEL;
+ fy2 = (TPos)SW_FT_UDIV( prod, dx );
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
+ fx1 = 0;
+ fy1 = fy2;
+ ex1++;
+ }
+ else /* ( prod + dy * ONE_PIXEL < 0 &&
+ prod > 0 ) down */
+ {
+ fx2 = (TPos)SW_FT_UDIV( prod, -dy );
+ fy2 = 0;
+ prod += dx * ONE_PIXEL;
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
+ fx1 = fx2;
+ fy1 = ONE_PIXEL;
+ ey1--;
}
- x2 = x + delta;
- gray_render_scanline( RAS_VAR_ ey1, x,
- (TCoord)( ONE_PIXEL - first ), x2,
- (TCoord)first );
- x = x2;
-
- ey1 += incr;
- gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
- }
+ gray_set_cell( RAS_VAR_ ex1, ey1 );
+ } while ( ex1 != ex2 || ey1 != ey2 );
}
- gray_render_scanline( RAS_VAR_ ey1, x,
- (TCoord)( ONE_PIXEL - first ), to_x,
- fy2 );
+ fx2 = to_x - SUBPIXELS( ex2 );
+ fy2 = to_y - SUBPIXELS( ey2 );
+
+ ras.cover += ( fy2 - fy1 );
+ ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
End:
ras.x = to_x;
ras.y = to_y;
- ras.last_ey = SUBPIXELS( ey2 );
}
-
static void
gray_split_conic( SW_FT_Vector* base )
{