/*
* Compute the largest value no greater than y which is on a
* grid row
*/
xFixed
RenderSampleFloorY (xFixed y, int n)
{
xFixed f = xFixedFrac(y);
xFixed i = xFixedFloor (y);
f = _div(f - Y_FRAC_FIRST(n), STEP_Y_SMALL(n)) * STEP_Y_SMALL(n) + Y_FRAC_FIRST(n);
if (f < Y_FRAC_FIRST(n))
{
f = Y_FRAC_LAST(n);
i -= xFixed1;
}
return (i | f);
}
xFixed
RenderSampleCeilY (xFixed y, int n)
{
xFixed f = xFixedFrac(y);
xFixed i = xFixedFloor(y);
f = ((f + Y_FRAC_FIRST(n)) / STEP_Y_SMALL(n)) * STEP_Y_SMALL(n) + Y_FRAC_FIRST(n);
if (f > Y_FRAC_LAST(n))
{
f = Y_FRAC_FIRST(n);
i += xFixed1;
}
return (i | f);
}
PIXMAN_EXPORT pixman_fixed_t
pixman_sample_ceil_y (pixman_fixed_t y, int n)
{
pixman_fixed_t f = pixman_fixed_frac (y);
pixman_fixed_t i = pixman_fixed_floor (y);
f = DIV (f - Y_FRAC_FIRST (n) + (STEP_Y_SMALL (n) - pixman_fixed_e), STEP_Y_SMALL (n)) * STEP_Y_SMALL (n) +
Y_FRAC_FIRST (n);
if (f > Y_FRAC_LAST (n))
{
if (pixman_fixed_to_int (i) == 0x7fff)
{
f = 0xffff; /* saturate */
}
else
{
f = Y_FRAC_FIRST (n);
i += pixman_fixed_1;
}
}
return (i | f);
}
/*
* Compute the largest value strictly less than y which is on a
* grid row.
*/
PIXMAN_EXPORT pixman_fixed_t
pixman_sample_floor_y (pixman_fixed_t y,
int n)
{
pixman_fixed_t f = pixman_fixed_frac (y);
pixman_fixed_t i = pixman_fixed_floor (y);
f = DIV (f - pixman_fixed_e - Y_FRAC_FIRST (n), STEP_Y_SMALL (n)) * STEP_Y_SMALL (n) +
Y_FRAC_FIRST (n);
if (f < Y_FRAC_FIRST (n))
{
if (pixman_fixed_to_int (i) == 0x8000)
{
f = 0; /* saturate */
}
else
{
f = Y_FRAC_LAST (n);
i -= pixman_fixed_1;
}
}
return (i | f);
}