/* * 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); }