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); }
/* * We want to detect the case where we add the same value to a long * span of pixels. The triangles on the end are filled in while we * count how many sub-pixel scanlines contribute to the middle section. * * +--------------------------+ * fill_height =| \ / * +------------------+ * |================| * fill_start fill_end */ static void rasterize_edges_8 (pixman_image_t *image, pixman_edge_t * l, pixman_edge_t * r, pixman_fixed_t t, pixman_fixed_t b) { pixman_fixed_t y = t; uint32_t *line; int fill_start = -1, fill_end = -1; int fill_size = 0; uint32_t *buf = (image)->bits.bits; int stride = (image)->bits.rowstride; int width = (image)->bits.width; line = buf + pixman_fixed_to_int (y) * stride; for (;;) { uint8_t *ap = (uint8_t *) line; pixman_fixed_t lx, rx; int lxi, rxi; /* clip X */ lx = l->x; if (lx < 0) lx = 0; rx = r->x; if (pixman_fixed_to_int (rx) >= width) { /* Use the last pixel of the scanline, covered 100%. * We can't use the first pixel following the scanline, * because accessing it could result in a buffer overrun. */ rx = pixman_int_to_fixed (width) - 1; } /* Skip empty (or backwards) sections */ if (rx > lx) { int lxs, rxs; /* Find pixel bounds for span. */ lxi = pixman_fixed_to_int (lx); rxi = pixman_fixed_to_int (rx); /* Sample coverage for edge pixels */ lxs = RENDER_SAMPLES_X (lx, 8); rxs = RENDER_SAMPLES_X (rx, 8); /* Add coverage across row */ if (lxi == rxi) { WRITE (image, ap + lxi, clip255 (READ (image, ap + lxi) + rxs - lxs)); } else { WRITE (image, ap + lxi, clip255 (READ (image, ap + lxi) + N_X_FRAC (8) - lxs)); /* Move forward so that lxi/rxi is the pixel span */ lxi++; /* Don't bother trying to optimize the fill unless * the span is longer than 4 pixels. */ if (rxi - lxi > 4) { if (fill_start < 0) { fill_start = lxi; fill_end = rxi; fill_size++; } else { if (lxi >= fill_end || rxi < fill_start) { /* We're beyond what we saved, just fill it */ ADD_SATURATE_8 (ap + fill_start, fill_size * N_X_FRAC (8), fill_end - fill_start); fill_start = lxi; fill_end = rxi; fill_size = 1; } else { /* Update fill_start */ if (lxi > fill_start) { ADD_SATURATE_8 (ap + fill_start, fill_size * N_X_FRAC (8), lxi - fill_start); fill_start = lxi; } else if (lxi < fill_start) { ADD_SATURATE_8 (ap + lxi, N_X_FRAC (8), fill_start - lxi); } /* Update fill_end */ if (rxi < fill_end) { ADD_SATURATE_8 (ap + rxi, fill_size * N_X_FRAC (8), fill_end - rxi); fill_end = rxi; } else if (fill_end < rxi) { ADD_SATURATE_8 (ap + fill_end, N_X_FRAC (8), rxi - fill_end); } fill_size++; } } } else { ADD_SATURATE_8 (ap + lxi, N_X_FRAC (8), rxi - lxi); } WRITE (image, ap + rxi, clip255 (READ (image, ap + rxi) + rxs)); } } if (y == b) { /* We're done, make sure we clean up any remaining fill. */ if (fill_start != fill_end) { if (fill_size == N_Y_FRAC (8)) { MEMSET_WRAPPED (image, ap + fill_start, 0xff, fill_end - fill_start); } else { ADD_SATURATE_8 (ap + fill_start, fill_size * N_X_FRAC (8), fill_end - fill_start); } } break; } if (pixman_fixed_frac (y) != Y_FRAC_LAST (8)) { RENDER_EDGE_STEP_SMALL (l); RENDER_EDGE_STEP_SMALL (r); y += STEP_Y_SMALL (8); } else { RENDER_EDGE_STEP_BIG (l); RENDER_EDGE_STEP_BIG (r); y += STEP_Y_BIG (8); if (fill_start != fill_end) { if (fill_size == N_Y_FRAC (8)) { MEMSET_WRAPPED (image, ap + fill_start, 0xff, fill_end - fill_start); } else { ADD_SATURATE_8 (ap + fill_start, fill_size * N_X_FRAC (8), fill_end - fill_start); } fill_start = fill_end = -1; fill_size = 0; } line += stride; } } }