+ /*
+ * The polynomial function
+ * 2x^3 - 3x^2 + 1
+ * is similar to the Lanczos function, but much easier to compute. It's
+ * applied here to improve sharpness.
+ */
+ {
+ double t = x_src_fp - x_src_left;
+ x_right_frac = -2.0 * t * t * t + 3.0 * t * t;
+
+ t = y_src_fp - y_src_top;
+ y_bottom_frac = -2.0 * t * t * t + 3.0 * t * t;
+ }
+