+/*
+ * Scale a color by another color and some scalar coefficient.
+ */
+INLINE_MAYBE
+color_t color_scale2(color_t c1, color_t c2, scal_t k)
+{
+ return color_scale(color_mult(c1, c2), k);
+}
+
+INLINE_MAYBE
+color_t color_blend(color_t d, color_t s)
+{
+ d.r = (S(1.0) - s.a) * d.r + s.a * s.r;
+ d.g = (S(1.0) - s.a) * d.g + s.a * s.g;
+ d.b = (S(1.0) - s.a) * d.b + s.a * s.b;
+ return d;
+}
+
+/*
+ * Clamp a color's channels to the normal range of 0.0 to 1.0.
+ */
+INLINE_MAYBE
+color_t color_clamp(color_t c)
+{
+ c.r = scal_clamp(c.r, S(0.0), S(1.0));
+ c.g = scal_clamp(c.g, S(0.0), S(1.0));
+ c.b = scal_clamp(c.b, S(0.0), S(1.0));
+ c.a = scal_clamp(c.a, S(0.0), S(1.0));
+ return c;
+}
+
+
+/*
+ * Interpolate smoothly between two colors with an alpha value.
+ */
+INLINE_MAYBE
+color_t color_interp(color_t c1, color_t c2, scal_t a)
+{
+ return color_new(c1.r * (S(1.0) - a) + c2.r * a,
+ c1.g * (S(1.0) - a) + c2.g * a,
+ c1.b * (S(1.0) - a) + c2.b * a, c1.a);
+}
+
+/*
+ * Interpolate smoothly between three colors with barycentric coordinates.
+ */
+INLINE_MAYBE
+color_t color_interp2(color_t c1, color_t c2, color_t c3, scal_t b[3])
+{
+ return color_new(c1.r * b[0] + c2.r * b[1] + c3.r * b[2],
+ c1.g * b[0] + c2.g * b[1] + c3.g * b[2],
+ c1.b * b[0] + c2.b * b[1] + c3.b * b[2], c1.a);
+}
+
+
+/*
+ * Define integer types for a 32-bit RGBA color representation.
+ */
+typedef uint8_t rgbachan_t;
+typedef uint32_t rgba_t;
+