Photoshop's remaining blend modes in its groups (12.7a); v1.2.2 kernels for 12.7b

kernels/AdjustPixels.h

@@ -13,6 +13,20 @@ void adjust_gradient_map(uint8_t *rgba, size_t width, size_t height, size_t stri
 // piece of an image gets the same grain as that part of the whole.
 void adjust_grain(uint8_t *rgba, size_t width, size_t height, size_t stride, double amount, double size,
                   double roughness, uint32_t seed, double originX, double originY, double unitsPerPixel);
+// Black & White on premultiplied RGBA pixels, the way Photoshop's is: a color is split into the gray
+// it contains, the secondary (cyan/magenta/yellow) between its two brightest channels, and the primary
+// (red/green/blue) of its brightest, and each of those six ranges has its own weight. `weights` is six
+// floats in the order red, yellow, green, cyan, blue, magenta, as fractions (Photoshop's 40% is 0.4).
+// Pure red at the default 40% comes out 40% gray, as it does there. With `tint`, the result is colored
+// at `tintHue` degrees and `tintSaturation` (0–1) while keeping that gray as its lightness.
+void adjust_black_white(uint8_t *rgba, size_t width, size_t height, size_t stride, const float *weights,
+                        int tint, double tintHue, double tintSaturation);
+// Color Balance on premultiplied RGBA pixels. `shadows`, `midtones` and `highlights` are each three
+// floats — cyan/red, magenta/green, yellow/blue — from -1 to 1 (Photoshop's -100 to 100). Each pixel is
+// shifted by however much it belongs to each tonal range, and with `preserveLuminosity` its original
+// brightness is put back afterwards, so only the color moves.
+void adjust_color_balance(uint8_t *rgba, size_t width, size_t height, size_t stride, const float *shadows,
+                          const float *midtones, const float *highlights, int preserveLuminosity);
 // After resampling with a filter that rings (Lanczos), premultiplied RGBA colors can exceed their alpha;
 // this clamps each channel back to its pixel's alpha. `count` is the number of pixels.
 void rgba_clamp_premultiplied(uint8_t *rgba, size_t count);