From 74e64c178df7086798426412d79f18a1e8d71d09 Mon Sep 17 00:00:00 2001
From: bbedward <bbedward@gmail.com>
Date: Wed, 27 Aug 2025 15:04:32 -0400
Subject: [PATCH] dank16: ensure contrast against background

---
 matugen/dank16.py         | 165 +++++++++++++++++++++++++++++---------
 scripts/matugen-worker.sh |   5 +-
 2 files changed, 130 insertions(+), 40 deletions(-)

diff --git a/matugen/dank16.py b/matugen/dank16.py
index e1753755..60f36a3f 100755
--- a/matugen/dank16.py
+++ b/matugen/dank16.py
@@ -12,63 +12,126 @@ def rgb_to_hex(r, g, b):
     b = max(0, min(1, b))
     return f"#{int(r*255):02x}{int(g*255):02x}{int(b*255):02x}"
 
-def generate_palette(base_color, is_light=False, honor_primary=None):
+def luminance(hex_color):
+    r, g, b = hex_to_rgb(hex_color)
+    def srgb_to_linear(c):
+        return c/12.92 if c <= 0.03928 else ((c + 0.055)/1.055) ** 2.4
+    return 0.2126 * srgb_to_linear(r) + 0.7152 * srgb_to_linear(g) + 0.0722 * srgb_to_linear(b)
+
+def contrast_ratio(hex_fg, hex_bg):
+    lum_fg = luminance(hex_fg)
+    lum_bg = luminance(hex_bg)
+    lighter = max(lum_fg, lum_bg)
+    darker = min(lum_fg, lum_bg)
+    return (lighter + 0.05) / (darker + 0.05)
+
+def ensure_contrast(hex_color, hex_bg, min_ratio=4.5, is_light_mode=False):
+    current_ratio = contrast_ratio(hex_color, hex_bg)
+    if current_ratio >= min_ratio:
+        return hex_color
+    
+    r, g, b = hex_to_rgb(hex_color)
+    h, s, v = colorsys.rgb_to_hsv(r, g, b)
+    
+    for step in range(1, 30):
+        delta = step * 0.02
+        
+        if is_light_mode:
+            new_v = max(0, v - delta)
+            candidate = rgb_to_hex(*colorsys.hsv_to_rgb(h, s, new_v))
+            if contrast_ratio(candidate, hex_bg) >= min_ratio:
+                return candidate
+                
+            new_v = min(1, v + delta)
+            candidate = rgb_to_hex(*colorsys.hsv_to_rgb(h, s, new_v))
+            if contrast_ratio(candidate, hex_bg) >= min_ratio:
+                return candidate
+        else:
+            new_v = min(1, v + delta)
+            candidate = rgb_to_hex(*colorsys.hsv_to_rgb(h, s, new_v))
+            if contrast_ratio(candidate, hex_bg) >= min_ratio:
+                return candidate
+                
+            new_v = max(0, v - delta)
+            candidate = rgb_to_hex(*colorsys.hsv_to_rgb(h, s, new_v))
+            if contrast_ratio(candidate, hex_bg) >= min_ratio:
+                return candidate
+    
+    return hex_color
+
+def generate_palette(base_color, is_light=False, honor_primary=None, background=None):
     r, g, b = hex_to_rgb(base_color)
     h, s, v = colorsys.rgb_to_hsv(r, g, b)
     
     palette = []
     
-    if is_light:
-        palette.append("#f8f8f8")
+    if background:
+        bg_color = background
+        palette.append(bg_color)
+    elif is_light:
+        bg_color = "#f8f8f8"
+        palette.append(bg_color)
     else:
-        palette.append("#1a1a1a")
+        bg_color = "#1a1a1a"
+        palette.append(bg_color)
     
     red_h = 0.0
     if is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.75, 0.85)))
+        red_color = rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.75, 0.85))
+        palette.append(ensure_contrast(red_color, bg_color, 4.5, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.6, 0.8)))
+        red_color = rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.6, 0.8))
+        palette.append(ensure_contrast(red_color, bg_color, 4.5, is_light))
     
     green_h = 0.33
     if is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.9, 0.75), v * 0.6)))
+        green_color = rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.9, 0.75), v * 0.6))
+        palette.append(ensure_contrast(green_color, bg_color, 4.5, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.65, 0.5), v * 0.9)))
+        green_color = rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.65, 0.5), v * 0.9))
+        palette.append(ensure_contrast(green_color, bg_color, 4.5, is_light))
     
     yellow_h = 0.08
     if is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.85, 0.7), v * 0.7)))
+        yellow_color = rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.85, 0.7), v * 0.7))
+        palette.append(ensure_contrast(yellow_color, bg_color, 4.5, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.5, 0.45), v * 1.4)))
+        yellow_color = rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.5, 0.45), v * 1.4))
+        palette.append(ensure_contrast(yellow_color, bg_color, 4.5, is_light))
     
     if is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.9, 0.7), v * 1.1)))
+        blue_color = rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.9, 0.7), v * 1.1))
+        palette.append(ensure_contrast(blue_color, bg_color, 4.5, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.8, 0.6), min(v * 1.6, 1.0))))
+        blue_color = rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.8, 0.6), min(v * 1.6, 1.0)))
+        palette.append(ensure_contrast(blue_color, bg_color, 4.5, is_light))
     
     mag_h = h - 0.03 if h >= 0.03 else h + 0.97
     if honor_primary:
         hr, hg, hb = hex_to_rgb(honor_primary)
         hh, hs, hv = colorsys.rgb_to_hsv(hr, hg, hb)
         if is_light:
-            palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(hh, max(hs * 0.9, 0.7), hv * 0.85)))
+            mag_color = rgb_to_hex(*colorsys.hsv_to_rgb(hh, max(hs * 0.9, 0.7), hv * 0.85))
+            palette.append(ensure_contrast(mag_color, bg_color, 4.5, is_light))
         else:
-            palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(hh, hs * 0.8, hv * 0.75)))
+            mag_color = rgb_to_hex(*colorsys.hsv_to_rgb(hh, hs * 0.8, hv * 0.75))
+            palette.append(ensure_contrast(mag_color, bg_color, 4.5, is_light))
     elif is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.75, 0.6), v * 0.9)))
+        mag_color = rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.75, 0.6), v * 0.9))
+        palette.append(ensure_contrast(mag_color, bg_color, 4.5, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.7, 0.6), v * 0.85)))
+        mag_color = rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.7, 0.6), v * 0.85))
+        palette.append(ensure_contrast(mag_color, bg_color, 4.5, is_light))
     
     cyan_h = h + 0.08
     if honor_primary:
-        if is_light:
-            palette.append(honor_primary)
-        else:
-            palette.append(honor_primary)
+        palette.append(ensure_contrast(honor_primary, bg_color, 4.5, is_light))
     elif is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(cyan_h, max(s * 0.8, 0.65), v * 1.05)))
+        cyan_color = rgb_to_hex(*colorsys.hsv_to_rgb(cyan_h, max(s * 0.8, 0.65), v * 1.05))
+        palette.append(ensure_contrast(cyan_color, bg_color, 4.5, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(cyan_h, max(s * 0.6, 0.5), min(v * 1.25, 0.85))))
+        cyan_color = rgb_to_hex(*colorsys.hsv_to_rgb(cyan_h, max(s * 0.6, 0.5), min(v * 1.25, 0.85)))
+        palette.append(ensure_contrast(cyan_color, bg_color, 4.5, is_light))
     
     if is_light:
         palette.append("#2e2e2e")
@@ -78,29 +141,43 @@ def generate_palette(base_color, is_light=False, honor_primary=None):
         palette.append("#5c6370")
     
     if is_light:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.6, 0.9)))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.8, 0.7), v * 0.65)))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.75, 0.65), v * 0.75)))
+        bright_red = rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.6, 0.9))
+        palette.append(ensure_contrast(bright_red, bg_color, 3.0, is_light))
+        bright_green = rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.8, 0.7), v * 0.65))
+        palette.append(ensure_contrast(bright_green, bg_color, 3.0, is_light))
+        bright_yellow = rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.75, 0.65), v * 0.75))
+        palette.append(ensure_contrast(bright_yellow, bg_color, 3.0, is_light))
         if honor_primary:
             hr, hg, hb = hex_to_rgb(honor_primary)
             hh, hs, hv = colorsys.rgb_to_hsv(hr, hg, hb)
-            palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(hh, min(hs * 1.1, 1.0), min(hv * 1.2, 1.0))))
+            bright_blue = rgb_to_hex(*colorsys.hsv_to_rgb(hh, min(hs * 1.1, 1.0), min(hv * 1.2, 1.0)))
+            palette.append(ensure_contrast(bright_blue, bg_color, 3.0, is_light))
         else:
-            palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.8, 0.7), min(v * 1.3, 1.0))))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.9, 0.75), min(v * 1.25, 1.0))))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(cyan_h, max(s * 0.75, 0.65), min(v * 1.25, 1.0))))
+            bright_blue = rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.8, 0.7), min(v * 1.3, 1.0)))
+            palette.append(ensure_contrast(bright_blue, bg_color, 3.0, is_light))
+        bright_mag = rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.9, 0.75), min(v * 1.25, 1.0)))
+        palette.append(ensure_contrast(bright_mag, bg_color, 3.0, is_light))
+        bright_cyan = rgb_to_hex(*colorsys.hsv_to_rgb(cyan_h, max(s * 0.75, 0.65), min(v * 1.25, 1.0)))
+        palette.append(ensure_contrast(bright_cyan, bg_color, 3.0, is_light))
     else:
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.45, min(1.0, 0.9))))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.5, 0.4), min(v * 1.5, 0.9))))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.4, 0.35), min(v * 1.6, 0.95))))
+        bright_red = rgb_to_hex(*colorsys.hsv_to_rgb(red_h, 0.45, min(1.0, 0.9)))
+        palette.append(ensure_contrast(bright_red, bg_color, 3.0, is_light))
+        bright_green = rgb_to_hex(*colorsys.hsv_to_rgb(green_h, max(s * 0.5, 0.4), min(v * 1.5, 0.9)))
+        palette.append(ensure_contrast(bright_green, bg_color, 3.0, is_light))
+        bright_yellow = rgb_to_hex(*colorsys.hsv_to_rgb(yellow_h, max(s * 0.4, 0.35), min(v * 1.6, 0.95)))
+        palette.append(ensure_contrast(bright_yellow, bg_color, 3.0, is_light))
         if honor_primary:
             hr, hg, hb = hex_to_rgb(honor_primary)
             hh, hs, hv = colorsys.rgb_to_hsv(hr, hg, hb)
-            palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(hh, min(hs * 1.2, 1.0), min(hv * 1.1, 1.0))))
+            bright_blue = rgb_to_hex(*colorsys.hsv_to_rgb(hh, min(hs * 1.2, 1.0), min(hv * 1.1, 1.0)))
+            palette.append(ensure_contrast(bright_blue, bg_color, 3.0, is_light))
         else:
-            palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.6, 0.5), min(v * 1.5, 0.9))))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.7, 0.6), min(v * 1.3, 0.9))))
-        palette.append(rgb_to_hex(*colorsys.hsv_to_rgb(h + 0.02 if h + 0.02 <= 1.0 else h + 0.02 - 1.0, max(s * 0.6, 0.5), min(v * 1.2, 0.85))))
+            bright_blue = rgb_to_hex(*colorsys.hsv_to_rgb(h, max(s * 0.6, 0.5), min(v * 1.5, 0.9)))
+            palette.append(ensure_contrast(bright_blue, bg_color, 3.0, is_light))
+        bright_mag = rgb_to_hex(*colorsys.hsv_to_rgb(mag_h, max(s * 0.7, 0.6), min(v * 1.3, 0.9)))
+        palette.append(ensure_contrast(bright_mag, bg_color, 3.0, is_light))
+        bright_cyan = rgb_to_hex(*colorsys.hsv_to_rgb(h + 0.02 if h + 0.02 <= 1.0 else h + 0.02 - 1.0, max(s * 0.6, 0.5), min(v * 1.2, 0.85)))
+        palette.append(ensure_contrast(bright_cyan, bg_color, 3.0, is_light))
     
     if is_light:
         palette.append("#1a1a1a")
@@ -111,7 +188,7 @@ def generate_palette(base_color, is_light=False, honor_primary=None):
 
 if __name__ == "__main__":
     if len(sys.argv) < 2:
-        print("Usage: dank16.py <hex_color> [--light] [--kitty] [--honor-primary HEX]", file=sys.stderr)
+        print("Usage: dank16.py <hex_color> [--light] [--kitty] [--honor-primary HEX] [--background HEX]", file=sys.stderr)
         sys.exit(1)
     
     base = sys.argv[1]
@@ -133,7 +210,19 @@ if __name__ == "__main__":
             print("Error: --honor-primary requires a hex color", file=sys.stderr)
             sys.exit(1)
     
-    colors = generate_palette(base, is_light, honor_primary)
+    background = None
+    if "--background" in sys.argv:
+        try:
+            bg_idx = sys.argv.index("--background")
+            if bg_idx + 1 < len(sys.argv):
+                background = sys.argv[bg_idx + 1]
+                if not background.startswith('#'):
+                    background = '#' + background
+        except (ValueError, IndexError):
+            print("Error: --background requires a hex color", file=sys.stderr)
+            sys.exit(1)
+    
+    colors = generate_palette(base, is_light, honor_primary, background)
     
     if is_kitty:
         # Kitty color format mapping
diff --git a/scripts/matugen-worker.sh b/scripts/matugen-worker.sh
index afcb0cb2..a1312766 100755
--- a/scripts/matugen-worker.sh
+++ b/scripts/matugen-worker.sh
@@ -155,9 +155,10 @@ build_once() {
 
   PRIMARY=$(echo "$SECTION" | sed -n 's/.*"primary_container":"\(#[0-9a-fA-F]\{6\}\)".*/\1/p')
   HONOR=$(echo "$SECTION"  | sed -n 's/.*"primary":"\(#[0-9a-fA-F]\{6\}\)".*/\1/p')
+  SURFACE=$(echo "$SECTION" | sed -n 's/.*"surface":"\(#[0-9a-fA-F]\{6\}\)".*/\1/p')
 
   if command -v ghostty >/dev/null 2>&1 && [[ -f "$CONFIG_DIR/ghostty/config-dankcolors" ]]; then
-    OUT=$("$SHELL_DIR/matugen/dank16.py" "$PRIMARY" $([[ "$mode" == "light" ]] && echo --light) ${HONOR:+--honor-primary "$HONOR"} 2>/dev/null || true)
+    OUT=$("$SHELL_DIR/matugen/dank16.py" "$PRIMARY" $([[ "$mode" == "light" ]] && echo --light) ${HONOR:+--honor-primary "$HONOR"} ${SURFACE:+--background "$SURFACE"} 2>/dev/null || true)
     if [[ -n "${OUT:-}" ]]; then
       TMP="$(mktemp)"
       printf "%s\n\n" "$OUT" > "$TMP"
@@ -167,7 +168,7 @@ build_once() {
   fi
 
   if command -v kitty >/dev/null 2>&1 && [[ -f "$CONFIG_DIR/kitty/dank-theme.conf" ]]; then
-    OUT=$("$SHELL_DIR/matugen/dank16.py" "$PRIMARY" $([[ "$mode" == "light" ]] && echo --light) ${HONOR:+--honor-primary "$HONOR"} --kitty 2>/dev/null || true)
+    OUT=$("$SHELL_DIR/matugen/dank16.py" "$PRIMARY" $([[ "$mode" == "light" ]] && echo --light) ${HONOR:+--honor-primary "$HONOR"} ${SURFACE:+--background "$SURFACE"} --kitty 2>/dev/null || true)
     if [[ -n "${OUT:-}" ]]; then
       TMP="$(mktemp)"
       printf "%s\n\n" "$OUT" > "$TMP"