[Catalog][a11y] Select text color based on optimal contrast against b…

…ackground

PiperOrigin-RevId: 632242630

catalog/java/io/material/catalog/color/ColorDemoUtils.java

@@ -18,15 +18,20 @@
 
 import android.graphics.Color;
 import androidx.annotation.ColorInt;
-import com.google.android.material.color.MaterialColors;
+import androidx.core.graphics.ColorUtils;
 
 /** Utility methods for Color. */
 final class ColorDemoUtils {
 
  private ColorDemoUtils() {}
 
  static int getTextColor(@ColorInt int backgroundColor) {
- // Use white text color if the background color is considered dark.
- return MaterialColors.isColorLight(backgroundColor) ? Color.BLACK : Color.WHITE;
+ // Use the text color with the best contrast against the background color.
+ if (ColorUtils.calculateContrast(Color.BLACK, backgroundColor)
+ > ColorUtils.calculateContrast(Color.WHITE, backgroundColor)) {
+ return Color.BLACK;
+ } else {
+ return Color.WHITE;
+ }
  }
 }