static Color adjustColorForVisibilityOnBackground(Color textColor, Color backgroundColor) { int d = differenceSquared(textColor, backgroundColor); // Semi-arbitrarily chose 65025 (255^2) value here after a few tests. if (d > 65025) return textColor; int distanceFromWhite = differenceSquared(textColor, Color::white); int distanceFromBlack = differenceSquared(textColor, Color::black); if (distanceFromWhite < distanceFromBlack) return textColor.dark(); return textColor.light(); }
static Color disabledTextColor(const Color& textColor, const Color& backgroundColor) { // The explicit check for black is an optimization for the 99% case (black on white). // This also means that black on black will turn into grey on black when disabled. Color disabledColor; if (textColor.rgb() == Color::black || differenceSquared(textColor, Color::white) > differenceSquared(backgroundColor, Color::white)) disabledColor = textColor.light(); else disabledColor = textColor.dark(); // If there's not very much contrast between the disabled color and the background color, // just leave the text color alone. We don't want to change a good contrast color scheme so that it has really bad contrast. // If the the contrast was already poor, then it doesn't do any good to change it to a different poor contrast color scheme. if (differenceSquared(disabledColor, backgroundColor) < minColorContrastValue) return textColor; return disabledColor; }
Color correctedTextColor(Color textColor, Color backgroundColor) { // Adjust the text color if it is too close to the background color, // by darkening or lightening it to move it further away. int d = differenceSquared(textColor, backgroundColor); // semi-arbitrarily chose 65025 (255^2) value here after a few tests; if (d > 65025) { return textColor; } int distanceFromWhite = differenceSquared(textColor, Color::white); int distanceFromBlack = differenceSquared(textColor, Color::black); if (distanceFromWhite < distanceFromBlack) { return textColor.dark(); } return textColor.light(); }
Color TextPainter::textColorForWhiteBackground(Color textColor) { int distanceFromWhite = differenceSquared(textColor, Color::white); // semi-arbitrarily chose 65025 (255^2) value here after a few tests; return distanceFromWhite > 65025 ? textColor : textColor.dark(); }