Определите цвет шрифта на основе цвета фона
Если вы зайдете на http://kenwheeler.github.io/slick/ и выполните поиск для синхронизации слайдера, он покажет демо, функционирующее очень похоже на то, что вы описываете. [112 ]
Чтобы перенаправить слайд по клику, в HTML сделайте ссылки на контент слайдов с помощью ссылки, указывающей, куда вы хотите перейти.
Если я не пропустил ваше намерение, это почти точно поведение ползунка, показанное на https://www.masterclass.com .
Дайте мне знать, если это поможет! Удачи!
3 ответа
I encountered similar problem. I had to find a good method of selecting contrastive font color to display text labels on colorscales/heatmaps. It had to be universal method and generated color had to be "good looking", which means that simple generating complementary color was not good solution - sometimes it generated strange, very intensive colors that were hard to watch and read.
After long hours of testing and trying to solve this problem, I found out that the best solution is to select white font for "dark" colors, and black font for "bright" colors.
Here's an example of function I am using in C#:
Color ContrastColor(Color color)
{
int d = 0;
// Counting the perceptive luminance - human eye favors green color...
double luminance = ( 0.299 * color.R + 0.587 * color.G + 0.114 * color.B)/255;
if (luminance > 0.5)
d = 0; // bright colors - black font
else
d = 255; // dark colors - white font
return Color.FromArgb(d, d, d);
}
This was tested for many various colorscales (rainbow, grayscale, heat, ice, and many others) and is the only "universal" method I found out.
Edit
Changed the formula of counting a to "perceptive luminance" - it really looks better! Already implemented it in my software, looks great.
Edit 2 @WebSeed provided a great working example of this algorithm: http://codepen.io/WebSeed/full/pvgqEq/
Примечание там является алгоритмом для этого в библиотека закрытия Google что ссылки w3c рекомендация: http://www.w3.org/TR/AERT#color-contrast . Однако в этом API Вы предоставляете список предложенных цветов как начальная точка.
/**
* Find the "best" (highest-contrast) of the suggested colors for the prime
* color. Uses W3C formula for judging readability and visual accessibility:
* http://www.w3.org/TR/AERT#color-contrast
* @param {goog.color.Rgb} prime Color represented as a rgb array.
* @param {Array<goog.color.Rgb>} suggestions Array of colors,
* each representing a rgb array.
* @return {!goog.color.Rgb} Highest-contrast color represented by an array.
*/
goog.color.highContrast = function(prime, suggestions) {
var suggestionsWithDiff = [];
for (var i = 0; i < suggestions.length; i++) {
suggestionsWithDiff.push({
color: suggestions[i],
diff: goog.color.yiqBrightnessDiff_(suggestions[i], prime) +
goog.color.colorDiff_(suggestions[i], prime)
});
}
suggestionsWithDiff.sort(function(a, b) { return b.diff - a.diff; });
return suggestionsWithDiff[0].color;
};
/**
* Calculate brightness of a color according to YIQ formula (brightness is Y).
* More info on YIQ here: http://en.wikipedia.org/wiki/YIQ. Helper method for
* goog.color.highContrast()
* @param {goog.color.Rgb} rgb Color represented by a rgb array.
* @return {number} brightness (Y).
* @private
*/
goog.color.yiqBrightness_ = function(rgb) {
return Math.round((rgb[0] * 299 + rgb[1] * 587 + rgb[2] * 114) / 1000);
};
/**
* Calculate difference in brightness of two colors. Helper method for
* goog.color.highContrast()
* @param {goog.color.Rgb} rgb1 Color represented by a rgb array.
* @param {goog.color.Rgb} rgb2 Color represented by a rgb array.
* @return {number} Brightness difference.
* @private
*/
goog.color.yiqBrightnessDiff_ = function(rgb1, rgb2) {
return Math.abs(
goog.color.yiqBrightness_(rgb1) - goog.color.yiqBrightness_(rgb2));
};
/**
* Calculate color difference between two colors. Helper method for
* goog.color.highContrast()
* @param {goog.color.Rgb} rgb1 Color represented by a rgb array.
* @param {goog.color.Rgb} rgb2 Color represented by a rgb array.
* @return {number} Color difference.
* @private
*/
goog.color.colorDiff_ = function(rgb1, rgb2) {
return Math.abs(rgb1[0] - rgb2[0]) + Math.abs(rgb1[1] - rgb2[1]) +
Math.abs(rgb1[2] - rgb2[2]);
};
If you're manipulating color spaces for visual effect it's generally easier to work in HSL (Hue, Saturation and Lightness) than RGB. Moving colours in RGB to give naturally pleasing effects tends to be quite conceptually difficult, whereas converting into HSL, manipulating there, then converting back out again is more intuitive in concept and invariably gives better looking results.
Wikipedia has a good introduction to HSL and the closely related HSV. And there's free code around the net to do the conversion (for example here is a javascript implementation)
What precise transformation you use is a matter of taste, but personally I'd have thought reversing the Hue and Lightness components would be certain to generate a good high contrast colour as a first approximation, but you can easily go for more subtle effects.