Method mix

src/common/overlay/levelRenderer/Color.js:698–731

* @function LevelRenderer.Tool.Color.prototype.mix * @description 简单两种颜色混合 * @param {string} color1 - 第一种颜色。 * @param {string} color2 - 第二种颜色。 * @param {number} weight - 混合权重[0-1]。 * @returns {string} 结果色。rgb(r,g,b)或rgba(r,g,b,a)

(color1, color2, weight)

     * @returns {string} 结果色。rgb(r,g,b)或rgba(r,g,b,a)
     */
    mix(color1, color2, weight) {
        if (!this.isCalculableColor(color1) || !this.isCalculableColor(color2)) {
            return color1;
        }

        if (typeof weight === 'undefined') {
            weight = 0.5;
        }
        weight = 1 - this.adjust(weight, [0, 1]);

        var w = weight * 2 - 1;
        var data1 = this.getData(this.toRGBA(color1));
        var data2 = this.getData(this.toRGBA(color2));

        var d = data1[3] - data2[3];

        var weight1 = (((w * d === -1) ? w : (w + d) / (1 + w * d)) + 1) / 2;
        var weight2 = 1 - weight1;

        var data = [];

        for (var i = 0; i < 3; i++) {
            data[i] = data1[i] * weight1 + data2[i] * weight2;
        }

        var alpha = data1[3] * weight + data2[3] * (1 - weight);
        alpha = Math.max(0, Math.min(1, alpha));

        if (data1[3] === 1 && data2[3] === 1) {// 不考虑透明度
            return this.toColor(data, 'rgb');
        }
        data[3] = alpha;
        return this.toColor(data, 'rgba');
    }

    /**
     * @function LevelRenderer.Tool.Color.prototype.random