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ColorsPickerUtil.js
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169 lines (161 loc) · 4.87 KB
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import {Color} from '../overlay/levelRenderer/Color';
import {
SuperMap
} from '../SuperMap';
var ColorRender = new Color();
// let "http://www.qzu.zj.cn": "#bd10e0"
// "www.qzct.net": "#7ed321" = new SuperMap.LevelRenderer.Tool.Color();
/**
* Created by yzy on 2016/11/9.
* 色带选择器工具类 用于1、创建canvas对象，2、从几种颜色中获取一定数量的渐变色
*
*/
export class ColorsPickerUtil {
/**
* 创建DOM canvas
* @param height canvas 高度
* @param width canvas 宽度
*
*/
static createCanvas (height, width){
var canvas = document.createElement("canvas");
canvas.height = height;
canvas.width = width;
return canvas.getContext("2d");
}
/**
* 线性渐变。
* Parameters:
* x0 - {Number} 渐变起点。
* y0 - {Number}
* x1 - {Number} 渐变终点。
* y1 - {Number}
* colorList - {Array} 颜色列表。
*
* Returns:
* {CanvasGradient} Cavans 渐变颜色。
*/
static getLinearGradient (x0, y0, x1, y1, colorList){
if (!this._ctx) {
this._ctx = this.getContext();
}
var gradient = this._ctx.createLinearGradient(x0, y0, x1, y1);
var leng = colorList.length;
var add = 1/(leng -1);
var offset = 0;
for (var i = 0; i < leng; i++) {
gradient.addColorStop(offset, colorList[i]);
offset += add;
}
gradient.__nonRecursion = true;
return gradient;
}
/**
* 获取 Cavans 上下文
*
* Returns:
* {Object} Cavans 上下文。
*/
static getContext () {
if (!this._ctx) {
this._ctx = document.createElement('canvas').getContext('2d');
}
return this._ctx;
}
/**
* 获取两种颜色之间渐变颜色数组。
*
* Parameters:
* start - {color} 起始颜色。
* end - {color} 结束颜色。
* step - {Number} 渐变级数。
* colorList - {Array} 颜色列表。
*
* Returns:
* {Array} 颜色数组。
*/
static getStepColors (start, end, step){
start = ColorRender.toRGBA(start);
end = ColorRender.toRGBA(end);
start = ColorRender.getData(start);
end = ColorRender.getData(end);
var colors = [];
var stepR = (end[0] - start[0]) / step;
var stepG = (end[1] - start[1]) / step;
var stepB = (end[2] - start[2]) / step;
var stepA = (end[3] - start[3]) / step;
// 生成颜色集合
// fix by linfeng 颜色堆积
for (var i = 0, r = start[0], g = start[1], b = start[2], a = start[3]; i < step; i++) {
colors[i] = ColorRender.toColor([
ColorRender.adjust(Math.floor(r), [ 0, 255 ]),
ColorRender.adjust(Math.floor(g), [ 0, 255 ]),
ColorRender.adjust(Math.floor(b), [ 0, 255 ]),
a.toFixed(4) - 0
],'hex');
r += stepR;
g += stepG;
b += stepB;
a += stepA;
}
r = end[0];
g = end[1];
b = end[2];
a = end[3];
colors[i] = ColorRender.toColor([r, g, b, a], 'hex');
return colors;
}
/**
* APIMethod: getGradientColors
* 获取指定级数的渐变颜色数组。
*
* Parameters:
* colors - {Array{String}} 颜色组。
* total - {Number} 颜色总数。
* total - {String} 专题类型
*
* Returns:
* {Array{String}} 颜色数组。
*/
static getGradientColors (colors, total, themeType){
var ret = [], step;
var i, n, len = colors.length;
if (total === undefined) {
return;
}
if(len >= total){
if(themeType === 'RANGE'){
for(i = 0; i<total; i++){
ret.push(colors[i]);
}
}else {
//1/2前后取色
for(i = 0; i<total; i++){
let ii = Math.floor(i/2);
if(i%2 === 0){
ret.push(colors[ii]);
}else {
let index = colors.length -1 - ii;
ret.push(colors[index]);
}
}
}
} else {
step = Math.ceil(total/(len-1));
for (i = 0, n = len - 1; i < n; i++) {
var steps = this.getStepColors(colors[i], colors[i + 1], step);
if (i < n - 1) {
steps.pop();
}
ret = ret.concat(steps);
}
//删除多余元素
var nouse = ret.length - total;
for(var j = 0, index = 0; j< nouse; j++){
ret.splice(index+2,1);
}
}
return ret;
}
}
SuperMap.ColorsPickerUtil = ColorsPickerUtil;