Cette fois, je vais vous montrer comment encapsuler Canvas dans un plug-in en utilisant js Quelles sont les précautions pour encapsuler Canvas dans un plug-in en utilisant js. est un cas pratique, jetons-y un coup d'œil.
J'ai déjà dit que je voulais écrire un plug-in pour dessiner des graphiques statistiques sur toile, et maintenant je l'ai écrit
Parlons d'abord des fonctions implémentées :
1. Vous pouvez dessiner des graphiques statistiques proportionnellement en personnalisant les attributs de coordonnées de l'axe X et les attributs de coordonnées de l'axe Y
2. Vous pouvez choisir de dessiner un graphique de remise ou un histogramme, ou les deux
3. Vous pouvez définir librement la couleur de remise, la couleur de coordination, la couleur de la colonne et la couleur de la bordure de la toile. Bien sûr, vous pouvez également choisir d'avoir ou non la bordure
. 4. Vous pouvez choisir d'implémenter ou non l'animation des histogrammes et des graphiques de remise
Processus de mise en œuvre
Dessinez des coordonnées - dessinez des flèches - marquez l'axe X et l'axe Y - dessinez un histogramme - dessinez un tableau de remise
Sans plus attendre, voici le code
(function(window,document){
var ChartDraws = function(options){
if(!(this instanceof ChartDraws))return new ChartDraws(options);
this.options = $.extend({
//报表所需的参数
"containerId" : "", //canvas所在容器id
"canvasWidth" : 400,
"canvasHeight" : 300,
"paddingLeft" : 20,
"paddingTop" : 20,
"columnChartData" :[], //柱形图的数量和对应得名称以及百分比
"yChartData" :[], //y轴的数量及名称
"axisColor" : "white", //坐标轴颜色
"columnChartColor" : "#EEE685", //柱形图颜色
"isNeedAnimation" : true, //是否需要动画
"isNeedLineChart" : true, //是否需要折线图
"isNeedColumnChart" : true, //是否需要柱形图
"lineChartColor" : "#90EE90", //折线图颜色，当isNeedLineChart=true时有效
"isNeedBorder" : false, //canvas是否需要外边框
"borderColor" : "white" //外边框颜色
},options);
if(this.options.canvasWidth<=500)
{
this.axisBorderWidth = 3;
this.fontSize = 8;
}
else if(this.options.canvasWidth<=800){
this.axisBorderWidth = 4;
this.fontSize = 12;
}
else{
this.axisBorderWidth = 5;
this.fontSize = 16;
}
var self = this;
_init();
function _init(){
var canvasDom = document.createElement("canvas");
canvasDom.id = self.options.containerId+"_"+"canvas";
canvasDom.width = self.options.canvasWidth;
canvasDom.height = self.options.canvasHeight;
if(self.options.isNeedBorder){
canvasDom.style.borderWidth = 1;
canvasDom.style.borderStyle = "solid";
canvasDom.style.borderColor = self.options.borderColor;
}
document.getElementById(self.options.containerId).appendChild(canvasDom);
self.context = document.getElementById(self.options.containerId+"_"+"canvas");
self.ctx = self.context.getContext("2d");
_drawAxis();
}
function _drawAxis(){
var XYData =transformAxis( [{x:self.options.paddingLeft,y:self.options.canvasHeight-self.options.paddingTop},{x:self.options.paddingLeft,y:self.options.paddingTop},{x:self.options.canvasWidth-self.options.paddingLeft,y:self.options.paddingTop}]);
self.ctx.strokeStyle=self.options.axisColor;
drawLine(self.ctx,XYData,self.axisBorderWidth);
//画三角箭头
//画y轴三角箭头
drawLine(self.ctx,transformAxis([{x:self.options.paddingLeft-self.axisBorderWidth,y:self.options.canvasHeight-self.options.paddingTop-self.axisBorderWidth*2},{x:self.options.paddingLeft,y:self.options.canvasHeight-self.options.paddingTop},{x:self.options.paddingLeft+self.axisBorderWidth,y:self.options.canvasHeight-self.options.paddingTop-self.axisBorderWidth*2}]),self.axisBorderWidth);
//画x轴三角箭头
drawLine(self.ctx,transformAxis([{x:self.options.canvasWidth-self.options.paddingLeft-self.axisBorderWidth*2,y:self.options.paddingTop+self.axisBorderWidth},{x:self.options.canvasWidth-self.options.paddingLeft,y:self.options.paddingTop},{x:self.options.canvasWidth-self.options.paddingLeft-self.axisBorderWidth*2,y:self.options.paddingTop-self.axisBorderWidth}]),self.axisBorderWidth);
_drawCoordinatePoints();
}
function _drawCoordinatePoints(){
self.reactAngleWidth = (1-2*0.04)*(self.options.canvasWidth-(2*self.options.paddingLeft))/(self.options.columnChartData.length*2-1);
self.lineDataList = [];
for(var i = 0;i<self.options.columnChartData.length;i++)
{
drawXText(self.ctx,2*self.options.columnChartData[i].NO*self.reactAngleWidth+self.options.paddingLeft+0.04*(self.options.canvasWidth-(2*self.options.paddingLeft))+self.reactAngleWidth/2,self.options.paddingTop/2,self.options.columnChartData[i].Name);
self.lineDataList.push({
x:2*self.options.columnChartData[i].NO*self.reactAngleWidth+self.options.paddingLeft+0.04*(self.options.canvasWidth-(2*self.options.paddingLeft))+self.reactAngleWidth/2,
y:self.options.canvasHeight-(self.options.paddingTop+(self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[i].PT)
})
}
//画Y轴title 画y轴虚线
self.reactAngleHeight = (self.options.canvasHeight-2*self.options.paddingTop)/(self.options.yChartData.length+1);
for(var j = 0;j<self.options.yChartData.length;j++)
{
drawYText(self.ctx,3*self.options.paddingLeft/4,self.options.paddingTop+self.reactAngleHeight*(j+1),self.options.yChartData[j].Name);
//画虚线
drawDottedLine(self.ctx,self.options.paddingLeft,self.options.paddingTop+self.reactAngleHeight*(j+1),self.options.canvasWidth-self.options.paddingLeft,self.options.paddingTop+self.reactAngleHeight*(j+1),self.options.canvasWidth-2*self.options.paddingLeft,10,self.axisBorderWidth/2);
}
_drawColumnChart();
}
function _drawColumnChart(){
//柱形图循环
var reactAngleTimer = 1;
function loopColumnChart()
{
var columnChartLooped = window.requestAnimationFrame(loopColumnChart);
if(reactAngleTimer<=100)
{
for(var k=0;k<self.options.columnChartData.length;k++)
{
self.ctx.fillStyle =self.options.columnChartColor;
drawRectangle(self.ctx,self.lineDataList[k].x-self.reactAngleWidth/2,self.options.canvasHeight-((self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT*reactAngleTimer/100+self.options.paddingTop),self.reactAngleWidth,(self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT*reactAngleTimer/100);
}
reactAngleTimer++;
}
else
{
window.cancelAnimationFrame(columnChartLooped);
columnChartLooped = null;
reactAngleTimer = 1;
if(self.options.isNeedLineChart)
{
loopLineChart();
}
}
}
//折线图循环
var lineTimer = 0;
function loopLineChart()
{
var lineChartLooped = window.requestAnimationFrame(loopLineChart);
if(lineTimer<self.lineDataList.length-1)
{
self.ctx.lineWidth = 2*self.axisBorderWidth/3;
if(lineTimer == 0)
{
drawCircle(self.ctx,self.lineDataList[lineTimer].x,self.lineDataList[lineTimer].y);
}
drawCircle(self.ctx,self.lineDataList[lineTimer+1].x,self.lineDataList[lineTimer+1].y);
self.ctx.beginPath();
self.ctx.moveTo(self.lineDataList[lineTimer].x,self.lineDataList[lineTimer].y);
self.ctx.lineTo(self.lineDataList[lineTimer+1].x,self.lineDataList[lineTimer+1].y);
self.ctx.strokeStyle = self.options.lineChartColor;
self.ctx.lineWidth = 2*self.axisBorderWidth/3;
self.ctx.stroke();
lineTimer++;
}
else
{
window.cancelAnimationFrame(lineChartLooped);
lineChartLooped = null;
lineTimer = 0;
}
}
//画柱形图
function drawRectangle(context,x,y,width,height){
context.beginPath();
context.fillRect(x,y,width,height);
}
//画圆
function drawCircle(context,x,y){
context.beginPath();
context.arc(x,y,self.axisBorderWidth/2,0,2*Math.PI,true);
context.strokeStyle=self.options.lineChartColor;
context.stroke();
context.closePath();
}
if(self.options.isNeedAnimation)
{
if(self.options.isNeedColumnChart)
{
loopColumnChart();
}
else
{
if(self.options.isNeedLineChart) {
loopLineChart();
}
}
}
else
{
if(self.options.isNeedColumnChart)
{
for(var k=0;k<self.options.columnChartData.length;k++)
{
self.ctx.fillStyle =self.options.columnChartColor;
drawRectangle(self.ctx,self.lineDataList[k].x-self.reactAngleWidth/2,self.options.canvasHeight-((self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT+self.options.paddingTop),self.reactAngleWidth,(self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT);
}
}
if(self.options.isNeedLineChart) {
for (var l = 0; l < self.lineDataList.length - 1; l++) {
self.ctx.lineWidth = 4;
if (l == 0) {
drawCircle(self.ctx, self.lineDataList[l].x, self.lineDataList[l].y);
}
drawCircle(self.ctx, self.lineDataList[l + 1].x, self.lineDataList[l + 1].y);
self.ctx.beginPath();
self.ctx.moveTo(self.lineDataList[l].x, self.lineDataList[l].y);
self.ctx.lineTo(self.lineDataList[l + 1].x, self.lineDataList[l + 1].y);
self.ctx.strokeStyle = self.options.lineChartColor;
self.ctx.lineWidth = 2*self.axisBorderWidth/3;
self.ctx.stroke();
}
}
}
}
function transformAxis(data)
{
var newData=[];
for(var i=0;i<data.length;i++){
newData.push({
x:data[i].x,
y:self.options.canvasHeight-data[i].y
})
}
return newData;
}
function drawLine(context,point,width){
context.beginPath();
context.moveTo(point[0].x,point[0].y);
if(point.length>2)
{
for(var i=1;i<point.length;i++)
{
context.lineTo(point[i].x,point[i].y);
}
}
context.lineWidth = width;
context.lineJoin='round';
context.stroke();
context.closePath();
}
//画y轴title
function drawYText(context,x,y,str) {
context.beginPath();
context.font = '{fontSize} Microsoft Yahei'.replace("{fontSize}",self.fontSize+"px");
context.fillStyle = 'white';
context.textAlign = 'right';
context.fillText(str,x,self.options.canvasHeight-y);
context.closePath();
}
//画x轴title
function drawXText(context,x,y,str) {
context.beginPath();
context.font = '{fontSize} Microsoft Yahei'.replace("{fontSize}",self.fontSize+"px");
context.fillStyle = 'white';
context.textAlign = 'center';
context.fillText(str,x,self.options.canvasHeight-y);
context.closePath();
}
function drawDottedLine(context,x1,y1,x2,y2,totalLength,length,lineWidth){
y1 = self.options.canvasHeight-y1;
y2 = self.options.canvasHeight-y2;
var dashLen = length === undefined ? 5 : length;
//计算有多少个线段
context.beginPath();
var num = Math.floor(totalLength/dashLen);
context.lineWidth = lineWidth;
for(var i = 0 ; i < num; i++)
{
context[i%2==0 ? 'moveTo' : 'lineTo'](x1+(x2-x1)/num*i,y1+(y2-y1)/num*i);
}
context.stroke();
}
};
window.ChartDraws = ChartDraws;
}(window,document));Il y en a un autre ci-dessous qui implémente la compatibilité du navigateur requestAnimationFrame
(function(){
var lastTime = 0;
var prefixes = ['ms','webkit','o','moz']; //各浏览器前缀
var requestAnimationFrame = window.requestAnimationFrame;
var cancelAnimationFrame = window.cancelAnimationFrame;
var prefix;
//通过遍历各浏览器前缀，来得到requestAnimationFrame和cancelAnimationFrame在当前浏览器的实现形式
for( var i = 0; i < prefixes.length; i++ ) {
if ( requestAnimationFrame && cancelAnimationFrame ) {
break;
}
prefix = prefixes[i];
requestAnimationFrame = requestAnimationFrame || window[ prefix + 'RequestAnimationFrame' ];
cancelAnimationFrame = cancelAnimationFrame || window[ prefix + 'CancelAnimationFrame' ] || window[ prefix + 'CancelRequestAnimationFrame' ];
}
//如果当前浏览器不支持requestAnimationFrame和cancelAnimationFrame，则会退到setTimeout
if ( !requestAnimationFrame || !cancelAnimationFrame ) {
requestAnimationFrame = function( callback, element ) {
var currTime = new Date().getTime();
//为了使setTimteout的尽可能的接近每秒60帧的效果
var timeToCall = Math.max( 0, 16 - ( currTime - lastTime ) );
var id = window.setTimeout( function() {
callback( currTime + timeToCall );
}, timeToCall );
lastTime = currTime + timeToCall;
return id;
};
cancelAnimationFrame = function( id ) {
window.clearTimeout( id );
};
}
window.requestAnimationFrame = requestAnimationFrame;
window.cancelAnimationFrame = cancelAnimationFrame;
}());Ci-joint
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