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实现代码
JavaScript
var canvas = document.getElementById("mycanvas");var w = window.innerWidth;var h = window.innerHeight;canvas.height = 1000;canvas.width = 1400;var ctx = canvas.getContext('2d');var poppable = true;var slices = [];function shadeColor(color, percent) { var f = parseInt(color.slice(1), 16), t = percent < 0 ? 0 : 255, p = percent < 0 ? percent * -1 : percent, R = f >> 16, G = f >> 8 & 0x00FF, B = f & 0x0000FF; return "#" + (0x1000000 + (Math.round((t - R) * p) + R) * 0x10000 + (Math.round((t - G) * p) + G) * 0x100 + (Math.round((t - B) * p) + B)).toString(16).slice(1);}function pieSlice(oX, oY, r, pos, len, col,data) { this.data = data this.originX = oX; this.originY = oY; this.radius = r; this.startingRadian = pos; this.length = len; this.color = col; this.highlightedColor = shadeColor(this.color, .6); this.highlighted = false; this.popped = false; this.animationFrame = 0; function setColor(c) { this.color = c; }}pieSlice.prototype.displayData = function(){ ctx.fillStyle= this.color; ctx.fillRect(this.originX - this.radius - 40, this.originY-this.radius-35, 25,25); ctx.fillStyle= "white"; ctx.font = "15px Arial"; ctx.fillText(this.data, this.originX - this.radius - 10, this.originY - this.radius - 18);}pieSlice.prototype.render = function() { if (!this.highlighted) { ctx.fillStyle = this.color; ctx.strokeStyle = this.color; } else { if(!this.popped && poppable){ this.displayData(); } // ctx.fillStyle = this.color; ctx.fillStyle = this.highlightedColor; ctx.strokeStyle = this.color; } ctx.beginPath(); var xOffset = Math.cos(this.length / 2 + this.startingRadian) * this.animationFrame; var yOffset = Math.sin(this.length / 2 + this.startingRadian) * this.animationFrame; ctx.moveTo(this.originX + xOffset, this.originY + yOffset); var x = this.originX + xOffset + this.radius * Math.cos(this.startingRadian); var y = this.originY + yOffset + this.radius * Math.sin(this.startingRadian); ctx.lineTo(x, y); ctx.arc(this.originX + xOffset, this.originY + yOffset, this.radius, this.startingRadian, this.startingRadian + this.length); if (this.popped) { var fill = ctx.fillStyle; this.displayData(); ctx.fillStyle = fill; if (this.animationFrame < 30) { this.animationFrame += 2; } } else { if (this.animationFrame > 0) { this.animationFrame -= 2; } } ctx.closePath(); //ctx.stroke(); //if (this.highlighted) { ctx.fill(); // }}pieSlice.prototype.update = function() {}function pieChart(s) { this.slices = s;}pieChart.prototype.render = function() { this.slices.forEach(function(p) { p.render(); });};pieChart.prototype.update = function() { this.slices.forEach(function(p) { p.update(); }); } //PIE ONEvar pie = new pieSlice(700, 170, 125, 0, Math.PI / 4, "#FFD1DC", 12);var slice2 = new pieSlice(700, 170, 125, Math.PI / 4, Math.PI / 4, "#08E8DE");var slice3 = new pieSlice(700, 170, 125, Math.PI / 2, Math.PI / 4, "#6699CC");var slice4 = new pieSlice(700, 170, 125, 3 * Math.PI / 4, Math.PI, "#ADD8E6");var slice5 = new pieSlice(700, 170, 125, 7 * Math.PI / 4, Math.PI / 4, "#B19CD9");var slices1 = [pie, slice2, slice3, slice4, slice5];var pink = new pieSlice(220, 170, 125, 0, Math.PI / 3, "#FF4B4B");var orange = new pieSlice(220, 170, 125, Math.PI / 3, Math.PI / 3, "#FF931B");var yellow = new pieSlice(220, 170, 125, 2 * Math.PI / 3, Math.PI / 3, "#FFE21B");var green = new pieSlice(220, 170, 125, 3 * Math.PI / 3, Math.PI / 3, "#90E64E");var blue = new pieSlice(220, 170, 125, 4 * Math.PI / 3, Math.PI / 3, "#6097D9");var purple = new pieSlice(220, 170, 125, 5 * Math.PI / 3, Math.PI / 3, "#8365DD");var redd = new pieSlice(1180, 170, 125, 0, 2 * Math.PI / 3, "#B3989B");var orangee = new pieSlice(1180, 170, 125, 2 * Math.PI / 3, 1 * Math.PI / 8, "#C1AEE0");var bluee = new pieSlice(1180, 170, 125, 19 * Math.PI / 24, 4 * Math.PI / 24, "#928CE9");var greenn = new pieSlice(1180, 170, 125, 23 * Math.PI/24, 3* Math.PI/8, "#676675");var purplee = new pieSlice(1180, 170, 125, 4 * Math.PI/3, 3* Math.PI/8, "#947D59");var ceci = new pieSlice(1180, 170, 125, 41 * Math.PI/24, 7*Math.PI/24, "#D994E0");var slices3 = [redd, orangee, bluee, greenn, purplee, ceci];var slices2 = [pink, orange, yellow, green, blue, purple];var pie1 = new pieChart(slices1);var pie2 = new pieChart(slices2);var pie3 = new pieChart(slices3);var update = function() { pie1.update();}var render = function() { ctx.clearRect(0, 0, canvas.width, canvas.height); pie1.render(); pie2.render(); pie3.render();}var step = function() { update(); render(); animate(step);}var animate = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60); };slices.push.apply(slices, slices1);slices.push.apply(slices, slices2);slices.push.apply(slices, slices3);canvas.addEventListener("mousemove", function(e) { var x = e.clientX; var y = e.clientY; slices.forEach(function(slice) { ctx.beginPath(); var xOffset = Math.cos(slice.length / 2 + slice.startingRadian) * slice.animationFrame; var yOffset = Math.sin(slice.length / 2 + slice.startingRadian) * slice.animationFrame; ctx.moveTo(slice.originX + xOffset, slice.originY + yOffset); var xx = slice.originX + xOffset + slice.radius * Math.cos(slice.startingRadian); var yy = slice.originY + yOffset + slice.radius * Math.sin(slice.startingRadian); ctx.lineTo(xx, yy); ctx.arc(slice.originX + xOffset, slice.originY + yOffset, slice.radius, slice.startingRadian, slice.startingRadian + slice.length); if (ctx.isPointInPath(x, y)) { slice.highlighted = true; slice.displayData(); } else { slice.highlighted = false; } ctx.closePath(); });});canvas.addEventListener("click", function(e) { var x = e.clientX; var y = e.clientY; slices.forEach(function(slice) { ctx.beginPath(); var xOffset = Math.cos(slice.length / 2 + slice.startingRadian) * slice.animationFrame; var yOffset = Math.sin(slice.length / 2 + slice.startingRadian) * slice.animationFrame; ctx.moveTo(slice.originX + xOffset, slice.originY + yOffset); var xx = slice.originX + xOffset + slice.radius * Math.cos(slice.startingRadian); var yy = slice.originY + yOffset + slice.radius * Math.sin(slice.startingRadian); ctx.lineTo(xx, yy); ctx.arc(slice.originX + xOffset, slice.originY + yOffset, slice.radius, slice.startingRadian, slice.startingRadian + slice.length); if (ctx.isPointInPath(x, y)) { if (slice.popped) { slice.popped = false; poppable = true; } else { if(poppable){ slice.popped = true; poppable = false; } } slice.highlighted = false; } ctx.closePath(); });});//start the loopanimate(step);html
<canvas id="mycanvas"></canvas>关于使用JavaScript怎么绘制一个饼图就分享到这里了，希望以上内容可以对大家有一定的帮助，可以学到更多知识。如果觉得文章不错，可以把它分享出去让更多的人看到。
