html5实现饼图和线图-我们到底能走多远系列（34）
我们到底能走多远系列（34）
扯淡：
送给各位一段话：
人生是一个不断做加法的过程
从赤条条无牵无挂的来
到学会荣辱羞耻 礼仪规范
再到赚取世间的名声 财富 地位
但是人生还要学会做减法
财富名声这些身外之物有一天会失去
朋友 亲人终有一天会离你而去
我们自己会衰老 迟钝
最后赤条条的离开这个世界
我们都不太擅长做人生的减法
很难学会放下
放不下面子 所以要打肿脸充胖子
放不下逝去的情感 就会沉溺其中 痛苦不堪
放不下输赢 所以总是如履薄冰 心惊胆战
佛说 我执 是痛苦的根源
人生要学会 断 舍 离
断绝不需要的东西
舍弃多余的废物
脱离对物品的执念
所以想幸福 请先放下
主题：
最近想用html5来话图表，就接触了下，发现html5 是一个总称而已，进去后里面分成各种标签比如：HTML5 Video，HTML5 Audio，HTML5 Canvas等等，各不相关，所以学习起来也不复杂，比如我想画图表就先学习下Canvas就好了。
所以，我感觉这东西也就是调下api，没什么太大的难度，难得地方是要实现一个东西还需要学习css，javascript这些东西才行。
自己画的线图: 用一个function包起来，是为了简单的封装一下内部的变量。
需要注意的是代码依赖jquery。
这是一个比较初步的实现，对于canvas上画图，其实直接理解成现实中那笔在话就可以了，像下面的线图，先画好x y 轴，然后再话线，再来画事件现实文字。画面变化的产生目前我发现的是用clearRect方法先清空画面，然后重画....
function lineChart(data){ var xPadding = 60;//x轴离边框的距离 var yPadding = 50;//y轴离边框的距离 var canvasWidth; var canvasHeight; var xAxisLength; //x轴长度 var yAxisLength; //y轴长度 var xTextColour = "#000000"; // x轴字体颜色 var yTextColour = "#000000"; // y轴字体颜色 var dotsColour = "#183487"; // 图标点的颜色 var lineWidth = 2 //线宽度 var lineColour = "#194E9C"; // 线颜色 var lineShadowColour = "rgba( 0, 0, 0, .5 )"; // 线阴影颜色 var lineShadowBlur = 15; var lineShadowOffsetX = 3; var lineShadowOffsetY = 3; var xyColour = "#4B0082"; //xy轴颜色 var xToTextlength = 20; //x轴和文字的间距 var yToTextlength = 10; //y轴和文字的间距 var yTextNum = 6; //y轴和文字数量 var chartLineFont = "bold 16px 'Trebuchet MS', Verdana, sans-serif";// xy轴字体 var chooseDotTextFont = "bold 16px 'Trebuchet MS', Verdana, sans-serif";//显示提示字体 var dotsToDotsXLength; //x轴间距 var dotsXArray = []; var divideXArray = []; //分割每个点的竖切线的x坐标 var lineChart; // The canvas element in the page init(data); function init(data){ lineChart = document.getElementById('lineChart'); // Initialise some properties of the canvas and chart canvasWidth = lineChart.width; canvasHeight = lineChart.height; xAxisLength = canvasWidth - 2*xPadding; yAxisLength = canvasHeight - 2*yPadding; dotsToDotsXLength = xAxisLength / data.length; drawLineChart(); // 添加事件 $('#lineChart').mousemove(handleDotsMousemoveEvent); } function drawLineChart(index){ var c = lineChart.getContext('2d'); // Clear the canvas, ready for the new frame c.clearRect ( 0, 0, canvasWidth, canvasHeight ); c.lineWidth = lineWidth; c.strokeStyle = xyColour; // Draw the axises c.beginPath(); c.moveTo(xPadding, yPadding); // y轴 c.lineTo(xPadding, lineChart.height - yPadding); // x轴 c.lineTo(lineChart.width - yPadding, lineChart.height - yPadding); c.stroke(); // Draw the the background line c.beginPath(); c.strokeStyle = '#D9D6D6'; for(var i = 0; i <= getMaxYPoint(getMaxY()); i += getYSpace()) { if(i != 0){ c.moveTo(xPadding + 2, getYPixel(i)); c.lineTo(xPadding + xAxisLength + 2, getYPixel(i)); } } c.stroke(); // Draw the X value texts c.font = chartLineFont; c.fillStyle = xTextColour; c.textAlign = "center"; var step = parseInt(data.length/yTextNum); for(var i = 0; i < data.length; i =i + step) { c.fillText(data[i].X, getXPixel(i), lineChart.height - yPadding + xToTextlength); } // Draw the Y value texts c.textAlign = "right"; c.textBaseline = "middle"; c.fillStyle = yTextColour; for(var i = 0; i <= getMaxYPoint(getMaxY()); i += getYSpace()) { c.fillText(formatNum(i), xPadding - yToTextlength, getYPixel(i)); } // Draw the line graph drawLineAndDots(c, index); } /** * 画线 * @param c * @param index */ function drawLineAndDots(c, index){ c.beginPath(); c.strokeStyle = lineColour; c.moveTo(getXPixel(0), getYPixel(data[0].value)); for(var i = 1; i < data.length; i ++) { // 使用直线 //c.lineTo(getXPixel(i), getYPixel(data[i].value)); //var cps = getControlPoints(getXPixel(i-1),getYPixel(data[i-1].value),getXPixel(i),getYPixel(data[i].value)); //为了更美观一点 使用了弯曲的线 c.bezierCurveTo(getXPixel(i-1)+9,getYPixel(data[i-1].value)+9,getXPixel(i)-9,getYPixel(data[i].value)-9,getXPixel(i), getYPixel(data[i].value)) /** // 线的阴影部分 c.shadowBlur = lineShadowBlur; c.shadowOffsetX = lineShadowOffsetX; c.shadowOffsetY = lineShadowOffsetY; c.shadowColor = lineShadowColour; **/ } c.stroke(); c.shadowColor = "rgba( 0, 0, 0, 0 )"; c.closePath(); // Draw the dots c.fillStyle = dotsColour; for(var i = 0; i < data.length; i ++) { // 有点中的节点 if(i == index){ c.beginPath(); c.arc(getXPixel(i), getYPixel(data[i].value), 8, 0, Math.PI * 2, true); c.fill(); c.textAlign = "center"; c.font = chooseDotTextFont; c.fillText(data[i].X, xAxisLength + xPadding + 5 , 20 ) c.fillText(data[i].value, xAxisLength + xPadding + 5 , 40 ) }else{ c.beginPath(); c.arc(getXPixel(i), getYPixel(data[i].value), 4, 0, Math.PI * 2, true); c.fill(); } divideXArray[i] = getXPixel(i) + dotsToDotsXLength/2; } } function getMaxY() { var max = 0; for(var i = 0; i < data.length; i ++) { if(data[i].value > max) { max = data[i].value; } } max += 10 - max % 10; return max; } /** * 计算x轴间距 * @param val * @returns {number} */ function getXPixel(val) { return (dotsToDotsXLength) * val + (xPadding * 1.5); } /** * 计算y轴间距 * @param val * @returns {number} */ function getYPixel(val) { return lineChart.height - ((yAxisLength / getMaxYPoint(getMaxY())) * val) - yPadding; } /** * 计算Y轴显示最大值 * 输入1234 输出2000 * @param maxY */ function getMaxYPoint(maxY){ var firstDigit = parseInt((maxY + '').substring(0,1)) + 1; var digitNum = parseInt((maxY+"").length); for(var i = 1; i<digitNum; i++){ firstDigit = firstDigit *10 } return firstDigit; } /** * 计算Y轴坐标增加数量 * @returns {number} */ function getYSpace(){ return getMaxYPoint(getMaxY())/5; } /** * 格式化:三位数字加逗号 * @param num * @returns {*} */ function formatNum(num){ if(!/^(+|-)?d+(.d+)?$/.test(num)){ alert("wrong!"); return num; } var re = new RegExp(); re.compile("(\d)(\d{3})(,|\.|$)"); num += ""; while(re.test(num)){ num = num.replace(re, "$1,$2$3") } return num; } //鼠标事件 function handleDotsMousemoveEvent(mousemoveEvent){ //取得鼠标位置 var mouseX = mousemoveEvent.pageX - this.offsetLeft; var dot = 0; if(0 < mouseX && mouseX< xPadding){ return; } if((xPadding + xAxisLength) < mouseX){ return; } for(var i=0; i<divideXArray.length; i++){ if(mouseX < divideXArray[i]){ dot = i; break; } } drawLineChart(dot); } }
效果：
饼图：
里面有详细的解释。
注意以上网站上的源码无法直接使用所以 本人进行了部分的修改，以实现能够动态的处理后台传输的数据，并增加一个栏目，使功能完整。可以直接作为插件放入项目。
修改后的代码：（直接保存html文件即可）
<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Pie Chart with HTML5 and jQuery - 1.0</title> <meta http-equiv="Content-Type" content="text/html;charset=utf-8" > <style> body { background: #fff; color: #333; font-family: "Trebuchet MS", Verdana, Arial, Helvetica, sans-serif; font-size: 0.9em; padding: 40px; } #container { 900px; margin: 0 auto; } .chart, .chartData { border: 1px solid #333; background: #ebedf2 url("images/gradient.png") repeat-x 0 0; } .chart { display: block; margin: 0 0 50px 0; float: left; cursor: pointer; } .chartData { 200px; margin: 0 40px 0 0; float: right; border-collapse: collapse; box-shadow: 0 0 1em rgba(0, 0, 0, 0.5); -moz-box-shadow: 0 0 1em rgba(0, 0, 0, 0.5); -webkit-box-shadow: 0 0 1em rgba(0, 0, 0, 0.5); background-position: 0 -100px; } .chartData th, .chartData td { padding: 0.5em; border: 1px dotted #666; text-align: left; } .chartData th { border-bottom: 2px solid #333; text-transform: uppercase; } .chartData td { cursor: pointer; } .chartData td.highlight { background: #e8e8e8; } .chartData tr:hover td { background: #f0f0f0; } </style> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script> <!--[if IE]> <script src="http://explorercanvas.googlecode.com/svn/trunk/excanvas.js"></script> <![endif]--> </head> <body> <div id="container"> <canvas id="chart" width="600" height="500" class="chart"></canvas> <table id="chartData" class="chartData"> <tr><th>Widget</th><th>Sales ($)</th><th>prcent (%)</th></tr> </table> </div> </body> </html> <script> var data=[{label:"SuperWidget",value:1862.12},{label:"MegaWidget1",value:1316.00},{label:"redasd",value:1300.00},{label:"hope",value:300.00},{label:"hack",value:300.00},{label:"MegaWidget",value:1316.00},{label:"redasd",value:1300.00},{label:"hope",value:300.00},{label:"hack",value:300.00}]; // Run the code when the DOM is ready //$( pieChart ); pieChart(data, 'chart', 'chartData'); function pieChart(data, chartElementId, chartTableElementId) { // Config settings var chartSizePercent = 55; // The chart radius relative to the canvas width/height (in percent) var sliceBorderWidth = 1; // Width (in pixels) of the border around each slice var sliceBorderStyle = "#fff"; // Colour of the border around each slice var sliceGradientColour = "#ddd"; // Colour to use for one end of the chart gradient var maxPullOutDistance = 25; // How far, in pixels, to pull slices out when clicked var pullOutFrameStep = 4; // How many pixels to move a slice with each animation frame var pullOutFrameInterval = 40; // How long (in ms) between each animation frame var pullOutLabelPadding = 65; // Padding between pulled-out slice and its label var pullOutLabelFont = "bold 16px 'Trebuchet MS', Verdana, sans-serif"; // Pull-out slice label font var pullOutValueFont = "bold 12px 'Trebuchet MS', Verdana, sans-serif"; // Pull-out slice value font var pullOutValuePrefix = ""; // Pull-out slice value prefix var pullOutShadowColour = "rgba( 0, 0, 0, .5 )"; // Colour to use for the pull-out slice shadow var pullOutShadowOffsetX = 5; // X-offset (in pixels) of the pull-out slice shadow var pullOutShadowOffsetY = 5; // Y-offset (in pixels) of the pull-out slice shadow var pullOutShadowBlur = 5; // How much to blur the pull-out slice shadow var pullOutBorderWidth = 2; // Width (in pixels) of the pull-out slice border var pullOutBorderStyle = "#333"; // Colour of the pull-out slice border var chartStartAngle = -.5 * Math.PI; // Start the chart at 12 o'clock instead of 3 o'clock // Declare some variables for the chart var canvas; // The canvas element in the page var currentPullOutSlice = -1; // The slice currently pulled out (-1 = no slice) var currentPullOutDistance = 0; // How many pixels the pulled-out slice is currently pulled out in the animation var animationId = 0; // Tracks the interval ID for the animation created by setInterval() var chartData = data; // Chart data (labels, values, and angles) var chartColours = []; // Chart colours (pulled from the HTML table) var totalValue = 0; // Total of all the values in the chart var canvasWidth; // Width of the canvas, in pixels var canvasHeight; // Height of the canvas, in pixels var centreX; // X-coordinate of centre of the canvas/chart var centreY; // Y-coordinate of centre of the canvas/chart var chartRadius; // Radius of the pie chart, in pixels var chartElementId = chartElementId; // 圆饼元素id var chartTableElementId = chartTableElementId; // 数据表格元素id // Set things up and draw the chart init(); /** * Set up the chart data and colours, as well as the chart and table click handlers, * and draw the initial pie chart */ function init() { var colors=['#FF4500','#0DA068','#194E9C','#ED9C13','#ED5713','#CD00CD','#7A378B','#B8860B','#8B2500','#9932CC','#5F91DC','#F88E5D','#0000FF','#B3EE3A','#7A378B','#FF1493','#F5DA81','#80FF00','#173B0B','#0B3B39','#0B0B3B','#A901DB','#6E6E6E','#5F04B4','#01DFD7','#A31A1A','#1A653C','#A49D0C','#790CA4','#CA80E8','#6E87D7','#D76ED2','#D7B86E','#49543B','#9EEBE8','#9ED9EB','#549B21'] // Get the canvas element in the page canvas = document.getElementById(chartElementId); // Exit if the browser isn't canvas-capable if ( typeof canvas.getContext === 'undefined' ) return; // Initialise some properties of the canvas and chart canvasWidth = canvas.width; canvasHeight = canvas.height; centreX = canvasWidth / 2; centreY = canvasHeight / 2; chartRadius = Math.min( canvasWidth, canvasHeight ) / 2 * ( chartSizePercent / 100 ); // Grab the data from the table, // and assign click handlers to the table data cells var currentRow = 0; var currentCell = 0; //$('#chartData').append('<tr><th>Widget</th><th>Sales ($)</th><th>prcent (%)</th></tr>') $.each(chartData, function(index,value){ totalValue += value.value; }); $.each(chartData, function(index,value){ $('#'+chartTableElementId).append('<tr style="color: '+colors[index]+'"><td>'+value.label+'</td><td>'+value.value+'</td><td>'+ ( value.value / totalValue * 100 + .5 ).toFixed(2) + '%'+'</td></tr>') }); $('#'+chartTableElementId+' td').each( function() { currentCell++; // Store the slice index in this cell, and attach a click handler to it $(this).data( 'slice', currentRow ); $(this).click( handleTableClick ); // Extract and store the cell colour if ( rgb = $(this).css('color').match( /rgb((d+), (d+), (d+)/) ) { chartColours[currentRow] = [ rgb[1], rgb[2], rgb[3] ]; } else if ( hex = $(this).css('color').match(/#([a-fA-F0-9]{2})([a-fA-F0-9]{2})([a-fA-F0-9]{2})/) ) { chartColours[currentRow] = [ parseInt(hex[1],16) ,parseInt(hex[2],16), parseInt(hex[3], 16) ]; } else { alert( "Error: Colour could not be determined! Please specify table colours using the format '#xxxxxx'" ); return; } if(currentCell % 3 == 0){ currentRow++; } } ); // Now compute and store the start and end angles of each slice in the chart data var currentPos = 0; // The current position of the slice in the pie (from 0 to 1) for ( var slice in chartData ) { chartData[slice]['startAngle'] = 2 * Math.PI * currentPos; chartData[slice]['endAngle'] = 2 * Math.PI * ( currentPos + ( chartData[slice]['value'] / totalValue ) ); currentPos += chartData[slice]['value'] / totalValue; } // All ready! Now draw the pie chart, and add the click handler to it drawChart(); $('#'+chartElementId).click ( handleChartClick ); } /** * Process mouse clicks in the chart area. * * If a slice was clicked, toggle it in or out. * If the user clicked outside the pie, push any slices back in. * * @param Event The click event */ function handleChartClick ( clickEvent ) { // Get the mouse cursor position at the time of the click, relative to the canvas var mouseX = clickEvent.pageX - this.offsetLeft; var mouseY = clickEvent.pageY - this.offsetTop; // Was the click inside the pie chart? var xFromCentre = mouseX - centreX; var yFromCentre = mouseY - centreY; var distanceFromCentre = Math.sqrt( Math.pow( Math.abs( xFromCentre ), 2 ) + Math.pow( Math.abs( yFromCentre ), 2 ) ); if ( distanceFromCentre <= chartRadius ) { // Yes, the click was inside the chart. // Find the slice that was clicked by comparing angles relative to the chart centre. var clickAngle = Math.atan2( yFromCentre, xFromCentre ) - chartStartAngle; if ( clickAngle < 0 ) clickAngle = 2 * Math.PI + clickAngle; for ( var slice in chartData ) { if ( clickAngle >= chartData[slice]['startAngle'] && clickAngle <= chartData[slice]['endAngle'] ) { // Slice found. Pull it out or push it in, as required. toggleSlice ( slice ); return; } } } // User must have clicked outside the pie. Push any pulled-out slice back in. pushIn(); } /** * Process mouse clicks in the table area. * * Retrieve the slice number from the jQuery data stored in the * clicked table cell, then toggle the slice * * @param Event The click event */ function handleTableClick ( clickEvent ) { var slice = $(this).data('slice'); toggleSlice ( slice ); } /** * Push a slice in or out. * * If it's already pulled out, push it in. Otherwise, pull it out. * * @param Number The slice index (between 0 and the number of slices - 1) */ function toggleSlice ( slice ) { if ( slice == currentPullOutSlice ) { pushIn(); } else { startPullOut ( slice ); } } /** * Start pulling a slice out from the pie. * * @param Number The slice index (between 0 and the number of slices - 1) */ function startPullOut ( slice ) { // Exit if we're already pulling out this slice if ( currentPullOutSlice == slice ) return; // Record the slice that we're pulling out, clear any previous animation, then start the animation currentPullOutSlice = slice; currentPullOutDistance = 0; clearInterval( animationId ); animationId = setInterval( function() { animatePullOut( slice ); }, pullOutFrameInterval ); // Highlight the corresponding row in the key table $('#'+chartTableElementId+' td').removeClass('highlight'); var labelCell = $('#'+chartTableElementId+' td:eq(' + (slice*3) + ')'); var valueCell = $('#'+chartTableElementId+' td:eq(' + (slice*3+1) + ')'); var prcentCell = $('#'+chartTableElementId+' td:eq(' + (slice*3+2) + ')'); labelCell.addClass('highlight'); valueCell.addClass('highlight'); prcentCell.addClass('highlight'); } /** * Draw a frame of the pull-out animation. * * @param Number The index of the slice being pulled out */ function animatePullOut ( slice ) { // Pull the slice out some more currentPullOutDistance += pullOutFrameStep; // If we've pulled it right out, stop animating if ( currentPullOutDistance >= maxPullOutDistance ) { clearInterval( animationId ); return; } // Draw the frame drawChart(); } /** * Push any pulled-out slice back in. * * Resets the animation variables and redraws the chart. * Also un-highlights all rows in the table. */ function pushIn() { currentPullOutSlice = -1; currentPullOutDistance = 0; clearInterval( animationId ); drawChart(); $('#'+chartTableElementId+' td').removeClass('highlight'); } /** * Draw the chart. * * Loop through each slice of the pie, and draw it. */ function drawChart() { // Get a drawing context var context = canvas.getContext('2d'); // Clear the canvas, ready for the new frame context.clearRect ( 0, 0, canvasWidth, canvasHeight ); // Draw each slice of the chart, skipping the pull-out slice (if any) for ( var slice in chartData ) { if ( slice != currentPullOutSlice ) drawSlice( context, slice ); } // If there's a pull-out slice in effect, draw it. // (We draw the pull-out slice last so its drop shadow doesn't get painted over.) if ( currentPullOutSlice != -1 ) drawSlice( context, currentPullOutSlice ); } /** * Draw an individual slice in the chart. * * @param Context A canvas context to draw on * @param Number The index of the slice to draw */ function drawSlice ( context, slice ) { // Compute the adjusted start and end angles for the slice var startAngle = chartData[slice]['startAngle'] + chartStartAngle; var endAngle = chartData[slice]['endAngle'] + chartStartAngle; if ( slice == currentPullOutSlice ) { // We're pulling (or have pulled) this slice out. // Offset it from the pie centre, draw the text label, // and add a drop shadow. var midAngle = (startAngle + endAngle) / 2; var actualPullOutDistance = currentPullOutDistance * easeOut( currentPullOutDistance/maxPullOutDistance, .8 ); startX = centreX + Math.cos(midAngle) * actualPullOutDistance; startY = centreY + Math.sin(midAngle) * actualPullOutDistance; context.fillStyle = 'rgb(' + chartColours[slice].join(',') + ')'; context.textAlign = "center"; context.font = pullOutLabelFont; context.fillText( chartData[slice]['label'], centreX + Math.cos(midAngle) * ( chartRadius + maxPullOutDistance + pullOutLabelPadding ), centreY + Math.sin(midAngle) * ( chartRadius + maxPullOutDistance + pullOutLabelPadding ) ); context.font = pullOutValueFont; context.fillText( pullOutValuePrefix + chartData[slice]['value'] + " (" + ( chartData[slice]['value'] / totalValue * 100 + .5 ).toFixed(2) + "%)", centreX + Math.cos(midAngle) * ( chartRadius + maxPullOutDistance + pullOutLabelPadding ), centreY + Math.sin(midAngle) * ( chartRadius + maxPullOutDistance + pullOutLabelPadding ) + 20 ); context.shadowOffsetX = pullOutShadowOffsetX; context.shadowOffsetY = pullOutShadowOffsetY; context.shadowBlur = pullOutShadowBlur; } else { // This slice isn't pulled out, so draw it from the pie centre startX = centreX; startY = centreY; } // Set up the gradient fill for the slice var sliceGradient = context.createLinearGradient( 0, 0, canvasWidth*.75, canvasHeight*.75 ); sliceGradient.addColorStop( 0, sliceGradientColour ); sliceGradient.addColorStop( 1, 'rgb(' + chartColours[slice].join(',') + ')' ); // Draw the slice context.beginPath(); context.moveTo( startX, startY ); context.arc( startX, startY, chartRadius, startAngle, endAngle, false ); context.lineTo( startX, startY ); context.closePath(); context.fillStyle = sliceGradient; context.shadowColor = ( slice == currentPullOutSlice ) ? pullOutShadowColour : "rgba( 0, 0, 0, 0 )"; context.fill(); context.shadowColor = "rgba( 0, 0, 0, 0 )"; // Style the slice border appropriately if ( slice == currentPullOutSlice ) { context.lineWidth = pullOutBorderWidth; context.strokeStyle = pullOutBorderStyle; } else { context.lineWidth = sliceBorderWidth; context.strokeStyle = sliceBorderStyle; } // Draw the slice border context.stroke(); } /** * Easing function. * * * @param Number The ratio of the current distance travelled to the maximum distance * @param Number The power (higher numbers = more gradual easing) * @return Number The new ratio */ function easeOut( ratio, power ) { return ( Math.pow ( 1 - ratio, power ) + 1 ); } }; </script>
总结：
1,我们完全可以只利用API画出自己想要的东西：API
3，阅读网站：http://diveintohtml5.info/
4，不管html5以后发不发展，学点然后做个比较复杂的动画玩玩，也不错
让我们继续前行
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努力不一定成功，但不努力肯定不会成功。
共勉。
分类: html5, 我们到底能走多远系列