canvas函数图 | 佳佳酱

【初始编辑】2013/4/21 14:55
【更新 2013/5/1 14:36 】
更新日志：加上坐标轴的箭头，加了两个函数(其实这个不算更新吧。。)。
优化了一下绘制方法：修改了清除画布的方法，极大提高效率。
自定义函数的功能还是没有修好。
代码中已经包含了一部分下次更新的功能：差不多是坐标轴的单位线

昨天我翻出来了以前一时兴起做的一个渣渣函数图绘制的代码，然后又一时兴起想把它改好一点，于是就出现了今天的这篇文章。
【我可是冒着期中考试前不复习的风险来做这个的】
【用chrome浏览效果更佳，其他浏览器可能会有卡顿现象】
现在已经做成了这个样子
<span data-mce-type="bookmark" style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;" class="mce_SELRES_start"></span>

源地址在这里，佳佳实验室的地址在这里，代码在文章最下面，自带注释

介绍，这是一个基于x坐标进行绘图[至少现在还是这样]的东东。
已经完成的功能：
画图
用鼠标拖动
滚轮放大缩小
回到中心

然后有一个功能”自定义函数”虽然显示在那里了，但还是不可以用的，有些错误还没时间解决。
现在的用法是打开源代码修改里面的函数数组，demo里的函数是这些

/*格式：函数，颜色，线宽，是否显示*/

functionlist[0]=["3*x+2","#66ccff",1,true];

functionlist[1]=["x*x+2*x-7","#123456",1,true];

functionlist[2]=["Math.tan(x)","#654321",1,true];

functionlist[3]=["Math.sin(x)","rgba(221,123,159,0.5)",20,true];

functionlist[4]=["1","#66ccff",1,true];

从这个代码里可以看出其实还有很多功能还没有做出来[上学的孩子苦逼啊]。

在以后的某个时间里我可能又会突然兴起在升级一下，现在就做到这样了，毕竟作为一个苦逼又たま的大天朝学生没有那么多时间来做这个，况且还有iti要做。

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<html>

<head>

</script>

/*这里摆了一些图片的datauri，为了防止太多零碎文件就都放在这里了*/

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/*回到中心 25*25 */

icons.upjiantou = "data:image/png;base64,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";

/*上箭头 7*10 */

icons.rightjiantou = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAHCAYAAAAxrNxjAAAACXBIWXMAAAsTAAALEwEAmpwYAAAKTWlDQ1BQaG90b3Nob3AgSUNDIHByb2ZpbGUAAHjanVN3WJP3Fj7f92UPVkLY8LGXbIEAIiOsCMgQWaIQkgBhhBASQMWFiApWFBURnEhVxILVCkidiOKgKLhnQYqIWotVXDjuH9yntX167+3t+9f7vOec5/zOec8PgBESJpHmomoAOVKFPDrYH49PSMTJvYACFUjgBCAQ5svCZwXFAADwA3l4fnSwP/wBr28AAgBw1S4kEsfh/4O6UCZXACCRAOAiEucLAZBSAMguVMgUAMgYALBTs2QKAJQAAGx5fEIiAKoNAOz0ST4FANipk9wXANiiHKkIAI0BAJkoRyQCQLsAYFWBUiwCwMIAoKxAIi4EwK4BgFm2MkcCgL0FAHaOWJAPQGAAgJlCLMwAIDgCAEMeE80DIEwDoDDSv+CpX3CFuEgBAMDLlc2XS9IzFLiV0Bp38vDg4iHiwmyxQmEXKRBmCeQinJebIxNI5wNMzgwAABr50cH+OD+Q5+bk4eZm52zv9MWi/mvwbyI+IfHf/ryMAgQAEE7P79pf5eXWA3DHAbB1v2upWwDaVgBo3/ldM9sJoFoK0Hr5i3k4/EAenqFQyDwdHAoLC+0lYqG9MOOLPv8z4W/gi372/EAe/tt68ABxmkCZrcCjg/1xYW52rlKO58sEQjFu9+cj/seFf/2OKdHiNLFcLBWK8ViJuFAiTcd5uVKRRCHJleIS6X8y8R+W/QmTdw0ArIZPwE62B7XLbMB+7gECiw5Y0nYAQH7zLYwaC5EAEGc0Mnn3AACTv/mPQCsBAM2XpOMAALzoGFyolBdMxggAAESggSqwQQcMwRSswA6cwR28wBcCYQZEQAwkwDwQQgbkgBwKoRiWQRlUwDrYBLWwAxqgEZrhELTBMTgN5+ASXIHrcBcGYBiewhi8hgkEQcgIE2EhOogRYo7YIs4IF5mOBCJhSDSSgKQg6YgUUSLFyHKkAqlCapFdSCPyLXIUOY1cQPqQ28ggMor8irxHMZSBslED1AJ1QLmoHxqKxqBz0XQ0D12AlqJr0Rq0Hj2AtqKn0UvodXQAfYqOY4DRMQ5mjNlhXIyHRWCJWBomxxZj5Vg1Vo81Yx1YN3YVG8CeYe8IJAKLgBPsCF6EEMJsgpCQR1hMWEOoJewjtBK6CFcJg4Qxwicik6hPtCV6EvnEeGI6sZBYRqwm7iEeIZ4lXicOE1+TSCQOyZLkTgohJZAySQtJa0jbSC2kU6Q+0hBpnEwm65Btyd7kCLKArCCXkbeQD5BPkvvJw+S3FDrFiOJMCaIkUqSUEko1ZT/lBKWfMkKZoKpRzame1AiqiDqfWkltoHZQL1OHqRM0dZolzZsWQ8ukLaPV0JppZ2n3aC/pdLoJ3YMeRZfQl9Jr6Afp5+mD9HcMDYYNg8dIYigZaxl7GacYtxkvmUymBdOXmchUMNcyG5lnmA+Yb1VYKvYqfBWRyhKVOpVWlX6V56pUVXNVP9V5qgtUq1UPq15WfaZGVbNQ46kJ1Bar1akdVbupNq7OUndSj1DPUV+jvl/9gvpjDbKGhUaghkijVGO3xhmNIRbGMmXxWELWclYD6yxrmE1iW7L57Ex2Bfsbdi97TFNDc6pmrGaRZp3mcc0BDsax4PA52ZxKziHODc57LQMtPy2x1mqtZq1+rTfaetq+2mLtcu0W7eva73VwnUCdLJ31Om0693UJuja6UbqFutt1z+o+02PreekJ9cr1Dund0Uf1bfSj9Rfq79bv0R83MDQINpAZbDE4Y/DMkGPoa5hpuNHwhOGoEctoupHEaKPRSaMnuCbuh2fjNXgXPmasbxxirDTeZdxrPGFiaTLbpMSkxeS+Kc2Ua5pmutG003TMzMgs3KzYrMnsjjnVnGueYb7ZvNv8jYWlRZzFSos2i8eW2pZ8ywWWTZb3rJhWPlZ5VvVW16xJ1lzrLOtt1ldsUBtXmwybOpvLtqitm63Edptt3xTiFI8p0in1U27aMez87ArsmuwG7Tn2YfYl9m32zx3MHBId1jt0O3xydHXMdmxwvOuk4TTDqcSpw+lXZxtnoXOd8zUXpkuQyxKXdpcXU22niqdun3rLleUa7rrStdP1o5u7m9yt2W3U3cw9xX2r+00umxvJXcM970H08PdY4nHM452nm6fC85DnL152Xlle+70eT7OcJp7WMG3I28Rb4L3Le2A6Pj1l+s7pAz7GPgKfep+Hvqa+It89viN+1n6Zfgf8nvs7+sv9j/i/4XnyFvFOBWABwQHlAb2BGoGzA2sDHwSZBKUHNQWNBbsGLww+FUIMCQ1ZH3KTb8AX8hv5YzPcZyya0RXKCJ0VWhv6MMwmTB7WEY6GzwjfEH5vpvlM6cy2CIjgR2yIuB9pGZkX+X0UKSoyqi7qUbRTdHF09yzWrORZ+2e9jvGPqYy5O9tqtnJ2Z6xqbFJsY+ybuIC4qriBeIf4RfGXEnQTJAntieTE2MQ9ieNzAudsmjOc5JpUlnRjruXcorkX5unOy553PFk1WZB8OIWYEpeyP+WDIEJQLxhP5aduTR0T8oSbhU9FvqKNolGxt7hKPJLmnVaV9jjdO31D+miGT0Z1xjMJT1IreZEZkrkj801WRNberM/ZcdktOZSclJyjUg1plrQr1zC3KLdPZisrkw3keeZtyhuTh8r35CP5c/PbFWyFTNGjtFKuUA4WTC+oK3hbGFt4uEi9SFrUM99m/ur5IwuCFny9kLBQuLCz2Lh4WfHgIr9FuxYji1MXdy4xXVK6ZHhp8NJ9y2jLspb9UOJYUlXyannc8o5Sg9KlpUMrglc0lamUycturvRauWMVYZVkVe9ql9VbVn8qF5VfrHCsqK74sEa45uJXTl/VfPV5bdra3kq3yu3rSOuk626s91m/r0q9akHV0IbwDa0b8Y3lG19tSt50oXpq9Y7NtM3KzQM1YTXtW8y2rNvyoTaj9nqdf13LVv2tq7e+2Sba1r/dd3vzDoMdFTve75TsvLUreFdrvUV99W7S7oLdjxpiG7q/5n7duEd3T8Wej3ulewf2Re/ranRvbNyvv7+yCW1SNo0eSDpw5ZuAb9qb7Zp3tXBaKg7CQeXBJ9+mfHvjUOihzsPcw83fmX+39QjrSHkr0jq/dawto22gPaG97+iMo50dXh1Hvrf/fu8x42N1xzWPV56gnSg98fnkgpPjp2Snnp1OPz3Umdx590z8mWtdUV29Z0PPnj8XdO5Mt1/3yfPe549d8Lxw9CL3Ytslt0utPa49R35w/eFIr1tv62X3y+1XPK509E3rO9Hv03/6asDVc9f41y5dn3m978bsG7duJt0cuCW69fh29u0XdwruTNxdeo94r/y+2v3qB/oP6n+0/rFlwG3g+GDAYM/DWQ/vDgmHnv6U/9OH4dJHzEfVI0YjjY+dHx8bDRq98mTOk+GnsqcTz8p+Vv9563Or59/94vtLz1j82PAL+YvPv655qfNy76uprzrHI8cfvM55PfGm/K3O233vuO+638e9H5ko/ED+UPPR+mPHp9BP9z7nfP78L/eE8/sl0p8zAAAAIGNIUk0AAHolAACAgwAA+f8AAIDpAAB1MAAA6mAAADqYAAAXb5JfxUYAAABkSURBVHjafM+xDcIAEEPRh0xFm8nYAInlKCiSJlNQUjJFQn9UkU4IYulXvrNs4Rlu4RxOQaeqVBWhGmuYwzUM/eEQym8teGDEtHfY9T7umGtLHL87LmEKl61jH/MK93+rNz4DAI5OI4aniW+EAAAAAElFTkSuQmCC";

/*右箭头 10*7 */

icons.heng5px = "data:image/bmp;base64,Qk1CAAAAAAAAAD4AAAAoAAAACQAAAAEAAAABAAEAAAAAAAQAAAATCwAAEwsAAAAAAAAAAAAAAAAAAP///wAAAAAA";

/*横着5px*/

icons.shu5px = "data:image/bmp;base64,Qk1iAAAAAAAAAD4AAAAoAAAAAQAAAAkAAAABAAEAAAAAACQAAAATCwAAEwsAAAAAAAAAAAAAAAAAAP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";

/*竖着5px*/

upjiantouimg = new Image();

rightjiantouimg = new Image();

heng5px = new Image();

shu5px = new Image();

heng5px.src = icons.heng5px;

shu5px.src = icons.shu5px;

upjiantouimg.src = icons.upjiantou;

rightjiantouimg.src = icons.rightjiantou;

/*把图标载入image对象*/

</script>

<style>

body { padding: 0; margin: 0; cursor: default; } #zuobiaozhou { position:

absolute; top: 0; left: 0; cursor: default; z-index: 0; } #hanshutu { position:

absolute; top: 0; left: 0; cursor: default; z-index: 1; } div#control {

position: fixed; right: -266px; top: 0px; height: 100%; width: 250px; background-color:

rgba(129, 150, 141, 0.6); padding: 1em; overflow-x: hidden; z-index: 999;

} div#home { height: 25px; width: 25px; cursor: pointer; } div.sidediv

{ width: 100%; color: rgb(67, 49, 162); font-size: 13px; } textarea#zidingyifunction

{ width: 100%; max-width: 100%; max-height: 160px; height: 160px; }

</style>

var functionlist = new Array();

/*格式：函数，颜色，线宽，是否显示*/

functionlist[0] = ["3*x+2", "#66ccff", 1, true];

functionlist[1] = ["x*x+2*x-7", "#123456", 1, true];

functionlist[3] = ["Math.sin(x)", "rgba(221,123,159,0.5)", 10, true];

functionlist[4] = ["1", "#66ccff", 1, true];

functionlist[5] = ["Math.pow(-1,x)", "#CC33FF", 2, true];

functionlist[2] = ["Math.pow(2,x)", "#CC6633", 1, true];

functionlist[6] = ["Math.sqrt(64-x*x)", "rgb(255,204,0)", 6, true];

functionlist[7] = ["-Math.sqrt(64-x*x)", "red", 2, true];

functionlist[8] = ["Math.acos(Math.sqrt(Math.sin(x)))", "blue", 1, true];

functionlist[9] = ["x/(x*x+3*x+1)", "blue", 1, true];

</script>

</head>

<body>

</canvas>

如果你什么都看不到，请到

<a href="http://browsehappy.com/" title="browsehappy" target="_blank"

style="color:rgb(153,153,51);text-decoration:none;">

这里

</a>

寻找最新的浏览器~

</canvas>

</div>

</abbr>

自定义函数

刷新自定义函数

</span>

<br>

</textarea>

</div>

<br>

刷新函数

</span>

<br>

</div>

/*变量名中的V觉绝大部分意思是虚拟*/

/*定义变量*/

var zuobiao$obj, pianyix = 0,

pianyiy = 0,

/*偏移量*/

bei = 1,

/*缩放倍数*/

clickpointx = 0,

clickpointy = 0,

/*点击坐标*/

vzoom = new Object,

/*虚拟坐标系空间函数对象*/

zuobiaocanvasobj,

/*坐标轴canvas dom对象*/

zuobiaozhoudrawobj,

/*坐标轴绘图上下文*/

hanshutucanvasobj,

/*函数图canvas dom对象*/

hanshutudrawobj,

/*函数图绘图上下文*/

windowwidth = window.innerWidth,

windowheight = window.innerHeight,

/*用于快速存取的整体长宽变量*/

xcenter = windowwidth / 2,

/*中心坐标*/

ycenter = windowheight / 2,

hanshutuurltmp,

/*没有用*/

realxtmp, realytmp,

/*真实坐标的临时变量*/

vxtmp, vytmp,

/*虚拟坐标的临时变量*/

v1danwei,

/*虚拟坐标里的一个单位的真实像素数*/

basetimestemp = 0,

/*单位基数乘次计数*/

basenumber = 1,

/*单位基数*/

zuobiaozhoux, zuobiaozhouy,

/*坐标轴的两条轴位置*/

zuobiaoxianx, zuobiaoxiany,

zuobiao$obj = $("#zuobiaozhou"),

hanshu$obj = $("#hanshutu"),

zuobiaocanvasobj = zuobiao$obj[0],

hanshutucanvasobj = hanshu$obj[0],

zuobiaozhoudrawobj = zuobiaocanvasobj.getContext("2d"),

hanshutudrawobj = hanshutucanvasobj.getContext("2d");

hanshutudrawobj.fillStyle = 'rgba(255,255,255,0)';

zuobiaozhoudrawobj.fillStyle = 'rgba(255,255,255,0)';

/*虚拟坐标算法和反算法*/

//参数：虚拟位置坐标。返回值:在canvas元素里的实际坐标

vzoom.realx = function(vx) {

return xcenter + pianyix + vx * 40 * bei;

}

vzoom.realy = function(vy) {

return ycenter - pianyiy - vy * 40 * bei;

}

//参数：实际位置坐标。返回值:虚拟坐标

vzoom.vx = function(realx) {

return (realx - xcenter - pianyix) / bei / 40;

}

vzoom.vy = function(realy) {

return (realy - ycenter + pianyiy) / -bei / 40;

}

/*函数解析方法*/

var funs = new Array();

funs.refreshfuns = function() {

var tmpfun

for (i = 0; functionlist[i]; i++) {

tmpfun = functionlist[i][0];

try {

eval('funs[' + i + ']=function(x){return ' + tmpfun + ';}');

} catch(e) {

console.log("第" + (i + 1) + "个函数解析失败");

continue;

};

}

/*设置宽高*/

function setkuangao() {

zuobiaocanvasobj.width = windowwidth;

zuobiaocanvasobj.height = windowheight;

hanshutucanvasobj.width = windowwidth;

hanshutucanvasobj.height = windowheight;

}

/*画线*/

function paintline(x, y) {

hanshutudrawobj.lineTo(x, y);

}

/*画函数图*/

function drawhanshutu() {

hanshutudrawobj.clearRect(0, 0, windowwidth, windowheight);

for (funnunm = 0; functionlist[funnunm]; funnunm++) {

if (functionlist[funnunm][3]) {

hanshutudrawobj.strokeStyle = functionlist[funnunm][1];

hanshutudrawobj.lineWidth = functionlist[funnunm][2];

hanshutudrawobj.beginPath();

for (i = 0; i < windowwidth; i++) {

vxtmp = vzoom.vx(i);

if (funs[funnunm](vxtmp) != Infinity) {

paintline(i, vzoom.realy(funs[funnunm](vxtmp)));

} else {

nextpoint = vzoom.vx(i + 1);

hanshutudrawobj.moveTo(i + 1, funs[funnunm](nextpoint))

}

hanshutudrawobj.stroke();

}

/*画坐标轴*/

function drawzuobiaozhou() {

zuobiaozhoudrawobj.beginPath();

zuobiaozhoudrawobj.clearRect(0, 0, windowwidth, windowheight);

zuobiaozhoudrawobj.strokeStyle = "#000";

zuobiaozhoudrawobj.lineWidth = 1;

realxtmp = vzoom.realx(0);

realytmp = vzoom.realy(0);

//console.log(realxtmp+" "+realytmp);//调试用信息输出

/*以下都是让xy轴保持显示在显示区内*/

if (realxtmp >= windowwidth) {

zuobiaozhoux = windowwidth - 0.5;

} else if (realxtmp <= 0) {

zuobiaozhoux = 0.5;

} else {

zuobiaozhoux = xcenter + pianyix;

}

if (realytmp <= 0) {

zuobiaozhouy = 0.5;

} else if (realytmp >= windowheight) {

zuobiaozhouy = windowheight - 0.5;

} else {

zuobiaozhouy = ycenter - pianyiy;

}

zuobiaozhoudrawobj.moveTo(zuobiaozhoux, 0);

zuobiaozhoudrawobj.lineTo(zuobiaozhoux, windowheight);

zuobiaozhoudrawobj.moveTo(0, zuobiaozhouy);

zuobiaozhoudrawobj.lineTo(windowwidth, zuobiaozhouy);

zuobiaozhoudrawobj.drawImage(upjiantouimg, zuobiaozhoux - 3.5, 0);

zuobiaozhoudrawobj.drawImage(rightjiantouimg, windowwidth - 10, zuobiaozhouy - 3.5);

zuobiaoxianx = vzoom.vx(0);

zuobiaoxiany = vzoom.vy(windowheight);

/*for*/

zuobiaozhoudrawobj.stroke();

}

/*取距离1、2、5距离最近的数*/

function getfrom125(number) {

if (number <= 1) return 1;

else if (number > 1 && number <= 2.5) return 2;

else if (number > 2.5) return 5;

}

/*设置单位基数*/

function setbasenumber() {

v1danwei = 50 / (vzoom.realx(1) - vzoom.realx(0));

if (v1danwei < 1) {

for (; v1danwei < 1; basetimestemp++) {

v1danwei *= Math.pow(10, basetimestemp);

}

basenumber = getfrom125(v1danwei);

basenumber *= Math.pow(10, -basetimestemp);

} else if (v1danwei > 10) {

for (; v1danwei > 10; basetimestemp--) {

v1danwei *= Math.pow(10, basetimestemp);

}

basenumber = getfrom125(v1danwei);

basenumber *= Math.pow(10, -basetimestemp);

} else {

basenumber = 1;

}

function refreshzidinghanshu() {

localStorage.zidingyifunction = document.getElementById("zidingyifunction").value;

eval(document.getElementById("zidingyifunction").value);

drawhanshutu();

}

function loadzidinghanshu() {

if (localStorage.zidingyifunction) {

eval(localStorage.zidingyifunction);

document.getElementById("zidingyifunction").value = localStorage.zidingyifunction;

}

/*由鼠标引发的移动事件*/

hanshu$obj.mousedown(function(event) {

event.preventDefault();

clickpointx = event.clientX;

clickpointy = event.clientY;

/*hanshu$obj.unbind("mouseup");

hanshu$obj.unbind("mousemove");*/

hanshu$obj.mouseup(function(event) {

hanshu$obj.unbind("mousemove");

hanshu$obj.unbind("mouseup");

hanshu$obj.unbind("mouseout");

});

hanshu$obj.mousemove(function(event) {

event.preventDefault();

pianyix = pianyix + event.clientX - clickpointx;

pianyiy = pianyiy - event.clientY + clickpointy;

drawzuobiaozhou();

drawhanshutu();

clickpointx = event.clientX;

clickpointy = event.clientY;

});

hanshu$obj.mouseout(function() {

hanshu$obj.unbind("mouseup");

hanshu$obj.unbind("mousemove");

});

$(window).resize(function() {

/*尺寸改变的时候*/

windowwidth = window.innerWidth;

/*重新计算虚拟坐标所需的宽高*/

windowheight = window.innerHeight;

xcenter = windowwidth / 2;

ycenter = windowheight / 2;

setkuangao();

/*重新设置宽高*/

drawzuobiaozhou();

/*重画*/

drawhanshutu();

});

setkuangao();

funs.refreshfuns();

/*开始画之前先刷新一下函数列表*/

drawzuobiaozhou();

drawhanshutu();

$("#home").click(function(e) {

/*回到中心*/

pianyix = pianyiy = 0;

bei = 1;

drawzuobiaozhou();

drawhanshutu();

});

var controlpannel = $("#control");

controlpannel.mouseenter(function(e) {

controlpannel.stop().animate({

right: 0

"fast");

});

controlpannel.mouseleave(function(e) {

controlpannel.stop().animate({

right: -266

"fast");

});

/*滚轮控制部分*/

var scrollFunc = function(e) {

var direct = 0;

e = e || window.event;

var t1 = document.getElementById("wheelDelta");

var t2 = document.getElementById("detail");

var data = e.wheelDelta ? e.wheelDelta: e.detail;

if (data == -3 || data == 120) {

/*不知为什么firefox的数值和其他浏览器是反的。。*/

bei *= 1.1;

/*按1.1倍放大*/

pianyix *= 1.1,

pianyiy *= 1.1;

/*同时倍增偏移量使放大中心保持在显示区中心*/

} else if (data == 3 || data == -120) {

bei *= 0.9;

pianyix *= 0.9,

pianyiy *= 0.9;

}

drawzuobiaozhou();

drawhanshutu();

}

if (document.addEventListener) {

document.addEventListener('DOMMouseScroll', scrollFunc, false);

}

hanshutucanvasobj.onmousewheel = scrollFunc;

/*刷新自定义函数*/

$("#refreshzidingfun").click(function(e) {

refreshzidinghanshu();

});

/*刷新函数列表*/

$("#refreshfuns").click(function(e) {

funs.refreshfuns();

});

/*下面都杂项函数*/

function fillicons() {

document.getElementById("home").style.backgroundImage = "url(" + icons.home + ")";

}

</script>

fillicons();

upjiantouimg.onload = function() {

drawzuobiaozhou();

}

rightjiantouimg.onload = function() {

drawzuobiaozhou();

}

</script>

</body>

</html>

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