マウスダウンでフリーハンドの線を描く|HTML5

マウスダウンでフリーハンドの線を描く|HTML5

マウスダウンでフリーハンドの線を描く|HTML5(HTML5, JavaScript, CSS3) : デモ

マウスダウンでフリーハンドの線を描く|HTML5(HTML5, JavaScript, CSS3) : ZIPファイル(6kb)

1.HTML

<!DOCTYPE html>
<html lang="jp">
    <head>
        <meta charset="UTF-8" />
        <title>ライン描画</title>
        <link href="css/base.css" rel="stylesheet" type="text/css">
        <script src="js/devicecheck.js"></script>
        <script src="js/base.js"></script>
    </head>
    <body>
        <div id="contents">
            <canvas id="canvas" width="300" height="300">
            </canvas>
        </div>
    </body>
</html>

2.CSS

@charset "utf-8";
 
body
{
    margin:0;
    padding:0;
    background-color: #fff;
    font-family:Helvetica, HiraKakuProN-W3, sans-serif; 
    font-size:12px;
    color:#000;
}
 
#contents
{
    position: absolute;
    top: 0;
    left: 0;
    width: 300px;
    height:300px;
    border: 1px solid #000;
    overflow:hidden;
}
 
#canvas
{
    position: absolute;
    top: 0;
    left: 0;
    width: 300px;
    height:300px;
}
 
#dis
{
    position: absolute;
    top: 10px;
    left: 10px;
    width: 200px;
    height:50px;
}

3.JavaScript

base.js

window.addEventListener("load", init, false);
 
var mouseX = 0;
var mouseY = 0;
var offsetX = 0;
var offsetY = 0;
var ctx = null;
var w = 5;
var h = 5;
var buttonStart = null;
var buttonMove = null;
var buttonEnd = null;
var theCanvas = null;
 
function init()
{
    var theContents = document.getElementById("contents");
    offsetX = (theContents.currentStyle || document.defaultView.getComputedStyle(theContents,'')).width;
    offsetX = Number(offsetX.replace('px',''));
    offsetX =  offsetX / 2;
    offsetY = (theContents.currentStyle || document.defaultView.getComputedStyle(theContents,'')).height;
    offsetY = Number(offsetY.replace('px',''));
    offsetY =  offsetY / 2;
     
    document.getElementById('canvas').addEventListener('touchstart', function() 
    {
        event.preventDefault();
    });
    document.getElementById('canvas').addEventListener('touchmove', function() 
    {
        event.preventDefault();
    });
    document.getElementById('canvas').addEventListener('touchend', function() 
    {
        event.preventDefault();
    });
     
    //ボタンタイプ
    if(g_mobiledevice==true)
    {
        buttonStart = 'touchstart';
        buttonMove = 'touchmove';
        buttonEnd = 'touchend';
    }
    else
    {
        buttonStart = 'mousedown';
        buttonMove = 'mousemove';
        buttonEnd = 'mouseup';
    }
     
    theCanvas = document.getElementById("canvas");
    ctx = theCanvas.getContext("2d");
    theCanvas.addEventListener(buttonStart, mouseDownHandler, false);
    theCanvas.addEventListener(buttonEnd, mouseUpHandler, false);
     
    ctx.strokeStyle="#000000";
    ctx.fillStyle = "#000000";
    ctx.lineWidth=1;
}
 
function setMouseXY(e)
{
    if(g_mobiledevice)
    {
        var rect = event.currentTarget.getBoundingClientRect();
        mouseX = event.touches[0].pageX - rect.left;
        mouseY = event.touches[0].pageY - rect.top;
    }
    else
    if(g_browsername == 'MSIE' || g_browsername == 'Opera')
    {
        rect = document.getElementById("canvas").getBoundingClientRect();
        mouseX = event.clientX - rect.left;
        mouseY = event.clientY - rect.top;
    }
    else
    if(g_browsername == 'Firefox')
    {
        rect = document.getElementById("canvas").getBoundingClientRect();
        mouseX = e.clientX - rect.left;
        mouseY = e.clientY - rect.top;
    }
    else
    {
        rect = event.currentTarget.getBoundingClientRect();
        mouseX =  event.clientX - rect.left;
        mouseY =  event.clientY - rect.top;
    }
}
 
function mouseDownHandler(e)
{
    setMouseXY(e);
    ctx.strokeStyle="#000000";
    ctx.lineWidth=1;
    ctx.beginPath();
    ctx.moveTo(mouseX, mouseY);
    theCanvas.addEventListener(buttonMove, mouseMoveHandler, false);
}
 
function mouseUpHandler()
{
    theCanvas.removeEventListener(buttonMove, mouseMoveHandler, false);
}
 
function mouseMoveHandler(e)
{
    setMouseXY(e);
    ctx.lineTo(mouseX, mouseY);
    ctx.stroke();
}

devicecheck.js

var g_mobiledevice = false; //iPhone、iPad、Androidのときtrue
var g_browsername = 'unknown';
var g_browserver = -1;
 
if(checkUserAgent() == false)
{
    window.alert('このブラウザは対象外です');
}
 
function checkUserAgent()
{
    var ua = navigator.userAgent;
 
    //iPhoneか?  
    var mstr = ua.match(/iPhone OS \d+/);
    if(mstr != null){
        var vstr = mstr[0].match(/\d+/);
        if(parseInt(vstr[0]) >= 3) 
        {
            g_mobiledevice = true;
            g_browsername = 'iPhone';
            //alert('major-version ' + vstr);
            return true;
        }
    }
    //iPadか?
    if(ua.indexOf('iPad') > -1)
    {
        mstr = ua.match(/CPU OS \d+/);
        if(mstr != null)
        {
            var vstr = mstr[0].match(/\d+/);
            if(parseInt(vstr[0]) >= 3) {
                g_mobiledevice = true;
                g_browsername = 'iPad';
                //alert('major-version ' + vstr);
                return true;
            }       
        }       
    }   
    //Androidか? 
    var mstr = ua.match(/Android \d+\.\d+/);
    if(mstr != null)
    {
        g_browsername = 'Android';
        var vstr = mstr[0].match(/\d+\.\d+/);
        g_browserver = parseFloat(vstr[0]);
        g_mobiledevice = true;
        if(pg_browserver > 2.1) 
        {
            //alert('version ' + vstr);
            return true;
        }
    }
    //Chromeか?
    mstr = ua.match(/Chrome\/\d+/);
    if(mstr != null)
    {
        g_browsername = 'Chrome';
        var vstr = mstr[0].match(/\d+/);
        g_browserver = parseInt(vstr[0]);
        if(g_browserver >= 9) 
        {
            //alert('major-version ' + vstr);
             
            return true;
        }       
    }
    //Safariか?
    if(ua.indexOf('Safari') > -1)
    {
        mstr = ua.match(/Version\/\d+/);
        if(mstr != null){
            var vstr = mstr[0].match(/\d+/);
            if(parseInt(vstr[0]) >= 5) 
            {
                g_browsername = 'Safari';
                //alert('major-version ' + vstr);
                return true;
            }       
        }       
    }
    //Internet Explorerか?
    mstr = ua.match(/MSIE \d+/);
    if(mstr != null)
    {
        var vstr = mstr[0].match(/\d+/);
        if(parseInt(vstr[0]) >= 9) 
        {
            g_browsername = 'MSIE';
            //alert('major-version ' + vstr);
            return true;
        }       
    }
    //Firefoxか?
    mstr = ua.match(/Firefox\/\d+/);
    if(mstr != null){
        var vstr = mstr[0].match(/\d+/);
        if(parseInt(vstr[0]) >= 4) 
        {
            g_browsername = 'Firefox';
            //alert('major-version ' + vstr);
            return true;
        }       
    }
    //Operaか?
    if(ua.indexOf('Opera') > -1)
    {
        mstr = ua.match(/Version\/\d+/);
        if(mstr != null){
            var vstr = mstr[0].match(/\d+/);
            if(parseInt(vstr[0]) >= 11) 
            {
                g_browsername = 'Opera';
                //alert('major-version ' + vstr);
                return true;
            }       
        }       
    }
     
    return false;
}

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