86 
jQuery('#carregar').click(function() {
  var canvas    = document.getElementById('canvas');
  var image   = document.getElementById('image');
  var element = canvas.getContext("2d");
  element.clearRect(0, 0, canvas.width, canvas.height);
  element.drawImage(image, 0, 0, 300, 300);
});

jsfiddle.net/ブラジル/nWyDE/

画像を右または左に 90 ° 回転するのに問題があります。

キャンバス上の画像を使用します。同じ画面には、例と同じキャンバスがいくつかありますが、できるだけプロジェクトに近づけました。

「左に回転」と「右に回転」をクリックしたときに、画像を左または右に90°回転させるにはどうすればよいですか？

インターネットでいくつかのコードを試しましたが、どれも機能しませんでした。

4

11 に答える 11

172

キャンバスの context.translate と context.rotate を使用して、画像を回転させることができます

ここに画像の説明を入力

指定した角度だけ回転した画像を描画する関数は次のとおりです。

function drawRotated(degrees){
    context.clearRect(0,0,canvas.width,canvas.height);

    // save the unrotated context of the canvas so we can restore it later
    // the alternative is to untranslate & unrotate after drawing
    context.save();

    // move to the center of the canvas
    context.translate(canvas.width/2,canvas.height/2);

    // rotate the canvas to the specified degrees
    context.rotate(degrees*Math.PI/180);

    // draw the image
    // since the context is rotated, the image will be rotated also
    context.drawImage(image,-image.width/2,-image.width/2);

    // we’re done with the rotating so restore the unrotated context
    context.restore();
}

ここにコードとフィドルがあります: http://jsfiddle.net/m1erickson/6ZsCz/

<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>

<style>
    body{ background-color: ivory; }
    canvas{border:1px solid red;}
</style>

<script>
$(function(){

    var canvas=document.getElementById("canvas");
    var ctx=canvas.getContext("2d");

    var angleInDegrees=0;

    var image=document.createElement("img");
    image.onload=function(){
        ctx.drawImage(image,canvas.width/2-image.width/2,canvas.height/2-image.width/2);
    }
    image.src="houseicon.png";

    $("#clockwise").click(function(){ 
        angleInDegrees+=30;
        drawRotated(angleInDegrees);
    });

    $("#counterclockwise").click(function(){ 
        angleInDegrees-=30;
        drawRotated(angleInDegrees);
    });

    function drawRotated(degrees){
        ctx.clearRect(0,0,canvas.width,canvas.height);
        ctx.save();
        ctx.translate(canvas.width/2,canvas.height/2);
        ctx.rotate(degrees*Math.PI/180);
        ctx.drawImage(image,-image.width/2,-image.width/2);
        ctx.restore();
    }


}); // end $(function(){});
</script>

</head>

<body>
    <canvas id="canvas" width=300 height=300></canvas><br>
    <button id="clockwise">Rotate right</button>
    <button id="counterclockwise">Rotate left</button>
</body>
</html>
于 2013-07-01T19:41:46.173 に答える
10

これは、回転およびスケーリングされた画像を描画する最も簡単なコードです。

function drawImage(ctx, image, x, y, w, h, degrees){
  ctx.save();
  ctx.translate(x+w/2, y+h/2);
  ctx.rotate(degrees*Math.PI/180.0);
  ctx.translate(-x-w/2, -y-h/2);
  ctx.drawImage(image, x, y, w, h);
  ctx.restore();
}
于 2017-05-11T23:57:02.027 に答える
2

これが私がやったことです

var ImgRotator = {
    angle:parseInt(45),
    image:{},
    src:"",
    canvasID:"",
    intervalMS:parseInt(500),
    jump:parseInt(5),
    start_action:function(canvasID, imgSrc, interval, jumgAngle){
        ImgRotator.jump = jumgAngle;
        ImgRotator.intervalMS = interval;
        ImgRotator.canvasID = canvasID;
        ImgRotator.src = imgSrc ;
        var image = new Image();
        var canvas = document.getElementById(ImgRotator.canvasID);
        image.onload = function() {
            ImgRotator.image = image;
            canvas.height = canvas.width = Math.sqrt( image.width* image.width+image.height*image.height);
            window.setInterval(ImgRotator.keepRotating,ImgRotator.intervalMS);
            //theApp.keepRotating();
        };
        image.src = ImgRotator.src;   
    },
    keepRotating:function(){
        ImgRotator.angle+=ImgRotator.jump;
        var canvas = document.getElementById(ImgRotator.canvasID);
        var ctx = canvas.getContext("2d");
        ctx.save();
        ctx.clearRect(0,0,canvas.width,canvas.height);
        ctx.translate(canvas.width/2,canvas.height/2);
        ctx.rotate(ImgRotator.angle*Math.PI/180); 
        ctx.drawImage(ImgRotator.image, -ImgRotator.image.width/2,-ImgRotator.image.height/2);
        ctx.restore();
    }
}

利用方法

ImgRotator.start_action("canva",
            "data:image/jpeg;base64,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",
            500,15
            );

HTML 

<canvas id="canva" width="350" height="350" style="border:solid thin black;"></canvas>
于 2016-04-20T12:21:10.213 に答える