Javascript function to Rotate a base 64 image by X degrees and return new base64

Question

I want a javascript function that will rotate a base64 image by X degrees and return the new base64 image.

Example I wish to call a function with something like:

var newImg = rotateImg(imageData, 90); //which should return a base64 string of the original image rotated 90 degrees.

(Sample base64 image string at the bottom)

Ideally, the function will be backwards compatible with non html5 browsers, but pure canvas solutions are welcome for simplicity.

I have been battling with this for days.

I understand that the solution will probably be, load an image object with the original string, create a temp canvas object and context, then rotate context, then convert canvas back to image string but just can get it to work.... Please HELP!!

Sample image string:

data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACIAAABBCAMAAACD+YYEAAAABGdBTUEAALGPC/xhBQAAAwBQTFRFpI8jl5FIn5V0paijNzAfJiIavsHNlpabcnB6iH0XZ2Z4gH6BnJM2paSHu7NVoqGdoi8pRDwnnz40vrl4qJtgpqKNg3pRoJBL8+UJPj08nJeCNCkQhWgG5erh0q2RxcnKyYcT8POb391VRTAE+/rqzsqsqZ8xsaBa38sVgXU0jI6SpKKUdlpLk4VEfXAcjId2UFBMo5tc5bwCdX6noJtzwLIkkYAvmI5fu61GfnlMjn4Y39gPeXJVlY99gYKNb19afnli186St58T0cUPV09Azb8fX1w/nJqdp5s3dGtHMzhLGRcex8Fk4tZspoYSdnNxpKBxko51tKRg5d6Ig4B1181vX2BgFxEQWFE8W1dDiYuVdG5l5NQyraqZa2lmamppY15AgH5shYN8d3NocG1feXhyAAAA15Bry6847fPEPEWJv0E28+ZTw76K/txB3cpM3NvAkpKecVsJjouKXGKJ9+Io7ezNnqGts69tf3pT9vOt/vYY9d46/uwVHx0mZm6hv6AmmZJh8uWS5t6jYWd78e2RVEQQ7+qzCQ9JsrCY7dlNVVVapZIq/PMw1rkI7eVzxrgM7u4Ih24lg30UYl0krp5HnpqI0sdhzKEM3tWEj4tp7uiE69dY3MEKxsB6//2zz8JRKjBW/fdZXlpFua0O/tsM/9IB/+5oLB0B/O0D//7cxq8h8t4DSk9sBgII7NkL//mQ//lH4MMlPzgm/vCq/OdH/vJ4lY4XNjIu1c99IiM0//zI/uAMVlpuenp1//5wvbFJISRE//yE9dQFTkk6REA3NjU5s5oimY5J/+Ag0bAF+dwCqpwN7s8FWVlX//yaEhE2FhQpMysgQEVamH8V+OcC//yoU1NS18Ay/vq7/+2aEw4d/+yP/+uGdHqZamxwHhkZ5c4E/+E5DAshBAMY/+AV/+NPSkpMGRcf/+h9/+Vm/+At/9YBLSss/+dy/+ZaLy0y/vQCJyUn/+JFAwMlOjk5QEBG/+UAKCUg/fsA/+0BJCEgIh4e/+AB/9oA/9wA1H7CggAAAGd0Uk5T4vLQweDsx83XzcXoyNrZx/LL4NeTbrKm/vHL8f38/vH9/vv7/v3Vs/2JmryxXKtd5cn8/P7V+YLKb/v9gmv+npv+/vpj5ktDs/398/j+/k+8mf7+ef7+/rQhLir9FTMVij8iCQ8DAMXyiFIAAAZySURBVEjHhdYHUBNZGABg5+68fmdX7AVRKYeKgAIK0osUaSIQKSmevfcCWCgCgkqvgiC9SS/SqxRpoWNIDCVIkUAKCSn3djcLnufM/TOb2cl88//v7fv3vV108n9j0cItHou1dQRhY2ODxX2D4KxtLUyPwiEtLS1lYWKN+4rgdCT1/jSMigqytCwoUFeX2PyjlA7+XwSvJauNwWRmYjzDfX3DzM1D3Ldv/EkL/wXB6cjIR2GaKOn3zn0adb1zx/1RyKNLm3/Wsp8nBDu1fTfNIppS7ufET37o7SxK2n5D3SyQ9KsJDiVYi98uy7tQOrhDM58nR/t7s3uAiXxwVVUKKyI4k9/LopIjGtj812PDnyY/wCbpUeR5iT92E0RESft5uk8TXyh4/S4nPhci2UVJ7pbmPeqmeIRgD6twKPVNbC6Xc/dNaWlFRnPny54id0vLzq1HbRFiqyfWUe/TwaFzOM8x27YZ+Zpv7QQopCyseYUJASaOO8QoPimc588a/fz8/f2rYvRDbxW4doZFGVUYKuEhQvhLgd/U1KHi5zZLYwxCQW1lxjwIyQ0Pz7XcLyLaiYKGZ1d4DAaD1kft63MqLCwsby8x9Lz3ymg/Di4ECKXRjcpgtPJmQUxPMKtZrPbiErPup9tWooStkdXSSiPPzc7x5gCpYY68P/aYpBpwHSPK4qjAJ7Z4TLXxeHM8cE1PTDFZXccG9u17kK6phBNNutK43IOZTybz5kDAZOQ9IAEUBR1k0jZr5IKrylnMaTIZJtMIIV0+JadnBz06AnbVAbl6/WjWSA0PToMWcg7sllOwwBJOLsIr7dCsD37R3t41MgEGOzc7kQ+GCwgp0CX42Q4le0C0flFWNlb0an/vVUOzooFwmoJmNECSN96guEPSGhSy1nFYtkGxODU11WAwLQ1+uoVTrJFikhlRXG23HR5uBt1lV+qunUkt7spvy8+qrqqqrmYxWakksw3rtfDIjE7q/uDmHVpSF1BWVmZoCN6AyPNPAkNVLwdcWW9xQtSYqxYnaGBUVO4+ffOqtKKiGWqXntMbL5W5kQ+LCM4CEDqHfh+QeNB1SEttTwoSt0IJ/uARq0YOnT80dmH486fJ0Q/9/b292UVFF8XT1LALxJhOF7weuzADEcQUvewWTzuOEocjfcZcLmjujzPD86an+VRC2nHbBUJM5AqFQ2OIAbU+9PZk1CYMogTncIRK7OAKBHzUjI6O9ndW1CZQF8hsH5ELkbdIKThPcy5ErBFi7zAHCF0oEKJpIJNR6tJGQ7NARLmBCwg6nM+gWMar5Kzp43YEdLitLyrZQoEAyvNubGZmGGTKfaORNXHcDs0y3QIIHwghH4wHJAKZ4nNq88sXCi1uedHEhgvxEQNVu1dbbSAjGu6Jg8xCIlIIVm+HoEQ51zWqDOYXwGJtjbeQLUACLjY0NDZ2PzmGdVhEcIfWMmv5CwQpN8TdpT+CEsKhPdW148JxwRdIyG9g77rtZYq21O49VS5x4yDAz7xraNC8fewLEpPMZwvH4+LGYSkYjxOw2Q3dofMEFNLP5HPpXC642Hw29MtOZDdg5AcWuk6/LrO+UTPxOQcEHbo6xHYlZ3pG1q2ebynFskziVLVfXl5eY+yz2NjGvDzFuhIzo4JaWdEC4CWJ3UPKHh7lLVTabFtb28RUeXT7NedAc6NkWfTprtGgcL2jo1ktYCtjUKmMlvLo4sekJw/DY/VEa2SzM7iS6w3e+ywymeYE3vspVtdAieqTh571ejYoqa/8WNee2jVBhja7aeith0lOxAFdpF+wO+Veh8sXF3fxrOD9ZaoG2l5IN9VzKlFiv7KJf/Gq80CVaJdCdiDSzcic6/NEche3W9X5Wr4VGd5UQZaR949JVw1fndsrmjTuoCYnoo50piWtzwnZyGoM2h+XPAgq9V1thy6ANicxIkC/dZABz7q1tdDAK/RWUFizuam9aBl1D1A6Uij1RP+sNh6N2teaH3P7lqW5a/bDFYdwInJiv/GWYB9KOkUztrExT7nOzNIobKv5pr/NTG0I6Alro7b07BaV9BR4CZ++AafWndObzi6VWTg+oSN2+ZYUMUp6SiIdHGwVro9ubNy0XMYE/8VRTsBqySpgukFgLhqFqEtIXNosbWGH+/qbQWf/zr0gvlu3bt2SJd9LOdoT/vvlYW8HfXeYOMKBJXzr4+Qk/C+BMH8rin8A/Bof4kY+PtwAAAAASUVORK5CIIA=

Answer 1

Here is the code

<html>
<head>

</head>
<body>
<canvas id="c"/>
</body>
<script>
function rotateBase64Image(base64data, callback) {
    var canvas = document.getElementById("c");
    var ctx = canvas.getContext("2d");

    var image = new Image();
    image.src = base64data;
    image.onload = function() {
        ctx.translate(image.width, image.height);
        ctx.rotate(180 * Math.PI / 180);
        ctx.drawImage(image, 0, 0); 
        window.eval(""+callback+"('"+canvas.toDataURL()+"')");
    };

}
rotateBase64Image("data:image/png;base64,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", 'callback');
function callback(base64data) {
    console.log(base64data);
}
</script>
</html>

Answer 2

I a little bit generalized method above to convert base64Image string without any dependencies clockwise or counterclockwise

      /**
       * Rotates base64 image string iether 
       * clockwise or counterclockwise
       *
       * @param isClockwise - true or false
       *
       * WARNING!!! Method not null save - assumes all input data are valid
       */
      function rotateBase64Image90deg(base64Image, isClockwise) {
            // create an off-screen canvas
            var offScreenCanvas = document.createElement('canvas');
            offScreenCanvasCtx = offScreenCanvas.getContext('2d');

            // cteate Image
            var img = new Image();
            img.src = base64Image;

            // set its dimension to rotated size
            offScreenCanvas.height = img.width;
            offScreenCanvas.width = img.height;

            // rotate and draw source image into the off-screen canvas:
            if (isClockwise) { 
                offScreenCanvasCtx.rotate(90 * Math.PI / 180);
                offScreenCanvasCtx.translate(0, -offScreenCanvas.width);
            } else {
                offScreenCanvasCtx.rotate(-90 * Math.PI / 180);
                offScreenCanvasCtx.translate(-offScreenCanvas.height, 0);
            }
            offScreenCanvasCtx.drawImage(img, 0, 0);

            // encode image to data-uri with base64
            return offScreenCanvas.toDataURL("image/jpeg", 100);
      }