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Dynamically retrieve image dimensions using html/js

I am currently trying to create a web app to be able to upload images on a canvas using fabric.js. I am able to upload the images but have been unable to retrieve the dimensions of the image when I resize the image inside the canvas. Is there a way, that can be solved? Also, how do I handle it when multiple images are uploaded in realtime?

<!DOCTYPE html>
<html>
<head>
<title>Test Project</title>
</head>
<body>

<style>
canvas{
  border: 1px solid black;
  position: absolute;
  top: 0px;
  left: 0px;
}
</style>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://rawgit.com/kangax/fabric.js/master/dist/fabric.min.js"></script>
<input type="file" id="file"><br />
<canvas id="canvas" width="1000" height="1000"></canvas>


<script>
var canvas = new fabric.Canvas('canvas');
document.getElementById('file').addEventListener("change", function (e) {
  var file = e.target.files[0];
  var reader = new FileReader();
  reader.onload = function (f) {
    var data = f.target.result;                    
    fabric.Image.fromURL(data, function (img) {
      var oImg = img.set({left: 0, top: 0, angle: 0}).scale(0.2);
      console.log(oImg.height)
      console.log(oImg.width)
      canvas.add(oImg).renderAll();
      var a = canvas.setActiveObject(oImg);
      var dataURL = canvas.toDataURL({format: 'png', quality: 1});
      oImg.setControlsVisibility({ mtr: false })
      
     
    });
  };
  reader.readAsDataURL(file);
});

</script>

</body>
</html>

about 4 years ago · Juan Pablo Isaza
1 answers
Answer question

0

In Fabric.js, an image's scaled width/height values can be obtained with the getScaledWidth() and getScaledHeight() methods.

<!DOCTYPE html>
<html>
<head>
<title>Test Project</title>
</head>
<body>

<style>
canvas{
  border: 1px solid black;
  position: absolute;
  top: 0px;
  left: 0px;
}
</style>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://rawgit.com/kangax/fabric.js/master/dist/fabric.min.js"></script>
<input type="file" id="file"><br />
<canvas id="canvas" width="1000" height="1000"></canvas>


<script>
var canvas = new fabric.Canvas('canvas');
document.getElementById('file').addEventListener("change", function (e) {
  var file = e.target.files[0];
  var reader = new FileReader();
  reader.onload = function (f) {
    var data = f.target.result;                    
    fabric.Image.fromURL(data, function (img) {
      var oImg = img.set({left: 0, top: 0, angle: 0}).scale(0.2);
      console.log(oImg.getScaledWidth())
      console.log(oImg.getScaledHeight())
      canvas.add(oImg).renderAll();
      var a = canvas.setActiveObject(oImg);
      var dataURL = canvas.toDataURL({format: 'png', quality: 1});
      oImg.setControlsVisibility({ mtr: false })
      
     
    });
  };
  reader.readAsDataURL(file);
});

</script>

</body>
</html>

about 4 years ago · Juan Pablo Isaza Report
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