How to resize an Image using Dropzone.js
To resize an image using Dropzone.js, you can utilize the thumbnail
event and the canvas
element to perform the resizing. Here's an example of how you can achieve this:
<!DOCTYPE html> <html> <head> <!-- Include the necessary CSS and JavaScript files for Dropzone.js --> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/dropzone/5.9.2/dropzone.min.css" /> <script src="https://cdnjs.cloudflare.com/ajax/libs/dropzone/5.9.2/dropzone.min.js"></script> </head> <body> <!-- Create a Dropzone container --> <div id="myDropzone" class="dropzone"></div>
<script> // Initialize Dropzone Dropzone.autoDiscover = false; var myDropzone = new Dropzone("#myDropzone", { thumbnailWidth: 200, thumbnailHeight: 200, maxFilesize: 2, // Set the maximum file size in MB acceptedFiles: ".jpeg,.jpg,.png" // Define the accepted file types });
// Resize the image on thumbnail event myDropzone.on("thumbnail", function(file, dataUrl) { var img = new Image(); img.onload = function() { // Create a canvas element var canvas = document.createElement("canvas"); var ctx = canvas.getContext("2d"); // Set the canvas dimensions to the desired size canvas.width = 400; // Set the width you want for the resized image canvas.height = 300; // Set the height you want for the resized image // Perform the resizing ctx.drawImage(img, 0, 0, canvas.width, canvas.height); // Get the resized image as a data URL var resizedDataUrl = canvas.toDataURL("image/jpeg"); // Update the Dropzone thumbnail with the resized image myDropzone.emit("thumbnail", file, resizedDataUrl); }; img.src = dataUrl; });
</script> </body> </html>
In the above example, we set the thumbnailWidth
and thumbnailHeight
options to specify the size of the thumbnail to be displayed. The maxFilesize
option limits the size of the uploaded file, and the acceptedFiles
option restricts the file types to JPEG and PNG.
Inside the thumbnail
event handler, we create an Image
object and load the original image data URL. Then, we create a canvas
element and set its dimensions to the desired size for the resized image. The drawImage
method is used to perform the resizing, and the resulting image is obtained as a data URL using toDataURL
. Finally, we update the Dropzone thumbnail with the resized image by emitting another thumbnail
event with the resized data URL.
Please note that this example resizes the image on the client-side, and the resulting data URL will be the resized version. The original file is still uploaded, but you can access the resized image data for further processing or display purposes.