There are libraries like fabric.js that offer rich APIs.Īpart from the above two reasons, in almost all cases, you would want to get the resized images from the backend itself so that client doesn't have to deal with heavy processing tasks. Image manipulation in JavaScript is done using the canvas element. Imagine this with operations like undo/redo and complex text and image overlays. If a user is manipulating a heavy image, it will take a lot of time to download transformed images from the server. The speed is critical for the user in these editors.
Rich image editors that work on client-sideĪ rich image editor that offers image resize, crop, rotation, zoom IN and zoom OUT capabilities often require image manipulation on the client-side.You can first resize images on the browser and then upload them to reduce upload time and improve application performance. Uploading a large file on your server will take a lot of time. Resizing images before uploading to server.However, there are a couple of situations where you might need to resize images purely using JavaScript on the client side. This approach also saves data while transmitting images from the server to the client. The code is available from Github github.Image resizing is computationally expensive and usually done on the server-side so that right-sized image files are delivered to the client-side.Img.src = src Draw an image with a certain size on a Canvas ctx.drawImage(image, 0, 0, 1024, 576) Fill content of a canvas into an image $('#outputImage').attr('src', canvas.toDataURL("image/jpeg")) The image will be filled with base64 encoded data Demo Resizing an Image with Javascript is fairly simple, the key points are: How to create an Image Object var img = new Image() One advantage of this approach, is of course, the smaller upload size. After the image is resized, you can upload it with ajax and store it on the filesystem of your server. It basically boils down to the question if you need to support anything lower than IE 9. If you choose this approach you must be aware that it will only work on Browsers that support Canvas. I decided to resize the images in the client with Javascript. On a Javascript heavy project, I was facing the same decision and decided to go a different path. Usually when you are implementing an image upload, you have to decide whether you use GD or ImageMagic.
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