Like almost all Javascript functions, drawImage is synchronous, i.e. it’ll only return once it has actually done what it’s supposed to do. That said, what it’s supposed to do, like most other DOM calls, is queue-up lists of things to be repainted next time the browser gets into the event loop. There’s no event you … Read more
You don’t need to iterate pixel buffer to create a pixelating effect. Simply turn off image smoothing and enlarge a small version of the image to the canvas. This will also mean you can use any image as source (CORS-wise). Example: Fiddle demo // get a block size (see demo for this approach) var size … Read more
I was also getting same error. To fix this I moved the chart script into separate graph.js file. Still I was getting same error. Which is fixed later when I put tag in following order before end of tag as shown below. <script src=”https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.4.0/Chart.min.js”></script> <script type=”text/javascript” src=”jscript/graph.js”></script> </body> The page look like this: var ctx … Read more
If you don’t mind having the calendar icon inside the date input field then a cross browser alternative would be to position a calendar icon over top of the triangle calendar picker indicator and then set the calendar icon to pointer-events: none which will cause all click events to be passed through to the triangle … Read more
Here is how to move an object along a particular path Animation involves movement over time. So for each “frame” of your animation you need to know the XY coordinate where to draw your moving object (rectangle). This code takes in a percent-complete (0.00 to 1.00) and returns the XY coordinate which is that percentage … Read more
If you’re doing complex, layered drawing, you can use globalCompositeOperation to emulate clipping in a second, scratch canvas. You can then use drawImage to copy the scratch canvas back into the original canvas. I can’t guarantee the performance of this approach, but it’s the only way I know to get what you want. //set-up – … Read more
Canvas can’t generate (animated) GIFs. You need to use a JavaScript library to do so. There is jsgif, a JS library to generate animated GIFs: http://github.com/antimatter15/jsgif This blog post explains the usage: http://antimatter15.com/wp/2010/07/javascript-to-animated-gif/
In Chrome, Safari, Firefox and Edge you could make use of the Path2D API to draw Paths in Canvas based on SVG path data. The Path2D constructor can optionally take a SVG path data as its input and generate the equivalent path on Canvas. This API is not supported by Internet Explorer, Android Browser or … Read more
Games that require a lot of mouse interaction and not much continuous animation (such as checkers or chess, or any board game for that matter) are better suited for SVG because you work with dom elements. Consider a simple button hover, in SVG you can add event listeners or even just place g.button:hover path {fill: … Read more
Edited (see comments) function cropImageFromCanvas(ctx) { var canvas = ctx.canvas, w = canvas.width, h = canvas.height, pix = {x:[], y:[]}, imageData = ctx.getImageData(0,0,canvas.width,canvas.height), x, y, index; for (y = 0; y < h; y++) { for (x = 0; x < w; x++) { index = (y * w + x) * 4; if (imageData.data[index+3] … Read more