LIVE DEMO at jsfiddle.net This demo illustrates the viewport usage in a real game scenario. Use arrows keys to move the player over the room. The large room is generated on the fly using rectangles and the result is saved into an image. Notice that the player is always in the middle except when near … Read more
Yes, it can be done. It is based on the new HTML5 “download” attribute of anchor tags. The flow should be something like this: load the image draw the image into a canvas with the crop boundaries specified get the image data from the canvas and make it a href attribute for an anchor tag … Read more
Update 1/2017: I rewrote the entire answer as it started to become rather messy, and to address some of the issues pointed out in the comments. The original answer can be found here. The new answer has in essence the same code but improved, and with a couple of new techniques, one utilizes a new … Read more
Set the tabindex of the canvas element to 1 or something like this <canvas tabindex=’1′></canvas> It’s an old trick to make any element focusable
As simple as I can get it. You’ll have to prepend context.beginPath() and append context.stroke() yourself: ctx = document.getElementById(“c”).getContext(“2d”); ctx.beginPath(); canvas_arrow(ctx, 10, 30, 200, 150); canvas_arrow(ctx, 100, 200, 400, 50); canvas_arrow(ctx, 200, 30, 10, 150); canvas_arrow(ctx, 400, 200, 100, 50); ctx.stroke(); function canvas_arrow(context, fromx, fromy, tox, toy) { var headlen = 10; // length of … Read more
context.drawImage(imageObj, 0, 0, 100, 100 * imageObj.height / imageObj.width)
You won’t get real HTML rendering to <canvas> per se currently, because canvas context does not have functions to render HTML elements. There are some emulations: html2canvas project http://html2canvas.hertzen.com/index.html (basically a HTML renderer attempt built on Javascript + canvas) HTML to SVG to <canvas> might be possible depending on your use case: https://github.com/miohtama/Krusovice/blob/master/src/tools/html2svg2canvas.js Also if … Read more
You’ll need to read the exif data and check if exif.Orientation is one of the following: fileReader.onloadend = function() { var exif = EXIF.readFromBinaryFile(new BinaryFile(this.result)); switch(exif.Orientation){ case 8: ctx.rotate(90*Math.PI/180); break; case 3: ctx.rotate(180*Math.PI/180); break; case 6: ctx.rotate(-90*Math.PI/180); break; } };
A way to avoid the main HTML to be affected is to create an off-screen canvas that is kept out of the DOM-tree. This will provide a bitmap buffer and native compiled code to encode the image data. It is straight forward to do: function imageToDataUri(img, width, height) { // create an off-screen canvas var … Read more
I assume you mean, to load an image into the canvas and not uploading the image from the canvas. It’d probably be a good idea to read through all the canvas articles they have over here https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Canvas_tutorial/Using_images But basically what you want to do is create an image in javascript, and set the image.src = … Read more