canvas

问题 Ok, so I'm making an html5 canvas/javascript game. I'm playing around with the idea of making it available to anyone who wants to put the game on their own website, via one little script snippet that links to an external js file. Inside the external js file, the whole entire game is included, all I need is to find the best way to create a canvas tag via javascript code. The external js link: <script src="http://host.com/game.js"></script> Here is the single line of canvas code that I need to

问题 Is there any way to set line color of specific sections in between two points in chart.js? I would like to color the section 00-07 gray, 07-15 red, and 15-23 blue. Here is what I am passing as the data attribute in the options object to initialize the chart: var chartData = { labels: [/* a single dimensional array of strings */], datasets: [ { label: '', data: [/* a single dimensional array of totals */], fill: false, backgroundColor: '#e7eaeb', borderColor: red } ] }; I think this is where I

问题 Is there any way to set line color of specific sections in between two points in chart.js? I would like to color the section 00-07 gray, 07-15 red, and 15-23 blue. Here is what I am passing as the data attribute in the options object to initialize the chart: var chartData = { labels: [/* a single dimensional array of strings */], datasets: [ { label: '', data: [/* a single dimensional array of totals */], fill: false, backgroundColor: '#e7eaeb', borderColor: red } ] }; I think this is where I

问题 I want to make an online filter web app. So I made some filter effects and drag and drop upload (with preview) on a <div> but I can't download it(using the download button) when the filter is applied as I don't know about Screen capture API or <svg> .So I want to draw the image on <canvas> as I know how to download the filtered image from the <canvas> but it appears that the functionality of drag and drop doesn't work anymore if I use it or I don't know how to use the drag effects (like on

问题 Right now I'm using this, but I would like to skip the base64 conversion step if possible function getJpegBytes() { var jpgImg = canvas.toDataURL("image/jpeg"); jpgImg = jpgImg.replace('data:image/jpeg;base64,', ''); return _base64ToArrayBuffer(jpgImg); } function _base64ToArrayBuffer(base64) { var binary_string = window.atob(base64); var len = binary_string.length; var bytes = new Uint8Array(len); for (var i = 0; i < len; i++) { bytes[i] = binary_string.charCodeAt(i); } return bytes; } 回答1:

问题 Right now I'm using this, but I would like to skip the base64 conversion step if possible function getJpegBytes() { var jpgImg = canvas.toDataURL("image/jpeg"); jpgImg = jpgImg.replace('data:image/jpeg;base64,', ''); return _base64ToArrayBuffer(jpgImg); } function _base64ToArrayBuffer(base64) { var binary_string = window.atob(base64); var len = binary_string.length; var bytes = new Uint8Array(len); for (var i = 0; i < len; i++) { bytes[i] = binary_string.charCodeAt(i); } return bytes; } 回答1:

问题 I would like to create a floor map which show foot print of user or heat map based on user movement on floor. I'm not sure how to create this heat map by using .dwg file. I also need to show this live map on my website which give real time data on map and show where users are more (currently I have only .dwg file which is auto cad file where i have complete drawing of my floor plan). I'm open to use any technology which supports on website and can be used with JavaScript, PHP etc. Is there

问题 I would like to create a floor map which show foot print of user or heat map based on user movement on floor. I'm not sure how to create this heat map by using .dwg file. I also need to show this live map on my website which give real time data on map and show where users are more (currently I have only .dwg file which is auto cad file where i have complete drawing of my floor plan). I'm open to use any technology which supports on website and can be used with JavaScript, PHP etc. Is there

问题 I'm trying to stream the content of a html5 canvas on a live basis using websockets and nodejs . The content of the html5 canvas is just a video. What I have done so far is: I convert the canvas to blob and then get the blob URL and send that URL to my nodejs server using websockets. I get the blob URL like this: canvas.toBlob(function(blob) { url = window.URL.createObjectURL(blob); }); The blob URLs are generated per video frame (20 frames per second to be exact) and they look something like

问题 I'm trying to render a THREE.js scene + some overlaid HTML elements using html2canvas.js. It works most times , but not all the time. In the failure cases, the HTML elements are rendered (the background, overlays, etc.) but nothing else. The THREE.js scene acts as if it's completely empty, even though it visibly has data in it. I can say that it usually fails for larger models, but only early into the rendering. It does eventually work in all cases, but the larger models take about 30 seconds