html5-canvas

Multiple points/colors gradient on HTML5 canvas

由 巧了我就是萌 提交于 2020-07-18 08:08:11
问题 I would like to fill a shape on a html5 canvas with a gradient created from several differents colors at different positions, like on this picture. Do you have any ideas on how I could do that? 回答1: Searching a little I have found this example from Mozilla Development Network function draw() { var ctx = document.getElementById('canvas').getContext('2d'); var radgrad = ctx.createRadialGradient(0,0,1,0,0,150); radgrad.addColorStop(0, '#A7D30C'); radgrad.addColorStop(1, 'rgba(1,159,98,0)'); var

An OffscreenCanvas could not be cloned because it was detached

由 为君一笑 提交于 2020-07-16 06:30:54
问题 yesterday returned to my hobby with HTML canvas and tried to do a rendering in a separate thread, just to face the following error in the console: Uncaught DOMException: Failed to execute 'postMessage' on 'Worker': An OffscreenCanvas could not be cloned because it was detached. at main (http://localhost:8000/responsivetemplate/:47:14) [index.html] <!DOCTYPE HTML> <html> <head> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" /> <meta http-equiv="cache-control" content="max-age=0"

An OffscreenCanvas could not be cloned because it was detached

由 我与影子孤独终老i 提交于 2020-07-16 06:30:32
问题 yesterday returned to my hobby with HTML canvas and tried to do a rendering in a separate thread, just to face the following error in the console: Uncaught DOMException: Failed to execute 'postMessage' on 'Worker': An OffscreenCanvas could not be cloned because it was detached. at main (http://localhost:8000/responsivetemplate/:47:14) [index.html] <!DOCTYPE HTML> <html> <head> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" /> <meta http-equiv="cache-control" content="max-age=0"

CSS min-height on canvas (or even svg) has a limit?

由 此生再无相见时 提交于 2020-07-09 11:56:06
问题 The Use case Let's said you've a couple of <div> in 2 nested flex (one for column, the other for rows), in order to get something like: You can resize the parent <div> , in any direction, and everything works as expected. note <div> are defined with { /* flex: 1 1 0px */ flex-grow: 1 flex-shrink: 1 flex-basis: 0px /* i.e. independant of content */ } <html> <style type="text/css"> html, body { height: 100%; margin: 0px; } body { padding-left: 30px } span { display: block; margin-top: 30px }

MediaRecorder switch video tracks

由 你说的曾经没有我的故事 提交于 2020-07-09 10:18:31
问题 I am using MediaRecorder API to record videos in web applications. The application has the option to switch between the camera and screen. I am using Canvas to augment stream recording. The logic involves capturing stream from the camera and redirecting it to the video element. This video is then rendered on canvas and the stream from canvas is passed to MediaRecorder . What I noticed is that switching from screen to video (and vice-versa) works fine as long as the user doesn't switch

How to add image to polygon in fabric js?

由 时光怂恿深爱的人放手 提交于 2020-07-08 02:08:31
问题 1I am creating a polygon with definite points,when i try to add an image to the polygon object.Image is not rendering in the polygon.it is rendering from starting point of the canvas. Below is the code i used.Please tell me where i am doing wrong. Appreciate any help!Thanks Jsfiddle Link https://jsfiddle.net/u3bfscom/6/ Add Points and create polygon later add Texture. fabric.Image.fromURL('https://image.freepik.com/free-photo/roof-texture_21206171.jpg', function (oImg) { for(var i=0;canvas

How to add image to polygon in fabric js?

由 ぐ巨炮叔叔 提交于 2020-07-08 02:06:46
问题 1I am creating a polygon with definite points,when i try to add an image to the polygon object.Image is not rendering in the polygon.it is rendering from starting point of the canvas. Below is the code i used.Please tell me where i am doing wrong. Appreciate any help!Thanks Jsfiddle Link https://jsfiddle.net/u3bfscom/6/ Add Points and create polygon later add Texture. fabric.Image.fromURL('https://image.freepik.com/free-photo/roof-texture_21206171.jpg', function (oImg) { for(var i=0;canvas

Rendering Canvas context in Worker thread for smooth playback

由 限于喜欢 提交于 2020-06-17 05:53:36
问题 I have two videos here showing the rendering of a decoded MJPEG video sequence this one only rending one video: Video description: Left (Source), Middle (Canvas copy of stream), Right (Decoded from network). At this point the video is smooth both from source to network and back (websocket). And at least up to 5 video decoded and rendered is reasonably smooth. However if I render like 20 videos things start to lag: My question is what is the best algorithm that will allow to render (or in

Animated footsteps in html svg

由 余生颓废 提交于 2020-06-13 08:57:25
问题 Is it possible to create small animated footsteps in HTML SVG or Canvas. I am just starting out with these technologies, and it is very much necessary for a small project i am working on. My current idea was to create and use a "gif" of animated footsteps. But i would like to know if it can be achieved in any other way through HTML/CSS/JS PS : The footsteps i keep mentioning should be similar to the footsteps that appear on the "Marauders Map" in harry potter Movies. Thanks for any help 回答1:

Animated footsteps in html svg

由 不打扰是莪最后的温柔 提交于 2020-06-13 08:55:44
问题 Is it possible to create small animated footsteps in HTML SVG or Canvas. I am just starting out with these technologies, and it is very much necessary for a small project i am working on. My current idea was to create and use a "gif" of animated footsteps. But i would like to know if it can be achieved in any other way through HTML/CSS/JS PS : The footsteps i keep mentioning should be similar to the footsteps that appear on the "Marauders Map" in harry potter Movies. Thanks for any help 回答1:
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