globalCompositeOperation

Using image mask with globalCompositeOperation on KonvaJS?

由 我与影子孤独终老i 提交于 2021-01-27 10:44:15
问题 I am using Konva.js framework and trying to apply an image mask over an other one. The code is fully copied from this post. In this jsfiddle example there is small modifications to add a background (Rect). The problem is that the background is not properly drawn. To see it in action in the code there is a line to comment/uncomment (to see the problem in action). Is someone have any idea to achieve this ? Best let stage = new Konva.Stage({ container: 'container', width: window.innerWidth,

Using image mask with globalCompositeOperation on KonvaJS?

由 此生再无相见时 提交于 2021-01-27 10:42:04
问题 I am using Konva.js framework and trying to apply an image mask over an other one. The code is fully copied from this post. In this jsfiddle example there is small modifications to add a background (Rect). The problem is that the background is not properly drawn. To see it in action in the code there is a line to comment/uncomment (to see the problem in action). Is someone have any idea to achieve this ? Best let stage = new Konva.Stage({ container: 'container', width: window.innerWidth,

globalCompositeOperation and concentric, hollow, moving shapes

由 |▌冷眼眸甩不掉的悲伤 提交于 2019-12-25 02:20:06
问题 I'm trying to achieve the following: A number of concentric circles (or rings) are drawn on a canvas. Each circle has a "hole" in it, so the smaller circles, drawn behind it are partially visible. Each frame (we're using window.requestAnimationFrame to render) the radius of each circle/shape/ring is slightly increased. A scenario with two rings is depicted in the image here. The code: function draw() { drawBgr(); for (var i = 0, len = rings.length; i < len; i++) { rings[i].draw(); } }

JS: How to get list of supported HTML canvas globalCompositeOperation types

由 折月煮酒 提交于 2019-12-17 20:55:30
问题 I want to make a HTML select list, with which I can choose which type of globalCompositeOperation will be applied when blending two canvas elements, like this: <select name="blending-modes" id="blending-modes"> <option value="source-over">source-over</option> <option value="source-in">source-in</option> <option value="source-out">source-out</option> ... </select> Is there a way to programatically get list of available globalCompositeOperation types as a Javascript object or array, so it could

Canvas disappears when animating “source-in” globalCompositeOperation mask

由 ☆樱花仙子☆ 提交于 2019-12-12 03:58:26
问题 I'm using "source-in" compositing gradient mask on a canvas and I want to animate the stretching of the mask shape & gradient. Here's the compositing code, a function called drawList : var r = ctx.createLinearGradient(1100, 0, 1200 + stretch,0); r.addColorStop(0,"rgba(255, 255, 255, 1.0"); r.addColorStop(0.8,"rgba(255, 255, 255, 0.0"); ctx.fillStyle = r; ctx.globalCompositeOperation = "source-in"; ctx.fillRect(300, 0, 1200 + stretch, 1000); stretch starts at 0 and increases in an animating

Can we drag and drop Composite shapes from one canvas to another [closed]

由 懵懂的女人 提交于 2019-12-12 00:33:17
问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 6 years ago . I am new to HTML5 , as I know only basics about this. If anyone could help me in this that would be great for me. I need to design diff shapes and drag

use globalcompositeoperations on KineticJS 4.7.2

由 喜欢而已 提交于 2019-12-11 18:04:23
问题 This was answered at this question using KineticJS 4.6.0 providing this fiddle But... any idea how to do this on the latest version of kineticjs? I tried the same fiddle with kineticjs 4.7.2: http://jsfiddle.net/qNtSg/ I just changed drawFunc with the new API drawFunc: function (context) { ... context.fillStrokeShape(this); } compositing is not working 回答1: The Kinetic.Shape has changed in recent versions. Now the Shape drawFunc receives a wrapper of the context rather than a canvas. However,

Place object between another two

由 淺唱寂寞╮ 提交于 2019-12-02 14:53:26
问题 I'm new to canvas and I wanted to move my DOM (HTML+JS) animation to canvas. I tried to mimic the solar system animation in Basic animations - Web API Interfaces | MDN and I managed to do it. Fiddle. I have a problem regarding the globalCompositeOperation . In the animation, earth is casting a shadow (low opacity rectangle), and when the moon is orbiting this dark area, moon should be under the shadow rectangle. If I use context.globalCompositeOperation = 'destination-over'; at the top of

Place object between another two

由 让人想犯罪 __ 提交于 2019-12-02 08:47:55
I'm new to canvas and I wanted to move my DOM (HTML+JS) animation to canvas. I tried to mimic the solar system animation in Basic animations - Web API Interfaces | MDN and I managed to do it. Fiddle . I have a problem regarding the globalCompositeOperation . In the animation, earth is casting a shadow (low opacity rectangle), and when the moon is orbiting this dark area, moon should be under the shadow rectangle. If I use context.globalCompositeOperation = 'destination-over'; at the top of draw function, I get the intended result ( fiddle ), but then moon and the earth rotates beneath the

HT for Web基于HTML5的图像操作（二）

由 Deadly 提交于 2019-11-26 23:23:43
上篇 介绍了 HT for Web 采用HTML5 Canvas的getImageData和setImageData函数，通过颜色乘积实现的染色效果，本文将再次介绍另一种更为高效的实现方式，当然要实现的功能效果是完全一样的。这次我们依然基于HTML5技术，但采用Canvas的globalCompositeOperation属性进行各种blending效果： 各种globalCompositeOperation效果可参考 https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API/Tutorial/Compositing 的说明，我们采用“multiply”和“destination-atop”这两种blending效果，通过以下三个步骤实现: 1、先以染色颜色填充图片大小的矩形区域 2、采用“multiply”进行drawImage的绘制，达到以下效果 3、最后一步采用“destination-atop”的globalCompositeOperation方式，再次drawImage，这次绘制效果将会抠出图片像素区域，剔除非图片部分，最终达到我们所要的染色效果图片： 所有代码如下 function createColorImage2(image, color) { var width = image.width; var
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