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Create HTML canvas from Ajax Arraybuffer response type

由 删除回忆录丶 提交于 2020-01-06 01:48:42
问题 I am doing a Ajax call to Server for a Jpeg file. I have the data returned as Array buffer. Now how can I render this Array buffer on the canvas. Now please dont suggest any answer like setting the source url to the image. I want to hold the image data on memory for some processing. 回答1: If you don't want to use the buffer as an image source, the only option left is to parse the raw buffer yourself. Just have in mind that this buffer contains the unprocessed (raw) file, so by parsing it means

Create HTML canvas from Ajax Arraybuffer response type

由 假装没事ソ 提交于 2020-01-06 01:48:08
问题 I am doing a Ajax call to Server for a Jpeg file. I have the data returned as Array buffer. Now how can I render this Array buffer on the canvas. Now please dont suggest any answer like setting the source url to the image. I want to hold the image data on memory for some processing. 回答1: If you don't want to use the buffer as an image source, the only option left is to parse the raw buffer yourself. Just have in mind that this buffer contains the unprocessed (raw) file, so by parsing it means

html5 getImageData then putImageData results in fading image

由 冷暖自知 提交于 2020-01-03 02:59:08
问题 I'm very new to Html5 and I was wondering if someone could shed some light on this: <script type="text/javascript"> window.onload = function () { var canvas = document.getElementById('canvas'); //682 x 111 pixel canvas var context = canvas.getContext('2d'); var image = new Image(); image.src = "/Content/ImageTestOne/logo-for-dissolve.png"; //682 x 111 pixel image image.onload = function () { context.drawImage(image, 0, 0); drawFrame(); }; function drawFrame() { window.requestAnimationFrame

Fastest way to iterate pixels in a canvas and copy some of them in another one

由 a 夏天 提交于 2020-01-01 11:57:09
问题 I'm into a 2D/3D graphic project and I'm facing a performance problem. My algorithm takes two images: a picture and the relative grayscale depth map. I have also an array of 10 canvases ("layers") initally blank. A note: all the images have the same dimension. I need to check every pixel X;Y of the depth map and, depending on its color value, access one of the 10 canvases and draw the X;Y pixel of the original image on it. Resulting algorithm is someting like: for (var y = 0; y < totalHeight;

How to generate an Image from imageData in javascript?

由 淺唱寂寞╮ 提交于 2019-12-30 00:14:52
问题 I would like to know if there is any way to create a new Image from imageData, which was previously obtained from a canvas element? I've searched for a solution, but they all seem to be drawing the result to a canvas. So basically I need a way to convert an ImageData object to Image directly, if its possible. 回答1: You can use toDataURL method in Canvas. It makes a image data as Data URI. var canvas = document.createElement("canvas"); canvas.width = 100; canvas.height = 100; var ctx = canvas

Draw image from pixel array on canvas with putImageData

由 爷，独闯天下 提交于 2019-12-21 04:07:02
问题 I am working on a project that can encrypt an image and redraw the decrypted image on canvas. As I am still pretty new to coding and programming, I am currently having issues redrawing the decrypted image data, which is a pixel array in the form R,G,B,A. I thought this would be possible by simply putting the data into ctx.putImageData(imgd,0,0); But firebug tells me that the value does not implement the interface for imagedata. I have posted the entire array here. The image is 160px wide and

imageData set in InternetExplorer

由 ╄→гoц情女王★ 提交于 2019-12-12 13:26:10
问题 I have an arraybuffer - named MEM - larger than the canvas width*height size. And I would like to draw the arrayBuffer data to the canvas. imgData.data.set(...) should work, because imgData.data is an Uint8Array, which has the .set hethod. It works in FireFox, and Chrome, but in IE I get this error: Object doesn't support this property or method: 'set' Initializaton: var MEM = new ArrayBuffer(2*1024*1024); var canvas, ctx, imgData; var init = function() { canvas = document.getElementById(

Animating / Move canvas image that has been placed by putImageData

由 六月ゝ 毕业季﹏ 提交于 2019-12-12 06:02:53
问题 I have a jpeg image that has been decoded, and I am writing it to canvas with putImageData. Is it possible to then move this image around? I cannot find any documentation on it. The idea is that I will crop a certain part of the decoded image with dirtyX and dirtyY, and now I would like to crop another part of the image. I'm using the decoded image like a spritesheet. 回答1: Use the clipping version of drawImage to draw your individual sprites to the canvas (Don't use getImageData &

I'm having troubles with copying transparent pixels with canvas putImageData from another canvas/image(png)

由 牧云@^-^@ 提交于 2019-12-12 02:54:26
问题 I'm trying to copy method discribed here on stackoverflow. But I'm having some problems which I don't know how to solve. I set up jsfiddle to demonstrate everything. Here is the second jsfiddle with only particles moving and being drawn. My problem lies in drawing, profiler showed that with around 10000 particles drawImage takes 40% of overall loop time. Without drawing directly and only calculations nothing hinders code exectuion so problem lies in drawing. Is there a way how to use this

html5 getImageData then putImageData results in fading image

由 ≡放荡痞女 提交于 2019-12-06 14:57:40
I'm very new to Html5 and I was wondering if someone could shed some light on this: <script type="text/javascript"> window.onload = function () { var canvas = document.getElementById('canvas'); //682 x 111 pixel canvas var context = canvas.getContext('2d'); var image = new Image(); image.src = "/Content/ImageTestOne/logo-for-dissolve.png"; //682 x 111 pixel image image.onload = function () { context.drawImage(image, 0, 0); drawFrame(); }; function drawFrame() { window.requestAnimationFrame(drawFrame, canvas); imageData = context.getImageData(0, 0, canvas.width, canvas.height); //Do something
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