I have found a few different posts and even questions on stackoverflow answering this question. I am basically implementing this same thing as this post. So here is my issue. When I upload the photo, I also need to submit the rest of the form. Here is my html: Previously, I did not need to resize the image, s…
Tag: canvas
How can I stop the alpha-premultiplication with canvas imageData?
Is there a way to stop the premultiplication of the alpha channel for canvas data, or a workaround? I want to generate an image (in this case some random rgba values) and save the canvas as an image. During the second step, I want to compare the original image with the generated image using the imageData, how…
javascript canvas doesn’t draw images
I’m developing hybrid javascript app for android using cordova. In the following code I use two ways of drawing image on canvas: with setTimeout and without. Following code (wrapped with cordova) on android device doesn’t react on func1 but does react on func2. The second click on func1 finally dr…
Print canvas contents
http://jsfiddle.net/vpetrychuk/LWup5/. As you can see text in the canvas displays ok, but after clicking “Print” button (and saving page as PDF) output image becomes ugly. Any chance to print the canvas contents without blur? Answer You need to make the actual canvas at print size then scale it on…
Custom linear congruential generator in JavaScript
I am trying to create a custom linear congruential generator (LCQ) in JavaScript (the one used in glibc). Its properties as it’s stated on Wikipedia are: m=2^31 , a=1103515245 , c=12345. Now I am getting next seed value with Although the generator seems to work, but when the numbers are tested on canvas…
Canvas clip image with two quadraticCurves
I just wanted to clip image in a curve .. but not happening this.. Only image is showing and but not with clip. Answer You have to move everything from the line context.save(); to context.clip(); inside the function object of your imgObj’s onload handler: See http://jsfiddle.net/CSkP6/1/ for an example.
How to generate an Image from ImageData in JavaScript?
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. I need a way to convert an ImageData object to an Image directly, if it’s possib…
execute javascript from textarea
I’m not entirely sure if this is possible, but I’m trying to create a mini faux editor in a browser that runs javascript on the page. Here’s what I’ve been trying to do in theory HTML javascript more specifically I’m trying to write to a canvas element via the ‘code’ …
Drawing at cursor position on canvas with JavaScript
I am trying to draw over a canvas by clicking and dragging the mouse. My problem is that, apart from the fact that the line has a very poor quality (I want a more pronounced border) it only respects the mouse position when this is at 0,0. As I move the mouse to the lower corner, the line increments its
HTML5, canvas, and strokeRect: some lines too narrow and blurry
A stupid simple canvas usage: Yields a rectangle with narrower lines along top and left: Why does this happen? Do I need to offset with padding? It’s annoying. Answer 2 things. First, odd lineWidths (1, 3, 5, …) will never apply cleanly with drawn on integer pixel values. This is because X and Y r…