I am accessing an image from a folder in localhost.
Image loads correctly in img tag. But, when I try to draw that image onto canvas, it doesn't appear!
I have implemented it such that when image is dropped onto the canvas, it is drawn onto it and I draw it by getting the image from original source. When I drag again and again, then, after some attempts, it appears.
The functionality is working perfectly in Firefox and I.E.
This is the source of my image on localhost:
b.src = "http://localhost/casema...E/2780Chrysanthemum.jpg"
ctx1.drawImage(b, x2-15*z, y2-15*z, w1, h1 );
In HTML5, it not for sure that an image will always load immediately, so you
need to make sure that the image has fully loaded beford you draw it. this code may help you :
var myImage = new Image();
myImage.src = "path/to/your/image";
myImage.onload = function(){
//context is the canvas context
context.drawImage(myImage,x,y,weight,height);
}
Are you using a local HTML file on your computer? If so you need to add the parameter
--allow-file-access-from-files
when calling Chrome.
Related
I'm using fabric.js to make a draw and export the canvas to a .png without background. The thing is that I've been searching and this is the only thing that, in a way, makes sense to me:
document.getElementById("downloadbtn").onclick = saveImage();
function saveImage(c) {
this.href = canvas.toDataURL({
format: 'png',
quality: 0.8
});
this.download = 'testimage.png'
}
But it doesn't work... I've also tried a bunch of different stuff but the same thing happens:
Failed to execute toDataURL... error in the console.
Any helps? Ty
For those who had the same issue as me, the thing is:
You can save easily the canvas to an image, but you can't do it if you have an image inside the canvas, let me explain. If you have imported a nonlocal image into the canvas (like pasting an image with fromURL), the CORS of the web will detect this as a probable threat for the system, and will block the action.
For me, saving the canvas without the url image is fine, so I have no other solution for those who try to save the canvas with an external image, but maybe save first locally the image and then save it will work for you.
Hope it can help!
I have a p5 game and I want to save the canvas as a p5.Image so I can show it on the canvas later. However I only found the saveCanvas() function which directly downloads an image of the canvas. Is there a way to save it as an image for later use?
AFAIK the p5.js library does not provide a way to do this. However, you can transform it into a data url via this code:
const dataURL = document.querySelector("#myCanvas")
.toDataURL()
.replace("image/png", "image/octet-stream");
You can then use this as a regular image source, e.g. you could redirect the current page to the image:
window.location.href = dataURL;
I cant seem to get my drawimage function to work on my canvas. I tried using the onload method I tried using the file on the application. Nothing seems to work, however. All I want to do is print the image from the url into my canvas.
Change line 5 to let image = document.createElement("img");
When drawing images to a canvas you must provide an image element, created with document.createElement or stored in your index.html
I am making a timeline using javascript and a canvas element. Typically, when the event on the timeline has an image associated to it, I use to following code to draw the image on the canvas:
var img = new Image();
img.src = 'image file name';
context.drawImage(img, 0, 0);
However, occasionally the 'image file name' is not actually an image, it's a video. In this case, I would just like to draw a frame of the video on the canvas. It could be any frame. However, I am unsure of how to do this.
i do not know (i am not web developer , i am android developer ) it is good or bed idea working with canvas for timeline but i think you should not use canvas . but i have find a video which can help you in this scenario in this video you can see that you can put image or video according your need in timeline here is the link .
NOTE : -
i do not own this channel or video or do not have any relation with firm .
Thank you .
I have an small drawing application made in processing.js. I would like to save the image made using the application to a server using a php file (no problem on this).
I know the canvas element has a method to get that content, canvas.toDataURL() but I dont know how to do the same with processing.js
Any hint?
Cheers!
perhaps
var image = document.getElementsByTagName("canvas")[0].toDataURL();
So when you use saveFrame() in processing.js. The image opens in a new window and i found it hard to intercept the data. The soultion is to get the image from the canvas in javascript.
// this grabs the canvas and turns it into a base64 image
var image = document.getElementsByTagName("canvas")[0].toDataURL();
// Log the data to the canvas to check it working
console.log(image);
// then you can place the image on your web page
document.getElementById("theImage").src=image;
Then the html is easy. Just add
<img id="theImage"></img>
If you want to upload the image to a server you can acsess the data in js with.
image
Note that you can also use style display:none; and have the canvas render image for you without the canvas displaying. It also supports transparent pngs and the canvas by default is transparent