I am using openseadragon for displaying tile source. The tile source server is expecting the parameters like following
jpg/0,0,500,800/105,/0/default.jpg
How to build this url from openseadragon's getTileUrl(level, x, y) callback?
I get only the level,x,y. My question is how to build it inside getTileUrl() method?
Related
I am trying to load images from a local folder using fabric.js in node.
There seems to be very little up to date documentation on how to do this.
Most example use fabric.Image.fromURL(imageurl)
As far as I'm aware, this only works for web urls, not local paths.
Correct me if I'm wrong, but I have tried
fabric.Image.fromURL(imgpath, (img) => {
...
}
which throws the error Coul not load img: /image/path/img.jpg
Where
fs.readFile(imagepath, (err, i) => {
...
})
will successfully read the file, i will be a buffer.
What is the correct way to load a local image.
I know there is a fabric.Image.fromObject but I have no idea what type of object it wants.
I am currently loading the image into a 2d canvas object, converting it with canvas.toDataURL() and putting that url into fabric.Image.fromURL() which works but converting the image to a url is very slow due to large images. There must be a way to load the image directly and avoid this problem.
If you are using fabricjs 3+, that uses the new jsdom, you can use the file urls!
fabric.Image.fromURL(file://${__dirname}${filepath});
Check here on the fabricJS codebase how they handle reading files in browser and node for the visual test images
https://github.com/fabricjs/fabric.js/blob/master/test/lib/visualTestLoop.js#L139
try this one:
fabric.Image.fromURL(require("../../assets/mockup/100.png"), (img) => {...}
I have a simple utility that i use to size image on the fly via url params.
Having some troubles with the ruby image libraries (cmyk to rvb is, how to say… "unavailable"), i gave it a shot via nodejs, which solved the issue.
Basically, if the image does not exists, node or ruby transforms it. Otherwise when the image has already been requested/transformed, the ruby or node processes aren't touched, the image is returned statically
The ruby works perfectly, a bit slow if lot of transforms are requested at once, but very stable, it always go through whatever the amount (i see the images arriving one the page one after another)
With node, it works also perfectly, but when a large amount of images are requested, for a single page load, the first images is transformed, then all the others requests returns the very same image (the last transformed one). If I refresh the page, the first images (already transformed) is returned right away, the second one is returned correctly transformed, but then all the other images returned are the same as the one just newly transformed. and it goes on the same for every refresh. not optimal , basically the resquests are "merged" at some point and all return the same image. for reason i don't understand
(When using 'large amount', i mean more than 1)
The ruby version :
get "/:commands/*" do |commands,remote_path|
path = "./public/#{commands}/#{remote_path}"
root_domain = request.host.split(/\./).last(2).join(".")
url = "https://storage.googleapis.com/thebucket/store/#{remote_path}"
img = Dragonfly.app.fetch_url(url)
resized_img = img.thumb(commands).to_response(env)
return resized_img
end
The node js version :
app.get('/:transform/:id', function(req,res,next){
parser.parse(req.params,function(resized_img){
// the transform are done via lovell/sharp
// parser.parse parse the params, write the file,
// return the file path
// then :
fs.readFileSync(resized_img, function(error,data){
res.write(data)
res.end()
})
})
})
Feels like I'm missing here a crucial point in node. I expected the same behaviour with node and ruby, but obviously the same pattern transposed in the node area just does not work as expected. Node is not waiting for a request to process, rather processes those somehow in an order that is not clear to me
I also understand that i'm not putting the right words to describe the issue, hoping that it might speak to some experienced users, let them provide clarifiactions to get a better understanding of what happens behind the node scenes
I have been looking at the mobify.js website for a while now, but I fail to understand the benefits of using it. (I am stumped to see why would one replace all the images on the page by GrumpyCat image?).
Could you kindly point me to a clear and lucid example, wherein, I can see that depending on the browser resolution my image size changes.
I have done the following tasks till now:
0. Included mobify.js header information
1. Used the mountains.jpg and forest.jpg image in my hosted website (The page contains only these two images)
2. Request the page from a desktop machine, from a tablet (Samsung Galaxy 10 inch), from an android mobile phone.
3. In all the three cases, I see the same image getting downloaded, the size of the image stays the same in all the cases.
I understand that the magic of size reduction can't happen on the fly, but how do I achieve this?
I realize that the Grumpy Cat example is a bit cheeky, but the same concept applies to solve your problem. Instead of replacing the images with Grumpy Cat images, you could write some logic to replace the images with lower-resolution images (i.e. mountains-320.jpg and forest-320.jpg).
With Mobify.js, you need to write the adaptations in the JavaScript snippet that you added to your site. So, to load smaller images for mobile, you could define the path to the lower resolution image in your original HTML like this:
<img src="mountain.jpg" data-mobile-src="mountain-320.jpg" />
<img src="forest.jpg" data-mobile-src="forest-320.jpg" />
Then, in the JavaScript snippet, you could modify it to grab the image in the data-mobile-src attribute instead like this:
if (capturing) {
// Grab reference to a newly created document
Mobify.Capture.init(function(capture){
// Grab reference to the captured document in progres
var capturedDoc = capture.capturedDoc;
var imgs = capturedDoc.getElementsByTagName("img[data-mobile-src]");
for(var i = 0; i < imgs.length; i++) {
var img = imgs[i];
var ogImage = img.getAttribute("x-src");
var mobileImage = img.getAttribute("data-mobile-src");
img.setAttribute("x-src", mobileImage);
img.setAttribute("old-src", ogImage);
}
// Render source DOM to document
capture.renderCapturedDoc();
});
}
Then, you'll see that the mobile site will download and render mountain-320.jpg or forest-320.jpg, but it will not download mountain.jpg or forest.jpg.
Just out of curiousity, what site are you wanting to use Mobify.js on?
When creating a SVG image you have to set width,height and position otherwise it will not be rendered.
How do I read them from the original image?
Using Dart I first load the html image and after it's loaded I get the size and then define the SVG image and use the info I got before. This is a bit cumbersome and I wondered if there is another way.
The dart code looks like this:
ImageElement img = new ImageElement(src:'2.jpg'); //401x600
img.onLoad.listen((e) {
svg.ImageElement image = new svg.ImageElement();
image.setAttribute('x', '0');
image.setAttribute('y', '0');
image.setAttribute('width', img.width.toString());
image.setAttribute('height', img.height.toString());
image.getNamespacedAttributes('http://www.w3.org/1999/xlink')['href'] = '2.jpg';
});
There seems not to be a more convenient method (also not in JavaScript except when you use jQuery or another framework that includes methods for this).
Just create a method yourself and reuse that method for each image you load.
I am making application on vLine.
I wonder is it possible to change the direction of movie.
Currently,the pitcure on my camera(small frame) is left-right side reversed like a mirror.
It is sometimes a bit confusing.
If we can also switch upside-down ,
it is very useful especially using outside camera.
NOTE: This answer assumes that you are not using the uiVideoPanel widget.
You can style the HTML element that is created as a result of calling MediaStream.createMediaElement() or MediaStream.createVideoElement() with CSS. By default, the local video will be mirrored and the remote video will not. You can see an example of this by making a call with the shell example.
You can apply a CSS transform to the HTML element to mirror the image or flip it upside down.
To mirror, you'd use transform: scaleX(-1) and to flip upside down you'd use transform: scaleY(-1). Also, you may need to add a vendor-specific prefix to transform, such as -webkit-transform.
For example, in the shell example you can add the following in the mediaSession:addRemoteStream handler:
// flip remote video upside-down
// 'stream' is the MediaStream
// 'elem' is the result from stream.CreateMediaElement()
if (stream.isRemote()) {
elem.css('transform', 'scaleY(-1)'); // Firefox
elem.css('-webkit-transform', 'scaleY(-1)'); // Chrome
}