How to change image source attribute through directive - angularjs

I have the following image tag:
<img src="default.png" data-new-image/>
newImage is a directive that I have defined that will fetch the image from the server (based on some criteria) and while it calculates and fetches the image, I have the default.png image file shown.
In this directive, I have defined the link function as:
return {
link: function (scope, element, attrs) {
//My custom logic here to determine which image to show
//and then fetch from the server
//After HTTP request, assigning image to image source
attrs.src = "image_fetched_from_server.png";
}
};
But this does not update the images src attribute. I can see the image fetched clearly and a console.log(attrs) after assigning the image shows that the source attribute was updated with new image. But the DOM inspector in the browser shows no change to the source - it still shows default.png
I am using directive here and not controller - I understand I can use controller and use ng-src but I have this logic across multiple controllers and a directive is the best option I have. How do I change the source of the image tag? I wonder how ng-src does it?

I found the cause.
To set values in the attribute, I needed to use attrs.$set(attribute_name, value).
Thus, I replaced attrs.src with attrs.$set('src', 'image_fetched_from_server.png'); and it worked!

ng-src is nothing but another directive which passes a "source" attribute (or binds it) to a given directive / whatever.
So - what is the name of the directive you are trying to make? One option might be to encompass the entire <img.../> tag in your image-loader-directive
The other issue that might be occurring, could have to do with the fact that your DOM defines src="default.png" instead of something like src="{{ image_src }}". This way the minute your directive decides to change the meaning of image_src - the DOM will refresh and hence pull the correct image from its source.

Related

How to find and replace a specific text on a page

How to find and replace a specific text on a html page using AngularJs
That text is on a third party component so the id and the class is keeping changing. What I can reference is the text itself that I want to change.
That specific text on the html page is no class or id or any ng-tag around it.
I am not a angularjs developer and the page was built on asp.net mvc with the view (cshtml) using angularjs version1.
Is there a way in angularjs to find and place the text like the way in javascript:
document.body.innerHTML = document.body.innerHTML.replace('old_text', 'new_text');
Thank you!
In angularjs each application state(page) has a controller. The logic to access the Dom should placed in said controller.
To manipulate the DOM please see this answer
In Angular world, it's called data binding. Here are the official docs on data binding.
Here is the working DEMO of data being updated in time. First, html displays "Initial Text" and in 5 seconds it's changed to "New Text".
What was done for this demo:
An angular component was created with a dedicated variable $scope.text that holds text values that will change in time.
Then, this variable is used in the HTML markup, like this: {{ text }}.
Angular handles the HTML re-rendering automatically for you, so when the value of $scope.text is modified in the component, Angular forces re-rendering of the html in the browser
UPD another example with Angular two-way binding: DEMO.
Here user can change $scope.text value in the input field, which automatically changes its value in the controller. Try to edit the input field and you will see how it instantly updates in the header above the input field.

Why does AngularJS select all options instead of just the one clicked?

In my AngularJS app I have an HTML form with some option elements, and when I change one option the other options also get changed. After reloading the page I can change individual values.
A function changeVariant is called on change and the values will be changed.
What causes this and how can I fix it?
This is the angularjs feature 2 way binding. if a scope variable is changed in controller the reference (object reference) value will also get changed in corresponding html pages. to restrict this you have to break the object reference. please check the below url to get some idea.
https://www.bennadel.com/blog/2863-breaking-direct-object-references-at-cache-boundaries-in-angularjs.htm

AngularJs - routing between css files

​Hi all..
referring to ngRoute,
i created a single page application but would like to apply different css rules to each sub-page like background image
how can i do that?
i assigned a different controller to each sub-page
and in the link tag i used ng-href and {{name}}.css to tell the browser to grap the correct css file where is name is giving the value of the file name and attached to the scope inside the corresponding controller.
is there a need to use more than one ng-controller ?
here is the view : http://shireefkhatab.github.io/imax-design
and my code : https://github.com/shireefkhatab/imax-design​
hope to get a response
thank you all in advance.
Reefo.
You can include those styles in your template (views) or make separate route for styles, add its view in head section and then change state from your controller using $state.go('where.ever.you.want.to.go');

Web app attempting to retrieve data before AngularJS is loaded

I am adding images to divs with ng-repeat which works fine. The image location data is nested in an array. The images show up as expected. My partial looks like:
<div class="image-wrapper">
<img src={{item.user.img_src}}>
</div>
However, it appears the page is to attempting to retrieve the string before AngularJS is loaded. I get the following console warning:
GET http://localhost:3000/%7B%7Bitem.user.img_src%7D%7D 404 (Not Found)
How do I prevent this?
The src attribute is buggy when Angular markup is used. Use ngSrc instead of src.
Thus, <img ng-src="{{item.user.img_src}}">
When the browser first loads the page it sees your src exactly as you wrote it. It's not until Angular loads and processes the page that it updates your dynamic source. Neither of these is what you want to have happen (especially since you could accidentally create the bad empty src attribute). Instead, use ngSrc directive so that no src will be set until Angular has evaluated your expression:
http://docs.angularjs.org/api/ng/directive/ngSrc

Image crop with AngularJS

I want to let the user crop an image, I found this JQuery plugin - http://deepliquid.com/content/Jcrop.html
I tried to use it with Angular-ui's Jquery passthrough option, adding the ui-jq=Jcrop directive to the <img>
The problem is that If I use ng-src to dynamically change the image it doesn't work and nothing is seen. If I change it to src and put a static url I can see the image and Jcrop.
how can I fix that ?
also, how can I listen to Jcrop's callbacks to know what is the user's selection ?
is there a better / simpler way to add image cropping functionality to AngularJS ?
Here is my solution:
I've written a directive that create img element and apply plugin on it. When src is changed, this img is removed and content that was created by plugin is also destroyed and then re-created new img with new src and again applied plugin on it.
Also provided 'selected' callback to be able to get coordinated that were selected (wrapped in $apply so you can modify your scope values in it).
Check my solution at Plunker
I've built a demo using AngularJS and Jcrop here:
Demo: https://coolaj86.github.com/angular-image-crop
On Github: https://github.com/coolaj86/angular-image-crop
You can leverage ui-event to create an event definition object with the keys being the event names and the values being the callbacks. Or you can simply pass these events as options to Jcrop (according to the documentation)
Finally, there is a new update coming to ui-jq that lets you add ui-refresh which is an expression to be watched to re-trigger the plugin.
Theoretically you should be able to do
<img ui-jq="Jcrop"
ui-options="{onSelect:myCallback}"
ui-event="{onChange:'myCallback($event)'}"
ui-refresh="imgSrc"
ng-src="imgSrc" />
Note: this simply re-fires the passthrough again, and doesn't automatically mean this will fix the problem or that the plugin will behave properly when re-initialized
We're still working on a good way to allow you to trigger different events at different times.

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