Angular
Real-time image & video resizing, automatic optimization, and file uploading in Angular using ImageKit.io.
This quick start guide shows you how to integrate ImageKit into an Angular application. The code samples covered here are hosted on GitHub: https://github.com/imagekit-samples/quickstart/tree/master/angular.
This guide walks you through the following topics:
Setup ImageKit Angular SDK
For this tutorial, it is recommended to create an Angular dummy app, as shown below.
Create an Angular app:
We will be using the following in this guide:
Node version 14.21.1
Angular version 15
Let's use the ng new <project name>
CLI utility provided by Angular to build a new project:
Navigate to the project directory:
Open up the project in your text editor of choice, and navigate to src/app/
. This is where we will do most of our work.
Install libraries (if not already):
Now run the app:
In your web browser, navigate to http://localhost:4200/
You should see the dummy app created by Angular CLI.
For simplicity, let's remove everything from src/app/app.component.html
so we can begin with a clean slate.
Let's add one line in src/app/app.component.html
to title our page :
Now we can begin our work.
Install the ImageKit Angular SDK:
Installing the ImageKit Angular SDK in our app is pretty simple:
Initialize the Angular SDK:
Before the SDK can be used, let's learn about and obtain the requisite initialization parameters:
urlEndpoint
is a required parameter. This can be obtained from the URL-endpoint section or the developer section on your ImageKit dashboard.publicKey
andauthenticator
parameters are optional and only needed if you want to use the SDK for client-side file upload.publicKey
can be obtained from the Developer section on your ImageKit dashboard.authenticator
expects an asynchronous function that resolves with an object containing the necessary security parameters i.e signature, token, and expire.
Note: Do not include your private key in any client-side code.
ImageKit Components:
The SDK includes 3 Components and the ability to access the core component:
ik-image for image resizing. This renders a
<img>
tag.ik-video for video resizing. This renders a
<video>
tag.ik-upload for client-side file uploading. This renders a
<input type="file">
tag.
Accessing the underlying ImageKit javascript SDK. See here for more details.
Note: URL endpoints of each component can be overridden explicitly. See here for more details
Configure the app for ImageKit:
Let's import the SDK.
Rendering images
Loading image from relative path:
Let's use the default image that we have. It should be available at the following URL:
Let's fetch and display it! For this, we will use the ik-image
component.
We use the tag <ik-image>
for rendering images. For now, we will do a simple image rendering with a path
prop. For a full list of options, check here
Let's insert the following into app.component.html
.
Rendered HTML element:
Your Angular app should now display the default image in its full size:
You can pass styles and other attributes as props. For e.g. let's add 400px width by adding the transformation.width
prop:
Let's try creating a transformation object in app.component.ts
.
And now, we can use it in app.component.html
as such:
This is how the output should look now:
Note that here we have set the width to 400px at the <img>
tag level only. Intrinsically, the fetched image is still 1000px wide.
There are other transformations available - see the list of different tranformations
Loading image from an absolute path:
If you have an absolute image path coming from the backend API e.g. https://www.custom-domain.com/default-image.jpg
, then you can use the src
prop to load the image.
For example:
The output looks like this:
Basic image manipulation
Let’s now learn how to manipulate images using transformations.
The Angular SDK gives a name to each transformation parameter, e.g., height
for h
and width
for the w
parameter. It makes your code more readable. If the property does not match any of the available options, it is added as it is. See the full list of supported transformations in Angular SDK on GitHub.
You can also use h
and w
parameter instead of height
and width
.
See the complete list of transformations supported in ImageKit here.
Height and width manipulation
To resize an image along with its height or width, we need to pass the transformation
object as a prop to ik-image
.
Let’s resize the default image to 200px height and width:
Rendered HTML element:
Refresh your browser to get the resized image.
Quality manipulation
You can use the quality parameter to change image quality like this:
Rendered HTML:
Crop mode
Let’s now see how cropping works. We will try the extract
crop strategy. In this strategy, instead of resizing the whole image, we extract a region of the requested dimension from the original image. You can read more about this here.
Rendered HTML element:
Chained transformation
Chained transformations provide a simple way to control the sequence in which transformations are applied.
Let’s try it out by resizing an image, then rotating it:
First, we will apply resizing transformations:
Transformation URL:
Now, rotate the image by 90 degrees.
Chained Transformation URL:
Let’s flip the order of transformation and see what happens.
Chained Transformation URL:
Adding overlays
ImageKit.io enables you to apply overlays to images and videos using the raw parameter with the concept of layers. The raw parameter facilitates incorporating transformations directly in the URL. A layer is a distinct type of transformation that allows you to define an asset to serve as an overlay, along with its positioning and additional transformations.
Text as overlays
You can add any text string over a base video or image using a text layer (l-text).
For example:
Sample Result URL
Output Image:
Image as overlays
You can add an image over a base video or image using an image layer (l-image).
For example:
Sample Result URL
Output Image:
Solid color blocks as overlays
You can add solid color blocks over a base video or image using an image layer (l-image).
For example:
Sample Result URL
Output Image:
Lazy-loading images in Angular
You can lazy load images using the loading
prop in the ik-image
component. When you use loading="lazy"
, all images that are immediately viewable without scrolling load normally. Those that are far below the device viewport are only fetched when the user scrolls near them.
The SDK uses a fixed threshold based on the effective connection type to ensure that images are loaded early enough so that they have finished loading once the user scrolls near to them.
You should always set the height and width of the image element to avoid layout shift when lazy-loading images.
You should always set the height and width of the image element to avoid layout shift when lazy-loading images.
Rendered HTML element:
Blurred image placeholder
To improve user experience, you can use a low-quality blurred variant of the original image as a placeholder while the original image is being loaded in the background. Once the loading of the original image is finished, the placeholder is replaced with the original image.
Combining lazy loading with low-quality placeholders
You have the option to lazy-load the original image only when the user scrolls near them. Until then, only a low-quality placeholder is loaded. This saves a lot of network bandwidth if the user never scrolls further down.
Uploading files in Angular
Let's now learn how to upload an image to our media library.
Angular SDK provides ik-upload
component, which renders an input type="file"
tag that you can use to upload files to the ImageKit media library directly from the client-side.
To implement this functionality, a backend server is needed to authenticate the request using your API private key.
Setup the backend app
For this quickstart guide, we will create a sample Node.js server that will provide an authentication endpoint at http://localhost:3000/auth
.
Let's a new folder, server
, and create files app.js
and package.json
inside the new folder in the project root.
Package.json should look like:
Now do npm install
.
Next we setup the content for app.js
.
We would also need a .env file to indicate value for PRIVATE_KEY. This can be taken from your imagekit account's setting page where PUBLIC_KEY can also be found. Sample .env file should look like this.
Let's run the backend server.
You should see a log saying that the app is “Live on port 3000”.
If you GET http://localhost:3000/auth
, you should see a JSON response like this. Actual values will vary.
Configure authentication in the frontend app
Now that we have our authentication server up and running, let's configure the publicKey
and authenticator
in the frontend Angular app:
Add the following to src/app/app.module.js
file to initialize the SDK with auth params:
Add the following to src/app/app.component.js
:
Upload an image
For this, we will use the ik-upload
component and authenticator
function as well as a couple of event handlers for upload error and success, onError
and onSuccess
respectively. Let's use it in our app.component.html
file:
This is how it looks in the UI:
Direct file uploading from the browser
Let’s now upload an image by selecting a file from the file input.
When you choose a file, the file is immediately uploaded. You can pass optional onSuccess
and onError
callback functions as props like we have.
You can verify that file was successfully uploaded by checking the browser console. In case of success, it should print a success message, like this:
The response object would look similar to this (values may vary):
After a successful upload, you should see the newly uploaded image in the Media Library section of your ImageKit dashboard.
If you don't see the image, check if there are any errors in the browser console log. Then verify whether the API private key has been configured correctly in the server app and if the server app is running.
Fetching uploaded file
Fetch the uploaded image and show in UI using ik-image
with the filePath
returned in the upload response.
The app should display your uploaded image correctly!
Advanced file upload
A more detailed example of how to use the file upload component (and an explanation of each advanced feature) is presented below:
Custom Upload Button
The buttonRef
property for ik-upload
can be used so that the file selector component inside ik-upload
will be invisible. This allows you to create your own button
, with your own stylings, and reference it using #<buttonRefValue>
.
Here's an example:
Upload start
The onUploadStart
prop is called when the file upload starts. This can be used for common use cases like showing a spinner, progress bar, etc.
Abort uploads
Supported from imagekitio-angular v2.0.1 onwards.
Aborting of uploads can be done by invoking the abort
method for the component.
Here's an example written in the app.component.ts
.
Show progress bar
The onUploadProgress
prop can be passed like above, which will have a ProgressEvent. This can be used to show the percentage of upload progress to the end user.
Validate file before upload
Arbitrary validation (file type, file size, file name) etc can be added using the validateFile
prop. An example has been added above that shows how to prevent upload if the file size is bigger than 1 MB.
Additional options to the upload function
All the parameters supported by the ImageKit Upload API can be passed as shown above (e.g. extensions
, webhookUrl
, customMetadata
etc.)
**Abort upload
Rendering videos
Rendering videos works similarly to rendering images in terms of usage of urlEndpoint
param.
Loading video from relative path:
What's next
The possibilities for image manipulation and optimization with ImageKit are endless. Learn more about it here:
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