Xamarin Forms essential: FFImageLoading, manage your images

Discover 'FFLoadingImage' library

Today I want to make a quick presentation of a really good library for Xamarin Forms. This is the kind of library we would like to see more often on XF... This one is dedicated to image manipulation. It's called "FFImageLoading".

If I take time to make this presentation, it's because I think that we should use it in almost all our "basic" Xamarin Forms applications. When I say basic, I exclude Games or other specific apps. But in my mind, I suggest you to change all your traditional "<Image />" by "<FF:CachedImage />" in your apps.

Before to start, where to find it ?
On Github: https://github.com/luberda-molinet/FFImageLoading
On Nuget: https://www.nuget.org/packages/Xamarin.FFImageLoading

Main features

So what will you find using this library ? I will not explain all the details but the main interesting features of the library.

Multi-platform

The good point is that this library supports multiple platforms:

• - All the xamarin platforms: iOS, Android, MAC, and Xamarin Forms 
• - But also Windows (WinRT & UWP)

So you can use the library either in your XAML code or in your code behind. It's really flexible, ideal for Xamarin Forms projects.

Image cache system

The main feature provided by the library is a picture cache system. This system is pretty complete and you are able to customize it if you want (XAML and code behind). You can set cache keys to your images, you can set a lifetime and so on...

Thanks to the cache you can greatly improve performances of long lists for instance (with images in their data items). 

Here is a XAML example on how to use the 'CachedImage' control:

<!-- contact image -->
<FFImg:CachedImage 
  Source="{Binding ProfilePictureUrl}"
  LoadingPlaceholder="ic_loader.jpg"
  ErrorPlaceholder="profilemale.jpg"
  HorizontalOptions="Center" 
  CacheType="Memory"
  Margin="30,20,30,5"
  Aspect="AspectFit"
  DownsampleWidth="130"                                            
  >
 <FFImg:CachedImage.Transformations>
  <FFTr:CircleTransformation BorderHexColor="#FFFFFFFF" BorderSize="0" />
 </FFImg:CachedImage.Transformations>
</FFImg:CachedImage>

'CachedImage' used in long list for better performances:

Image loading and PlaceHolders

Thanks to "FFImageLoading" you can load images from different sources (from XAML or code-behind):

• - from stream sources
• - from file image sources
• - or from Uri sources

But the user-friendly point is that you can specify temporary images for the loading process and in case of error.

For instance if you load an image from the web, it can take some times, so the temporary picture will be displayed instead. 

And if an error occurs when loading the image, the "Error placeholder image" will be displayed automatically. From a user point of view, it's really cool and now it costs nothing ;)

Download properties

When you want to display a FFImageLoading image , you can specify several usefull parameters (XAML and code behind).

• - we already talk about cache parameters like "CacheDuration" property
• - you can also specify "retry" parameters in case of errors like "RetryCount" to tell how many times you want to retry or "RetryDelay" to wait before retrying loading the image.
• - But you can also specify download properties like "DownSampleWidth" or "DownSampleHeight" to specify a new size for the downloaded image

SVG / Gif support

A good point to notice too, is that the library support the SVG and Gif formats. So instead of loading traditionnal pictures, you can load a SVG image for a loading placeholder for instance.

If you are a good designer and replace your icons and simple pictures by SVG files, it can make you save size on your final app's packages !

Transformations

FFImageLoading offers "transformation" capabilities. That means that you can apply effects on images before to display it. These effects are of 2 kinds:

• - image rendering effects, to apply some effects on colors
• - or image clipping effects to make the image looks rounded, circle or cropped...
• - AND you can also implement your own effect thanks to the provided "ITransformation" interface !

Some effects / transformations:

Optimizations

All these features look optimized (without any complicated setup for you) and I didn't really have any issue by using it. I just noticed a better user navigation thanks to the quick loading of images. So if you want to learn more about this library, I suggest you to follow the following links:

The Wiki:
https://github.com/luberda-molinet/FFImageLoading/wiki

How to use it in details (tutorial in video):
https://www.youtube.com/watch?v=eVA9C7Ik_AM