Xamarin Forms Image fill width with proper aspect

Question

Here is xaml (an image in stacklayout). Everything is logical: I set Aspect to AspectFit and HorizontalOptions to FillAndExpand. Width of image must fill the width of stacklayout. Height must be calculated in order to image Aspect.

<Image BackgroundColor="Fuchsia"
       Aspect="AspectFit"
       Source="{Binding GroupLogo}"
       HorizontalOptions="FillAndExpand"
       VerticalOptions="FillAndExpand"/>

It fill the width but It doesn't want to draw image full width. Why?

Solution 1

AspectFit does what it says on the tin, it will fit the whole image into the View, which may leave parts of the view empty. Straight from Xamarin's documentation:

Scale the image to fit the view. Some parts may be left empty (letter boxing).

What you're looking for is AspectFill, which will scale the image to fit:

Scale the image to fill the view. Some parts may be clipped in order to fill the view.

If you are trying to get the image view to be the height of the image, I'd suggest adding a HeightRequest to the height of the image. Image controls don't seem to automatically scale in Xamarin, in my experience, as the native controls don't appear to support that by default either.

Reference

Solution 2

I had a similar problem. I wanted to fill the width and the height of a StackLayout when possible but without cropping the actual image. The answers here have helped me find the correct way. Here is what has worked for me:

            <Grid 
                HorizontalOptions="FillAndExpand"
                VerticalOptions="FillAndExpand"
                 >
                <Image
                   x:Name="photo"                         
                   Aspect="AspectFit"                    
                />
            </Grid>

Maybe it will be of use for someone.

Clarification:

HorizontalOptions and VerticalOptions are with the value FillAndExpand, so the height and the width of the Grid are adjusted to fill the parent, in this case that is the Stacklayout. The image is a child of the Grid, so it transforms according to the parent (we haven't given any additional options to the image).

The aspect of the image is set to AspectFit, so that the image will fit the view (in this case the Grid) and also preserve its ratios.

In this way, if the image is in portrait mode but too narrow, it will fill the Grid's (StackLayout's) height but won't fill the width in order to preserve its ratios and to not be cropped from above or under.

If the image is in landscape mode, it will fill the Grid's (StackLayout's) width but won't fill the height in order to preserve its ratios and to not be cropped from left or right.

Solution 3

As I've found no working example. This works perfectly for me:

<Grid VerticalOptions="FillAndExpand">
      <Image Source="{Binding MyImageSrc}" Aspect="AspectFill" />
</Grid>

Solution 4

Up until now, the only solution I've found is to set Aspect="AspectFill" and set HeightRequest.

You can bind HeightRequest to a property and calculate the height based on the page width.

In my case the images are always the same proportion, so I do:

HeightRequest = (int)Math.Truncate(Xamarin.Forms.Application.Current.MainPage.Width / 1.41);

Solution 5

Try using CachedImage from FFImageLoading NuGet package

MyPage.xaml

<StackLayout HorizontalOptions="FillAndExpand"
             VerticalOptions="FillAndExpand"
             Padding="0">
    <ff:CachedImage Source="{Binding GroupLogo}"
                    HorizontalOptions="Fill"
                    VerticalOptions="Fill"
                    Aspect="Fill"
                    DownsampleToViewSize="True"/>
</StackLayout>

This will results image trying to horizontally fill the container and to automatically generate the width while maintaining its aspect.

Add this line of code to MainActivity.xaml after global::Xamarin.Forms.Forms.Init(this, bundle);

CachedImageRenderer.Init(true);

Example can be found here

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