Forum Xamarin.Forms

Xamarin Forms Image with 100% of parent container width and auto Height to maintain aspect ratio

Hello, I have read similar questions both here and on SO but apparently this cannot be done without implementing custom renderers? I simply want to have an Image to take 100% width of its parent container while actually fitting the whole image within this container without clipping and having height automatically adjusted to preserve aspect ratio. Why is this such an issue for Xamarin Forms? Implementing a custom renderer for such a trivial task is an overkill and a huge embarrassment for Xamarin in my opinion; unless I am understanding something wrong.

Best Answer

  • astralmasterastralmaster ✭✭
    edited March 14 Accepted Answer

    I was unable to find a pure XAML solution to this problem and therefore decided to use ffimageloading's Success event to find out the original width and height of loaded image and get aspect ratio from these values, store it, and use it in SizeAllocated event to maintain aspect ratio of the image while making sure its width is 100% of the parent container.

    Sample code in the answer here

Answers

  • LandLuLandLu Member, Xamarin Team Xamurai

    There's an Aspect property of Image which could help us adjust the displaying mode. If you want to make its larger side fill full of the parent container we could use AspectFit. I defined a layout like:

    <StackLayout>
        <Grid HeightRequest="400" BackgroundColor="Red">
            <Image Aspect="AspectFit" Source="image.jpg"/>
        </Grid>
    </StackLayout>
    

    Here is the effect:

    Make sure the original image's width is lager than its height or the blank space will apear at the horizontal side.

  • astralmasterastralmaster Member ✭✭
    edited March 13

    Thank you for the answer. Unfortunately that results in empty space at the top as you have shown the screenshot. I forgot to mention that the final effect I am looking for is similar to this:

    Where the image begins at the top of the screen and fills the 100% width of the screen and maintains aspect ratio (automatic height)

  • DirkWilhelmDirkWilhelm USMember ✭✭✭✭

    Try this:

    <StackLayout>
            <Grid BackgroundColor="Red" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
                <Image Aspect="AspectFit" Source="image.jpg" VerticalOptions="Start"/>
            </Grid>
    </StackLayout>
    
  • astralmasterastralmaster Member ✭✭
    edited March 13

    This does not fill 100% of the width of parent container.

  • astralmasterastralmaster Member ✭✭
    edited March 14 Accepted Answer

    I was unable to find a pure XAML solution to this problem and therefore decided to use ffimageloading's Success event to find out the original width and height of loaded image and get aspect ratio from these values, store it, and use it in SizeAllocated event to maintain aspect ratio of the image while making sure its width is 100% of the parent container.

    Sample code in the answer here

  • sandaliasandalia Member ✭✭
    edited April 11

    Wow, It is surprising that such an obvious goal requires such a complex solution. Thanks for the code!!
    In my case just want to add two images in a row without distortion and without the horrible empty space in the view....

  • sandaliasandalia Member ✭✭

    I think I just found a XAML solution for this using a frame and binding its height to the image height.

      <Label Text="one lable" FontSize="Large"></Label>
                        <Grid  HorizontalOptions="Center"  BackgroundColor="Yellow" Margin="0"  >
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*" />
                                <ColumnDefinition Width="*" />
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"></RowDefinition>
                            </Grid.RowDefinitions>
                            <Frame Padding="0" Margin="0"  BackgroundColor="Accent" HeightRequest="{Binding Source={x:Reference image}, Path=Height}" HasShadow="False"   Grid.Row="0" Grid.Column="0" VerticalOptions="Start" >
                                <Image x:Name="image"   Source="roth9_2.bmp" Aspect="AspectFit" ></Image>
                            </Frame>
                        </Grid>
    
    <Label Text="another label" FontSize="Large"></Label>
    

  • astralmasterastralmaster Member ✭✭

    Right now I don't have access to PC with Xamarin on it, but if you have managed to get the following effect

    where the gray area is the phone screen in its entirety, and the green area is the image that starts at position X=0, Y=0 of the phone screen and has aspect ratio maintained without clipping, then well done my friend!

  • sandaliasandalia Member ✭✭
    edited April 12

    hummm.... maybe we are talking about different things hahaha...

    I do not have any issues when the image covers the whole width of the parent view (the whole screen in your case). A simple code like the following works fine: it takes 100% the width, preserves ratio and does not take extra space (see the example with the Xamarin logo)

     <StackLayout>
            <Image Aspect="AspectFit" Source="img.jpg" VerticalOptions="Start"/>
            <Label Text="My Label" FontSize="Large"></Label>
        </StackLayout>
    

    My problem was that if you force the image NOT to cover 100% of its parent view (to cover half the screen for example). then the parent view does not adapt to the height and you end up with blank space. This can be fixed by either binding the height or much simpler by adding an extra container so that the image does take 100% of a parent view like in the following (see result in the other image)

        <StackLayout  BackgroundColor="LightGray">
            <Grid  BackgroundColor="Accent" >
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="*" />
                </Grid.ColumnDefinitions>
                <Grid Grid.Row="0" Grid.Column="0" BackgroundColor="Yellow">
                    <Image x:Name="image"   Aspect="AspectFit" Source="aaa.png" ></Image>
                </Grid>
            </Grid>
            <Label Text="my label" FontSize="Large"></Label>
        </StackLayout>
    


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