Xamarin.Forms: Tiny icons are getting cut ever so slightly when size is set with grid value - xaml

Question

this is a simple grid with a tiny button in it:
<!--ReverseButton-->
<Grid Grid.Row="1" RowSpacing="0" >
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="5*"/>
<ColumnDefinition Width="1*"/>
</Grid.ColumnDefinitions>
<ImageButton
Source="btn_reversed_unpressed"
x:Name="btn_reverse_list_mainmenu"
BackgroundColor="#00000000"
Grid.Column="1"
Clicked="ReverseListForSwipeView"
/>
</Grid>
The size of this Row (row 1) is set here:
<Grid.RowDefinitions>
<RowDefinition Height="auto" />
<RowDefinition Height="0.17*" />
<RowDefinition Height="4.5*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
I set the value to 0.17* to have the button always be very tiny. If i would set the row to "auto" the icon would become much bigger (since the source image is bigger in size)
If I make the size to, lets say 0.25* instead of 0.17* the row and therefore the button both get bigger and everything is fine. (Except now it is too big)
But with size 0.17* it is just about right... Well except for this:
It is quite hard to see, but the icon at the bottom is cut of slightly. The border is not as big as it is on the top.
This I have noticed quite some time now.
I tried setting the rowspacing to 0 or even negative values, but nothing worked.
Why is the icon cut off.
The top part isnt cut and both parts (top and bottom) touch the row end and beginning pixel perfect.

Answer 1

An answer based on my comment above. I suggest setting the HeightRequest of the ImageButton to the size you want the icon to be and then just set the row height to Auto and let the layout manager do the rest. See my example where I create a Grid with 3 rows set to Auto size and then just use the HeightRequest property to have it draw at the correct size. I left the grey background of the button in so you can see how the row sizes dynamically.
<ContentPage.Content>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ImageButton Source="ic_email_dark"
Aspect="AspectFit"
HeightRequest="50"
HorizontalOptions="Fill"
VerticalOptions="Center"
Grid.Row="0" />
<ImageButton Source="ic_email_dark"
Aspect="AspectFit"
HeightRequest="75"
HorizontalOptions="Fill"
VerticalOptions="Center"
Grid.Row="1" />
<ImageButton Source="ic_email_dark"
Aspect="AspectFit"
HeightRequest="100"
HorizontalOptions="Fill"
VerticalOptions="Center"
Grid.Row="2" />
</Grid>
</ContentPage.Content>
Gives the following: