CODEWITHSUNDEEP
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simon
simon

Reputation: 1191

Inverting color depending on the background windows and desktop

I have a transparent wpf window ( WindowStyle="None" ) with black label. I need to make that label change its color dynamically, depending on the background of the content below my window (other windows, desktop), so it will be always visible and contrast.

How can this be implemented? Do I need to make a screenshot and read color values from there or there is some way to do it with WPF tools?

Will it be more difficult if label has a gradient?

Upvotes: 2

Views: 2077

Answers (1)

NathanAW
NathanAW

Reputation: 3367

I don't suppose it's an option to make the text of the label have a contrasting outline around the letters?

You can sort of do this with a drop shadow type effect that uses a contrasting color to make (for example), black text have a white border.

<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid Background="Black">  
    <TextBlock Text="This is some text" FontSize="24" Margin="30" Foreground="Black" FontWeight="Bold">
      <TextBlock.Effect>
        <DropShadowEffect ShadowDepth="0" Opacity="1" BlurRadius="4" Color="White"/>
      </TextBlock.Effect>
    </TextBlock>
  </Grid>
</Page>

The drop shadow isn't exactly well defined, but something like this is very visible. The code's not pretty, but it works. Maybe someone else has a better idea how to get this to work using a built in effect or something.

<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid Background="Black">  
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="28,30" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="32,30" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="30,28" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="30,32" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="28,28" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="32,32" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="32,28" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="28,32" Foreground="White" />
    <TextBlock Text="This is some text" FontWeight="Bold" FontSize="24" Margin="30" Foreground="Black"></TextBlock>
  </Grid>
</Page>

EDIT

MSDN has info on creating outlined text using WPFs ability to convert text to geometries, or to simply creating formatted text.

Upvotes: 2

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