How to draw a line on an existing BitmapSource in WPF? - wpf

Question

I would like to draw a line (or any geometric shape) on an existing BitmapSource object in my WPF application. What is the best way to do it ?
The BitmapSource is the result of a BitmapSource.Create(...) call.
Thanks
Romain

Answer 1

Below sample will display an image created from a BitmapSource with a red line on top of it. Is that what you are trying to achieve?
XAML:
<Window x:Class="WpfApplication.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid Background="LightBlue">
<Image Source="{Binding Path=ImageSource}" />
<Line
Stroke="Red" StrokeThickness="10"
X1="0"
Y1="0"
X2="{Binding Path=ActualWidth, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Grid}}}"
Y2="{Binding Path=ActualHeight, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Grid}}}" />
</Grid>
</Window>
Code behind:
using System;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
namespace WpfApplication
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
DataContext = this;
}
public BitmapSource ImageSource
{
get
{
PixelFormat pf = PixelFormats.Bgr32;
int width = 200;
int height = 200;
int rawStride = (width * pf.BitsPerPixel + 7) / 8;
byte[] rawImage = new byte[rawStride * height];
Random value = new Random();
value.NextBytes(rawImage);
return BitmapSource.Create(width, height, 96, 96, pf, null, rawImage, rawStride);
}
}
}
}