IDrawable mouse event

I have simple canvas that create one red line

xaml

 <ContentPage.Resources>
        <drawable:GraphicsDrawable  x:Key="drawable" />
    </ContentPage.Resources>

    <GraphicsView Drawable="{StaticResource drawable}"/>

cs

public class GraphicsDrawable : IDrawable
{
    public void Draw(ICanvas canvas, RectF dirtyRect)
    {
        canvas.StrokeColor = Colors.Red;
        canvas.StrokeSize = 6;
        canvas.DrawLine(10, 10, 99999, 10000);
        canvas.FillColor = Colors.Red;
    }
}

But how can I implement mouse event? Basically I want to get coordinates of place on canvas where I clicked how can I do this?