RenderTargetBitmap doesn't seem to render my rectangle

Question

I have the following code:

        LinearGradientBrush linGrBrush = new LinearGradientBrush();
        linGrBrush.StartPoint = new Point(0,0);
        linGrB         


        

Answer 1

Arrange has to be called after Measure, and the Rect values should be passed correctly.

Instead of

rect.Arrange(new Rect(0, 0, 1, 1000)); // wrong width and height
rect.Measure(new Size(1000, 1));

you should do

var rect = new Rectangle { Fill = linGrBrush };
var size = new Size(1000, 1);
rect.Measure(size);
rect.Arrange(new Rect(size));

var bmp = new RenderTargetBitmap(1000, 1, 96, 96, PixelFormats.Pbgra32);
bmp.Render(rect);