It\'s embarrassing to ask this question but can\'t find an answer.
I tried this in vain.
Image resultImage = new Bitmap(image1.Width, image1.Height,
You are assigning a new image to resultImage
, thereby overwriting your previous attempt at creating a white image (which should succeed, by the way).
So just remove the line
resultImage = new Bitmap(image1.Width, image1.Height, grp);
You almost had it:
private Bitmap DrawFilledRectangle(int x, int y)
{
Bitmap bmp = new Bitmap(x, y);
using (Graphics graph = Graphics.FromImage(bmp))
{
Rectangle ImageSize = new Rectangle(0,0,x,y);
graph.FillRectangle(Brushes.White, ImageSize);
}
return bmp;
}
Another approach,
Create a unit bitmap
var b = new Bitmap(1, 1);
b.SetPixel(0, 0, Color.White);
And scale it
var result = new Bitmap(b, 1024, 1024);
Graphics.Clear(Color)
Bitmap bmp = new Bitmap(1024, 1024);
using (Graphics g = Graphics.FromImage(bmp)){g.Clear(Color.White);}