DrawImage does not expand bitmap correctly

[rafi x]

I've created a BitMap 1 pixel wide & 256 pixel height
when i try to draw this bitmap as 2 pixels wide using:

public void DrawImage(Image image,RectangleF rect)

The bitmap is not drawn correctly. There are white
slim stripes in bitween each bitmap column.
see the simple code below:

   private void Form1_Paint(object sender, 
                                 PaintEventArgs e)
        {
            Graphics gr = e.Graphics;
 
            Bitmap bitmap = new Bitmap(1, 256);
            for (int y = 0; y < 256; y++)
            {
                bitmap.SetPixel(0, y, Color.Red);
            }
 
            RectangleF rectf = new RectangleF();
 
            for (int x = 0; x < 500; x++)
            {
                float factor = 2;
                rectf.X = x*factor;
                rectf.Y = 0;
                rectf.Width = fact;
                rectf.Height = 500;
// should draw bitmap as 2 pixels wide 
// but draws it with white slim stripes in between
                gr.DrawImage(bitmap, rectf);
            }           
        }

[Rabbit]

Shouldn't the rectf.Width be factor? You put fact.

[GaryTexmo]

I took a look at this and yea, it's definitely funny. I did a bit of digging and I think it might have something to do with the InterpolationMode property on the Graphics object. Setting it to NearestNeighbor seemed to remove the smoothing, but it also appeared to cut the scaling in half (width wise) sometimes plus or minus one pixel. It was actually quite odd.

Maybe try playing around with that setting but another thing I stumbled across was the idea of using transforms. There should be one for scaling that might help you out. I've never actually used them (except a brief and failed experiment with rotations) but it's an avenue of exploration.