How to create 1024x1024 RGB bitmap image of white?

Question

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, PixelFormat.Format24bppRgb);

using (Graphics grp = Graphics.FromImage(resultImage)) 
{
    grp.FillRectangle(
        Brushes.White, 0, 0, image1.Width, image1.Height);
    resultImage = new Bitmap(image1.Width, image1.Height, grp);
}

I basically want to fill a 1024x1024 RGB bitmap image with white in C#. How can I do that?

You are looking solution for your problem but my problem solved with your code, thanks :) — muratoner, May 07 '18 at 07:47

score 46 · Answer 1 · edited Jan 08 '17 at 15:11

46

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;
}

edited Jan 08 '17 at 15:11

Uwe Keim

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answered Sep 19 '12 at 20:35

Lee Harrison

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score 35 · Accepted Answer · answered Sep 19 '12 at 20:30

35

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);

answered Sep 19 '12 at 20:30

Joey

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prashanth · Answer 3 · 2012-09-19T21:14:00.447

23

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);

edited Sep 19 '12 at 21:14

answered Sep 19 '12 at 21:05

prashanth

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1

I like this approach! Thanks! – NoWar Nov 24 '14 at 12:54
4

Careful! When you use `Color.FromArgb()` you will get a gradient when scaling the bitmap. Better use the [solution](http://stackoverflow.com/a/12502497/489772) from @LeeHarrison. – Jan Feb 16 '15 at 20:32

score 5 · Answer 4 · answered Mar 12 '19 at 06:27

5

Graphics.Clear(Color)

Bitmap bmp = new Bitmap(1024, 1024);
using (Graphics g = Graphics.FromImage(bmp)){g.Clear(Color.White);}

answered Mar 12 '19 at 06:27

Top Systems

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score 1 · Answer 5 · answered Jan 16 '21 at 23:25

Depending on your needs, a BitmapSource might suit. You can quickly fill a byte array with the 0xff (i.e. white) using Enumerable.Repeat().

int w = 1024;
int h = 1024;
byte[] pix = Enumerable.Repeat((byte)0xff, w * h * 4).ToArray();
SomeImage.Source = BitmapSource.Create(w, h, 96, 96, PixelFormats.Pbgra32, null, pix, w * 4);

How to create 1024x1024 RGB bitmap image of white?

5 Answers5

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