generate random number between two numbers

Question

I am coding a program that is generating binary(black n white) image . The ARGB(Alpha,Red,Green,Blue) for the white color is(0,255,255,255) and (0,0,0,0) for the black color . so I am using Random number to generate the binary bitmap

int a = rnd.Next(256);
int r = rnd.Next(256);
int g = rnd.Next(256);
int b = rnd.Next(256);

but with this range of numbers it will generate a colors image , so I only need Random numbers that are 0 or 255 , no thing between them . Remember it's a binary not a scale-gray image .

Generate a random int between 0 and 2 (so either 0 or 1) and multiply with 255. — Niko, Oct 23 '14 at 19:19
Generate random number between 0 and 1, if it is 0 then 0, if it is 1 then it is 255!! — stackunderflow, Oct 23 '14 at 19:21
Officially both values are transparent, Transparent white and transparent black :). Don't you mean `(255,255,255,255)` and `(255,0,0,0)`? — Silvermind, Oct 23 '14 at 19:26

Dmitry · Answer 1 · 2014-10-23T19:30:26.153

7

The simplest way is:

int a = 255;
int r = rnd.Next(2) * 255;
int g = r;
int b = r;

Or you can achieve the same via:

Color color = rnd.Next(2) == 0 ? Color.Black : Color.White;

edited Oct 23 '14 at 19:30

answered Oct 23 '14 at 19:19

Dmitry

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The first code will give you a variation of eight different colors. You should get a single random number and use for all three components. – Guffa Oct 23 '14 at 19:29
@Guffa Oops, you are right. Fixed it. Thank you. – Dmitry Oct 23 '14 at 19:30
1

Fix it again. You are assigning `b` to `b`. :) – Guffa Oct 23 '14 at 19:31
@Guffa And thank you very much again. I'm so sloppy, shame on me! – Dmitry Oct 23 '14 at 19:33

score 1 · Answer 2 · edited Oct 23 '14 at 23:52

1

Thank you all guys :) this way has worked with me :-

for (int y = 0; y < height; y++)
{
    for (int x = 0; x < width; x++)
    {
        pixel_color = rnd.Next(0, 2);
        if (pixel_color == 0)
        {
            r = 0;
            g = 0;
            b = 0;
        }
        else
        {
            r = 255;
            g = 255;
            b = 255;
        }
        bmp.SetPixel(x, y, Color.FromArgb(r, g, b));
    }
}

edited Oct 23 '14 at 23:52

Lee Taylor

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answered Oct 23 '14 at 21:30

Ãhmëd Säßrý

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Instead of posting essentially duplicate answer you should commented/voted/accepted existing answer. At very least you should show updating raw bits of bitmap as `SetPixel` is one of the slowest function you can use. – Alexei Levenkov Oct 24 '14 at 06:03

generate random number between two numbers

2 Answers2