Question

This is my bitmap creation code

public static Bitmap Plot24(ref byte[] bufferArray, int lengthOfBufferArray, String fileName)
    {
        int position = 0;      

        int rows = (int)Math.Ceiling((double)lengthOfBufferArray / (3*columns) );

        Bitmap b = new Bitmap(columns , rows, PixelFormat.Format24bppRgb);
        BitmapData bmd = b.LockBits(new Rectangle(0, 0, columns , rows), ImageLockMode.ReadWrite, b.PixelFormat); 

            unsafe
            {
                for (int j = 0; j < rows; j++)
                {                    
                    byte* row = (byte*)bmd.Scan0 + ((j * bmd.Stride) ); 

                    for (int i = 0; i < columns*3; i+=3)
                    {                                                
                        if (position < lengthOfBufferArray)
                        {                                                                         

                            try
                            {
                                row[i+2] = bufferArray[position];
                                position++;
                                if (position < lengthOfBufferArray)
                                {
                                    row[i+1] = bufferArray[position];
                                    position++;
                                }
                                else
                                {                                   
                                    break;                                       
                                }

                                if (position < lengthOfBufferArray)
                                {
                                    row[i] = bufferArray[position];
                                    position++;
                                }
                                else
                                {                                       
                                    break;                               
                                }
                            }
                            catch (Exception e)
                            {
                                Console.WriteLine(e.ToString());

                            }
                        }
                    }
                }

                b.UnlockBits(bmd);

                return b;
            } 
    }

And this is how i save the returned bitmap

 b.Save(outputFilename, ImageFormat.Bmp);

When i have all FF hexadecimals in the bufferArray still the white pixels are not that white.

And when i have random values in the bufferArray other colors also look like they are washed away.

How can i make it save in the normal brightness level ?

Answer 1

I tested your sample code and it worked just fine. I have an excerpt of you sample at the bottom of mine with some slight modification to the method parameters.

Could you supply in your question a sample of how you use your Plot24 method? Maybe the problem lies there.

    void Main()
    {
        int rows = 100;
        int columns = 100;

        var random = new Random(DateTime.Now.Ticks.GetHashCode());

        byte[] bytes = Enumerable
            .Range(0, columns * rows)

            // White
            .SelectMany(i => new[] { (byte)0xFF, (byte)0xFF, (byte)0xFF, } )

            // Random
            /*.SelectMany(i => 
                {
                    byte[] buffer = new byte[3];
                    random.NextBytes(buffer);
                    return buffer; 
                })*/

            .ToArray();

        using (var bm = Plot24(ref bytes, columns))
        {
            bm.Save(@"c:\test.bmp", ImageFormat.Bmp);
        }
    }

    public static Bitmap Plot24(ref byte[] bufferArray, int columns)
    {
        int position = 0;      
        int lengthOfBufferArray = bufferArray.Length;

        int rows = (int)Math.Ceiling((double)lengthOfBufferArray / (3*columns) );
        // ... the rest of your code is just fine