字节级别的颜色操作问题

问题描述

您好，

我当前项目还有一个问题：

我想通过对其应用比例来为位图着色。比例的颜色存储在SynchronizedCollection中，以使Thread安全。当我想为我的Bitmap着色时，一切正常，但是位图中的颜色不是刻度的颜色（这应该是不可能的）。所以我认为我对Bitmap的Bytewise操作有问题。我找不到错，所以也许你可以帮助我：

Hello,
I have one more problem with my current project:
I want to color a bitmap by applying a scale to it. The colors of the scale are stored in a SynchronizedCollection, to make things Thread safe. When I want to color my Bitmap everything works fine except, that there are colors in the bitmap which are not in the colors of the scale (which should be impossible). So I think there is something wrong with my Bytewise manipulation of the Bitmap. I can't find the fault, so maybe you can help me:

private unsafe Bitmap COLOR_BMP(double min_press, double max_press, double f_p_b, Bitmap bmp)
        {
            try
            {
                Bitmap result = new Bitmap(bmp.Width, bmp.Height, PixelFormat.Format32bppArgb);
                BitmapData bitmapData = result.LockBits(new Rectangle(0, 0, result.Width, result.Height), ImageLockMode.ReadWrite, result.PixelFormat);
                IntPtr ptr = bitmapData.Scan0;
                int bytesPerPixel = System.Drawing.Bitmap.GetPixelFormatSize(result.PixelFormat) / 8;
                int numBytes = bitmapData.Stride * bmp.Height;
                byte[] rgbValues = new byte[numBytes];
                System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, numBytes);
                int list_ct = 0;

                for (int counter = 0; counter < rgbValues.Length; counter++)
                {
                    if (BR_LIST[list_ct] >= BORDER)
                    {
                        double brightness = BR_LIST[list_ct];
                        double force = brightness * f_p_b;
                        double percent = force / (max_press - min_press);
                        int pos = (int)(percent * (double)SCALE_LIST.Count);
                        Color color = SCALE_LIST[pos];

                        if (counter % 4 == 0)   //A
                            rgbValues[counter] = color.A;
                        if (counter % 4 == 1)   //R
                            rgbValues[counter] = color.R;
                        if (counter % 4 == 2)   //G
                            rgbValues[counter] = color.G;
                        if (counter % 4 == 3)   //B
                        {
                            rgbValues[counter] = color.B;
                            list_ct++;
                        }
                    }
                    else
                    {
                        rgbValues[counter] = 0;
                        counter = counter + 3;
                        list_ct++;
                    }

                }

                System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, numBytes);
                result.UnlockBits(bitmapData);
                return result;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
                return bmp;
            }
        }

BR_LIST []每个像素保存一个值，因此每4个字节有一个值位图



结果如下：







如你所见，图像中有颜色，不在缩放中上面： - （

BR_LIST[] holds one value per pixel, so one value for every 4 bytes of the bitmap

The result looks like this:

CLICK ME

As you can see, there are colors in the image, that are not in the scaling above :-(

推荐答案

if (counter % 4 == 0)   //B    
    rgbValues[counter] = color.B;
if (counter % 4 == 1)   //G
    rgbValues[counter] = color.G;
if (counter % 4 == 2)   //R
    rgbValues[counter] = color.R;
if (counter % 4 == 3)   //A
{
    rgbValues[counter] = color.A;
    list_ct++;
}

这可以解决问题。

This should solve the problem.

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