我正在尝试将 3 个灰度位图组合成一个颜色位图。所有三个灰度图像的大小相同(这是基于来自哈勃的数据)。我的逻辑是:加载“蓝色”图像并转换为PixelFormat.Format24bppRgb
. 基于此,创建一个新的字节数组,其大小是蓝色数据数组长度/3 的 4 倍(因此它将是一个蓝色字节,一个绿色字节,一个红色字节,一个字节每个像素的 alpha,因为我的系统是小端)。从蓝色图像的“蓝色”字节填充数组的“蓝色”字节(在第一个循环中,将 alpha 字节设置为 255)。然后我加载绿色和红色位图,将它们转换为PixelFormat.Format24bppRgb
,然后提取 g/r 值并将其添加到数据数组中的正确位置。然后,根据我的判断,最终的数据数组正确设置了 bgra 字节。
当我填充了数据数组时,我用它来:
创建一个PixelFormats.Bgra32 BitmapSource
然后将其转换为位图。
PixelFormat.Format32bppArgb
使用 Bitmap 构造函数(宽度、高度、步幅、PixelForma、IntPtr)创建位图
PixelFormat.Format32bppArgb
使用指针创建位图
创建返回位图的所有三种方式都会导致图像“倾斜”(抱歉,我不知道更好的词)。
实际输出(生成最终位图的所有三种方式)是:实际输出
所需的输出类似于(这是在 Photoshop 中完成的,因此略有不同):所需的输出
三个文件名 ( _blueFileName, _greenFileName, _redFileName
) 在构造函数中设置,我在创建类之前检查以确保文件存在。如果有人想要,我可以发布该代码。
谁能告诉我我做错了什么?我猜这是由于步幅或类似的原因?
注意:我无法发布指向我用作输入的图像的链接,因为我没有 10 个声望点。如果有人也想要它们,也许我可以通过电子邮件或其他方式发送链接。
这是我的代码(注释掉了一些东西,注释描述了如果使用每个注释掉的块会发生什么):
public Bitmap Merge()
{
// Load original "blue" bitmap.
Bitmap tblueBitmap = (Bitmap)Image.FromFile(_blueFileName);
int width = tblueBitmap.Width;
int height = tblueBitmap.Height;
// Convert to 24 bpp rgb (which is bgr on little endian machines)
Bitmap blueBitmap = new Bitmap(width, height, PixelFormat.Format24bppRgb);
using (Graphics gr = Graphics.FromImage(blueBitmap))
{
gr.DrawImage(tblueBitmap, 0, 0, width, height);
}
tblueBitmap.Dispose();
// Lock and copy to byte array.
BitmapData blueData = blueBitmap.LockBits(new Rectangle(0, 0, blueBitmap.Width, blueBitmap.Height), ImageLockMode.ReadOnly,
blueBitmap.PixelFormat);
int numbBytes = blueData.Stride*blueBitmap.Height;
byte[] blueBytes = new byte[numbBytes];
Marshal.Copy(blueData.Scan0, blueBytes, 0, numbBytes);
blueBitmap.UnlockBits(blueData);
blueData = null;
blueBitmap.Dispose();
int mult = 4;
byte[] data = new byte[(numbBytes/3)*mult];
int count = 0;
// Copy every third byte starting at 0 to the final data array (data).
for (int i = 0; i < data.Length / mult; i++)
{
// Check for overflow
if (blueBytes.Length <= count*3 + 2)
{
continue;
}
// First pass, set Alpha channel.
data[i * mult + 3] = 255;
// Set blue byte.
data[i*mult] = blueBytes[count*3];
count++;
}
// Cleanup.
blueBytes = null;
int generation = GC.GetGeneration(this);
GC.Collect(generation);
Bitmap tgreenBitmap = (Bitmap)Image.FromFile(_greenFileName);
Bitmap greenBitmap = new Bitmap(width, height, PixelFormat.Format24bppRgb);
using (Graphics gr = Graphics.FromImage(greenBitmap))
{
gr.DrawImage(tgreenBitmap, 0, 0, width, height);
}
tgreenBitmap.Dispose();
BitmapData greenData = greenBitmap.LockBits(new Rectangle(0, 0, greenBitmap.Width, greenBitmap.Height), ImageLockMode.ReadOnly,
greenBitmap.PixelFormat);
numbBytes = greenData.Stride * greenBitmap.Height;
byte[] greenBytes = new byte[numbBytes];
Marshal.Copy(greenData.Scan0, greenBytes, 0, numbBytes);
greenBitmap.UnlockBits(greenData);
greenData = null;
greenBitmap.Dispose();
count = 0;
for (int i = 0; i < data.Length / mult; i++)
{
if (greenBytes.Length <= count * 3 + 1)
{
continue;
}
// Set green byte
data[i * mult + 1] = greenBytes[count * 3 + 1];
count++;
}
greenBytes = null;
generation = GC.GetGeneration(this);
GC.Collect(generation);
Bitmap tredBitmap = (Bitmap)Image.FromFile(_redFileName);
Bitmap redBitmap = new Bitmap(width, height, PixelFormat.Format24bppRgb);
using (Graphics gr = Graphics.FromImage(redBitmap))
{
gr.DrawImage(tredBitmap, 0, 0, width, height);
}
tredBitmap.Dispose();
BitmapData redData = redBitmap.LockBits(new Rectangle(0, 0, redBitmap.Width, redBitmap.Height), ImageLockMode.ReadOnly,
redBitmap.PixelFormat);
numbBytes = redData.Stride * redBitmap.Height;
byte[] redBytes = new byte[numbBytes];
Marshal.Copy(redData.Scan0, redBytes, 0, numbBytes);
redBitmap.UnlockBits(redData);
redData = null;
redBitmap.Dispose();
count = 0;
for (int i = 0; i < data.Length / mult; i++)
{
if (redBytes.Length <= count * 3+2)
{
count++;
continue;
}
// set red byte
data[i * mult + 2] = redBytes[count * 3 + 2];
count++;
}
redBytes = null;
generation = GC.GetGeneration(this);
GC.Collect(generation);
int stride = (width*32 + 7)/8;
var bi = BitmapSource.Create(width, height, 96, 96, PixelFormats.Bgra32, null, data, stride);
// uncomment out below to see what a bitmap source to bitmap does. So far, it is exactly the same as
// the uncommented out lines below.
// ---------------------------------------------------------------------------------------------------
//return BitmapImage2Bitmap(bi);
unsafe
{
fixed (byte* p = data)
{
IntPtr ptr = (IntPtr)p;
// Trying the commented out lines returns the same bitmap as the uncommented out lines.
// ------------------------------------------------------------------------------------
byte* p2 = (byte*)ptr;
Bitmap retBitmap = new Bitmap(width, height, PixelFormat.Format32bppArgb);
BitmapData fData = retBitmap.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite,
PixelFormat.Format32bppArgb);
unsafe
{
for (int i = 0; i < fData.Height; i++)
{
byte* imgPtr = (byte*)(fData.Scan0 + (fData.Stride * i));
for (int x = 0; x < fData.Width; x++)
{
for (int ii = 0; ii < 4; ii++)
{
*imgPtr++ = *p2++;
}
//*imgPtr++ = 255;
}
}
}
retBitmap.UnlockBits(fData);
//Bitmap retBitmap = new Bitmap(width, height, GetStride(width, PixelFormat.Format32bppArgb),
// PixelFormat.Format32bppArgb, ptr);
return retBitmap;
}
}
}
private Bitmap BitmapImage2Bitmap(BitmapSource bitmapSrc)
{
using (MemoryStream outStream = new MemoryStream())
{
BitmapEncoder enc = new BmpBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create(bitmapSrc));
enc.Save(outStream);
Bitmap bitmap = new Bitmap(outStream);
return new Bitmap(bitmap);
}
}
private int GetStride(int width, PixelFormat pxFormat)
{
int bitsPerPixel = ((int)pxFormat >> 8) & 0xFF;
int validBitsPerLine = width * bitsPerPixel;
int stride = ((validBitsPerLine + 31) / 32) * 4;
return stride;
}