使用 GetPixel 和 SetPixel 很简单,但速度很慢,因此我尝试使用 LockBits。
我很久以前就用过这个方法来比较两个图像:
public static Bitmap FastComparison(Bitmap bmp1,Bitmap bmp2)
{
tolerancenumeric = 15;
int tolerance = tolerancenumeric * tolerancenumeric +
tolerancenumeric * tolerancenumeric +
tolerancenumeric * tolerancenumeric; //dr * dr + dg * dg + db * db;
bmp3 = new Bitmap(512,512);
PixelFormat pxf = PixelFormat.Format24bppRgb;
Rectangle rect = new Rectangle(0, 0, bmp1.Width, bmp1.Height);
BitmapData bmpData1 = bmp1.LockBits(rect, ImageLockMode.ReadWrite, pxf);
BitmapData bmpData2 = bmp2.LockBits(rect, ImageLockMode.ReadWrite, pxf);
BitmapData bmpData3 = bmp3.LockBits(rect, ImageLockMode.ReadWrite, pxf);
IntPtr ptr1 = bmpData1.Scan0;
IntPtr ptr2 = bmpData2.Scan0;
IntPtr ptr3 = bmpData3.Scan0;
int numBytes = bmpData1.Stride * bmp1.Height;
byte[] rgbValues1 = new byte[numBytes];
Marshal.Copy(ptr1, rgbValues1, 0, numBytes);
bmp1.UnlockBits(bmpData1);
byte[] rgbValues2 = new byte[numBytes];
Marshal.Copy(ptr2, rgbValues2, 0, numBytes);
bmp2.UnlockBits(bmpData2);
for (int counter = 0; counter < rgbValues1.Length; counter += 3)
{
int dr, dg, db;
dr = (int)rgbValues2[counter] - (int)rgbValues1[counter];
dg = (int)rgbValues2[counter + 1] - (int)rgbValues1[counter + 1];
db = (int)rgbValues2[counter + 2] - (int)rgbValues1[counter + 2];
int error = dr * dr + dg * dg + db * db;
int y, x;
y = (counter / 3) / 512;
x = (counter - y * 512 * 3)/3;
if ((x == 479) && (y == 474))
{
Byte r1, g1, b1, r2, g2, b2;
r1 = rgbValues1[counter];
b1 = rgbValues1[counter+1];
g1 = rgbValues1[counter+2];
r2 = rgbValues2[counter];
b2 = rgbValues2[counter+1];
g2 = rgbValues2[counter+2];
}
if (error < tolerance)
{
rgbValues1[counter] = 0;
rgbValues1[counter + 1] = 0;
rgbValues1[counter + 2] = 0;
}
}
Marshal.Copy(rgbValues1, 0, ptr3, numBytes);
bmp3.UnlockBits(bmpData3);
return bmp3;
}
但现在我想也使用 LockBits,但只使用一张图像,并将所有非黑色像素着色为黄色。
我开始了新方法:
public Bitmap ChangeColors(Bitmap bmp1)
{
bmpColors = new Bitmap(512, 512);
PixelFormat pxf = PixelFormat.Format24bppRgb;
Rectangle rect = new Rectangle(0, 0, bmp1.Width, bmp1.Height);
BitmapData bmpData1 = bmp1.LockBits(rect, ImageLockMode.ReadWrite, pxf);
IntPtr ptr1 = bmpData1.Scan0;
int numBytes = bmpData1.Stride * bmp1.Height;
byte[] rgbValues1 = new byte[numBytes];
Marshal.Copy(ptr1, rgbValues1, 0, numBytes);
bmp1.UnlockBits(bmpData1);
for (int counter = 0; counter < rgbValues1.Length; counter += 3)
{
int y, x;
y = (counter / 3) / 512;
x = (counter - y * 512 * 3) / 3;
Byte r1, g1, b1;
r1 = rgbValues1[counter];
b1 = rgbValues1[counter + 1];
g1 = rgbValues1[counter + 2];
}
return bmpColors;
}
但不知道如何制作,以便位图 bmpColors 将是原始的,但所有像素不是黑色的,而是黄色的。
最佳答案
简单地测试字节并相应地设置它们怎么样?
Byte r1, g1, b1;
r1 = rgbValues1[counter]; // should be + 2 !!
b1 = rgbValues1[counter + 1]; // should be + 0 !!
g1 = rgbValues1[counter + 2]; // should be + 1 !!
if (r1 + b1 + g1 == 0 )
{
r1 = 255;
g1 = 255;
}
当然,这假设您可以接受真正的黑色和基本的黄色。
如果您需要更多控制,则需要更多代码,例如
if (r1 + b1 + g1 < threshold)
对于黑色阴影,对于黄色可能:
r1 = myYellow_R;
g1 = myYellow_G;
b1 = myYellow_B;
顺便说一句:您需要检查这些索引;上次我查看 LockBits 数组中的数据时,反转了:不是 RGB
(更不用说 RBG
了),而是 >BGR
! (对于 32bpp BGRA
!)
由于您使用的是旧方法,因此还请确保您的像素格式没问题;如果是 32bpp
,您将需要进行一些简单的修改。
关于c# - 如何使用 LockBits 将位图中非黑色的像素着色为黄色?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25976620/