假设我有两个具有相同高度和宽度的图像。pic1.jpg 和 pic2.jpg。两个图像看起来非常相似，差异最小。在下面的例程的帮助下，我们可以得到两个图像之间的区别。下面的例程不是我的例程。
public class ImageDifferences
{
private static ILog mLog = LogManager.GetLogger("ImageDifferences");
public static unsafe Bitmap PixelDiff(Image a, Image b)
{
if (!a.Size.Equals(b.Size)) return null;
if (!(a is Bitmap) || !(b is Bitmap)) return null;
return PixelDiff(a as Bitmap, b as Bitmap);
}
public static unsafe Bitmap PixelDiff(Bitmap a, Bitmap b)
{
Bitmap output = new Bitmap(
Math.Max(a.Width, b.Width),
Math.Max(a.Height, b.Height),
PixelFormat.Format32bppArgb);
Rectangle recta = new Rectangle(Point.Empty, a.Size);
Rectangle rectb = new Rectangle(Point.Empty, b.Size);
Rectangle rectOutput = new Rectangle(Point.Empty, output.Size);
BitmapData aData = a.LockBits(recta, ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
BitmapData bData = b.LockBits(rectb, ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
BitmapData outputData = output.LockBits(rectOutput, ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
try
{
byte* aPtr = (byte*)aData.Scan0;
byte* bPtr = (byte*)bData.Scan0;
byte* outputPtr = (byte*)outputData.Scan0;
int len = aData.Stride * aData.Height;
for (int i = 0; i < len; i++)
{
// For alpha use the average of both images (otherwise pixels with the same alpha won't be visible)
if ((i + 1) % 4 == 0)
*outputPtr = (byte)((*aPtr + *bPtr) / 2);
else
*outputPtr = (byte)~(*aPtr ^ *bPtr);
outputPtr++;
aPtr++;
bPtr++;
}
return output;
}
catch (Exception ex)
{
return null;
}
finally
{
a.UnlockBits(aData);
b.UnlockBits(bData);
output.UnlockBits(outputData);
}
}
}
}
在获得差异后，我如何合并第一张图像上的差异。
这下面我们可以合并
using (Graphics grfx = Graphics.FromImage(image))
{
grfx.DrawImage(newImage, x, y)
}
但我们需要知道新图像将在第一张图像上绘制的 x 和 y。谁能告诉我如何从上述称为PixelDiff()的例程中获取 x 和 y 位置，谢谢。