我有一个方法需要尽可能快,它使用不安全的内存指针,这是我第一次尝试这种类型的编码,所以我知道它可能会更快。
/// <summary>
/// Copies bitmapdata from one bitmap to another at a specified point on the output bitmapdata
/// </summary>
/// <param name="sourcebtmpdata">The sourcebitmap must be smaller that the destbitmap</param>
/// <param name="destbtmpdata"></param>
/// <param name="point">The point on the destination bitmap to draw at</param>
private static unsafe void CopyBitmapToDest(BitmapData sourcebtmpdata, BitmapData destbtmpdata, Point point)
{
// calculate total number of rows to draw.
var totalRow = Math.Min(
destbtmpdata.Height - point.Y,
sourcebtmpdata.Height);
//loop through each row on the source bitmap and get mem pointers
//to the source bitmap and dest bitmap
for (int i = 0; i < totalRow; i++)
{
int destRow = point.Y + i;
//get the pointer to the start of the current pixel "row" on the output image
byte* destRowPtr = (byte*)destbtmpdata.Scan0 + (destRow * destbtmpdata.Stride);
//get the pointer to the start of the FIRST pixel row on the source image
byte* srcRowPtr = (byte*)sourcebtmpdata.Scan0 + (i * sourcebtmpdata.Stride);
int pointX = point.X;
//the rowSize is pre-computed before the loop to improve performance
int rowSize = Math.Min(destbtmpdata.Width - pointX, sourcebtmpdata.Width);
//for each row each set each pixel
for (int j = 0; j < rowSize; j++)
{
int firstBlueByte = ((pointX + j)*3);
int srcByte = j *3;
destRowPtr[(firstBlueByte)] = srcRowPtr[srcByte];
destRowPtr[(firstBlueByte) + 1] = srcRowPtr[srcByte + 1];
destRowPtr[(firstBlueByte) + 2] = srcRowPtr[srcByte + 2];
}
}
}
那么有什么办法可以让这更快吗?暂时忽略待办事项,等我有一些基线性能测量后,我会修复它。
更新:对不起,应该提到我使用它而不是 Graphics.DrawImage 的原因是因为我实现了多线程,因此我不能使用 DrawImage。
更新 2:我仍然对性能不满意,而且我敢肯定还有更多毫秒的时间。