以下是图片的结构:
File Header
Info Header
Image Data

Start Size Name stdvalue Meaning
0 2 Type 0x424D Must be "BM" to mean Bitmap
2 4 Size -- Size of the file in bytes
6 2 Reserved1 0 Must be 0
8 2 Reserved2 0 Must be 0
10 4 Offset 1078 Offset from byte 0 to bitmap data

The format for the Info Header is:
Start Size Name stdvalue Meaning
14 4 Size 40 The size of this header, in bytes
18 4 Width -- Width of the image in pixels
22 4 Height -- Height of the image in pixels
26 2 Planes 1 Number of planes in target (must be 0)
28 2 BitCount 8 Number of bits per pixel
30 4 Compression 0 Type of compression (0 = none)
34 4 SizeImage 0 Size of image data (0 if no compression)
38 4 XPelsPerMeter 0 Horizontal pixels per meter
42 4 YPelsPerMeter 0 Vertical pixels per meter
46 4 ClrUsed 0 Number of colors (if 0, calculated from BitCount)
50 4 ClrImportant 0 Number of important colors (if 0, all are important)

请教如何如何算出蓝绿红每种象素的平均值啊?