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smwhotjay 2017-09-30
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还有硬件限制，是不是u太渣了？获得多个点，觉得单线程不给力？那就多线程采集
赵4老师 2017-09-30
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使用电脑计时有时误差会很大，因为待测程序段的运行会影响电脑时钟。
将待测程序段循环足够多次，手动掐秒表计时可能更准确。
赵4老师 2017-09-29
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那就正常。
schlafenhamster 2017-09-29
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“1点17ms“”
你是说 GetPixel ？
whhvc 2017-09-28
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多个点一起读一共花17毫秒，大概50个点一起读一共花17毫秒，读一点也是17毫秒
赵4老师 2017-09-28
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单独读一个点十几毫秒很正常，紧接着再读同一个位图中的另一个点仍用十几毫秒就不正常了。
whhvc 2017-09-28
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//**********创建一个与窗口描述表兼容的位图
hbitmap=CreateCompatibleBitmap(hWndDc, nWidth , nHeight);
//*********把窗口的位图考到内存中***********
holdmap=(HBITMAP)SelectObject(hmemdc,hbitmap);
//得到窗口位图的HANDLE；
BitBlt(hmemdc,0,0,nWidth ,nHeight,hWndDc,nposx,nposy,SRCCOPY);
hbitmap=(HBITMAP)SelectObject(hmemdc,holdmap);
转到bitmap 再读出来也是这个时间，多个点一起读也是17毫秒样子
worldy 2017-09-27
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1点17ms太夸张了，使用GetDIBits函数试试
GetDIBits
The GetDIBits function retrieves the bits of the specified bitmap and copies them into a buffer using the specified format.
int GetDIBits(
HDC hdc, // handle to device context
HBITMAP hbmp, // handle to bitmap
UINT uStartScan, // first scan line to set in destination bitmap
UINT cScanLines, // number of scan lines to copy
LPVOID lpvBits, // address of array for bitmap bits
LPBITMAPINFO lpbi, // address of structure with bitmap data
UINT uUsage // RGB or palette index
);
Parameters
hdc
Handle to the device context.
hbmp
Handle to the bitmap.
uStartScan
Specifies the first scan line to retrieve.
cScanLines
Specifies the number of scan lines to retrieve.
lpvBits
Pointer to a buffer to receive the bitmap data. If this parameter is NULL, the function passes the dimensions and format of the bitmap to the BITMAPINFO structure pointed to by the lpbi parameter.
lpbi
Pointer to a BITMAPINFO structure that specifies the desired format for the device-independent bitmap (DIB) data.
uUsage
Specifies the format of the bmiColors member of the BITMAPINFO structure. It must be one of the following values: Value Meaning
DIB_PAL_COLORS The color table should consist of an array of 16-bit indexes into the current logical palette.
DIB_RGB_COLORS The color table should consist of literal red, green, blue (RGB) values.
Return Values
If the lpvBits parameter is non-NULL and the function succeeds, the return value is the number of scan lines copied from the bitmap.
Windows 95 and Windows 98: If the lpvBits parameter is NULL and GetDIBits successfully fills the BITMAPINFO structure, the return value is the total number of scan lines in the bitmap.
Windows NT: If the lpvBits parameter is NULL and GetDIBits successfully fills the BITMAPINFO structure, the return value is non-zero.
If the function fails, the return value is zero.
Windows NT: To get extended error information, callGetLastError.
Remarks
If the requested format for the DIB matches its internal format, the RGB values for the bitmap are copied. If the requested format doesn't match the internal format, a color table is synthesized. The following table describes the color table synthesized for each format.
Value Meaning
1_BPP The color table consists of a black and a white entry.
4_BPP The color table consists of a mix of colors identical to the standard VGA palette.
8_BPP The color table consists of a general mix of 256 colors defined by GDI. (Included in these 256 colors are the 20 colors found in the default logical palette.)
24_BPP No color table is returned.
If the lpvBits parameter is a valid pointer, the first six members of the bitmap information header structure must be initialized to specify the size and format of the DIB.
Note A bitmap information header structure may be one of the following:
Operating System Bitmap Information Header
Windows NT 3.51 and earlier BITMAPINFOHEADER
Windows NT 4.0 and Windows 95 BITMAPV4HEADER
Windows NT 5.0 and Windows 98 BITMAPV5HEADER
A bottom-up DIB is specified by setting the height to a positive number, while a top-down DIB is specified by setting the height to a negative number. The bitmap's color table will be appended to the BITMAPINFO structure.
If lpvBits is NULL, GetDIBits examines the first member of the first structure pointed to by lpbi. This member must specify the size, in bytes, of a BITMAPCOREHEADER or a bitmap information header structure. The function uses the specified size to determine how the remaining members should be initialized.
If lpvBits is NULL and the bit count member of BITMAPINFO is initialized to zero, GetDIBits fills in a bitmap information header structure or BITMAPCOREHEADER without the color table. This technique can be used to query bitmap attributes.
The bitmap identified by the hbmp parameter must not be selected into a device context when the application calls this function.
The origin for a bottom-up DIB is the lower-left corner of the bitmap; the origin for a top-down DIB is the upper-left corner.
