Faster method of reading screen pixel in Python than PIL? Faster method of reading screen pixel in Python than PIL? windows windows

Faster method of reading screen pixel in Python than PIL?


This is the PIL's grabscreen source, Its does not accept any parameters, and Its grab the whole screen and convert it to bitmap.

PyImaging_GrabScreenWin32(PyObject* self, PyObject* args){    int width, height;    HBITMAP bitmap;    BITMAPCOREHEADER core;    HDC screen, screen_copy;    PyObject* buffer;    /* step 1: create a memory DC large enough to hold the       entire screen */    screen = CreateDC(";DISPLAY", NULL, NULL, NULL);     screen_copy = CreateCompatibleDC(screen);     width = GetDeviceCaps(screen, HORZRES);    height = GetDeviceCaps(screen, VERTRES);    bitmap = CreateCompatibleBitmap(screen, width, height);    if (!bitmap)        goto error;    if (!SelectObject(screen_copy, bitmap))        goto error;    /* step 2: copy bits into memory DC bitmap */    if (!BitBlt(screen_copy, 0, 0, width, height, screen, 0, 0, SRCCOPY))        goto error;    /* step 3: extract bits from bitmap */    buffer = PyString_FromStringAndSize(NULL, height * ((width*3 + 3) & -4));    if (!buffer)        return NULL;    core.bcSize = sizeof(core);    core.bcWidth = width;    core.bcHeight = height;    core.bcPlanes = 1;    core.bcBitCount = 24;    if (!GetDIBits(screen_copy, bitmap, 0, height, PyString_AS_STRING(buffer),                   (BITMAPINFO*) &core, DIB_RGB_COLORS))        goto error;    DeleteObject(bitmap);    DeleteDC(screen_copy);    DeleteDC(screen);    return Py_BuildValue("(ii)N", width, height, buffer);error:    PyErr_SetString(PyExc_IOError, "screen grab failed");    DeleteDC(screen_copy);    DeleteDC(screen);    return NULL;}

So, when I just go a little deep, found C approach is good

http://msdn.microsoft.com/en-us/library/dd144909(VS.85).aspx

And Python has ctypes, so here is my approach using ctypes (in Windows 10, winnt has been replaced with Windows):

>>> from ctypes import *>>> user= windll.LoadLibrary("c:\\winnt\\system32\\user32.dll") #I am in windows 2000, may be yours will be windows>>> h = user.GetDC(0)>>> gdi= windll.LoadLibrary("c:\\winnt\\system32\\gdi32.dll")>>> gdi.GetPixel(h,1023,767)16777215 #I believe its white color of RGB or BGR value, #FFFFFF (according to msdn it should be RGB)>>> gdi.GetPixel(h,1024,767)-1 #because my screen is only 1024x768

You could write a wrapper for function GetPixel like this

from ctypes import windlldc= windll.user32.GetDC(0)def getpixel(x,y):    return windll.gdi32.GetPixel(dc,x,y)

Then you can use like getpixel(0,0), getpixel(100,0), etc...

PS: Mine is Windows 2000, so I put winnt in the path, you may need to change it to windows or you chould completely remove path, just using user32.dll and gdi32.dll should work too.


Comment on S.Mark's solution: user32 library is already loaded by windll into windll.user32, so instead of the dc = ... line you can do:

def getpixel(x,y):    return gdi.GetPixel(windll.user32.GetDC(0),x,y)

...or preferably:

dc= windll.user32.GetDC(0)


You might be able to do it via SDL (?). Based on this question, SDL can access the screen. And it has python bindings.

Might be worth a shot? If it worked it would certainly be faster than doing a full screen capture in PIL.