"""Helper functions for Image object."""
from ctypes import *
from ctypes.wintypes import *
gdi = windll.gdi32
def todib(image):
"""Image.tostring('raw', rawmode, stride=0, ystep=1)
    "rawmode" is a pixel format. (ex. RGB, GBR...)
    "stride" is a line buffer size includes padding data.
    "ystep" indicates a vertical direction. If ystep is 1,
    then top to bottom. If ystep is -1, then bottom to top.
    """
if image.mode != 'RGB':
image = image.convert('RGB')
#Note: image.bits != sizeof(encoded pixel)
bits = 24
linesize = (bits * image.size[0] + 7) / 8 # a line size
stride = int((linesize + 3) / 4) * 4 # alignment to sizeof(DWORD)
ystep = -1
return image.tostring('raw', 'BGR', stride, ystep)
class BITMAPINFOHEADER(Structure):
_fields_ = [
('biSize', DWORD),
('biWidth', LONG),
('biHeight', LONG),
('biPlanes', WORD),
('biBitCount', WORD),
('biCompression', DWORD),
('biSizeImage', DWORD),
('biXPelsPerMeter', LONG),
('biYPelsPerMeter', LONG),
('biClrUsed', DWORD),
('biClrImportant', DWORD),
]
def __init__(self, w, h):
self.biSize = sizeof(self)
self.biWidth = w
self.biHeight = h
self.biPlanes = 1
self.biBitCount = 24
self.biSizeImage = w * h * 3
def tohbitmap(image):
"""convert Image object to win32 HBITMAP (int. not
    pywintypes.HANDLE object)
    If you call pywin32's function with result, do below codes:
    >>> from pywintypes import HANDLE
    >>> result = HANDLE(result)
    """
result = 0
hDC = gdi.CreateCompatibleDC(0)
try:
dataptr = c_void_p()
result = gdi.CreateDIBSection(
hDC, byref(BITMAPINFOHEADER(*image.size)), 0,
byref(dataptr), None, 0)
hOldBitmap = gdi.SelectObject(hDC, result)
try:
buf = todib(image)
memmove(dataptr, buf, len(buf))
finally:
gdi.SelectObject(hDC, hOldBitmap)
finally:
gdi.DeleteDC(hDC)
return result