makegrid.py - copy rectangular grids to the clipboard

makegrid.py

from PIL import Image, ImageDraw
import sys

from io import BytesIO
from ctypes import memmove, windll, c_size_t as SIZE_T
from ctypes.wintypes import UINT, LPVOID, BOOL, HWND, HANDLE

HGLOBAL = HANDLE 
GHND = 0x0042
GMEM_SHARE = 0x2000

GlobalAlloc = windll.kernel32.GlobalAlloc
GlobalAlloc.restype = HGLOBAL
GlobalAlloc.argtypes = [UINT, SIZE_T]

GlobalLock = windll.kernel32.GlobalLock
GlobalLock.restype = LPVOID
GlobalLock.argtypes = [HGLOBAL]

GlobalUnlock = windll.kernel32.GlobalUnlock
GlobalUnlock.restype = BOOL
GlobalUnlock.argtypes = [HGLOBAL]

CF_DIB = 8

OpenClipboard = windll.user32.OpenClipboard
OpenClipboard.restype = BOOL 
OpenClipboard.argtypes = [HWND]

EmptyClipboard = windll.user32.EmptyClipboard
EmptyClipboard.restype = BOOL
EmptyClipboard.argtypes = None

SetClipboardData = windll.user32.SetClipboardData
SetClipboardData.restype = HANDLE
SetClipboardData.argtypes = [UINT, HANDLE]

CloseClipboard = windll.user32.CloseClipboard
CloseClipboard.restype = BOOL
CloseClipboard.argtypes = None

def copy_to_clipboard(image):
    output = BytesIO()
    image.convert("RGB").save(output, "BMP")
    data = output.getvalue()[14:]
    output.close()

    hData = GlobalAlloc(GHND | GMEM_SHARE, len(data))
    pData = GlobalLock(hData)
    memmove(pData, data, len(data))
    GlobalUnlock(hData)

    OpenClipboard(None)
    EmptyClipboard()
    SetClipboardData(CF_DIB, pData)
    CloseClipboard()

def make_grid(num_cols, num_rows, col_width, row_height, background="white", line_color="black"):
    height = 1 + row_height*num_rows
    width = 1 + col_width*num_cols
    img = Image.new("RGB", (width, height), background)
    draw = ImageDraw.Draw(img)
    for i in range(num_cols+1):
        x = i * col_width
        draw.line((x, 0, x, height), fill=line_color)
    for j in range(num_rows+1):
        y = j * row_height
        draw.line((0, y, width, y), fill=line_color)
    return img


if len(sys.argv) < 5:
    print("Usage: makeGrid COLS ROWS CELLWIDTH CELLHEIGHT [BACKGROUNDCOLOR] [LINECOLOR]")
    exit(0)

_, *args = [int(s) if s.isdigit() else s for s in sys.argv]
copy_to_clipboard(make_grid(*args))