colorPicker.py

import ctypes
import ctypes.wintypes as wtypes

"""
https://stackoverflow.com/a/49237204/12471420
thanks!
"""


class CHOOSECOLOR(ctypes.Structure):
    """ " a class to represent CWPRETSTRUCT structure
    https://msdn.microsoft.com/en-us/library/windows/desktop/ms646830(v=vs.85).aspx"""

    _fields_ = [
        ("lStructSize", wtypes.DWORD),
        ("hwndOwner", wtypes.HWND),
        ("hInstance", wtypes.HWND),
        ("rgbResult", wtypes.COLORREF),
        ("lpCustColors", ctypes.POINTER(wtypes.COLORREF)),
        ("Flags", wtypes.DWORD),
        ("lCustData", wtypes.LPARAM),
        ("lpfnHook", wtypes.LPARAM),
        ("lpTemplateName", ctypes.c_char_p),
    ]


class ColorChooser:
    """a class to represent Color dialog box
    https://msdn.microsoft.com/en-gb/library/windows/desktop/ms646912(v=vs.85).aspx"""

    CC_SOLIDCOLOR = 0x80
    CC_FULLOPEN = 0x02
    CC_RGBINIT = 0x01
    WS_EX_TOPMOST = 0x08
    custom_color_array = ctypes.c_uint32 * 16
    color_chooser = ctypes.windll.Comdlg32.ChooseColorW

    def to_custom_color_array(self, custom_colors):
        custom_int_colors = self.custom_color_array()

        for i in range(16):
            custom_int_colors[i] = (
                rgb_to_int(*custom_colors[i]) if i < len(custom_colors) else rgb_to_int(*(255, 255, 255))
            )

        return custom_int_colors

    def askcolor(self, hostId, initialColor, custom_colors):
        struct = CHOOSECOLOR()

        ctypes.memset(ctypes.byref(struct), 0, ctypes.sizeof(struct))
        struct.lStructSize = ctypes.sizeof(struct)
        struct.Flags = self.CC_SOLIDCOLOR | self.CC_FULLOPEN | self.CC_RGBINIT
        struct.lpCustColors = self.to_custom_color_array(custom_colors)
        struct.rgbResult = rgb_to_int(*initialColor)
        struct.hwndOwner = hostId
        if self.color_chooser(ctypes.byref(struct)):
            result = int_to_rgb(struct.rgbResult)
        else:
            result = None

        return result, [int_to_rgb(struct.lpCustColors[i]) for i in range(16)]


def rgb_to_int(red, green, blue):
    return red + (green << 8) + (blue << 16)


def int_to_rgb(int_color):
    red = int_color & 255
    green = (int_color >> 8) & 255
    blue = (int_color >> 16) & 255

    return red, green, blue