tkinter - 为颜色选择器定义“自定义颜色”

我目前正在使用colorchooser from tkinter在项目中允许用户选择自定义颜色。至少，可以通过以下方式创建（在 Python 3.x 中）

from tkinter import colorchooser

cp = colorchooser.askcolor()

当此窗口出现时（至少在 Windows 中），有一个名为“自定义颜色”的部分

有什么方法可以用我选择的颜色预先填充此部分吗？

你所看到的都是常见的颜色对话框 https://msdn.microsoft.com/en-gb/library/windows/desktop/ms646912(v=vs.85).aspx，这是本机 Windows 对话框。无法在其中指定自定义颜色tkinter，因为它们是在低等级 https://github.com/NetSys/ups/blob/master/ns-allinone-2.35/tk8.5.10/win/tkWinDialog.c#L340.

天真的实现（使用ctypes https://docs.python.org/3/library/ctypes.html）可能是这样的：

import ctypes
import ctypes.wintypes as wtypes


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
    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])

        return custom_int_colors

    def askcolor(self, 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
        struct.lpCustColors = self.to_custom_color_array(custom_colors)

        if self.color_chooser(ctypes.byref(struct)):
            result = int_to_rgb(struct.rgbResult)
        else:
            result = None

        return result


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

colors = [(250, 0, 0), (0, 250, 0), (0, 0, 250), (255, 255, 255)] * 4

chooser = ColorChooser()
result_color = chooser.askcolor(colors)
print(result_color)

请记住，存在扩展空间，例如，在调用之间保留自定义颜色数组以及支持十六进制颜色/任意数组长度。