如何在pyqt中给无边框窗口添加DWM环绕阴影

前言

在之前的博客《如何在pyqt中通过调用SetWindowCompositionAttribute实现Win10亚克力效果》中，我们实现了窗口的亚克力效果，同时也用SetWindowCompositionAttribute() 给亚克力窗口加上了阴影。但是更多时候我们用不到亚克力效果，但又需要给无边框窗口加上阴影。一种方法是在当前窗口外再嵌套一层窗口，然后用 Qt 自带的 QGraphicsDropShadowEffect 给里面这层窗口加上阴影，还有一种就是重写 paintEvent()来绘制阴影。下面来讨论一下使用 dwmapi 来给无边框窗口添加阴影的方法。效果如下 (硝子太美啦٩(๑>◡<๑)۶ )：

实现过程

1. 为了实现DWM 环绕阴影，需要调用dwmapi 中的两个函数：

   • HRESULT DwmSetWindowAttribute (HWND hwnd, DWORD dwAttribute, LPCVOID pvAttribute, DWORD cbAttribute)，用来设置窗口的桌面窗口管理器（DWM）非客户端呈现属性的值，可以参见文档 DwmSetWindowAttribute函数；
   • HRESULT DwmExtendFrameIntoClientArea (HWND hWnd, const MARGINS *pMarInset)，用来将窗口框架扩展到工作区，参见文档DwmExtendFrameIntoClientArea函数 和 DWM模糊概述；

   在调用这两个函数之前，我们需要先在WindowEffect的构造函数中声明一下他们的函数原型

   self.dwmapi = WinDLL("dwmapi")
   self.DwmExtendFrameIntoClientArea = self.dwmapi.DwmExtendFrameIntoClientArea
   self.DwmSetWindowAttribute = self.dwmapi.DwmSetWindowAttribute
   self.DwmExtendFrameIntoClientArea.restype = LONG
   self.DwmSetWindowAttribute.restype = LONG
   self.DwmSetWindowAttribute.argtypes = [c_int, DWORD, LPCVOID, DWORD]
   self.DwmExtendFrameIntoClientArea.argtypes = [c_int, POINTER(MARGINS)]
   

2. 从MSDN文档可以得知，传入 DwmExtendFrameIntoClientArea() 的第二个参数 pMarInset 是一个结构体 MARGIN 的指针，所以我们下面定义一下 MARGIN ，同时定义一些要用到的枚举类（其他关于亚克力效果的结构体和枚举类见《如何在pyqt中通过调用SetWindowCompositionAttribute实现Win10亚克力效果》）：

   # coding: utf-8
   from ctypes import Structure, c_int
   from enum import Enum
   
   
   class DWMNCRENDERINGPOLICY(Enum):
       DWMNCRP_USEWINDOWSTYLE = 0
       DWMNCRP_DISABLED = 1
       DWMNCRP_ENABLED = 2
       DWMNCRP_LAS = 3
   
   
   class DWMWINDOWATTRIBUTE(Enum):
       DWMWA_NCRENDERING_ENABLED = 1
       DWMWA_NCRENDERING_POLICY = 2
       DWMWA_TRANSITIONS_FORCEDISABLED = 3
       DWMWA_ALLOW_NCPAINT = 4
       DWMWA_CAPTION_BUTTON_BOUNDS = 5
       DWMWA_NONCLIENT_RTL_LAYOUT = 6
       DWMWA_FORCE_ICONIC_REPRESENTATION = 7
       DWMWA_FLIP3D_POLICY = 8
       DWMWA_EXTENDED_FRAME_BOUNDS = 9
       DWMWA_HAS_ICONIC_BITMAP = 10
       DWMWA_DISALLOW_PEEK = 11
       DWMWA_EXCLUDED_FROM_PEEK = 12
       DWMWA_CLOAK = 13
       DWMWA_CLOAKED = 14
       DWMWA_FREEZE_REPRESENTATION = 25
       DWMWA_LAST = 16
   
   
   class MARGINS(Structure):
       _fields_ = [
           ("cxLeftWidth", c_int),
           ("cxRightWidth", c_int),
           ("cyTopHeight", c_int),
           ("cyBottomHeight", c_int),
       ]
   

3. 准备工作完成，我们来看一下 WindowEffect 中拿来给无边框窗口添加环绕阴影的函数：

   def addShadowEffect(self, hWnd):
       """ 给窗口添加阴影
   
       Parameter
       ----------
       hWnd: int or `sip.voidptr`
           窗口句柄
       """
       hWnd = int(hWnd)
       self.DwmSetWindowAttribute(
           hWnd,
           DWMWINDOWATTRIBUTE.DWMWA_NCRENDERING_POLICY.value,
           byref(c_int(DWMNCRENDERINGPOLICY.DWMNCRP_ENABLED.value)),
           4,
       )
       margins = MARGINS(-1, -1, -1, -1)
       self.DwmExtendFrameIntoClientArea(hWnd, byref(margins))
   

4. 下面给出整个 WindowEffect 类的代码，这里面包括了设置亚克力效果的方法、给窗口添加阴影的方法和移动窗口的方法：

   # coding:utf-8
   
   from ctypes import POINTER, c_bool, c_int, pointer, sizeof, WinDLL, byref
   from ctypes.wintypes import DWORD, HWND, LONG, LPCVOID
   
   from win32 import win32api, win32gui
   from win32.lib import win32con
   
   from .c_structures import (
       ACCENT_POLICY,
       ACCENT_STATE,
       MARGINS,
       DWMNCRENDERINGPOLICY,
       DWMWINDOWATTRIBUTE,
       WINDOWCOMPOSITIONATTRIB,
       WINDOWCOMPOSITIONATTRIBDATA,
   )
   
   
   class WindowEffect:
       """ 调用windows api实现窗口效果 """
   
       def __init__(self):
           # 调用api
           self.user32 = WinDLL("user32")
           self.dwmapi = WinDLL("dwmapi")
           self.SetWindowCompositionAttribute = self.user32.SetWindowCompositionAttribute
           self.DwmExtendFrameIntoClientArea = self.dwmapi.DwmExtendFrameIntoClientArea
           self.DwmSetWindowAttribute = self.dwmapi.DwmSetWindowAttribute
           self.SetWindowCompositionAttribute.restype = c_bool
           self.DwmExtendFrameIntoClientArea.restype = LONG
           self.DwmSetWindowAttribute.restype = LONG
           self.SetWindowCompositionAttribute.argtypes = [
               c_int,
               POINTER(WINDOWCOMPOSITIONATTRIBDATA),
           ]
           self.DwmSetWindowAttribute.argtypes = [c_int, DWORD, LPCVOID, DWORD]
           self.DwmExtendFrameIntoClientArea.argtypes = [c_int, POINTER(MARGINS)]
           # 初始化结构体
           self.accentPolicy = ACCENT_POLICY()
           self.winCompAttrData = WINDOWCOMPOSITIONATTRIBDATA()
           self.winCompAttrData.Attribute = WINDOWCOMPOSITIONATTRIB.WCA_ACCENT_POLICY.value[0]
           self.winCompAttrData.SizeOfData = sizeof(self.accentPolicy)
           self.winCompAttrData.Data = pointer(self.accentPolicy)
   
       def setAcrylicEffect(self, hWnd: int, gradientColor: str = "F2F2F230", isEnableShadow: bool = True, animationId: int = 0):
           """ 给窗口开启Win10的亚克力效果
   
           Parameters
           ----------
           hWnd: int
               窗口句柄
   
           gradientColor: str
               十六进制亚克力混合色，对应rgba四个分量
   
           isEnableShadow: bool
               控制是否启用窗口阴影
   
           animationId: int
               控制磨砂动画
           """
           # 亚克力混合色
           gradientColor = (
               gradientColor[6:]
               + gradientColor[4:6]
               + gradientColor[2:4]
               + gradientColor[:2]
           )
           gradientColor = DWORD(int(gradientColor, base=16))
           # 磨砂动画
           animationId = DWORD(animationId)
           # 窗口阴影
           accentFlags = DWORD(0x20 | 0x40 | 0x80 |
                               0x100) if isEnableShadow else DWORD(0)
           self.accentPolicy.AccentState = ACCENT_STATE.ACCENT_ENABLE_ACRYLICBLURBEHIND.value[
               0
           ]
           self.accentPolicy.GradientColor = gradientColor
           self.accentPolicy.AccentFlags = accentFlags
           self.accentPolicy.AnimationId = animationId
           # 开启亚克力
           self.SetWindowCompositionAttribute(hWnd, pointer(self.winCompAttrData))
   
       def setAeroEffect(self, hWnd: int):
           """ 给窗口开启Aero效果
   
           Parameter
           ----------
           hWnd : 窗口句柄
           """
           self.accentPolicy.AccentState = ACCENT_STATE.ACCENT_ENABLE_BLURBEHIND.value[0]
           # 开启Aero
           self.SetWindowCompositionAttribute(hWnd, pointer(self.winCompAttrData))
   
       def moveWindow(self, hWnd: int):
           """ 移动窗口
   
           Parameter
           ----------
           hWnd : 窗口句柄
           """
           win32gui.ReleaseCapture()
           win32api.SendMessage(
               hWnd, win32con.WM_SYSCOMMAND, win32con.SC_MOVE + win32con.HTCAPTION, 0
           )
   
       def addShadowEffect(self, hWnd):
           """ 给窗口添加阴影
   
           Parameter
           ----------
           hWnd: int or `sip.voidptr`
               窗口句柄
           """
           hWnd = int(hWnd)
           self.DwmSetWindowAttribute(
               hWnd,
               DWMWINDOWATTRIBUTE.DWMWA_NCRENDERING_POLICY.value,
               byref(c_int(DWMNCRENDERINGPOLICY.DWMNCRP_ENABLED.value)),
               4,
           )
           margins = MARGINS(-1, -1, -1, -1)
           self.DwmExtendFrameIntoClientArea(hWnd, byref(margins))
   

测试

# coding:utf-8
import sys

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QWidget

from my_window_effect import WindowEffect


class Demo(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.resize(500, 500)
        self.windowEffect = WindowEffect()
        # 取消窗口边框
        self.setWindowFlags(Qt.FramelessWindowHint)
        # 添加环绕阴影
        self.windowEffect.addShadowEffect(self.winId())

    def mousePressEvent(self, QMouseEvent):
        self.windowEffect.moveWindow(self.winId())


if __name__ == "__main__":
    app = QApplication(sys.argv)
    demo = Demo()
    demo.show()
    sys.exit(app.exec_())

后记

关于如何给无边框窗口添加DWM环绕阴影的介绍到此结束，有帮助的话就点个赞吧 []~(￣▽￣)~*。当然正如我在《如何在pyqt中在实现无边框窗体的同时保留Windows窗口动画效果》所言，无边框窗口意味着窗口动画的消失，之前用C++的 dll 解决了这个问题，以后有时间再试试 python 版本的吧。以上~~