Cannot set a transparent background in qt/tkinter

[Arkueid]

On some devices, the following code fails to display a transparent background.

import os
import sys
from typing import Optional

from OpenGL.raw.GL.VERSION.GL_1_0 import glEnable, GL_BLEND, glBlendFunc, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, \
    glClearColor, glClear, GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, glViewport
from PySide6.QtCore import Qt, QTimer, QPoint
from PySide6.QtGui import QSurfaceFormat, QMouseEvent
from PySide6.QtOpenGLWidgets import QOpenGLWidget
from PySide6.QtWidgets import QApplication, QMainWindow
import live2d.v3 as live2d
from live2d.v3.params import StandardParams



class Live2DWidget(QOpenGLWidget):
    def __init__(self, model_path: str):
        super().__init__()
        self.model_path = os.path.normpath(model_path)
        self.model: Optional[live2d.LAppModel] = None
        self.last_pos = QPoint()
        self.setAutoFillBackground(False)  # 在Live2DWidget构造函数中添加


        # OpenGL 高级配置

        fmt = QSurfaceFormat()
        fmt.setAlphaBufferSize(0)
        fmt.setSamples(4)
        self.setFormat(fmt)

        # 60FPS 定时器
        self.timer = QTimer(self)
        self.timer.timeout.connect(self.update)
        self.timer.start(16)

    def initializeGL(self):
        # 核心透明通道初始化[6,7](@ref)
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
        # glClearColor(1.0, 0.0, 0.0, 0.0)
        # live2d.clearBuffer()

        # Live2D 初始化
        live2d.init()
        live2d.glewInit()

        # 加载模型（增加异常处理）
        try:
            self.model = live2d.LAppModel()
            self.model.LoadModelJson(self.model_path)
            # 根据模型发布者或者模型 XXX.cdi3.json 中可查找到水印对应的参数 id

            # 假设查找到的模型参数 id 为 Param261，假设值为 0 表示显示水印，值为 1 表示消失
            self.model.SetParameterValue("Param14", 1, 1)
            # print(f"Part Count: {self.model.GetPartCount()}")
            # # 获取 part 名称的字符串数组
            # partIds = self.model.GetPartIds()
            # print(f"Part Ids: {partIds}")
            # # 设置部件 PartHairBack 的透明度为 50%
            # self.model.SetPartOpacity(partIds.index("PartHairBack"), 0.5)
            # self.model.SetPartOpacity(partIds.index("PartHairBack"), 0.5)
            self.model.Resize(self.width(), self.height())
        except Exception as e:
            print(f"模型加载失败: {str(e)}")
            QApplication.instance().quit()

    def paintGL(self):

        # glClearColor(0.0, 0.0, 0.0, 0.0)
        # glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)  # 关键修复点[1,6](@ref)
        # glClear(GL_COLOR_BUFFER_BIT)
        live2d.clearBuffer()
        if self.model:
            self.model.Update()
            self.model.Draw()

    def resizeGL(self, w: int, h: int):
        glViewport(0, 0, w, h)
        if self.model:
            self.model.Resize(w, h)
class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Live2D透明窗口")

        # 配置主窗口透明
        self.setAttribute(Qt.WidgetAttribute.WA_TranslucentBackground)
        self.setWindowFlag(Qt.WindowType.FramelessWindowHint)
        # self.setAttribute(Qt.WidgetAttribute.WA_TranslucentBackground, True)

        self.setStyleSheet("background:transparent;")

        # 创建Live2D部件
        self.live2d_widget = Live2DWidget(r"./recourse/mianfeimox/llny.model3.json")
        self.setCentralWidget(self.live2d_widget)

        #
        # # 窗口尺寸
        self.resize(800, 600)

        # 示例参数控制
        # QTimer.singleShot(1000, self.init_extra_controls)

    def init_extra_controls(self):
        # 初始化后控制示例
        if self.live2d_widget.model:
            # 设置透明度
            part_ids = self.live2d_widget.model.GetPartIds()
            if "PartHairBack" in part_ids:
                index = part_ids.index("PartHairBack")
                self.live2d_widget.model.SetPartOpacity(index, 0.7)

            # 控制嘴部
            self.live2d_widget.model.SetParameterValue(
                StandardParams.ParamMouthOpenY,
                0.5,
                1.0
            )

    def closeEvent(self, event):
        # 清理资源
        if self.live2d_widget.model:
            self.live2d_widget.model = None
        live2d.dispose()
        event.accept()


if __name__ == "__main__":
    # 配置OpenGL格式
    fmt = QSurfaceFormat()
    fmt.setVersion(3, 3)
    fmt.setProfile(QSurfaceFormat.CoreProfile)
    fmt.setAlphaBufferSize(8)
    QSurfaceFormat.setDefaultFormat(fmt)

    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec())

Originally posted by @gyl1314 in #30

[Soul-B5]

我将PySide6换成PyQT5和PyQT6进行测试，结果只有PyQT5是可以显示透明，PySide6、PyQT6均匀出现黑底

处理器 Intel(R) Core(TM) i5-8265U CPU @ 1.60GHz 1.80 GHz
显卡 NVIDIA GeForce MX250 (2 GB), Intel(R) UHD Graphics 620 (128 MB)
openGL 4.6
系统类型 Windows 10 专业版 64 位
Python 3.12.8
PyQT5 5.15.11
PyQT6 6.9.0
PySide6 6.9.1

# from PySide6.QtCore import Qt, QTimer, QPoint
# from PySide6.QtGui import QSurfaceFormat, QMouseEvent
# from PySide6.QtOpenGLWidgets import QOpenGLWidget
# from PySide6.QtWidgets import QApplication, QMainWindow

from PyQt5.QtCore import Qt, QTimer, QPoint
from PyQt5.QtGui import QSurfaceFormat, QMouseEvent
from PyQt5.QtWidgets import QOpenGLWidget
from PyQt5.QtWidgets import QApplication, QMainWindow

# from PyQt6.QtCore import Qt, QTimer, QPoint
# from PyQt6.QtGui import QSurfaceFormat, QMouseEvent
# from PyQt6.QtOpenGLWidgets import QOpenGLWidget
# from PyQt6.QtWidgets import QApplication, QMainWindow

[minghf85]

同样的问题

[minghf85]

pyqt6透明窗口测试

测试代码如下(忽略Touch功能只关注透明窗口)：

import os

import OpenGL.GL as gl
import numpy as np
from PIL import Image
from PyQt6.QtCore import QTimerEvent, Qt
from PyQt6.QtGui import QMouseEvent, QCursor
from PyQt6.QtOpenGLWidgets import QOpenGLWidget
from PyQt6.QtWidgets import QApplication
from PyQt6.QtGui import QGuiApplication

import live2d.v3 as live2d
# import live2d.v2 as live2d


def callback():
    print("motion end")


class Win(QOpenGLWidget):

    def __init__(self) -> None:
        super().__init__()
        self.isInLA = False
        self.clickInLA = False
        # self.setWindowFlags(Qt.WindowType.FramelessWindowHint)
        self.setAttribute(Qt.WidgetAttribute.WA_TranslucentBackground, True)
        self.a = 0
        self.resize(400, 500)
        self.read = False
        self.clickX = -1
        self.clickY = -1
        self.model: live2d.LAppModel | None = None
        self.systemScale = QGuiApplication.primaryScreen().devicePixelRatio()

    def initializeGL(self) -> None:
        # 将当前窗口作为 OpenGL 的上下文
        # 图形会被绘制到当前窗口
        live2d.glewInit()

        # 创建模型
        self.model = live2d.LAppModel()

        if live2d.LIVE2D_VERSION == 3:
            self.model.LoadModelJson("Haru/Haru.model3.json")
        else:
            self.model.LoadModelJson("v2/shizuku/shizuku.model.json")

        # 以 fps = 120 的频率进行绘图
        self.startTimer(int(1000 / 120))

    def resizeGL(self, w: int, h: int) -> None:
        # 使模型的参数按窗口大小进行更新
        if self.model:
            self.model.Resize(w, h)

    def paintGL(self) -> None:
        live2d.clearBuffer()

        self.model.Update()

        self.model.Draw()

        if not self.read:
            self.savePng('screenshot.png')

            self.read = True

    def savePng(self, fName):
        data = gl.glReadPixels(0, 0, self.width(), self.height(), gl.GL_RGBA, gl.GL_UNSIGNED_BYTE)
        data = np.frombuffer(data, dtype=np.uint8).reshape(self.height(), self.width(), 4)
        data = np.flipud(data)
        new_data = np.zeros_like(data)
        for rid, row in enumerate(data):
            for cid, col in enumerate(row):
                color = None
                new_data[rid][cid] = col
                if cid > 0 and data[rid][cid - 1][3] == 0 and col[3] != 0:
                    color = new_data[rid][cid - 1]
                elif cid > 0 and data[rid][cid - 1][3] != 0 and col[3] == 0:
                    color = new_data[rid][cid]
                if color is not None:
                    color[0] = 255
                    color[1] = 0
                    color[2] = 0
                    color[3] = 255
                color = None
                if rid > 0:
                    if data[rid - 1][cid][3] == 0 and col[3] != 0:
                        color = new_data[rid - 1][cid]
                    elif data[rid - 1][cid][3] != 0 and col[3] == 0:
                        color = new_data[rid][cid]
                elif col[3] != 0:
                    color = new_data[rid][cid]
                if color is not None:
                    color[0] = 255
                    color[1] = 0
                    color[2] = 0
                    color[3] = 255
        img = Image.fromarray(new_data, 'RGBA')
        img.save(fName)

    def timerEvent(self, a0: QTimerEvent | None) -> None:
        if not self.isVisible():
            return

        if self.a == 0:  # 测试一次播放动作和回调函数
            self.model.StartMotion("TapBody", 0, live2d.MotionPriority.FORCE, onFinishMotionHandler=callback)
            self.a += 1

        local_x, local_y = QCursor.pos().x() - self.x(), QCursor.pos().y() - self.y()
        if self.isInL2DArea(local_x, local_y):
            self.isInLA = True
            # print("in l2d area")
        else:
            self.isInLA = False
            # print("out of l2d area")

        self.update()

    def isInL2DArea(self, click_x, click_y):
        h = self.height()
        alpha = gl.glReadPixels(click_x * self.systemScale, (h - click_y) * self.systemScale, 1, 1, gl.GL_RGBA, gl.GL_UNSIGNED_BYTE)[3]
        return alpha > 0

    def mousePressEvent(self, event: QMouseEvent) -> None:
        x, y = event.position().x(), event.position().y()
        # 传入鼠标点击位置的窗口坐标
        if self.isInL2DArea(x, y):
            self.clickInLA = True
            self.clickX, self.clickY = x, y
            print("pressed")

    def mouseReleaseEvent(self, event):
        x, y = event.position().x(), event.position().y()
        # if self.isInL2DArea(x, y):
        if self.isInLA:
            self.model.Touch(x, y)
            self.clickInLA = False
            print("released")

    def mouseMoveEvent(self, event: QMouseEvent) -> None:
        x, y = event.position().x(), event.position().y()
        if self.clickInLA:
            self.move(int(self.x() + x - self.clickX), int(self.y() + y - self.clickY))


if __name__ == "__main__":
    import sys

    live2d.init()

    app = QApplication(sys.argv)
    win = Win()
    win.show()
    app.exec()

    live2d.dispose()

---

测试1

python=3.10.18+pyqt6=6.9.1(latest)+live2d-py=0.5.3.5(latest)
透明窗口未生效

测试2

python=3.10.18+pyqt6=6.8.0+live2d-py=0.5.3.5(latest)
透明窗口ok

其他测试

python版本更换和live2d-py版本更换无影响

细节

pyqt6=6.9.1

pyqt6=6.8.0

同样的代码在两个版本跑出来的结果抗锯齿不一样
用了win32api之后的透明窗口效果会有抗锯齿，6.8.0直接透明没用上win32api

结果

pyqt6的版本影响了这个透明窗口，考虑到其他tk、pyside也有影响，感觉是opengl部分的问题
@Arkueid

[Arkueid]

pyqt5，live2d-py lastest，main_pyqt5_canvas_opacity.py，第一帧窗口背景透明，但第一帧之后背景透明失效。

[Soul-B5]

qt6.9中弃用了DwmEnableBlurBehindWindow方法，会导致一些设备上出现OpenGL无法透明化的问题。
Link: Semi-transparency broken for frameless windows with OpenGL