PySide6 GUI 编程（42）：QPainter 的使用

from __future__ import annotations

import sys
from datetime import datetime

from PySide6.QtCore import QLine, QPoint, Qt
from PySide6.QtGui import QPainter, QPixmap
from PySide6.QtWidgets import QApplication, QLabel, QMainWindow


def get_time_str() -> str:
    return datetime.now().isoformat(sep = ' ')


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布大小
        self.pixmap = QPixmap(400, 300)
        self.pixmap.fill(Qt.GlobalColor.black)

        # 在画布上绘制图线
        self.painter = QPainter(self.pixmap)
        self.painter.setPen(Qt.GlobalColor.red)
        # 使用坐标画线
        self.painter.drawLine(0, 0, 400, 300)
        self.painter.drawLine(400, 0, 0, 300)
        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        self.painter.end()

        # 使用 QLine 画线
        self.painter = QPainter(self.pixmap)
        self.painter.setPen(Qt.GlobalColor.blue)
        self.painter.drawLine(QLine(0, 150, 400, 150))
        self.painter.end()

        # 使用 QPoint 画线
        self.painter = QPainter(self.pixmap)
        self.painter.setPen(Qt.GlobalColor.cyan)
        self.painter.drawLine(QPoint(0, 100), QPoint(400, 100))
        self.painter.end()

        self.label = QLabel()
        self.label.setPixmap(self.pixmap)
        self.setCentralWidget(self.label)

        self.update()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import sys
from random import choice, randint

from PySide6.QtCore import QPoint, Qt
from PySide6.QtGui import QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QLabel, QMainWindow


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布大小
        self.pixmap = QPixmap(400, 300)
        self.pixmap.fill(Qt.GlobalColor.black)

        # 在画布上绘制图线
        self.painter = QPainter(self.pixmap)
        self.pen = QPen()
        self.pen.setWidth(3)
        self.pen.setColor(Qt.GlobalColor.red)
        self.painter.setPen(self.pen)
        colors = [x for x in Qt.GlobalColor]
        # 使用坐标画线
        for i in range(1, 10000):
            self.pen.setColor(choice(colors))
            # 这里需要每次都重新设置 pen，否则颜色不生效
            # There can only ever be one  QPen active on a QPainter
            # -- the current pen.
            self.painter.setPen(self.pen)
            self.painter.drawPoint(QPoint(200 + randint(-100, 100), 150 + randint(-100, 100)))
        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，会导致程序崩溃或者运行效率降低
        """
        self.painter.end()

        self.label = QLabel()
        self.label.setPixmap(self.pixmap)
        self.setCentralWidget(self.label)

        self.update()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import sys

from PySide6.QtCore import QRect, Qt
from PySide6.QtGui import QBrush, QColor, QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QLabel, QMainWindow


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布大小
        self.pixmap = QPixmap(400, 300)
        self.pixmap.fill(Qt.GlobalColor.black)

        # 在画布上绘制图线
        self.painter = QPainter(self.pixmap)
        self.pen = QPen()
        self.pen.setWidth(3)
        self.pen.setColor(Qt.GlobalColor.red)
        self.painter.setPen(self.pen)
        # 第一个参数：x 坐标，表示矩形左上角的水平位置
        # 第二个参数：y 坐标，表示矩形左上角的垂直位置
        # 第三个参数：width，表示矩形的宽度
        # 第四个参数：height，表示矩形的高度
        self.painter.drawRect(10, 10, 200, 200)

        self.pen.setColor(Qt.GlobalColor.blue)
        self.painter.setPen(self.pen)
        self.painter.drawRects([QRect(20, 20, 20, 20),
                                QRect(20, 20, 30, 30),
                                QRect(20, 20, 40, 40),
                                QRect(20, 20, 50, 50),
                                QRect(20, 20, 60, 60)])

        self.pen.setColor(Qt.GlobalColor.green)
        self.painter.setPen(self.pen)
        self.brush = QBrush()
        self.brush.setStyle(Qt.BrushStyle.SolidPattern)
        self.brush.setColor(QColor("#FFD007"))
        self.painter.setBrush(self.brush)
        self.painter.drawRoundedRect(QRect(85, 85, 100, 100), 100, 100, Qt.SizeMode.RelativeSize)

        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        self.painter.end()

        self.label = QLabel()
        self.label.setPixmap(self.pixmap)
        self.setCentralWidget(self.label)

        self.update()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import sys

from PySide6.QtCore import QPoint, Qt
from PySide6.QtGui import QBrush, QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QLabel, QMainWindow


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布大小
        self.pixmap = QPixmap(400, 300)
        self.pixmap.fill(Qt.GlobalColor.black)

        # 在画布上绘制图线
        self.painter = QPainter(self.pixmap)
        self.pen = QPen()
        self.pen.setWidth(3)
        self.pen.setColor(Qt.GlobalColor.green)
        self.painter.setPen(self.pen)
        self.brush = QBrush()
        self.brush.setStyle(Qt.BrushStyle.SolidPattern)
        self.brush.setColor(Qt.GlobalColor.red)
        self.painter.setBrush(self.brush)
        self.painter.drawEllipse(QPoint(200, 150), 100, 50)

        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        self.painter.end()

        self.label = QLabel()
        self.label.setPixmap(self.pixmap)
        self.setCentralWidget(self.label)

        self.update()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import sys
from datetime import datetime

from PySide6.QtCore import Qt
from PySide6.QtGui import QFont, QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QLabel, QMainWindow


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布大小
        self.pixmap = QPixmap(600, 400)
        self.pixmap.fill(Qt.GlobalColor.black)

        # 在画布上绘制图线
        self.painter = QPainter(self.pixmap)
        self.pen = QPen()
        self.pen.setWidth(5)
        self.pen.setColor(Qt.GlobalColor.darkMagenta)
        self.painter.setPen(self.pen)

        self.font = QFont('ComicShannsMono Nerd Font', 40)
        # self.font.setBold(True)
        self.painter.setFont(self.font)
        self.painter.drawText(0, 0, 600, 400, Qt.AlignmentFlag.AlignCenter,
                              'Hello, PySide6!\n你好，GUI 编程！\n{}\n{}'.format(datetime.now().isoformat(), self.font.family()))
        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        self.painter.end()

        self.label = QLabel()
        self.label.setPixmap(self.pixmap)
        self.setCentralWidget(self.label)

        self.update()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import sys

from PySide6.QtCore import Qt
from PySide6.QtGui import QMouseEvent, QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QLabel, QMainWindow, QPushButton, QVBoxLayout, QWidget


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布初始状态
        self.pixmap = QPixmap(800, 600)
        self.pixmap.fill(Qt.GlobalColor.white)

        # 设置布局
        self.label = QLabel()
        self.label.setPixmap(self.pixmap)
        self.button = QPushButton('清除所有')
        self.button.clicked.connect(self.clear_all)
        self.v_layout = QVBoxLayout()
        self.v_layout.addWidget(self.label)
        self.v_layout.addWidget(self.button)
        self.container = QWidget()
        self.container.setLayout(self.v_layout)
        self.setCentralWidget(self.container)

        # 鼠标坐标
        self.last_x = None
        self.last_y = None

    def mouseMoveEvent(self, event: QMouseEvent) -> None:
        pos = event.position()
        if self.last_x is None and self.last_y is None:
            self.last_x = pos.x()
            self.last_y = pos.y()
            return

        # 在画布上绘制图线
        painter = QPainter(self.pixmap)
        pen = QPen()
        pen.setWidth(3)
        pen.setStyle(Qt.PenStyle.SolidLine)
        pen.setCosmetic(True)
        pen.setColor(Qt.GlobalColor.darkMagenta)
        painter.setPen(pen)
        painter.drawLine(self.last_x, self.last_y, int(pos.x()), int(pos.y()))
        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        painter.end()
        # 更新QLabel中显示的内容，使其显示最新的QPixmap
        self.label.setPixmap(self.pixmap)
        # 记录上一次的鼠标坐标
        self.last_x = pos.x()
        self.last_y = pos.y()
        # 显式刷新界面
        self.update()

    def mouseReleaseEvent(self, event: QMouseEvent) -> None:
        self.last_x = None
        self.last_y = None

    def clear_all(self) -> None:
        self.pixmap = QPixmap(800, 600)
        self.pixmap.fill(Qt.GlobalColor.white)
        self.label.setPixmap(self.pixmap)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import sys

from PySide6.QtCore import Qt
from PySide6.QtGui import QMouseEvent, QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QHBoxLayout, QLabel, QMainWindow, QPushButton, QVBoxLayout, QWidget


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布初始状态
        self.pixmap = QPixmap(800, 600)
        self.pixmap.fill(Qt.GlobalColor.white)

        # 设置布局
        self.label = QLabel()
        self.label.setPixmap(self.pixmap)

        # 颜色列表
        self.colors_v_layout = QVBoxLayout()
        colors_h_layout = QHBoxLayout()
        self.colors_map = {}
        colors_count = 0
        for x in Qt.GlobalColor:
            self.colors_map[x.name] = x
            # css中没有 darkYellow 这种颜色，需要用 #CCCC00 来表示
            # 因此为了逻辑上的方便，QPushButton 中不使用 darkYellow 来作为背景色
            # 同时像 transparent、color0、color1 这样的颜色也过滤掉
            # 由于画板的背景色已经是白色，因此这里也将 white 过滤掉
            if x.name in ('transparent', 'white', 'color0', 'color1', 'darkYellow'):
                continue
            color_button = QPushButton(x.name)
            style = """
            QPushButton { background-color: %s; color: white; }
            QPushButton:pressed { background-color: #CCCC00; }
            """ % x.name
            color_button.setStyleSheet(style)
            color_button.clicked.connect(self.color_changed)
            colors_h_layout.addWidget(color_button)
            colors_count += 1
            if colors_count % 9 == 0:
                self.colors_v_layout.addLayout(colors_h_layout)
                colors_h_layout = QHBoxLayout()
                colors_count = 0
        self.colors_v_layout.addLayout(colors_h_layout)

        # 清除按钮
        self.button = QPushButton('清除所有')
        self.button.clicked.connect(self.clear_all)

        # 布局
        self.v_layout = QVBoxLayout()
        self.v_layout.addWidget(self.label)
        self.v_layout.addLayout(self.colors_v_layout)
        self.v_layout.addWidget(self.button)

        # 容器
        self.container = QWidget()
        self.container.setLayout(self.v_layout)

        # 组件排布
        self.setCentralWidget(self.container)

        # 鼠标坐标
        self.last_x = None
        self.last_y = None
        self.current_color = Qt.GlobalColor.darkMagenta

    def mouseMoveEvent(self, event: QMouseEvent) -> None:
        pos = event.position()
        if self.last_x is None and self.last_y is None:
            self.last_x = pos.x()
            self.last_y = pos.y()
            return

        # 在画布上绘制图线
        painter = QPainter(self.pixmap)
        pen = QPen()
        pen.setWidth(3)
        pen.setStyle(Qt.PenStyle.SolidLine)
        pen.setCosmetic(True)
        pen.setColor(self.current_color)
        painter.setPen(pen)
        painter.drawLine(self.last_x, self.last_y, int(pos.x()), int(pos.y()))
        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        painter.end()
        # 更新QLabel中显示的内容，使其显示最新的QPixmap
        self.label.setPixmap(self.pixmap)
        # 记录上一次的鼠标坐标
        self.last_x = pos.x()
        self.last_y = pos.y()
        # 显式刷新界面
        self.update()

    def mouseReleaseEvent(self, event: QMouseEvent) -> None:
        self.last_x = None
        self.last_y = None

    def clear_all(self) -> None:
        self.pixmap = QPixmap(800, 600)
        self.pixmap.fill(Qt.GlobalColor.white)
        self.label.setPixmap(self.pixmap)

    def color_changed(self) -> None:
        self.current_color = self.colors_map[self.sender().text()]


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()

from __future__ import annotations

import random
import sys
from cmath import pi

from PySide6.QtCore import Qt
from PySide6.QtGui import QMouseEvent, QPainter, QPen, QPixmap
from PySide6.QtWidgets import QApplication, QHBoxLayout, QLabel, QMainWindow, QPushButton, QVBoxLayout, QWidget


class MyMainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Hello, PySide6!')
        self.setToolTip('A PySide6 GUI Application Demo')

        # 设置画布初始状态
        self.pixmap = QPixmap(800, 600)
        self.pixmap.fill(Qt.GlobalColor.white)

        # 设置布局
        self.label = QLabel()
        self.label.setPixmap(self.pixmap)

        # 颜色列表
        self.colors_v_layout = QVBoxLayout()
        colors_h_layout = QHBoxLayout()
        self.colors_map = {}
        colors_count = 0
        for x in Qt.GlobalColor:
            self.colors_map[x.name] = x
            # css中没有 darkYellow 这种颜色，需要用 #CCCC00 来表示
            # 因此为了逻辑上的方便，QPushButton 中不使用 darkYellow 来作为背景色
            # 同时像 transparent、color0、color1 这样的颜色也过滤掉
            # 由于画板的背景色已经是白色，因此这里也将 white 过滤掉
            if x.name in ('transparent', 'white', 'color0', 'color1', 'darkYellow'):
                continue
            color_button = QPushButton(x.name)
            style = """
            QPushButton { background-color: %s; color: white; }
            QPushButton:pressed { background-color: #CCCC00; }
            """ % x.name
            color_button.setStyleSheet(style)
            color_button.clicked.connect(self.color_changed)
            colors_h_layout.addWidget(color_button)
            colors_count += 1
            if colors_count % 9 == 0:
                self.colors_v_layout.addLayout(colors_h_layout)
                colors_h_layout = QHBoxLayout()
                colors_count = 0
        self.colors_v_layout.addLayout(colors_h_layout)

        # 清除按钮
        self.button = QPushButton('清除所有')
        self.button.clicked.connect(self.clear_all)

        # 布局
        self.v_layout = QVBoxLayout()
        self.v_layout.addWidget(self.label)
        self.v_layout.addLayout(self.colors_v_layout)
        self.v_layout.addWidget(self.button)

        # 容器
        self.container = QWidget()
        self.container.setLayout(self.v_layout)

        # 组件排布
        self.setCentralWidget(self.container)

        # 鼠标坐标
        self.current_color = Qt.GlobalColor.darkMagenta

    def mousePressEvent(self, event: QMouseEvent) -> None:
        pos = event.position()
        # 在画布上绘制图线
        painter = QPainter(self.pixmap)
        pen = QPen()
        pen.setWidth(3)
        pen.setStyle(Qt.PenStyle.SolidLine)
        pen.setCosmetic(True)
        pen.setColor(self.current_color)
        painter.setPen(pen)
        radius = 15
        for _ in range(0, int(pi * (radius ** 2))):
            x_offset = random.randint(0 - radius, radius)
            y_offset = random.randint(0 - radius, radius)
            # 画出一个半径为 radius 的圆
            if int(x_offset) ** 2 + int(y_offset) ** 2 <= radius ** 2:
                painter.drawPoint(int(pos.x() + x_offset), int(pos.y() + y_offset))
        """
        如果不调用这个方法，那么这些资源可能会被锁定，导致无法被其他QPainter对象使用，
        或者在某些情况下可能会导致内存泄漏，特别是当你在一个循环中多次使用QPainter对象时，
        如果不调用end()方法，可能会导致程序崩溃或者运行效率降低
        """
        painter.end()
        # 更新QLabel中显示的内容，使其显示最新的QPixmap
        self.label.setPixmap(self.pixmap)
        # 显式刷新界面
        self.update()

    def clear_all(self) -> None:
        self.pixmap = QPixmap(800, 600)
        self.pixmap.fill(Qt.GlobalColor.white)
        self.label.setPixmap(self.pixmap)

    def color_changed(self) -> None:
        self.current_color = self.colors_map[self.sender().text()]


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    app.exec()