实战
素材准备：
安装第三方模块：pip install PyQt5
效果先展示一下
本项目共分为3个模块 分别是 窗口组件功能代码、窗口组件代码、程序运行代码。
第一步：窗口组件功能代码
from PyQt5.QtWidgets import QWidget
from PyQt5.Qt import QPixmap, QPainter, QPoint, QPaintEvent, QMouseEvent, QPen, \
QColor, QSize
from PyQt5.QtCore import Qt
class PaintBoard(QWidget):
def __init__(self, Parent=None):
'''
Constructor
'''
super().__init__(Parent)
self.__InitData() # 先初始化数据，再初始化界面
self.__InitView()
def __InitData(self):
self.__size = QSize(480, 460)
# 新建QPixmap作为画板，尺寸为__size
self.__board = QPixmap(self.__size)
self.__board.fill(Qt.white) # 用白色填充画板
self.__IsEmpty = True # 默认为空画板
self.EraserMode = False # 默认为禁用橡皮擦模式
self.__lastPos = QPoint(0, 0) # 上一次鼠标位置
self.__currentPos = QPoint(0, 0) # 当前的鼠标位置
self.__painter = QPainter() # 新建绘图工具
self.__thickness = 10 # 默认画笔粗细为10px
self.__penColor = QColor("black") # 设置默认画笔颜色为黑色
self.__colorList = QColor.colorNames() # 获取颜色列表
def __InitView(self):
# 设置界面的尺寸为__size
self.setFixedSize(self.__size)
def Clear(self):
# 清空画板
self.__board.fill(Qt.white)
self.update()
self.__IsEmpty = True
def ChangePenColor(self, color="black"):
# 改变画笔颜色
self.__penColor = QColor(color)
def ChangePenThickness(self, thickness=10):
# 改变画笔粗细
self.__thickness = thickness
def IsEmpty(self):
# 返回画板是否为空
return self.__IsEmpty
def GetContentAsQImage(self):
# 获取画板内容（返回QImage）
image = self.__board.toImage()
return image
def paintEvent(self, paintEvent):
# 绘图事件
self.__painter.begin(self)
# 0,0为绘图的左上角起点的坐标
self.__painter.drawPixmap(0, 0, self.__board)
self.__painter.end()
def mousePressEvent(self, mouseEvent):
# 鼠标按下时，获取鼠标的当前位置保存为上一次位置
self.__currentPos = mouseEvent.pos()
self.__lastPos = self.__currentPos
def mouseMoveEvent(self, mouseEvent):
# 鼠标移动时，更新当前位置，并在上一个位置和当前位置间画线
self.__currentPos = mouseEvent.pos()
self.__painter.begin(self.__board)
if self.EraserMode == False:
# 非橡皮擦模式
self.__painter.setPen(QPen(self.__penColor, self.__thickness)) # 设置画笔颜色，粗细
else:
# 橡皮擦模式下画笔为纯白色，粗细为10
self.__painter.setPen(QPen(Qt.white, 10))
# 画线
self.__painter.drawLine(self.__lastPos, self.__currentPos)
self.__painter.end()
self.__lastPos = self.__currentPos
self.update() # 更新显示
def mouseReleaseEvent(self, mouseEvent):
self.__IsEmpty = False # 画板不再为空第二步：窗口组件代码
# -*- coding: utf-8 -*-
# @Author : Tony
from PyQt5.Qt import QWidget, QColor, QPixmap, QIcon, QSize, QCheckBox
from PyQt5.QtWidgets import QHBoxLayout, QVBoxLayout, QPushButton, QSplitter, \
QComboBox, QLabel, QSpinBox, QFileDialog
from *.PaintBoard import PaintBoard
class MainWidget(QWidget):
def __init__(self, Parent=None):
'''
Constructor
'''
super().__init__(Parent)
self.__InitData() # 先初始化数据，再初始化界面
self.__InitView()
def __InitData(self):
'''
初始化成员变量
'''
self.__paintBoard = PaintBoard(self)
# 获取颜色列表(字符串类型)
self.__colorList = QColor.colorNames()
def __InitView(self):
'''
初始化界面
'''
self.setFixedSize(640, 480)
self.setWindowTitle("PM_Tony老师定制的小画板·")
# 新建一个水平布局作为本窗体的主布局
main_layout = QHBoxLayout(self)
# 设置主布局内边距以及控件间距为10px
main_layout.setSpacing(10)
# 在主界面左侧放置画板
main_layout.addWidget(self.__paintBoard)
# 新建垂直子布局用于放置按键
sub_layout = QVBoxLayout()
# 设置此子布局和内部控件的间距为10px
sub_layout.setContentsMargins(10, 10, 10, 10)
self.__btn_Clear = QPushButton("清空画板")
self.__btn_Clear.setParent(self) # 设置父对象为本界面
# 将按键按下信号与画板清空函数相关联
self.__btn_Clear.clicked.connect(self.__paintBoard.Clear)
sub_layout.addWidget(self.__btn_Clear)
self.__btn_Quit = QPushButton("退出")
self.__btn_Quit.setParent(self) # 设置父对象为本界面
self.__btn_Quit.clicked.connect(self.Quit)
sub_layout.addWidget(self.__btn_Quit)
self.__btn_Save = QPushButton("保存作品")
self.__btn_Save.setParent(self)
self.__btn_Save.clicked.connect(self.on_btn_Save_Clicked)
sub_layout.addWidget(self.__btn_Save)
self.__cbtn_Eraser = QCheckBox(" 使用橡皮擦")
self.__cbtn_Eraser.setParent(self)
self.__cbtn_Eraser.clicked.connect(self.on_cbtn_Eraser_clicked)
sub_layout.addWidget(self.__cbtn_Eraser)
splitter = QSplitter(self) # 占位符
sub_layout.addWidget(splitter)
self.__label_penThickness = QLabel(self)
self.__label_penThickness.setText("画笔粗细")
self.__label_penThickness.setFixedHeight(20)
sub_layout.addWidget(self.__label_penThickness)
self.__spinBox_penThickness = QSpinBox(self)
self.__spinBox_penThickness.setMaximum(20)
self.__spinBox_penThickness.setMinimum(2)
self.__spinBox_penThickness.setValue(10) # 默认粗细为10
self.__spinBox_penThickness.setSingleStep(2) # 最小变化值为2
self.__spinBox_penThickness.valueChanged.connect(
self.on_PenThicknessChange) # 关联spinBox值变化信号和函数on_PenThicknessChange
sub_layout.addWidget(self.__spinBox_penThickness)
self.__label_penColor = QLabel(self)
self.__label_penColor.setText("画笔颜色")
self.__label_penColor.setFixedHeight(20)
sub_layout.addWidget(self.__label_penColor)
self.__comboBox_penColor = QComboBox(self)
self.__fillColorList(self.__comboBox_penColor) # 用各种颜色填充下拉列表
self.__comboBox_penColor.currentIndexChanged.connect(self.on_PenColorChange) # 关联下拉列表的当前索引变更信号与函数on_PenColorChange
sub_layout.addWidget(self.__comboBox_penColor)
main_layout.addLayout(sub_layout) # 将子布局加入主布局
def __fillColorList(self, comboBox):
index_black = 0
index = 0
for color in self.__colorList:
if color == "black":
index_black = index
index += 1
pix = QPixmap(70, 20)
pix.fill(QColor(color))
comboBox.addItem(QIcon(pix), None)
comboBox.setIconSize(QSize(70, 20))
comboBox.setSizeAdjustPolicy(QComboBox.AdjustToContents)
comboBox.setCurrentIndex(index_black)
def on_PenColorChange(self):
color_index = self.__comboBox_penColor.currentIndex()
color_str = self.__colorList[color_index]
self.__paintBoard.ChangePenColor(color_str)
def on_PenThicknessChange(self):
penThickness = self.__spinBox_penThickness.value()
self.__paintBoard.ChangePenThickness(penThickness)
def on_btn_Save_Clicked(self):
savePath = QFileDialog.getSaveFileName(self, 'Save Your Paint', '.\\', '*.png')
print(savePath)
if savePath[0] == "":
print("Save cancel")
return
image = self.__paintBoard.GetContentAsQImage()
image.save(savePath[0])
def on_cbtn_Eraser_clicked(self):
if self.__cbtn_Eraser.isChecked():
self.__paintBoard.EraserMode = True # 进入橡皮擦模式
else:
self.__paintBoard.EraserMode = False # 退出橡皮擦模式
def Quit(self):
self.close()
第三步：程序运行代码
from *.MainWidget import MainWidget
from PyQt5.QtWidgets import QApplication
import sys
if __name__ == '__main__':
app = QApplication(sys.argv)
# 创建窗口
mainWidget = MainWidget()
# 显示
mainWidget.show()
app.exit(app.exec_())效果展示
