大学营销型网站建设实训课程怎样建设网站首页

 这个画板仅仅是为了服务于个人设计的截图功能贴图功能中的画板，方便我直接进行继承拓展。

截图自制工具详见我的主页。个人认为设计可谓相当简洁优雅。

下面的快捷画布的使用方法：

①按住Ctrl键，调出画笔；松开即结束绘图；

②双击Ctrl键，调出调色板；

 ③按照Ctrl键并滚动鼠标中键，调整画笔粗细；

import time
import tkinter as tk
from tkinter import colorchooserclass CustomCanvas(tk.Canvas):def __init__(self, parent, **kwargs):super().__init__(parent, **kwargs)self._bind_events()self.focus_set()self.__preview_items: list[str] = list()self.__stroke_history: list[str] = list()self.__current_stroke: list[str] = list()self.pen_color: str = 'black'self.drawing_mode: bool = Falseself.last_ctrl_press: float = 0.0self.pen_size: int = 3self.last_x: int = Noneself.last_y: int = Nonedef _bind_events(self):# 控制键监听self.bind('<Control_L>', self.__start_drawing)self.bind('<Control-KeyRelease>', self.__stop_drawing)# 鼠标监听self.bind('<B1-Motion>', self.__draw_continuous)self.bind('<Motion>', self.__update_preview)self.bind('<Button-1>', self.__draw_single_point)self.bind("<ButtonRelease-1>", self.__finalize_stroke)# 功能快捷键self.bind('<Control-MouseWheel>', self.__adjust_pen_size)self.bind("<Control-z>", self.undo_last_stroke)def __start_drawing(self, event):if self._is_double_ctrl_click():self.__change_pen_color(event)self.drawing_mode = Trueself.config(cursor='pencil')def __stop_drawing(self, event):self.drawing_mode = Falseself.config(cursor='')def __finalize_stroke(self, event):self.last_x = self.last_y = Noneself.__stroke_history.append(self.__current_stroke)self.__current_stroke = []def __change_pen_color(self, event):color = colorchooser.askcolor()[1]if color:self.pen_color = colordef __adjust_pen_size(self, event):if event.delta > 0:self.pen_size = min(124, self.pen_size + 1)else:self.pen_size = max(1, self.pen_size - 1)self.__show_brush_preview(event)def __show_brush_preview(self, event):self.__update_preview(event, force=True)preview = self.__draw_single_point(event, record=False)self.__preview_items.append(preview)def __update_preview(self, event, force: bool = False):if force:self.__clear_preview()current_x, current_y = event.x, event.yif self.last_x is not None and self.last_y is not None:dx = abs(current_x - self.last_x)dy = abs(current_y - self.last_y)if dx < 10 and dy < 10:returnself.last_x, self.last_y = current_x, current_yif len(self.__preview_items) != 0:self.__clear_preview()def __clear_preview(self):for item in self.__preview_items:self.delete(item)self.__preview_items.clear()def _is_double_ctrl_click(self):current_time = time.time()is_double_click = (current_time - self.last_ctrl_press) < 0.3self.last_ctrl_press = current_timereturn is_double_clickdef __draw_continuous(self, event, record: bool = True) -> str:line = ""if not self.drawing_mode:return lineif self.last_x and self.last_y:line = self.create_line(self.last_x, self.last_y, event.x, event.y,fill=self.pen_color, width=self.pen_size,capstyle=tk.ROUND, joinstyle=tk.ROUND)if record:self.__current_stroke.append(line)self.last_x = event.xself.last_y = event.yreturn linedef __draw_single_point(self, event, record: bool = True) -> str:point = ""if not self.drawing_mode:return pointpoint = self.create_oval(event.x - self.pen_size // 2, event.y - self.pen_size // 2,event.x + self.pen_size // 2, event.y + self.pen_size // 2,fill=self.pen_color, outline=self.pen_color, )self.last_x = event.xself.last_y = event.yif record:self.__current_stroke.append(point)return pointdef undo_last_stroke(self, event):if len(self.__stroke_history) == 0:returnlast_draw = self.__stroke_history.pop()for item in last_draw:self.delete(item)if __name__ == '__main__':root = tk.Tk()canvas = CustomCanvas(root, bg='white', width=800, height=600)canvas.pack()root.mainloop()