以下是我想要的描述: 在tkinter画布中绘制一组几何对象(此处为矩形),然后使用鼠标浏览此画布。单击并拖动移动画布,滚动放大和缩小。
使用本主题,我找到了单击和拖动部分: Move a tkinter canvas with Mouse 用老鼠
我设法写了一些滚动缩放的东西。 移动和缩放效果都很好。
问题: 如果我移动然后放大,缩放的焦点不再是光标的位置。
有什么建议吗?
这里有一段代码要测试
[编辑:现在应该适用于linux和windows]
import Tkinter as tk
import random
class Example(tk.Frame):
def __init__(self, root):
tk.Frame.__init__(self, root)
self.canvas = tk.Canvas(self, width=400, height=400, background="bisque")
self.xsb = tk.Scrollbar(self, orient="horizontal", command=self.canvas.xview)
self.ysb = tk.Scrollbar(self, orient="vertical", command=self.canvas.yview)
self.canvas.configure(yscrollcommand=self.ysb.set, xscrollcommand=self.xsb.set)
self.canvas.configure(scrollregion=(0,0,1000,1000))
self.xsb.grid(row=1, column=0, sticky="ew")
self.ysb.grid(row=0, column=1, sticky="ns")
self.canvas.grid(row=0, column=0, sticky="nsew")
self.grid_rowconfigure(0, weight=1)
self.grid_columnconfigure(0, weight=1)
#Plot some rectangles
for n in range(50):
x0 = random.randint(0, 900)
y0 = random.randint(50, 900)
x1 = x0 + random.randint(50, 100)
y1 = y0 + random.randint(50,100)
color = ("red", "orange", "yellow", "green", "blue")[random.randint(0,4)]
self.canvas.create_rectangle(x0,y0,x1,y1, outline="black", fill=color, activefill="black", tags=n)
self.canvas.create_text(50,10, anchor="nw", text="Click and drag to move the canvas\nScroll to zoom.")
# This is what enables using the mouse:
self.canvas.bind("<ButtonPress-1>", self.move_start)
self.canvas.bind("<B1-Motion>", self.move_move)
#linux scroll
self.canvas.bind("<Button-4>", self.zoomerP)
self.canvas.bind("<Button-5>", self.zoomerM)
#windows scroll
self.canvas.bind("<MouseWheel>",self.zoomer)
#move
def move_start(self, event):
self.canvas.scan_mark(event.x, event.y)
def move_move(self, event):
self.canvas.scan_dragto(event.x, event.y, gain=1)
#windows zoom
def zoomer(self,event):
if (event.delta > 0):
self.canvas.scale("all", event.x, event.y, 1.1, 1.1)
elif (event.delta < 0):
self.canvas.scale("all", event.x, event.y, 0.9, 0.9)
self.canvas.configure(scrollregion = self.canvas.bbox("all"))
#linux zoom
def zoomerP(self,event):
self.canvas.scale("all", event.x, event.y, 1.1, 1.1)
self.canvas.configure(scrollregion = self.canvas.bbox("all"))
def zoomerM(self,event):
self.canvas.scale("all", event.x, event.y, 0.9, 0.9)
self.canvas.configure(scrollregion = self.canvas.bbox("all"))
if __name__ == "__main__":
root = tk.Tk()
Example(root).pack(fill="both", expand=True)
root.mainloop()
这是一个简化的缩放示例。你应该使用更先进的技术,不要在内存中塞满一个巨大的缩放图像。
不要忘记在脚本的末尾放置指向图像的路径。
p.S.用于高级缩放示例look here。
鼠标事件在“屏幕坐标”中报告。当你有一个卷轴 canvas,你经常需要把这些数字转换成canvas(即scrollregion) 坐标。
对于你的变焦焦点:
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