Question

我需要绘制多个闭合多边形，其中一旦创建了第一个多边形，后续多边形就连接到先前创建的多边形的一部分并由其组成。因此我需要： 1.创建闭合多边形。（说右键单击关闭打开Poly） 2.单击现有多边形的节点（线段的终点）以开始下一个新多边形....并在现有多边形上完成，以便新多边形具有由现有多边形的一部分形成的点。如图2（a）所示，当光标悬停在现有节点上时，光标形状从十字线变为DOT 在下面的Mock up图片中，它显示了一个红色的封闭多边形和一个与Red One相连的新绿色折线，应该用它来创建一个新的蓝色封闭多边形新的封闭多边形现在有两个来自Original Red One的新PolyLines，Blue One和Green One：此外应该能够点击移动重合节点，或在重合多边形中插入新点......

这最初似乎很简单......但很快就显得更复杂了？

我找到了允许绘制线条的基本代码，必须将其修改为1.关闭折线以形成多边形（线条在关闭时不能交叉）2。选择节点以创建新的多边形等。

`# Simple Canvas example
#
from Tkinter import *

#We define a drawing class here:
class Drawing():

    #This is the constructor. It draws the window with the canvas.
    def __init__(self, tkMainWin):
        frame = Frame(tkMainWin)
        frame.pack()

        self.lines = []
        self.lastX = None
        self.lastY = None
        self.redLine = None

        self.canvas = Canvas(frame)
        self.canvas.bind("<Button-1>",self.clicked)
        self.canvas.bind("<Button-3>",self.rightClicked)
        self.canvas.bind("<Motion>",self.mouseMoved)
        self.canvas.pack()

    #This event handler (callback) will draw lines, saving their ID
    #in a list.
    def clicked(self, event):

        print("Button down!")

        if self.lastX != None:
            l = self.canvas.create_line(self.lastX,self.lastY,event.x,event.y)
            self.lines.append(l)

        self.lastX = event.x
        self.lastY = event.y
        pass

    #This handler deals with "right-click" events, which cause the
    #last line drawn to be deleted!
    def rightClicked(self,event):
        print("rightClicked!")
        self.lastX = None
        self.lastY = None
        if (len( self.lines) > 0):
            self.canvas.delete( self.lines[-1])
            del self.lines[-1]  #Need to keep our data structure in
                            #sync with the canvas
        #Manage the red line!
        if self.redLine != None:
            self.canvas.delete(self.redLine)
            self.redLine = None


    #This handler deals with "mouse motion" events, and draws a red
    # "rubber-band" line illustrating where the next line will be
    # drawn if the user clicks now...
    def mouseMoved(self, event):
        print("Mouse Moved!")

        if self.lastX != None:
            if self.redLine != None:
                 self.canvas.delete(self.redLine);
            self.redLine = self.canvas.create_line(self.lastX, self.lastY,
                                        event.x, event.y, fill="red")
    #NEED a handler that deals with "mouse motion" that is close to an   existing X,Y point and changes the Cursor
    # to Allow Lock onto the point to create Coincident point in New Polygon
    # 
    def mousenearExistpoint(self, event):
        pass


#This code starts up TK and creates a main window.
mainWin = Tk()
#This code creates an instance of the TTT object.
ttt = Drawing( mainWin)
#This line starts the main event handling loop and sets us on our way...
mainWin.mainloop()`

在以后的日期，我想添加简单的属性，例如每个多边形的区域或名称...... 目的是协助建立Catchment模型。它就像一个非常简单的GIS应用程序。

从父多边形创建和编辑多个闭合多边形

0 个答案: