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Python Canvas.scan_dragto方法代码示例

本文整理汇总了Python中tkinter.Canvas.scan_dragto方法的典型用法代码示例。如果您正苦于以下问题:Python Canvas.scan_dragto方法的具体用法?Python Canvas.scan_dragto怎么用?Python Canvas.scan_dragto使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在tkinter.Canvas的用法示例。


在下文中一共展示了Canvas.scan_dragto方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Python代码示例。

示例1: LpoView

# 需要导入模块: from tkinter import Canvas [as 别名]
# 或者: from tkinter.Canvas import scan_dragto [as 别名]
class LpoView(Frame):
    """ This class implements a LPO widget.

    This class use a canvas to draw the Hasse diagram of a LPO.
    """

    def __init__(self, parent):
        """ This method creates a new, emtpy LpoView. """
        Frame.__init__(self, parent)
        self.__parent = parent
        self.__initUI()
        
        self.__lpo = None

    def __initUI(self):
        """ Set up user interface. """
        self.pack(fill=BOTH, expand=1)
        
        self.__canvas = Canvas(self) # canvas for LPO
        self.__canvas.pack(fill=BOTH, expand=1)
        # Scroll with mouse drag gestures
        self.__canvas.bind("<ButtonPress-1>", self.__scroll_start)
        self.__canvas.bind("<B1-Motion>", self.__scroll_move)

    def __scroll_start(self, event):
        """ Scroll LPO with mouse gestures: Start of scroll event. """
        self.__canvas.scan_mark(event.x, event.y)

    def __scroll_move(self, event):
        """ Scroll LPO with mouse gestures: Drag event. """
        self.__canvas.scan_dragto(event.x, event.y, gain=1)

        
    def showLpo(self, lpo_to_show):
        """ This method show the given LPO in this LpoView. """
        self.__lpo = lpo_to_show # set LPO reference
        self.__drawLpo() # create LPO graph

    def __drawLpo(self):
        """ This method draws the LPO. """
        # draw LPO arcs (arc layer is behind event layer)
        for arc in self.__lpo.arcs:
            # LPOs consists of all transitive arcs, the view shows only user defined arcs.
            if arc.user_drawn == True: 
                self.__drawArc(arc)

        # draw events
        for id, event in self.__lpo.events.items():
            self.__drawEvent(event)

    def __drawEvent(self, event):
        """ Draw the given event. """
        self.__canvas.create_rectangle(event.position[0] - 10, event.position[1] - 10, event.position[0] + 10, event.position[1] + 10, outline="#000", fill="#AAAAAA", width=2)
        self.__canvas.create_text(event.position[0], event.position[1] + 20, text=event.label)


    def __drawArc(self, arc):
        """ Draw the given arc. """
        start_event = self.__lpo.events[arc.source] # get start event
        end_event = self.__lpo.events[arc.target] # get end event

        intersections = self.__calculateIntersections(start_event, end_event) # calculate intersection points

        # start point of arc
        start = start_event.position[0] + intersections[0][0], start_event.position[1] + intersections[0][1]
        # end point of arc
        end = end_event.position[0] + intersections[1][0], end_event.position[1] + intersections[1][1]
        # create line with arrow head as end
        self.__canvas.create_line(start[0], start[1], end[0], end[1], arrow=LAST, arrowshape=(8.6, 10, 5), width=2)


    def __calculateIntersections(self, start, end):
        """ Calculate intersection point of start and end events with the arc.

        This method calculates two vectors which describe the intersection point of the arc from the
        given start event to the given end event.
        """

        # vector from the center of the start event to the center of the end event
        vector = float(end.position[0] - start.position[0]), float(end.position[1] - start.position[1])
        #calculate a factor to scale the x-component to 10px (half of side length)
        fact = 1
        if vector[0] != 0:
            fact = 10 / math.fabs(vector[0])
        # scale the vector
        start_vector = vector[0] * fact, vector[1] * fact

        # if y-component of vector is larger than 10px or x-component is 0, scale with y-component
        if math.fabs(start_vector[1]) > 10 or vector[0] == 0:
            fact = 10 / math.fabs(vector[1])
            start_vector = vector[0] * fact, vector[1] * fact
        #calculate intersection for arc end
        if vector[0] != 0:
            fact = 10 / math.fabs(vector[0])

        end_vector = -vector[0] * fact, -vector[1] * fact

        if math.fabs(end_vector[1]) > 10 or vector[0] == 0:
            fact = 10 / math.fabs(vector[1])
            end_vector = -vector[0] * fact, -vector[1] * fact
#.........这里部分代码省略.........
开发者ID:irgangla,项目名称:pntools,代码行数:103,代码来源:lpo_viewer_tk.py


注:本文中的tkinter.Canvas.scan_dragto方法示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。