Distinguishing between a mouse down and a mouse hold

Im currently working on a little graphics library for pyglet. The module is used to make vector graphics composed entirely of lines.

In its develoment i have have run into a problem where, clicking to drag (and move a point) also causes fires an on_mouse_press event that creates a new link between the last active link and the point you are trying to drag.

I cant seem to think of any way to fix this that dosent make creating links between points feel laggy, i have creating links on_mouse_release instead so that i could determine if the mouse had been draged before linking the point.

Does anyone else have any bright ideas on how i can get this to work without appearing laggy.

EDIT: to clarify im using pyglet with python

Solution

#!/usr/bin/python
import pyglet
from time import time, sleep

class Window(pyglet.window.Window):
    def __init__(self, refreshrate):
        super(Window, self).__init__(vsync = False)
        self.frames = 0
        self.framerate = pyglet.text.Label(text='Unknown', font_name='Verdana', font_size=8, x=10, y=10, color=(255,255,255,255))
        self.last = time()
        self.alive = 1
        self.refreshrate = refreshrate
        self.click = None
        self.drag = False

    def on_draw(self):
        self.render()

    def on_mouse_press(self, x, y, button, modifiers):
        self.click = x,y

    def on_mouse_drag(self, x, y, dx, dy, buttons, modifiers):
        if self.click:
            self.drag = True
            print 'Drag offset:',(dx,dy)

    def on_mouse_release(self, x, y, button, modifiers):
        if not self.drag and self.click:
            print 'You clicked here', self.click, 'Relese point:',(x,y)
        else:
            print 'You draged from', self.click, 'to:',(x,y)
        self.click = None
        self.drag = False

    def render(self):
        self.clear()
        if time() - self.last >= 1:
            self.framerate.text = str(self.frames)
            self.frames = 0
            self.last = time()
        else:
            self.frames += 1
        self.framerate.draw()
        self.flip()

    def on_close(self):
        self.alive = 0

    def run(self):
        while self.alive:
            self.render()
            # ----> Note: <----
            #  Without self.dispatc_events() the screen will freeze
            #  due to the fact that i don't call pyglet.app.run(),
            #  because i like to have the control when and what locks
            #  the application, since pyglet.app.run() is a locking call.
            event = self.dispatch_events()
            sleep(1.0/self.refreshrate)

win = Window(23) # set the fps
win.run()

Short description:

Keep track of the current mouse state within the window
Keep track of startpoint of mouse event
At mouse release, do waht you want to do or update whatever it is within the drag.

I know it's an old question, but it's under the "unanswered" so hoping to get it resolved and out of the list.