Import turtle turtle. Setup ( 400, 500 ) # Determine the window size wn = turtle.

I'm looking for an answer for this question for a a few months, there is a c++ code design for QT to allow a serial port communication, one of it's features that. Python Event Driven Serial. When you send data to the serial port. This is an event-driven approach and fits. Practical event-driven programming with Python.

Screen () # Get a reference to the window wn. Title ( 'Handling keypresses!' ) # Change the window title wn. Bgcolor ( 'lightgreen' ) # Set the background color tess = turtle. Turtle () # Create our favorite turtle # The next four functions are our 'event handlers'.

Def h1 (): tess. Forward ( 30 ) def h2 (): tess. Free Language Immersion Programs here. Left ( 45 ) def h3 (): tess.

Right ( 45 ) def h4 (): wn. Bye () # Close down the turtle window # These lines 'wire up' keypresses to the handlers we've defined. Onkey ( h1, 'Up' ) wn. Onkey ( h2, 'Left' ) wn. Onkey ( h3, 'Right' ) wn.

Onkey ( h4, 'q' ) # Now we need to tell the window to start listening for events, # If any of the keys that we're monitoring is pressed, its # handler will be called. Listen () wn. Mainloop () Here are some points to note: • We need the call to the window’s listen method at line 31, otherwise it won’t notice our keypresses. • We named our handler functions h1, h2 and so on, but we can choose better names. The handlers can be arbitrarily complex functions that call other functions, etc.

• Pressing the q key on the keyboard calls function h4 (because we bound the q key to h4 on line 26). While executing h4, the window’s bye method (line 24) closes the turtle window, which causes the window’s mainloop call (line 31) to end its execution. Since we did not write any more statements after line 32, this means that our program has completed everything, so it too will terminate.

• We can refer to keys on the keyboard by their character code (as we did in line 26), or by their symbolic names. Some of the symbolic names to try are Cancel (the Break key), BackSpace, Tab, Return(the Enter key), Shift_L (any Shift key), Control_L (any Control key), Alt_L (any Alt key), Pause, Caps_Lock, Escape, Prior (Page Up), Next (Page Down), End, Home, Left, Up, Right, Down, Print, Insert, Delete, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, Num_Lock, and Scroll_Lock. Import turtle turtle. Setup ( 400, 500 ) wn = turtle.

Screen () wn. Title ( 'How to handle mouse clicks on the window!' Bgcolor ( 'lightgreen' ) tess = turtle. Turtle () tess. Color ( 'purple' ) tess. Pensize ( 3 ) tess.

Shape ( 'circle' ) def h1 ( x, y ): tess. Goto ( x, y ) wn. Onclick ( h1 ) # Wire up a click on the window. Mainloop () There is a new turtle method used at line 14 — this allows us to move the turtle to an absolute coordinate position. (Most of the examples that we’ve seen so far move the turtle relative to where it currently is). So what this program does is move the turtle (and draw a line) to wherever the mouse is clicked. Java For Dummies Pdf Download. If we add this line before line 14, we’ll learn a useful debugging trick too.

Import turtle turtle. Setup ( 400, 500 ) wn = turtle. Screen () wn. Title ( 'Using a timer' ) wn. Bgcolor ( 'lightgreen' ) tess = turtle. Turtle () tess. Color ( 'purple' ) tess.

Pensize ( 3 ) def h1 (): tess. Forward ( 100 ) tess. Left ( 56 ) wn. Ontimer ( h1, 2000 ) wn. Mainloop () On line 16 the timer is started and set to explode in 2000 milliseconds (2 seconds).

When the event does occur, the handler is called, and tess springs into action. Unfortunately, when one sets a timer, it only goes off once.

So a common idiom, or style, is to restart the timer inside the handler. In this way the timer will keep on giving new events. Try this program. An example: state machines A state machine is a system that can be in one of a few different states. We draw a state diagram to represent the machine, where each state is drawn as a circle or an ellipse. Certain events occur which cause the system to leave one state and transition into a different state. These state transitions are usually drawn as an arrow on the diagram.