A Comprehensive Introduction to Python Programming and ... - MSDL

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6.2 Event Types and Properties 49 / 75 6.2 Event Types and Properties While event descriptors can be very specific, Tkinter also supports more general events. Currently, the following event types are available, and can be classified into tree major categories: Keyboard events : KeyPress, KeyRelease Mouse events : ButtonPress, ButtonRelease, Motion, Enter, Leave, MouseWheel Window events : Visibility, Unmap, Map, Expose, FocusIn, FocusOut, Circulate, Colourmap, Gravity, Reparent, Property, Destroy, Activate, Deactivate Each callback that is bound to an event reveices and an instance of the Event class as parameter when it is invoked. The Event class defines the following properties: Property Description char pressed character (as a char)(KeyPress, KeyRelease only) delta delta of wheel movement (MouseWheel) focus boolean which indicates whether the window has the focus (Enter, Leave only) height height of the exposed window (Configure, Expose only) keycode keycode of the pressed key (KeyPress, KeyRelease only) keysym keysym of the the event as a string (KeyPress, KeyRelease only) keysym num keysym of the event as a number (KeyPress, KeyRelease only) num number of the mouse button pressed (1=LEFT, 2=CENTER, 3=RIGHT, etc.) (ButtonPress, Button- Release only) serial serial number of the event state state of the event as a number (ButtonPress, Button- Release, Enter, KeyPress, KeyRelease, Leave, Motion only) or string indicating the source of the Visibility event (one of “VisibilityUnobscured”, “VisibilityPartiallyObscured”, and “VisibilityFullyObscured” time time at which the event occurred. Under Microsoft Windows, this is the value returned by the GetTick- Count( ) API function. Continued on next page
6.3 Event Descriptors 50 / 75 Continued from previous page Property Description type type of the event as a number x x-position of the mouse relative to the widget x root x-position of the mouse on the screen relative to the root (ButtonPress, ButtonRelease, KeyPress, KeyRelease, Motion only) y y-position of the mouse relative to the widget y root y-position of the mouse on the screen relative to the root (ButtonPress, ButtonRelease, KeyPress, KeyRelease, Motion only) widget widget for which the event occurred width width of the exposed window (Configure, Expose only) 6.3 Event Descriptors In Tkinter, all event handling requires a string description of the event to be bound. Each of these strings can be divided into three sections, and is usually enclosed in angular brackets. The general format is as follows: Not all three sections are required in order for an event descriptor string to be valid. In fact, event descriptors only rarely include the three sections. The meaning and the possible values for each section will de discussed next. 1. Type: The type is often the only required section in an event descriptor. It specifies the kind or class of the event. The values that it can take are as follows:
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Page 3 and 4: Contents 2 / 75 3.3 Additional Widg
Page 5 and 6: 1.2 Language Features 4 / 75 Hexade
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Page 19 and 20: 2.3 Why Tkinter? 18 / 75 wxPython :
Page 21 and 22: 2.5 Show me what you can do! 20 / 7
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Page 39 and 40: 4 Geometry Managers and Widget Plac
Page 41 and 42: 4.3 The “Grid” Geometry Manager
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Page 45 and 46: 5.2 Specifying Fonts 44 / 75 Tuples
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A Comprehensive Introduction to Python Programming and ... - MSDL

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