Utilities for Vispy. A collection of modules that are used in one or more Vispy sub-packages.
The event module implements the classes that make up the event system. The Event class and its subclasses are used to represent “stuff that happens”. The EventEmitter class provides an interface to connect to events and to emit events. The EmitterGroup groups EventEmitter objects.
For more information see http://github.com/vispy/vispy/wiki/API_Events
vispy.util.event.
Event
(type, native=None, **kwargs)[source]¶Class describing events that occur and can be reacted to with callbacks. Each event instance contains information about a single event that has occurred such as a key press, mouse motion, timer activation, etc.
Subclasses: KeyEvent
, MouseEvent
, TouchEvent
,
StylusEvent
The creation of events and passing of events to the appropriate callback
functions is the responsibility of EventEmitter
instances.
Note that each event object has an attribute for each of the input arguments listed below.
Parameters: | type : str
native : object (optional)
**kwargs : keyword arguments
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blocked
¶This boolean property indicates whether the event will be delivered to event callbacks. If it is set to True, then no further callbacks will receive the event. When possible, it is recommended to use Event.handled rather than Event.blocked.
handled
¶This boolean property indicates whether the event has already been acted on by an event handler. Since many handlers may have access to the same events, it is recommended that each check whether the event has already been handled as well as set handled=True if it decides to act on the event.
source
¶The object that the event applies to (i.e. the source of the event).
sources
¶List of objects that the event applies to (i.e. are or have been a source of the event). Can contain multiple objects in case the event traverses a hierarchy of objects.
vispy.app.canvas.
MouseEvent
(type, pos=None, button=None, buttons=None, modifiers=None, delta=None, last_event=None, press_event=None, **kwargs)[source]¶Mouse event class
Note that each event object has an attribute for each of the input arguments listed below, as well as a “time” attribute with the event’s precision start time.
Parameters: | type : str
pos : (int, int)
button : int | None
buttons : [int, …]
modifiers : tuple of Key instances
delta : (float, float)
press_event : MouseEvent
last_event : MouseEvent
native : object (optional)
**kwargs : keyword arguments
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drag_events
()[source]¶Return a list of all mouse events in the current drag operation.
Returns None if there is no current drag operation.
is_dragging
¶Indicates whether this event is part of a mouse drag operation.
vispy.app.canvas.
KeyEvent
(type, key=None, text='', modifiers=None, **kwargs)[source]¶Key event class
Note that each event object has an attribute for each of the input arguments listed below.
Parameters: | type : str
key : vispy.keys.Key instance
text : str
modifiers : tuple of Key instances
native : object (optional)
**kwargs : keyword arguments
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vispy.app.canvas.
ResizeEvent
(type, size=None, physical_size=None, **kwargs)[source]¶Resize event class
Note that each event object has an attribute for each of the input arguments listed below.
Parameters: | type : str
size : (int, int)
physical_size : (int, int)
native : object (optional)
**kwargs : extra keyword arguments
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vispy.app.canvas.
DrawEvent
(type, region=None, **kwargs)[source]¶Draw event class
This type of event is sent to Canvas.events.draw when a redraw is required.
Note that each event object has an attribute for each of the input arguments listed below.
Parameters: | type : str
region : (int, int, int, int) or None
native : object (optional)
**kwargs : extra keyword arguments
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vispy.util.event.
EventEmitter
(source=None, type=None, event_class=<class 'vispy.util.event.Event'>)[source]¶Encapsulates a list of event callbacks.
Each instance of EventEmitter represents the source of a stream of similar events, such as mouse click events or timer activation events. For example, the following diagram shows the propagation of a mouse click event to the list of callbacks that are registered to listen for that event:
User clicks |Canvas creates
mouse on |MouseEvent: |'mouse_press' EventEmitter: |callbacks in sequence: # noqa
Canvas | | | # noqa
-->|event = MouseEvent(...) -->|Canvas.events.mouse_press(event) -->|callback1(event) # noqa
| | -->|callback2(event) # noqa
| | -->|callback3(event) # noqa
Callback functions may be added or removed from an EventEmitter using
connect()
or
disconnect()
.
Calling an instance of EventEmitter will cause each of its callbacks
to be invoked in sequence. All callbacks are invoked with a single
argument which will be an instance of Event
.
EventEmitters are generally created by an EmitterGroup instance.
Parameters: | source : object
type : str or None
event_class : subclass of Event
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__call__
(**kwargs)[source]¶Invoke all callbacks for this emitter.
Emit a new event object, created with the given keyword arguments, which must match with the input arguments of the corresponding event class. Note that the ‘type’ argument is filled in by the emitter.
Alternatively, the emitter can also be called with an Event instance as the only argument. In this case, the specified Event will be used rather than generating a new one. This allows customized Event instances to be emitted and also allows EventEmitters to be chained by connecting one directly to another.
Note that the same Event instance is sent to all callbacks. This allows some level of communication between the callbacks (notably, via Event.handled) but also requires that callbacks be careful not to inadvertently modify the Event.
block
(callback=None)[source]¶Block this emitter. Any attempts to emit an event while blocked will be silently ignored. If callback is given, then the emitter is only blocked for that specific callback.
Calls to block are cumulative; the emitter must be unblocked the same number of times as it is blocked.
blocked
(callback=None)[source]¶Return boolean indicating whether the emitter is blocked for the given callback.
blocker
(callback=None)[source]¶Return an EventBlocker to be used in ‘with’ statements
Notes
For example, one could do:
with emitter.blocker():
pass # ..do stuff; no events will be emitted..
callback_refs
¶The set of callback references
callbacks
¶The set of callbacks
connect
(callback, ref=False, position='first', before=None, after=None)[source]¶Connect this emitter to a new callback.
Parameters: | callback : function | tuple
ref : bool | str
position : str
before : str | callback | list of str or callback | None
after : str | callback | list of str or callback | None
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Notes
If ref=True
, the callback reference will be determined from:
- If
callback
istuple
, the secend element in the tuple.- The
__name__
attribute.- The
__class__.__name__
attribute.
The current list of callback refs can be obtained using
event.callback_refs
. Callbacks can be referred to by either
their string reference (if given), or by the actual callback that
was attached (e.g., (canvas, 'swap_buffers')
).
If the specified callback is already connected, then the request is ignored.
If before is None and after is None (default), the new callback will be added to the beginning of the callback list. Thus the callback that is connected _last_ will be the _first_ to receive events from the emitter.
disconnect
(callback=None)[source]¶Disconnect a callback from this emitter.
If no callback is specified, then all callbacks are removed. If the callback was not already connected, then the call does nothing.
ignore_callback_errors
¶Whether exceptions during callbacks will be caught by the emitter
This allows it to continue invoking other callbacks if an error occurs.
print_callback_errors
¶Print a message and stack trace if a callback raises an exception
Valid values are “first” (only show first instance), “reminders” (show complete first instance, then counts), “always” (always show full traceback), or “never”.
This assumes ignore_callback_errors=True. These will be raised as warnings, so ensure that the vispy logging level is set to at least “warning”.
source
¶The object that events generated by this emitter apply to
The fonts module implements some helpful functions for dealing with system fonts.
Define constants for keys.
Each key constant is defined as a Key object, which allows comparison with
strings (e.g. ‘A’, ‘Escape’, ‘Shift’). This enables handling of key events
without using the key constants explicitly (e.g. if ev.key == 'Left':
).
In addition, key objects that represent characters can be matched to the integer ordinal (e.g. 32 for space, 65 for A). This behavior is mainly intended as a compatibility measure.
vispy.util.keys.
Key
(*names)[source]¶Represent the identity of a certain key.
This represents one or more names that the key in question is known by.
A Key object can be compared to one of its string names (case insensitive), to the integer ordinal of the key (only for keys that represent characters), and to another Key instance.
name
¶The primary name of the key.
Very simple transformation library that is needed for some examples.
vispy.util.transforms.
affine_map
(points1, points2)[source]¶Find a 3D transformation matrix that maps points1 onto points2.
Arguments are specified as arrays of four 3D coordinates, shape (4, 3).
vispy.util.transforms.
frustum
(left, right, bottom, top, znear, zfar)[source]¶Create view frustum
Parameters: | left : float
right : float
bottom : float
top : float
znear : float
zfar : float
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Returns: | M : ndarray
|
vispy.util.transforms.
ortho
(left, right, bottom, top, znear, zfar)[source]¶Create orthographic projection matrix
Parameters: | left : float
right : float
bottom : float
top : float
znear : float
zfar : float
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Returns: | M : ndarray
|
vispy.util.transforms.
perspective
(fovy, aspect, znear, zfar)[source]¶Create perspective projection matrix
Parameters: | fovy : float
aspect : float
znear : float
zfar : float
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Returns: | M : ndarray
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vispy.util.transforms.
rotate
(angle, axis, dtype=None)[source]¶The 3x3 rotation matrix for rotation about a vector.
Parameters: | angle : float
axis : ndarray
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Returns: | M : ndarray
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