Windows¶

Animations are displayed in dedicated windows created with anim.window. A single instantiation is enough to get a fully functional animation window: the Qt event loop, keyboard shortcuts, layout management, and movie recording are handled internally.

Creating a window¶

Start with the smallest possible setup:

import anim

W = anim.window('My animation')
W.add(anim.plane.canva(W))
W.show()

Then tune anim.window with constructor options:

Parameter	Default	Description
`title`	`'Animation'`	Title displayed in the window title bar.
`style`	`'dark'`	Visual theme. Available values are `'dark'`, `'light'`, and `'white'`.
`height`	`0.75`	Window height as a fraction of the screen height. For example, `0.75` means 75% of the screen height.
`width`	`None`	Window width as a fraction of the screen width. If `None`, the width is computed from `height` and `aspect_ratio`.
`aspect_ratio`	`1`	Width/height ratio of the animation area (excluding the information dock).
`information`	`None`	Custom `anim.information` subclass for the information dock.

Styling¶

Styling is controlled by the style argument of anim.window.

# Default dark theme
W = anim.window('Night view', style='dark')

# Bright theme for print-like visuals
W2 = anim.window('Day view', style='light')

The dark theme is usually best for high-contrast animated objects, while light is useful when your figure uses dark strokes and you want an interface close to standard report figures.

Adding canvas panels¶

Canvas panels are added with anim.window.add and arranged in a grid. By default, each new panel is appended to the right.

W.add(MyCanva)               # automatic placement
W.add(MyCanva, row=1, col=0) # explicit placement

You can pass a class (instantiated automatically) or an existing object. Extra keyword arguments are forwarded to the canvas constructor (for example anim.plane.canva subclasses):

W.add(clock, city='Europe/Paris')

For instance in the multiple canva demo, each canvas is added by a call to anim.window.add:

W.add(clock, city='America/New_York')
W.add(clock, city='Europe/Paris')
W.add(clock, city='Asia/Singapore')

Timing and playback¶

The animation runs at a fixed frame rate, defaulting to 25 fps. Each frame increments an integer step counter. Real time is step * dt where dt = 1 / fps.

The following attributes can be set before anim.window.show:

Attribute	Default	Description
`fps`	`25`	Frames per second.
`autoplay`	`True`	Start playing automatically when the window opens.
`step_max`	`None`	Maximum step. If set, animation pauses at this value.
`allow_backward`	`False`	Allow backward stepping.
`allow_negative_time`	`False`	Allow step values below zero.

W.fps = 30
W.autoplay = False
W.step_max = 200
W.allow_backward = True

Keyboard shortcuts¶

The following shortcuts are available in every window:

Key	Action
`Space`	Play/pause
`Right`	Step forward by one frame (when paused)
`Left`	Step backward by one frame (if `allow_backward=True`)
`i`	Show/hide the information panel
`Esc`	Close the window

Information dock behavior and content updates are documented in the information section.

Recording a movie¶

Set W.movieFile before calling anim.window.show to record the animation:

W.movieFile = 'output/my_movie.mp4'
W.show()

Additional recording options:

Attribute	Default	Description
`moviefps`	`25`	Output video frame rate.
`movieWidth`	`1600`	Output video width in pixels (must be a multiple of 16).
`keep_every`	`1`	Record one frame every `n` animation frames.