Gadgets

Gadgets are the building blocks of your app. All gadgets have a size, position, and children. Additionally, gadgets have attributes is_transparent, is_visible and is_enabled that determine whether the gadget is transparent (whether gadgets beneath are rendered), whether the gadget is rendered, or whether input events are dispatched, respectively.

The base gadget is little more than a container for other gadgets. Some other more interesting gadgets include: * Pane, a gadget with a background color. An alpha attribute can modify its transparency. * Graphics, a gadget for arbitrary RGBA textures. * Text, the most general gadget. Its state is an array of cells where each cell carries attributes a terminal character can have such as its character, whether it’s bold, or the color of its foreground.

Size and Pos Hints

If a gadget has a non-None size hint, it will have a size that is some proportion (given by the hint) of its parent. If the parent is resized, the gadget will update its size to follow the size hint. Similarly, for non-None position hints, a gadget will position itself at some proportion of its parent’s size. Position hints can be further controlled with the anchor which determines which point in the gadget is aligned with the position hint (the default is “center”).

Responding to Events

Each gadget has on_key(), on_mouse(), and on_paste() methods to enable responding to input events. Input events are dispatched to every gadget until one of these methods return True to signal that the event was handled.

Collisions

collides_point() will determina if a point is within a gadget’s visible region. to_local() converts a point from absolute coordinates to the gadget’s local coordinates. collides_gadget() can determine if one gadget overlaps another.