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This is the API documentation for Pugl.
This documentation is based around the [C API](@ref pugl_api),
there is also a [C++ API](@ref pugl) in the `pugl` namespace.
The Pugl API revolves around two main objects:
the [World](@ref world) and the [View](@ref view).
An application creates a single world to manage top-level state,
then creates one or more views to display.
## World
The [World](@ref world) contains all top-level state,
and manages views and the event loop.
A world must be [created](@ref puglNewWorld) before any views,
and it must outlive all views.
## View
A [View](@ref view) is a drawable region that receives events.
Creating a visible view is a multi-step process.
When a new view is [created](@ref puglNewView),
it does not yet represent a real system view or window.
To display, it must first have a [backend](@ref puglSetBackend)
and [event handler](@ref puglSetEventFunc) set,
and be configured by [setting hints](@ref puglSetViewHint)
and optionally [adjusting the frame](@ref frame).
The [Backend](@ref PuglBackend) controls drawing for a view.
Pugl includes [Cairo](@ref cairo) and [OpenGL](@ref gl) backends,
as well as a [stub](@ref stub) backend that creates a native window with no drawing context.
Once the view is configured,
it can be [created](@ref puglCreateWindow) and [shown](@ref puglShowWindow).
By default a view will correspond to a top-level system window.
To create a view within another window,
it must have a [parent window set](@ref puglSetParentWindow) before being created.
## Events
[Events](@ref events) are sent to a view when it has received user input or must be drawn.
Events are handled by the [event handler](@ref PuglEventFunc) set during initialisation.
This function is called whenever something happens that the view must respond to.
This includes user interaction like mouse and keyboard input,
and system events like window resizing and exposure.
## Event Loop
Two functions are used to drive the event loop:
* #puglPollEvents waits for events to become available.
* #puglDispatchEvents processes all pending events.
Redrawing is accomplished by calling #puglPostRedisplay or #puglPostRedisplayRect,
which post expose events to the queue.
## Error Handling
Most functions return a [Status](@ref status) which should be checked to detect failure.
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