wijjit.layout.scroll.ScrollManager

class wijjit.layout.scroll.ScrollManager(content_size, viewport_size, initial_position=0)[source]

Manages scroll state and operations for a scrollable container.

This class provides methods for scrolling, handles bounds checking, and calculates visible content ranges. It maintains the scroll state and ensures all scroll operations are valid.

Parameters:

content_size (int) – Total content size (lines or columns)
viewport_size (int) – Viewport size (visible lines or columns)
initial_position (int, optional) – Initial scroll position (default: 0)

Variables:

state (ScrollState) – Current scroll state

__init__(content_size, viewport_size, initial_position=0)[source]

Parameters:

content_size (int)
viewport_size (int)
initial_position (int)

Return type:

None

Methods

`__init__`(content_size, viewport_size[, ...])
`get_visible_range`()	Get the range of visible content indices.
`page_down`()	Scroll down by one viewport.
`page_up`()	Scroll up by one viewport.
`scroll_by`(delta)	Scroll by a relative amount.
`scroll_to`(position)	Scroll to an absolute position.
`scroll_to_bottom`()	Scroll to the end (maximum scroll position).
`scroll_to_top`()	Scroll to the beginning (position 0).
`update_content_size`(size)	Update content size and adjust scroll position if needed.
`update_viewport_size`(size)	Update viewport size and adjust scroll position if needed.

scroll_by(delta)[source]

Scroll by a relative amount.

Parameters:: delta (int) – Amount to scroll (positive = down/right, negative = up/left)
Returns:: New scroll position after clamping
Return type:: int

scroll_to(position)[source]

Scroll to an absolute position.

Parameters:: position (int) – Target scroll position
Returns:: Actual scroll position after clamping
Return type:: int

scroll_to_top()[source]

Scroll to the beginning (position 0).

Returns:: New scroll position (always 0)
Return type:: int

scroll_to_bottom()[source]

Scroll to the end (maximum scroll position).

Returns:: New scroll position (max_scroll)
Return type:: int

page_up()[source]

Scroll up by one viewport.

Returns:: New scroll position
Return type:: int

page_down()[source]

Scroll down by one viewport.

Returns:: New scroll position
Return type:: int

update_content_size(size)[source]

Update content size and adjust scroll position if needed.

Parameters:: size (int) – New content size
Return type:: None

Notes

If the new content size results in a smaller max_scroll, the scroll position will be clamped to the new maximum.

update_viewport_size(size)[source]

Update viewport size and adjust scroll position if needed.

Parameters:: size (int) – New viewport size
Return type:: None

Notes

If the new viewport size results in a smaller max_scroll, the scroll position will be clamped to the new maximum.

get_visible_range()[source]

Get the range of visible content indices.

Returns:: (start_index, end_index) where end_index is exclusive. For example, (5, 10) means indices 5, 6, 7, 8, 9 are visible.
Return type:: tuple of int

Examples

>>> manager = ScrollManager(content_size=100, viewport_size=10)
>>> manager.scroll_to(20)
20
>>> manager.get_visible_range()
(20, 30)