| from __future__ import annotations |
|
|
| from fractions import Fraction |
| from typing import cast, TYPE_CHECKING |
|
|
| from ..geometry import Region, Size |
| from .._layout import ArrangeResult, Layout, WidgetPlacement |
|
|
| if TYPE_CHECKING: |
| from ..widget import Widget |
|
|
|
|
| class VerticalLayout(Layout): |
| """Used to layout Widgets vertically on screen, from top to bottom.""" |
|
|
| name = "vertical" |
|
|
| def arrange( |
| self, parent: Widget, children: list[Widget], size: Size |
| ) -> ArrangeResult: |
|
|
| placements: list[WidgetPlacement] = [] |
| add_placement = placements.append |
|
|
| parent_size = parent.outer_size |
|
|
| styles = [child.styles for child in children if child.styles.height is not None] |
| total_fraction = sum( |
| [int(style.height.value) for style in styles if style.height.is_fraction] |
| ) |
| fraction_unit = Fraction(size.height, total_fraction or 1) |
|
|
| box_models = [ |
| widget._get_box_model(size, parent_size, fraction_unit) |
| for widget in children |
| ] |
|
|
| margins = [ |
| max((box1.margin.bottom, box2.margin.top)) |
| for box1, box2 in zip(box_models, box_models[1:]) |
| ] |
| if box_models: |
| margins.append(box_models[-1].margin.bottom) |
|
|
| y = Fraction(box_models[0].margin.top if box_models else 0) |
|
|
| _Region = Region |
| _WidgetPlacement = WidgetPlacement |
| for widget, box_model, margin in zip(children, box_models, margins): |
| content_width, content_height, box_margin = box_model |
| next_y = y + content_height |
| region = _Region( |
| box_margin.left, int(y), int(content_width), int(next_y) - int(y) |
| ) |
| add_placement(_WidgetPlacement(region, box_model.margin, widget, 0)) |
| y = next_y + margin |
|
|
| return placements, set(children) |
|
|
