File size: 1,873 Bytes
2c3c408 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | 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)
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