153 lines
5.7 KiB
Python
153 lines
5.7 KiB
Python
"""布局意图展开：算出每个组件的目标位置和尺寸，输出前端已有的 move 和 resize
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纯函数，只读大屏；只输出有变化的动作。坐标取整，相邻组件共用同一条边，避免累积误差
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"""
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from math import ceil
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from app.schemas.actions import (
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AlignAction,
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ArrangeAction,
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DistributeAction,
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MoveAction,
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ResizeAction,
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SetLayoutAction,
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)
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from app.schemas.actions.layout import Area
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from app.schemas.screen import Screen, ScreenNode
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Primitive = MoveAction | ResizeAction
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def _nodes(screen: Screen, ids: list[str]) -> list[ScreenNode]:
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by_id = {node.id: node for node in screen.nodes}
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if missing := [item for item in ids if item not in by_id]:
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raise ValueError(f"目标组件不存在: {'、'.join(missing)}")
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return [by_id[item] for item in ids]
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def _place(node: ScreenNode, x, y, width, height) -> list[Primitive]:
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"""从当前布局变成目标布局，没变的项不输出"""
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layout = node.layout
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result: list[Primitive] = []
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if (x, y) != (layout.x, layout.y):
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result.append(
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MoveAction(target_id=node.id, delta_x=x - layout.x, delta_y=y - layout.y)
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)
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if (width, height) != (layout.width, layout.height):
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result.append(ResizeAction(target_id=node.id, width=width, height=height))
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return result
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def _canvas_area(screen: Screen) -> Area:
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return Area(x=0, y=0, width=screen.canvas.width, height=screen.canvas.height)
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def _bounds(nodes: list[ScreenNode]) -> Area:
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left = min(n.layout.x for n in nodes)
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top = min(n.layout.y for n in nodes)
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right = max(n.layout.x + n.layout.width for n in nodes)
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bottom = max(n.layout.y + n.layout.height for n in nodes)
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return Area(x=left, y=top, width=right - left, height=bottom - top)
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def arrange(screen: Screen, action: ArrangeAction) -> list[Primitive]:
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nodes = _nodes(screen, action.target_ids)
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count = len(nodes)
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columns = {"row": count, "column": 1, "grid": action.columns}[action.mode]
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rows = ceil(count / columns)
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area = action.area or _canvas_area(screen)
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left = area.x + action.padding
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top = area.y + action.padding
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cell_w = (area.width - 2 * action.padding - action.gap * (columns - 1)) / columns
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cell_h = (area.height - 2 * action.padding - action.gap * (rows - 1)) / rows
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if cell_w <= 0 or cell_h <= 0:
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raise ValueError(
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f"区域放不下 {count} 个组件：区域 {area.width:g}x{area.height:g}，"
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f"边距 {action.padding:g}、间距 {action.gap:g}，减小间距或边距"
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)
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result: list[Primitive] = []
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for index, node in enumerate(nodes):
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row, column = divmod(index, columns)
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x0 = left + column * (cell_w + action.gap)
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y0 = top + row * (cell_h + action.gap)
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# 取整的是边，不是宽度，相邻单元格不会因为取整多出缝隙或重叠
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x, y = round(x0), round(y0)
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result += _place(node, x, y, round(x0 + cell_w) - x, round(y0 + cell_h) - y)
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return result
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def align(screen: Screen, action: AlignAction) -> list[Primitive]:
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nodes = _nodes(screen, action.target_ids)
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box = _canvas_area(screen) if action.to == "canvas" else _bounds(nodes)
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result: list[Primitive] = []
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for node in nodes:
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layout = node.layout
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x, y = layout.x, layout.y
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if action.horizontal == "left":
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x = box.x
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elif action.horizontal == "center":
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x = round(box.x + (box.width - layout.width) / 2)
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elif action.horizontal == "right":
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x = box.x + box.width - layout.width
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if action.vertical == "top":
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y = box.y
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elif action.vertical == "middle":
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y = round(box.y + (box.height - layout.height) / 2)
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elif action.vertical == "bottom":
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y = box.y + box.height - layout.height
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result += _place(node, x, y, layout.width, layout.height)
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return result
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def distribute(screen: Screen, action: DistributeAction) -> list[Primitive]:
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horizontal = action.axis == "horizontal"
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nodes = sorted(
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_nodes(screen, action.target_ids),
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key=lambda n: n.layout.x if horizontal else n.layout.y,
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)
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box = action.area or _bounds(nodes)
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start, span = (box.x, box.width) if horizontal else (box.y, box.height)
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sizes = [n.layout.width if horizontal else n.layout.height for n in nodes]
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if action.gap is not None:
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gap = action.gap
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elif len(nodes) < 2:
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raise ValueError("摊匀间距至少需要 2 个组件")
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else:
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gap = (span - sum(sizes)) / (len(nodes) - 1)
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if gap < 0:
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raise ValueError(
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f"这些组件的{'宽' if horizontal else '高'}度合计 {sum(sizes):g}，"
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f"超过可用的 {span:g}，排不开"
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)
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result: list[Primitive] = []
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cursor = start
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for node, size in zip(nodes, sizes, strict=True):
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position = round(cursor)
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layout = node.layout
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x, y = (position, layout.y) if horizontal else (layout.x, position)
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result += _place(node, x, y, layout.width, layout.height)
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cursor += size + gap
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return result
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def set_layout(screen: Screen, action: SetLayoutAction) -> list[Primitive]:
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(node,) = _nodes(screen, [action.target_id])
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layout = node.layout
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return _place(
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node,
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layout.x if action.x is None else action.x,
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layout.y if action.y is None else action.y,
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layout.width if action.width is None else action.width,
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layout.height if action.height is None else action.height,
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)
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# 布局意图的 type -> 展开函数；新增意图时在这里注册
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EXPANDERS = {
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"arrange": arrange,
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"align": align,
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"distribute": distribute,
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"set_layout": set_layout,
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}
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