certflow.widgets.flow_layout 源代码

"""自动换行的 ``FlowLayout``。

根治「标签 + 控件」稀疏单控件被 ``addStretch()`` 撑满整行的问题（重构计划第 4/5 节）。
控件按内容宽度排布，一行放不下自动折到下一行。
"""

from __future__ import annotations

from PySide6.QtCore import QRect, QSize, Qt
from PySide6.QtWidgets import QLayout, QWidget




class FlowLayout(QLayout):
    """流布局：水平排布子项，超出宽度自动换行。"""

    def __init__(self, parent: QWidget | None = None, margin: int = 0, spacing: int = -1) -> None:
        super().__init__(parent)
        if parent is not None:
            self.setContentsMargins(margin, margin, margin, margin)
        self.setSpacing(spacing if spacing >= 0 else 6)
        self._items: list[QLayout.Item] = []



    def addItem(self, item: QLayout.Item) -> None:  # noqa: N802
        self._items.append(item)




    def count(self) -> int:  # noqa: N802
        return len(self._items)




    def itemAt(self, index: int) -> QLayout.Item | None:  # noqa: N802
        return self._items[index] if 0 <= index < len(self._items) else None




    def takeAt(self, index: int) -> QLayout.Item | None:  # noqa: N802
        return self._items.pop(index) if 0 <= index < len(self._items) else None




    def expandingDirections(self) -> Qt.Orientations:  # noqa: N802
        return Qt.Orientation(0)




    def hasHeightForWidth(self) -> bool:  # noqa: N802
        return True




    def heightForWidth(self, width: int) -> int:  # noqa: N802
        return self._do_layout(QRect(0, 0, width, 0), True)




    def setGeometry(self, rect: QRect) -> None:  # noqa: N802
        super().setGeometry(rect)
        self._do_layout(rect, False)




    def sizeHint(self) -> QSize:  # noqa: N802
        return self.minimumSize()




    def minimumSize(self) -> QSize:  # noqa: N802
        size = QSize()
        for item in self._items:
            size = size.expandedTo(item.minimumSize())
        margins = self.contentsMargins()
        return size + QSize(
            2 * margins.left() + 2 * margins.right(),
            2 * margins.top() + 2 * margins.bottom(),
        )


    def _do_layout(self, rect: QRect, test_only: bool) -> int:
        margins = self.contentsMargins()
        effective = rect.adjusted(
            +margins.left(), +margins.top(), -margins.right(), -margins.bottom()
        )
        x = effective.x()
        y = effective.y()
        line_height = 0
        space_x = self.spacing()
        space_y = self.spacing()

        for item in self._items:
            w = item.sizeHint().width()
            h = item.sizeHint().height()
            next_x = x + w + space_x
            if next_x - space_x > effective.right() and line_height > 0:
                x = effective.x()
                y += line_height + space_y
                next_x = x + w + space_x
                line_height = 0
            if not test_only:
                item.setGeometry(QRect(x, y, w, h))
            x = next_x
            line_height = max(line_height, h)

        return y + line_height - rect.y() + margins.bottom()