class Paragraph: TextBlock {
    function measure(self: Paragraph, mount: Mount, constraints: Constraints): MeasureResult {
        return TextBlock.measure(self, mount, constraints)
    }
    function paint(self: Paragraph, mount: Mount, geometry: Bounds): DisplayList {
        return TextBlock.paint(self, mount, geometry)
    }
}
class Actions {
    window: Window
    paragraph: TextBlock
    full: String
    function narrow(self: Actions, event: Event): Unit { self.window.resize(800, 650) }
    function wide(self: Actions, event: Event): Unit { self.window.resize(1200, 650) }
    function short(self: Actions, event: Event): Unit { self.paragraph.setText("短文本：同一个对象、同一个 Mount。") }
    function restore(self: Actions, event: Event): Unit { self.paragraph.setText(self.full) }
}
full = "GUI 和代码操控同一套 Aster 内存对象。这个段落同时出现在两个窗口：对象内容相同，每个 Mount 根据自己的可用宽度换行。窗口变窄，段落高度增加，后面的对象向下移动；窗口变宽，段落高度减小，后面的对象向上移动。对象身份和已有 Mount 身份保持稳定。English words wrap at word boundaries; a_long_unbroken_identifier_also_wraps_when_it_cannot_fit_on_one_line. 中文、组合字符 é 与 emoji 👩‍💻 使用同一套字体整形。再次修改文字会重新计算高度，并更新两个窗口，不需要复制业务对象。"
paragraph = Paragraph(full)
tail = TextBlock("这一行的位置由前面段落的实际高度决定。")
actions = Actions(ui.window(), paragraph, full)
narrow = Button("变窄")
wide = Button("变宽")
short = Button("短文本")
restore = Button("恢复段落")
narrowConnection = narrow.on("click", actions.narrow)
wideConnection = wide.on("click", actions.wide)
shortConnection = short.on("click", actions.short)
restoreConnection = restore.on("click", actions.restore)
page = Page()
page.title = "约束下的文字换行"
page.render(Column(24, 16, Row(0, 12, narrow, wide, short, restore), paragraph, tail))
other = Window()
other.resize(720, 500)
other.setTitle("同一个段落 · 另一组宽度")
other.moveTo(1700, 80)
second = Page()
second.title = "共享 Paragraph"
second.render(Column(24, 16, paragraph))
second.open(other)
page.activate()
ui.window().resize(800, 650)
ui.window().setTitle("文字换行与相邻布局")
ui.window().moveTo(50, 80)
ui.window().focus()