36 lines
1.7 KiB
Plaintext
36 lines
1.7 KiB
Plaintext
class Policy {
|
|
width: Number
|
|
function narrow(self: Policy, event: Event): Unit { self.width = 280 }
|
|
function wide(self: Policy, event: Event): Unit { self.width = 560 }
|
|
}
|
|
class ArrangedColumn: Column {
|
|
policy: Policy
|
|
function arrange(self: ArrangedColumn, mount: Mount, geometry: Bounds): Arrangement {
|
|
result = Column.arrange(self, mount, geometry)
|
|
result.children.at(0).width = self.policy.width
|
|
return result
|
|
}
|
|
}
|
|
class MeasuredColumn: Column {
|
|
width: Number
|
|
function measure(self: MeasuredColumn, mount: Mount, constraints: Constraints): MeasureResult {
|
|
result = Column.measure(self, mount, constraints)
|
|
result.width = self.width
|
|
return result
|
|
}
|
|
}
|
|
policy = Policy(280)
|
|
paragraph = TextBlock("源码 arrange 改变分配宽度后，文字会按实际宽度重新测量。增加的高度继续影响容器和相邻对象，直到整棵布局稳定后才发布。这里与下面使用的是同一个 TextBlock；每个 Mount 都有自己的约束与几何。同一套内存对象不需要复制业务状态，也不通过丢弃传播来结束更新。")
|
|
tail = TextBlock("这一行跟随上方段落。")
|
|
arranged = ArrangedColumn(0, 12, paragraph, tail, policy)
|
|
measured = MeasuredColumn(0, 12, paragraph, TextBlock("这一段的宽度来自源码 measure。"), 360)
|
|
narrow = Button("arrange 为 280")
|
|
wide = Button("arrange 为 560")
|
|
narrowConnection = narrow.on("click", policy.narrow)
|
|
wideConnection = wide.on("click", policy.wide)
|
|
page = Page()
|
|
page.title = "约束协商"
|
|
page.render(Column(24, 16, Row(0, 12, narrow, wide), arranged, measured))
|
|
ui.window().resize(850, 700)
|
|
ui.window().setTitle("测量与排列直到稳定")
|