41 lines
1.3 KiB
Plaintext
41 lines
1.3 KiB
Plaintext
class WidthModel {
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width: Number
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function expand(self: WidthModel, event: Event): Unit {
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self.width = 260
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}
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}
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class Tint {
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color: String
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function blue(self: Tint, event: Event): Unit {
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self.color = "#526AC7"
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}
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}
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class CachedRect: RectBlock {
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dimensions: WidthModel
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tint: Tint
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function measure(self: CachedRect, mount: Mount, constraints: Constraints): MeasureResult {
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return MeasureResult(self.dimensions.width, 60)
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}
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function paint(self: CachedRect, mount: Mount, geometry: Bounds): DisplayList {
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drawing = RectBlock.paint(self, mount, geometry)
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drawing.commands.at(0).color = self.tint.color
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return drawing
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}
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}
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class ViewportBand: RectBlock {
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function measure(self: ViewportBand, mount: Mount, constraints: Constraints): MeasureResult {
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return MeasureResult(ui.viewport().width, 24)
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}
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}
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dimensions = WidthModel(200)
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tint = Tint("#ED6A5A")
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rect = CachedRect(80, 20, 0, "#ED6A5A", dimensions, tint)
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band = ViewportBand(80, 24, 0, "#237A45")
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blue = Button("只改绘制颜色")
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expand = Button("修改测量依赖")
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blueConnection = blue.on("click", tint.blue)
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expandConnection = expand.on("click", dimensions.expand)
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root = Column(24, 16, TextBlock("改变颜色保留测量缓存；改变宽度重新测量"), band, rect, blue, expand)
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page = Page()
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page.render(root)
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