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title: The Layout Process | ||
--- | ||
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The ability for all your views to render with the right dimensions and positions requires a run of "the layout process". When rendering, a recursive process runs through every view in the **view hierarchy** in two passes — a measure pass and a layout pass. | ||
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During **the measure pass** every view is measured to obtain its desired size. The following properties are considered during the measuring: | ||
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- `width`, `height` | ||
- `minWidth`, `minHeight` | ||
- `visibility` | ||
- `marginTop`, `marginRight`, `marginBottom`, `marginLeft` | ||
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During **the layout pass** every view is placed in a specific layout slot. The slot is determined by the result of the measure pass and the following properties: | ||
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- `marginTop`, `marginRight`, `marginBottom`, `marginLeft` | ||
- `horizontalAlignment`, `verticalAlignment` | ||
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The layout process is by nature an resource-intensive process and it's performance highly depends on the number views (and complexity). | ||
<!-- TODO: fix links --> | ||
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:::tip | ||
It's a good practice to minimize deep nesting of views. Instead, utilize different [Layout Containers](/ui/#layout-containers) to achieve a simpler and more organized view hierarchy. This approach improves readability, maintainability and performance. | ||
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**For example:** don't treat `<StackLayout>` as a `<div>` — instead try to use a `<GridLayout>` with specific `rows` and `columns` to achieve the same result: | ||
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- Bad Practice: | ||
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```html | ||
<StackLayout> | ||
<StackLayout orientation="horizontal"> | ||
<SomeItem /> | ||
<SomeItem /> | ||
</StackLayout> | ||
<StackLayout orientation="horizontal"> | ||
<!-- ... --> | ||
</StackLayout> | ||
</StackLayout> | ||
``` | ||
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- Good Practice: | ||
<!-- --> | ||
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```html | ||
<GridLayout rows="auto, auto" columns="auto, auto"> | ||
<SomeItem row="0" col="0" /> | ||
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<SomeItem row="0" col="1" /> | ||
<!-- ... row="1" ... --> | ||
</GridLayout> | ||
``` | ||
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One-offs are fine with the `<StackLayout>` approach, but building an entire app with the first approach will usually result in poor performance. | ||
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::: |
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