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45 lines
2.0 KiB
Markdown
Executable File
45 lines
2.0 KiB
Markdown
Executable File
---
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title: Hit Test Slop
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layout: docs
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permalink: /docs/hit-test-slop.html
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prevPage: layout-transition-api.html
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nextPage: batch-fetching-api.html
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---
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`ASDisplayNode` has a `hitTestSlop` property of type `UIEdgeInsets` that when set to a non-zero inset, increase the bounds for hit testing to make it easier to tap or perform gestures on this node.
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ASDisplayNode is the base class for all nodes, so this property is available on any of Texture's nodes.
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<div class = "note">
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<strong>Note:</strong> This affects the default implementation of <code>-hitTest</code> and <code>-pointInside</code>, so subclasses should call super if you override it and want hitTestSlop applied.
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</div>
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A node's ability to capture touch events is restricted by its parent's bounds + parent hitTestSlop UIEdgeInsets. Should you want to extend the hitTestSlop of a child outside its parent's bounds, simply extend the parent node's hitTestSlop to include the child's hitTestSlop needs.
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### Usage
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A common need for hit test slop, is when you have a text node (aka label) you'd like to use as a button. Often, the text node's height won't meet the 44 point minimum recommended for tappable areas. In that case, you can calculate the difference, and apply a negative inset to your label to increase the tappable area.
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<div class = "highlight-group">
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<span class="language-toggle"><a data-lang="swift" class="swiftButton">Swift</a><a data-lang="objective-c" class = "active objcButton">Objective-C</a></span>
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<div class = "code">
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<pre lang="objc" class="objcCode">
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ASTextNode *textNode = [[ASTextNode alloc] init];
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CGFloat padding = (44.0 - button.bounds.size.height)/2.0;
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textNode.hitTestSlop = UIEdgeInsetsMake(-padding, 0, -padding, 0);
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</pre>
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<pre lang="swift" class = "swiftCode hidden">
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let textNode = ASTextNode()
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let padding = (44.0 - button.bounds.size.height)/2.0
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textNode.hitTestSlop = UIEdgeInsetsMake(-padding, 0, -padding, 0)
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</pre>
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</div>
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</div>
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<div class = "note">
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To visualize <code>hitTestSlop</code>, check out the <a href="debug-tool-hit-test-visualization">debug tool</a>.
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</div>
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