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The Stac BoxConstraints class specifies minimum and maximum dimensions for a widget. It’s commonly used with ConstrainedBox or as part of button styles.

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Properties

PropertyTypeDescription
minWidthdouble?Minimum width constraint in logical pixels.
maxWidthdouble?Maximum width constraint in logical pixels.
minHeightdouble?Minimum height constraint in logical pixels.
maxHeightdouble?Maximum height constraint in logical pixels.

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Example

StacConstrainedBox(
  constraints: StacBoxConstraints(
    minWidth: 100.0,
    maxWidth: 300.0,
    minHeight: 50.0,
    maxHeight: 200.0,
  ),
  child: StacContainer(
    color: StacColors.blue,
    child: StacText(data: 'Constrained'),
  ),
)

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Common Constraint Patterns

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Fixed Width

StacConstrainedBox(
  constraints: StacBoxConstraints(
    minWidth: 200.0,
    maxWidth: 200.0,
  ),
  child: StacElevatedButton(
    child: StacText(data: 'Fixed Width Button'),
  ),
)

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Minimum Size

StacConstrainedBox(
  constraints: StacBoxConstraints(
    minWidth: 150.0,
    minHeight: 100.0,
  ),
  child: StacCard(
    child: StacCenter(
      child: StacText(data: 'At least 150x100'),
    ),
  ),
)

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Maximum Size

StacConstrainedBox(
  constraints: StacBoxConstraints(
    maxWidth: 400.0,
    maxHeight: 300.0,
  ),
  child: StacImage(
    network: 'https://example.com/large-image.jpg',
    fit: StacBoxFit.contain,
  ),
)

​
With Button Style

StacElevatedButton(
  style: StacButtonStyle(
    minimumSize: StacSize(width: 200.0, height: 48.0),
    maximumSize: StacSize(width: 300.0, height: 56.0),
  ),
  child: StacText(data: 'Styled Button'),
)

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Infinite Constraints

Use double.infinity for unbounded constraints: 
StacConstrainedBox(
  constraints: StacBoxConstraints(
    minWidth: double.infinity, // Full width
    minHeight: 100.0,
  ),
  child: StacContainer(
    color: StacColors.blue,
    child: StacCenter(
      child: StacText(
        data: 'Full Width',
        style: StacTextStyle(color: StacColors.white),
      ),
    ),
  ),
)