performLayout method
Implementation
@override
void performLayout(BoxConstraints constraints) {
final childConstraints = BoxConstraints(
minWidth: (constraints.minWidth - padding.horizontal).clamp(0, 0x3FFFFFFF),
maxWidth: (constraints.maxWidth - padding.horizontal).clamp(0, 0x3FFFFFFF),
minHeight: (constraints.minHeight - padding.vertical).clamp(0, 0x3FFFFFFF),
maxHeight: (constraints.maxHeight - padding.vertical).clamp(0, 0x3FFFFFFF),
);
child?.layout(childConstraints);
final childW = child?.width ?? 0;
final childH = child?.height ?? 0;
final w = (constraints.minWidth > childW + padding.horizontal)
? constraints.minWidth
: childW + padding.horizontal;
final h = (constraints.minHeight > childH + padding.vertical)
? constraints.minHeight
: childH + padding.vertical;
setSize(w, h);
child?.setOffset(padding.left, padding.top);
}