cssExpression property
Returns the expression part of a CSS declaration. Declaration is:
property:expression;
E.g., if property is color then expression could be rgba(255,255,0) the CSS declaration would be 'color:rgba(255,255,0);'.
then _cssExpression would return 'rgba(255,255,0)'. See www.w3.org/TR/CSS21/grammar.html
Implementation
@override
String get cssExpression => (top == left && bottom == right && top == right)
? '${left}px'
: "${top != null ? '$top' : '0'}px "
"${right != null ? '$right' : '0'}px "
"${bottom != null ? '$bottom' : '0'}px "
"${left != null ? '$left' : '0'}px";