equals method
Tests if an object is an AffineTransformation and has the same matrix as this transformation.
@param obj an object to test @return true if the given object is equal to this object
Implementation
bool equals(Object? obj) {
if (obj == null) return false;
if (!(obj is AffineTransformation)) return false;
AffineTransformation trans = obj;
return m00 == trans.m00 &&
m01 == trans.m01 &&
m02 == trans.m02 &&
m10 == trans.m10 &&
m11 == trans.m11 &&
m12 == trans.m12;
}