angle coordSystem coordSystem det dx dy getCoordSystem hasMirror inverse invert isConformal isEqualTo isIdentity isInvertible isOrtho kIdentity m11 m12 m21 m22 Matrix2d Matrix2d Matrix2d Matrix2d mirroring mirroring operator!= operator* operator* operator* operator*= operator*= operator/ operator/= operator== postMultBy preMultBy rotation scale scaleBy scaleBy scaleX scaleY scaling scaling set setCoordSystem setToIdentity setToMirroring setToMirroring setToProduct setToRotation setToScaling setToScaling setToShearing setToTranslation shearing transformPoints transformVectors transformWith2P translation

m21 float Matrix2d::m21 矩阵元素，代表Y方向线性变换分量