def scaled(size: QSizeF, constraint: QSizeF, mode=Qt.KeepAspectRatio) -> QSizeF:
"""
Return size scaled to fit in the constrains using the aspect mode `mode`.
If width or height of constraint are negative they are ignored,
ie. the result is not constrained in that dimension.
"""
size, constraint = QSizeF(size), QSizeF(constraint)
if size.isEmpty():
return size
if constraint.width() < 0 and constraint.height() < 0:
return size
if mode == Qt.IgnoreAspectRatio:
if constraint.width() >= 0:
size.setWidth(constraint.width())
if constraint.height() >= 0:
size.setHeight(constraint.height())
elif mode == Qt.KeepAspectRatio:
if constraint.width() < 0:
constraint.setWidth(QWIDGETSIZE_MAX)
if constraint.height() < 0:
constraint.setHeight(QWIDGETSIZE_MAX)
size.scale(constraint, mode)
elif mode == Qt.KeepAspectRatioByExpanding:
if constraint.width() < 0:
constraint.setWidth(0)
if constraint.height() < 0:
constraint.setHeight(0)
size.scale(constraint, mode)
return size
