An NSSliderCell controls the behaviour and appearance of an associated NSSlider, or a single slider in an NSMatrix. Tick marks are defined in the official standard, but are not implemented in GNUstep.
An NSSliderCell can be customized through its
set...
methods. If these do not provide
enough customization, a subclass can be created, which
overrides any of the follwing methods:
knobRectFlipped:
,
drawBarInside:flipped:
,
drawKnob:
, or
prefersTrackingUntilMouseUp
.
The default implementation returns YES
,
so that the slider continues to track the user's
movement even if the cursor leaves the slider's
track.
Do not call this method directly. Override it in subclasses where the tracking behaviour needs to be different.
Draws the slider's track, not including the bezel, in aRect flipped indicates whether the control view has a flipped coordinate system.
Do not call this method directly, it is provided for subclassing only.
Calculates the rect in which to draw the knob,
then calls drawKnob:
Before calling
this method, a lockFocus
message must
be sent to the cell's control view.
When subclassing NSSliderCell, do not override this
method. Override drawKnob:
instead.
Draws the knob in knobRect. Before
calling this method, a lockFocus
message must be sent to the cell's control view.
Do not call this method directly. It is included for subclassing only.
Returns the rect in which to draw the knob, based
on the coordinate system of the NSSlider or NSMatrix
this NSSliderCell is associated with.
flipped indicates whether or not that
coordinate system is flipped, which
can be determined by sending the
isFlipped
message to the associated
NSSlider or NSMatrix.
Do not call this method directly. It is included for subclassing only.