Instance Property

opaque

A Boolean value indicating whether the view fills its frame rectangle with opaque content.

Declaration

@property(getter=isOpaque, readonly) BOOL opaque;

Discussion

The default value of this property is NO to reflect the fact that views do no drawing by default. Subclasses can override this property and return YES to indicate that the view completely covers its frame rectangle with opaque content. Doing so can improve performance during drawing operations by eliminating the need to render content behind the view.

See Also

Invalidating the View’s Content

- setNeedsDisplayInRect:

Marks the region of the view within the specified rectangle as needing display, increasing the view’s existing invalid region to include it.

needsDisplay

A Boolean value that determines whether the view needs to be redrawn before being displayed.

- display

Displays the view and all its subviews if possible, invoking each of the NSView methods lockFocus, drawRect:, and unlockFocus as necessary.

- displayRect:

Acts as display, but confining drawing to a rectangular region of the view.

- displayRectIgnoringOpacity:

Displays the view but confines drawing to a specified region and does not back up to the first opaque ancestor—it simply causes the view and its descendants to execute their drawing code.

- displayRectIgnoringOpacity:inContext:

Causes the view and its descendants to be redrawn to the specified graphics context.

- displayIfNeeded

Displays the view and all its subviews if any part of the view has been marked as needing display.

- displayIfNeededInRect:

Acts as displayIfNeeded, confining drawing to a specified region of the view.

- displayIfNeededIgnoringOpacity

Acts as displayIfNeeded, except that this method doesn’t back up to the first opaque ancestor—it simply causes the view and its descendants to execute their drawing code.

- displayIfNeededInRectIgnoringOpacity:

Acts as displayIfNeeded, but confining drawing to aRect and not backing up to the first opaque ancestor—it simply causes the view and its descendants to execute their drawing code.

- translateRectsNeedingDisplayInRect:by:

Translates the display rectangles by the specified delta.

- viewWillDraw

Informs the view that it will be required to draw content.