View Full Version : Question about Apple's updated Sketch program

Oct 14, 2009, 01:12 AM
Hi All,
I think this is an easy issue...for those with more knowledge than I :)

I am puzzled about one of the setters of an NSArray (_graphics) in the document.m file. It clearly assigns any objects that were unarchived ( as the setter is called by:
- (BOOL)readFromData:(NSData *)data ofType:(NSString *)typeName error:(NSError **)outError {

....set up stuff.......
[self setGraphics:graphics]; ;

Which calls:

- (void)setGraphics:(NSArray *)graphics {
unsigned i = [_graphics count];
while (i-- > 0) {
[self removeGraphicAtIndex:i];
i = [graphics count];
while (i-- > 0) {
[self insertGraphic:[graphics objectAtIndex:i] atIndex:0];

which calls

- (void)insertGraphic:(SKTGraphic *)graphic atIndex:(unsigned)index {
[[[self undoManager] prepareWithInvocationTarget:self] removeGraphicAtIndex:index];
[_graphics insertObject:graphic atIndex:index];
[graphic setDocument:self];
[self invalidateGraphic:graphic];

and the part that I do not get

- (void)invalidateGraphic:(SKTGraphic *)graphic {
NSArray *windowControllers = [self windowControllers];

[windowControllers makeObjectsPerformSelector:@selector(invalidateGraphic:) withObject:graphic];

I see the general gist, but am lost in the details of the point of the "invalidiateGraphic" call and exactly what it does. If anyone sees the issue, I would gladly like to hear your point of view.
Thanks kindly in advance