Thanks everyone for your help on this.
I started using an image cache - but that did not improve the performance as
much as I thought it should. I then removed the section of my code that
creates NSTrackingsAreas - and the improvement was immediately noticeable.
For the calendar grid I was creating an NSTrackingArea for each cell - in my
case (the calendar is for 7 days with 15 minutes per cell) there was 672
NSTrackingAreas.
I will have to look at alternative solutions to all these NSTrackingAreas to
improve the performance.
Thanks,
Mazen
On Mar 11, 2010, at 2:44 AM, jonat...@mugginsoft.com wrote:
>
>
> On 10 Mar 2010, at 17:13, Mazen M. Abdel-Rahman wrote:
>
>> Hi All,
>>
>> I was able to write a simple calendar view that uses basic cocoa graphics to
>> draw directly on the view (NSBezierPath, etc.). I actually use several
>> different paths for drawing the calendar (it's a weekly calendar) to allow
>> different horizontal line widths (hour, half hour, etc.). The calendar view
>> is inside a scroll view - and is actually about 3 times longer than the view
>> window. The main problem is that the scrolling is not smooth - and my
>> assumption is that it's because the NSBezier stroke functions have to be
>> constantly called to render the calendar.
>>
>> For something as relatively simple as this would moving to core animation -
>> i.e. trying to render the calendar on a layer instead (I am still trying to
>> learn core animation) add performance benefits? And would it allow for
>> smoother scrolling?
>>
> As no one else has offered an opinion:
>
> Moving to CA might offer benefits but you can improve the performance of your
> existing code by using an image cache.
> I do this for an NSView with animated NSBezierPath content and it works fine.
>
> So I would draw my image when the view resizes and there after service -
> (void)drawRect:(NSRect)rect from the image cache.
> You only regen the cache when required, say on resize on content change.
>
> The rough code outline below might help you get something up an running:
>
> NSView subclass:
>
> ivars:
>
> NSRect _cacheRect;
> NSImage *_imageCache;
> BOOL _useImageCache;
>
> - (void)drawRect:(NSRect)rect
> {
>
> if (_useImageCache) {
>
> // validate our rect
> rect = [self validateDrawRect:rect];
>
> // if cache exists use it to update rect.
> // otherwise draw into our rect
> if (_imageCache) {
> [self drawRectFromCache:rect];
> return;
> }
>
> // draw to image cache
> _cacheRect = [self bounds];
> _imageCache = [[NSImage alloc] initWithSize:_cacheRect.size];
> [_imageCache lockFocus];
>
> }
>
> // draw entire bounds rect
> rect = [self bounds];
>
> // draw it
> NSBezierPath *bgPath = [NSBezierPath bezierPathWithRect:rect];
> NSColor *endColor = [NSColor colorWithCalibratedRed:0.988f green:0.988f
> blue:0.988f alpha:1.0f];
> NSColor *startColor = [NSColor colorWithCalibratedRed:0.875f
> green:0.875f blue:0.875f alpha:1.0f];
>
> NSGradient *gradient = [[NSGradient alloc]
> initWithStartingColor:startColor endingColor:endColor];
> [gradient drawInBezierPath:bgPath angle:90.0f];
>
>
> if (_useImageCache) {
> [_imageCache unlockFocus];
>
> // refresh view from cache
> [self drawRectFromCache:rect];
> }
>
> }
>
> /*
>
> draw rect from cache
>
> */
> - (void)drawRectFromCache:(NSRect)rect
> {
> [_imageCache drawInRect:rect fromRect:rect
> operation:NSCompositeSourceOver fraction:1.0f];
> }
> /*
>
> validate the draw rect
>
> */
> - (NSRect)validateDrawRect:(NSRect)rect
> {
> NSRect boundsRect = [self bounds];
>
> // if bounds rect and cache rect are not equal then
> // the cache will have to be updated
> if (!NSEqualRects(boundsRect, _cacheRect)) {
> [self clearDisplayCache];
> }
>
> // if no display cache available then need to draw bounds into cache
> if (!_imageCache) {
> rect = boundsRect;
> }
>
> return rect;
> }
>
> Regards
>
> Jonathan Mitchell
>
> Developer
> http://www.mugginsoft.com
>
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