Erm, but I obviously need to update the screen more often than every second. I 
don't understand why I should be using an update time of 1 second. I obviously 
need to call "setNeedsDisplay" more often than that...

On 23.10.2020 at 18:09 Alex Zavatone wrote:

> Naaah, it’s not that.  The OSes draw code already handles that at a
> much lower level.  You’re just creating what is a maximum update
> throttle.  You’re not blitting pixels in a video card driver.

> You can try my simple approach and just declare the next update
> time to be the current time + 1 second.  It should work without screen 
> flicker at all.

> We’re not doing low level code.  As far as i know, the MacOS code
> has a triple buffered system that already handles that.

>> On Oct 23, 2020, at 10:51 AM, Andreas Falkenhahn <andr...@falkenhahn.com> 
>> wrote:

>> The problem with that approach is that I'd need to find out the monitor's 
>> refresh rate in order to calculate "nextUpdateTime" and I'm not sure if I 
>> can get this information from all monitors reliably.

>> On 19.10.2020 at 00:09 Alex Zavatone wrote:

>>> It shouldn’t be too hard to roll your own simply based on milliseconds of a 
>>> timer.

>>> Even a simple 

>> if (myMilliseconds >> nextUpdateTime) {
>>>    [updateObject doThatUpdate];    
>>>    nextUpdateTime = myMilliseconds + msThrottle;
>>> }

>>> lets you get a basic throttle.

>>> Cheers, 
>>> Alex Zavatone

>>>> On Oct 15, 2020, at 2:13 PM, Andreas Falkenhahn via Cocoa-dev 
>>>> <cocoa-dev@lists.apple.com> wrote:

>>>> I'm drawing inside an NSView by simply setting its layer's contents to a 
>>>> CGImage which is updated for every frame, e.g. something like this:

>>>>      dp = CGDataProviderCreateWithData(NULL, frameBuf, frameBufSize, NULL);
>>>>      im = CGImageCreate(frameWidth, frameHeight, 8, 32, frameStride, 
>>>> theColorSpace, (CGBitmapInfo) kCGImageAlphaNoneSkipFirst, dp, NULL, FALSE, 
>>>> kCGRenderingIntentDefault);

>>>>      view.layer.contents = (id) im;
>>>>      CGImageRelease(im);
>>>>      CGDataProviderRelease(dp);

>>>> This works fine except that there is no throttle so this will draw as fast 
>>>> as the CPU allows, which of course is a waste of CPU cycles because the 
>>>> monitor only refreshes a certain amount of times per second.

>>>> So is there a convenient way to throttle drawing to the monitor's refresh 
>>>> rate or does this have to be done the hard way by querying the monitor's 
>>>> refresh rate and then setting up a timer which draws in exactly those 
>>>> refresh intervals or how should this be done?

>>>> Note that I'd like to avoid using OpenGL or Metal or whatever is the 
>>>> standard nowadays but I'm mainly interested in an AppKit solution...

>>>> -- 
>>>> Best regards,
>>>> Andreas Falkenhahn                          mailto:andr...@falkenhahn.com

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>> -- 
>> Best regards,
>> Andreas Falkenhahn                            mailto:andr...@falkenhahn.com





-- 
Best regards,
 Andreas Falkenhahn                            mailto:andr...@falkenhahn.com

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