Re: Throttling drawing to vertical refresh
Re: Throttling drawing to vertical refresh
- Subject: Re: Throttling drawing to vertical refresh
- From: Andreas Falkenhahn via Cocoa-dev <email@hidden>
- Date: Sun, 18 Oct 2020 11:37:04 +0200
Not quite. AppKit throttle view refresh to 60fps but it certainly won't
throttle code that changes the gfx more often than that, i.e. something like
this
for(;;) view.layer.contents = (id) getNextFrame();
will hog the CPU. So I need some external timing mechanism to set
layer.contents not more often than necessary. I need to see if CADisplayLink
can do that...
On 16.10.2020 at 00:48 Graham Cox wrote:
> Appkit already throttles view refreshes to 60fps. There’s nothing you need to
> do.
> —Graham
>> On 16 Oct 2020, at 6:13 am, Andreas Falkenhahn via Cocoa-dev
>> <email@hidden> 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:email@hidden
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--
Best regards,
Andreas Falkenhahn mailto:email@hidden
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