Re: Drawing on top of QTCaptureView
Re: Drawing on top of QTCaptureView
- Subject: Re: Drawing on top of QTCaptureView
- From: PCWiz <email@hidden>
- Date: Sun, 3 Jan 2010 10:20:47 -0700
This probably isn't relevant, but NSBoxes aren't the best way to create crosshairs. It would be cleaner to just make a (very) simple NSView subclass that draws the 2 lines.
Independent Cocoa Developer, Macatomy Software
http://macatomy.com
On 2010-01-03, at 9:30 AM, Bengt Nilsson wrote:
> Hi again,
>
> After reading about layer-backed views in http://www.macresearch.org/tutorial-intro-core-animation, I enabled it in IB and this was the solution.
> The cross-hair by two NSBox-es added in IB stayed on while the USB camera review was running.
> Thanks for all the support.
>
> 1 jan 2010 kl. 13.13 skrev Mike Abdullah:
>
>> QTCaptureView is almost certainly internally using something along the lines of OpenGL internally to draw onscreen with acceptable performance. This means you can't draw on top of it with standard Cocoa drawing techniques. The options:
>>
>> A) Use an overlay window
>>
>> B) Implement the -view:willDisplayImage: delegate method and return a new image that will draw with the crosshairs
>>
>> C) Place the capture view in a layer-backed view hierarchy and add an overlay view – I don't know if QTCaptureView supports being layer-backed, or if an overlay view will then work.
>>
>> D) Switch to QTCaptureLayer. Add an overlay layer for the crosshairs.
>>
>> On 31 Dec 2009, at 16:14, Bengt Nilsson wrote:
>>
>>> I need to draw a cross-hair on top of a QTCaptureView with a video preview from a USB camera.
>>> For this app, I am starting from the sample project QTRecorder.
>>> I create the cross-hair line in the Interface Builder.
>>> Problem is that the video is always on top, overwriting the cross-hair lines.
>>> Is there a way to let the cross-hair lines be drawn in front of the video, by some property setting in IB for the lines?
>>> I tried different settings, like "move to front", defining "parent", etc., but nothing seems to help.
>>> Or do they need to be drawn programatically?
>>>
>>> BN
>>>
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>
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