Re: Drawing on top of QTCaptureView
Re: Drawing on top of QTCaptureView
- Subject: Re: Drawing on top of QTCaptureView
- From: Bengt Nilsson <email@hidden>
- Date: Sat, 2 Jan 2010 14:42:25 +0100
- Auth-sender: email@hidden
Thanks for the advice. Some extreme newbie questions:
A) Any documentation on this subject? Can this be done in IB?
B) What is the simplest object that will draw a simple line? I have found NSBox (from IB) and NSBezierPath from docs, both with lots of bells and whistles... Is there no NSLine, NSPath?
C)
D) Not supported in IB, so I will wait with this for a while.
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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