Alpha matte in quartz composer

pho's picture

Hi,

I started using quartz composer recently and I've been exploring it a little bit. However, I didn't find a way of masking objects in the same way I would with an alpha matte in Adobe's After Effects. Does anyone know of a way to achieve that?

I made a video as an example of what i'm trying to do. Here it is: http://img268.imageshack.us/i/ylr.mp4/

Basically, there is a countdown that "cuts a hole" on a square shape.

Thanks

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kurt971's picture
Re: Alpha matte in quartz composer

Hi,

Just use a .png file for the square with hole for the number.... Use photoshop with no background file is the more easy... Or swap layers in QC with black and white .jpg files.. Black<->Alpha.. You can use string to image to made the squares shape too..

So easy I think...

pho's picture
Re: Alpha matte in quartz composer

Thanks for your reply,

I think that either I didn't make myself clear, or I didn't understand your post. I'm sending a qtz file in attachment. What I want is the countdown to make transparency to the orange background.

Regards

PreviewAttachmentSize
350.qtz16.25 KB

kurt971's picture
Re: Alpha matte in quartz composer

Some Math for positioning the text.. sorry..

PreviewAttachmentSize
350+.qtz24.3 KB

pho's picture
Re: Alpha matte in quartz composer

Thank you very much. It works perfectly.