Capture Pixels on any Display

[David E Blanton]

Here is what I am trying to do.

My users may scan a thread color say Robinson Anton Poly 40, by wrapping the thread around some cardboard stock and then placing this on the scanner bed. As you might imagine there will variations in the color due to the thread being wrapped … peaks , valleys, reflections, etc.

Now we want to bring that thread color into our embroidery program. The scanned image may be on any connected display.

I want to capture a rect centered on the point where the user clicked so I can get a best fit for the color.

This is easy to do on Windows using the SetCapture() functions which directs all events to my app.

How do I get this accomplished on OSX?

-koko

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[David Duncan]

On Feb 15, 2012, at 9:26 AM, David E Blanton wrote:

> I want to capture a rect centered on the point where the user clicked so I can get a best fit for the color.
>

> How do I get this accomplished on OSX?

CGWindow APIs (10.5+) or CGDisplayCreateImageForRect() (10.6+). The latter are preferred if you can require 10.6 or later. See the SonOfGrab sample for an example of the former.
--
David Duncan