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| -rw-r--r-- | docs/manual.md | 25 |
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diff --git a/docs/manual.md b/docs/manual.md index 584da8f..5600d3f 100644 --- a/docs/manual.md +++ b/docs/manual.md @@ -366,6 +366,31 @@ virtual methods. The simplest way is to take the `mock` camera and rename all occurences. Note, that if you class is going to be called `FooBar`, the upper case variant is `FOO_BAR` and the lower case variant is `foo_bar`. +In order to fully implement a camera, you need to override at least the +following virtual methods: + +* `start_recording`: Take suitable actions so that a subsequent call to + `grab` delivers an image or blocks until one is exposed. +* `stop_recording`: Stop recording so that subsequent calls to `grab` + fail. +* `grab`: Return an image from the camera or block until one is ready. + +## Asynchronous operation + +When the camera supports asynchronous acquisition and announces it with a true +boolean value for `"transfer-asynchronously"`, a mechanism must be setup up +during `start_recording` so that for each new frame the grab func callback is +called. + +## Cameras with internal memory + +Cameras such as the pco.dimax record into their own on-board memory rather than +streaming directly to the host PC. In this case, both `start_recording` and +`stop_recording` initiate and end acquisition to the on-board memory. To +initiate a data transfer, the host calls `start_readout` which must be suitably +implemented. The actual data transfer happens either with `grab` or +asynchronously. + [sub-classing]: http://developer.gnome.org/gobject/stable/howto-gobject.html |