FreeBSD Manual Pages
image_access_storage(3) Arcan Lua API image_access_storage(3) NAME image_access_storage - Access the underlying backing store of a tex- tured video object. SYNOPSIS true or false image_access_storage( vid, callback(vtbl:context, int:width, int:height) ) image_access_storage( vid, callback(vtbl:context, int:width, int:height, int:cols, int:rows) ) DESCRIPTION This function permits limited, blocking, access to a backing store. The primary purpose is to provide quick access to trivial measurements without the overhead of setting up a calctarget and performing read- backs. The function returns false if the backing store was unavailable. The context argument is described in define_calctarget . If the callback provides cols and rows it means that the table repre- sents a textual backing store rather than a pixel one. In that case the following extra functions are available in context : NOTES 1 The table provided in the callback is only valid during the scope of the callback, creating aliases outside this scope and trying to use any table method is a terminal state transition that may be difficult to debug. 2 Most frameserver connections do not synchronize the contents of the backing store buffer due to the added bandwidth cost of per- forming an extra copy each update. This behavior can be changed by calling target_flags and enable TARGET_VSTORE_SYNCH for the specific frameserver. 3 The backing store of a texture video object is not always avail- able, particularly when the engine is running in conservative mode. Make sure that your appl can handle scenarios where the backing store cannot be read. 4 :read is only permitted on a tui backed store. Calling it on a regular one is a terminal state transition. EXAMPLE function image_access_storage0() img = fill_surface(32, 32, 255, 0, 0); image_access_storage(a, function(tbl, w, h) print(w, h, tbl:get(1, 1)); end); end SEE ALSO: define_calctarget(3) image November 2025 image_access_storage(3)
NAME | SYNOPSIS | DESCRIPTION | NOTES | EXAMPLE | SEE ALSO:
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=image_access_storage&sektion=3&manpath=FreeBSD+Ports+15.0>