I'm thinking about enabling (simple) modules to draw on the screen while inactive.
To accomplish this, I'm using a function pointer which has a setter function. The setter function is exported, a module can use it to set a callback function (and un-set it prior to unloading).
The function pointer is checked and executed if not NULL in gui_draw_debug_vals_osd(). I'm using the existing gui_debug_display_modes[] array (core/gui.c) with an additional setting ("plugin") to enable/disable this display callback.
Potential uses are
- displaying special information about something the core doesn't support (example: my s1is port provides extra information about the movie frames while recording)
- enabling background display for my memory browser mod, so I can watch it while using the Canon UI
- I plan to port the EDMAC viewer from ML, it seems to be more useful when one can adjust camera settings while watching it
- ... ?
Proof of concept seems to work.
And here it is. The patch is BIG because it has quite a bit of dependencies.
Actually, all this is needed for the included EDMAC viewer to function as intended.
The EDMAC viewer has an unpleasant "bug" which isn't actually a bug: it needs to read certain DIGIC registers directly, which can cause camera crash:
- when powersave mode kicks in
- during(!) shutdown (from rec mode, usually)
It only happens when its display routine is working, so anybody who would like to try it: please quit the module (with the MENU button) before leaving the cam unattended or shutting it down.
I suspect the DIGIC registers in question should not be read in certain occasions.
I'm using Canon semaphore functions to "protect" the callback function - this protection may not be actually needed.
About the module:
- it only exits when MENU is pressed, otherwise it will stay loaded
- if "Miscellaneous stuff" -> "Debug parameters" -> "Debug data display" is set to "Plugin", it will show its output outside ALT mode as the prop/param/task viewer does
- display update can be enabled/disabled in its normal mode with the SET button
- LEFT/RIGHT switches between overview and detailed view
- UP/DOWN moves the list in detailed mode
- "size" in detailed mode is in bytes (AFAIK), the 1080x239 representation is byte count / row x number of rows
- all numbers are hexadecimal, except the "size" in its 1080x239 representation
- it currently uses an incomplete internal list to get the camera's DIGIC version, new cameras not on the list will default to DIGIC II
The EDMAC viewer is based on the utility built into Magic Lantern (src/edmac.h src/edmac.c src/debug.c). It's possible that some of its data is misinterpreted, in case there are differences between their and our DIGIC configurations.
Many things are not mentioned, I can answer questions.
