libgphoto2/OVERVIEW

Notes
=========================================================================

	* When the cache is turned on, the front-end should
	not manipulate images directly. use the gp_image_ functions to do
	manipulation. the gp_image_ functions return the changed image.
	Saving images is done through gp_file_save.

Program Flow
=========================================================================
Here is the program flow (covering most everything hopefully):

[FE] - Front-end
[GC] - gPhoto core
[LI] - gPhoto camera library

Choosing a Camera
------------------------------------------------------------------------
User selects "Choose Camera"

[FE] Calls "gp_camera_count" to retrieve the number of available cameras
	\
	[GC] open the library directory. opens each library
	supported-camera file ("libraryname.supported").
	A master list is generated and sorted. Total number
	of support cameras is returned.
	/
[FE] Retrieve each camera name by calling "gp_camera_name".
	\
	[GC] returns the camera name from the master list.
	/
[FE] Presents the camera list to the user. They choose. "gp_camera_set"
is then called
	\
	[GC] Camera library is loaded based on camera_number. 
	library functions are loaded. "init" is called.
		\
		[LI] Does whatever it needs to do to initialize
		/
	[GC] sits here and looks pretty
	/
[FE] Calls "gp_camera_abilities" to get the abilities of the selected
camera.
	\
	[GC] calls "abilities"
		\
		[LI] returns the cameras abilities
		/
	[GC] doh dee doh
	/
[FE] Configure GUI/settings according to the camera abilities (black
out "preview" if it doesn't support it, etc...)


Getting an Index
------------------------------------------------------------------------
User selects "Get Index"

[FE] calls "gp_folder_count"
	\
	[GC] calls "folder_count"
		\
		[LI] returns the number of folders on the camera.
		If folder don't exist (only 1 place to keep images),
		returns 1.
		/
	[GC] returns the number of folders
	/
[FE] if the number of folders is > 1, calls "gp_folder_name" for each
folder.
	\
	[GC] calls "folder_name"
		\
		[LI] returns the name of a particular folder
		/
	[GC] ...
	/
[FE] presents user with a folder list. user selects which folder. 
"gp_folder_set" is called
	\
	[GC] if another folder is open already, calls "folder_close"
		\
		[LI] does stuff to close the current folder
		/
	[GC] "folder_set" is called.
		\
		[LI] does stuff to set the current folder
		/
	[GC] "folder_open" is called
		\
		[LI] does stuff to open the current folder
		/
	[GC] uhhh..
	/
[FE] calls "gp_file_count" to retrieve the number of pictures in the
current folder.
	\
	[GC] calls "file_count"
		\
		[LI] returns the number of files.
		/
	[GC] nothing.
	/
[FE] calls "gp_file_get_preview" for each picture to get the thumbnail index.
	\
	[GC] "file_get_preview" is called
		\
		[LI] retrieves the preview
		/
	[GC] Caches the preview file. returns the file data
	/
[FE] displays the index

Getting a picture/sound/etc...
------------------------------------------------------------------------
User select "Get Picture/Sound/etc..."

[FE] calls "gp_file_get"
	\
	[GC] calls "file_get"
		\
		[LI] retrieves the file
		/
	[GC] caches the file. returns the file information.
	/
[FE] displays the file

Manipulating Images (rotate/flip)
------------------------------------------------------------------------
User selects "Rotate/Flip Image" (either full-size image, or thumbnail)

[FE] Calls 	gp_image_(flip_v | flip_h | rotate)
     or		gp_image_preview_(flip_v | flip_h | rotate)
	\
	[GC] Rotates image in cache. returns altered image.
	/
[FE] Displays new image

Saving Images
------------------------------------------------------------------------
User selects "Save (Image | Sound | whatever...)"

[FE] Calls "gp_file_save"
	\
	[GC] If file exists, calls gp_confirm. If return == GP_OK,
	then overwrites the file. If return == GP_ERROR, then just
	returns.
	/
[FE] Says "File saved as ...".

Retrieving library information (summary, manual, about)
------------------------------------------------------------------------
User wants to know something about the camera/library.

[FE] calls "gp_(summary | manual | about"
	\
	[GC] calls (summary | manual | about )
		\
		[LI] returns the appropriate information
		/
	[GC] ...
	/
[FE] displays the information

Files needed by each camera library
-----------------------------------
	* library itself
		"libgphoto_name.so"
		ex: "libgphoto_casio.so"

	* supported camera list
		"libgphoto_name.supported"
		ex: "libgphoto_casio.supported"

		contents are a list of cameras, each on a separate
		line, that that library supports.
		ex:
			Casio QV10
			Casio QV100
			Casio QV39483
		and so on. this makes it easy to add cameras to
		gPhoto when they are confirmed to work.

	* configuration specification
		"libgphoto_name.config"
		ex: "libgphoto_casio.config"

		contents are the spcification for the configuration
		interface. this format needs to be defined. check
		the gphoto.h file for a proposal. this makes it easy
		to change the configuration interface.