+++ /dev/null
-This file summarizes primary aspects of the NS port architecture. If
-possible, it should be updated for changes.
-
-Currently it summarizes the state as of:
-
- summer 2008 shortly after merging to trunk
-
-
-
-Startup
--------
-
-Init sequence:
- emacs.c: ns_alloc_autorelease_pool() nsterm.m
- emacs.c: ns_init_paths() nsterm.m
- - override EMACSLOADPATH, etc. so resources can be found in-bundle
- emacs.c: init_display() dispnew.c
- - sets Vwindow_system (window-system) to 'ns
- emacs.c: loadup.el -> startup.el -> ns-initialize-window-system
- -> x-open-connection (nsfns.m)
- - ns-list-services
- -> nsterm.m: ns_term_init()
- - EmacsApp sharedApplication
- - read NS defaults (org.gnu.Emacs.plist)
- - init X-style color list
- - ns_create_terminal()
- - NSApp run (goes to applicationDidFinishLaunching which terminates
- event loop -- see below)
-
-
-
-Event Loop
-----------
-
-In an NS application, the event loop is normally managed by system and all
-user code is event-driven. [NSApp run] is called by user and never returns.
-
-In Emacs, the event loop is managed by emacs itself.
-
-The NS port mediates between these two styles by intercepting the NS event
-dispatch at [NSApp sendEvent]. If a special event is detected, the event loop
-is broken, and control returned to Emacs. This special event is sent by
-ns_send_appdefined, which is called under these circumstances:
-
- - if a user input event is received
- - when a timeout fires
-
-NS event processing is instigated from Emacs through ns_select() and
-ns_read_socket() in nsterm.m. Parts of the codepaths leading to these
-functions are:
-
-
- keyboard.c:read_avail_input()
- -> ns_read_socket (ns_send_appdefined) -> [NSApp run]
-
- process.c:wait_reading_process_output()
- -> ns_select -> gobble_input (global inNsSelect=1)
- -> ns_read_socket (ns_send_appdefined if !expected) -> [NSApp run]
-
- sysdep.c:sys_select() -> read_input_waiting()
- -> ns_read_socket (send_appdefined) -> [NSApp run]
- [this codepath may not be used]
-
-
-Currently ctrl-g is not detected in as many circumstances as other emacsen.
-It is not certain whether this is due to the means of event loop integration,
-or errors of omission in the NS code. This is an area for improvement.
-Also, see the article here and its containing thread:
-
-http://article.gmane.org/gmane.emacs.devel/92021/match=handling%5fsignal
-
-
-
-
-Text Rendering and Font Handling
---------------------------------
-
-nsfont.m implements the font driver, responsible for managing fonts and
-rendering text. Fonts are obtained through NSFontManager. Rendering must be
-done at a low level due to emacs' fine control over this process, therefore
-there are different approachs under Cocoa and GNUstep. Under GNUstep, the
-original NeXT Display PostScript (DPS) APIs are available and used. Under
-Cocoa, these were removed and Quartz drawing functions replaced them.
-
-In both cases, font glyphs are accessed through UTF8 character
-representations. It would be preferable to use unicode indices, but prior
-attempts at this have failed.
-
-Multi-script fontsets are auto-created in nsfont_make_fontset_for_font() using
-the facilities of NSTextStorage and NSLayoutManager.
-
-
-Object Architecture
--------------------
-
-Unlike the other GUIs, the NS interface is based on a high-level and
-object-oriented API. This creates some tension in the code because emacs
-itself has been architected around the low-level Xlib and Xt APIs. The NS
-port tries to strike a balance between simplifying code on its side using OO
-features, and keeping code as similar as possible to other ports to ease
-maintenance. The following are the main classes (see nsterm.h):
-
-EmacsApp : NSApplication
- - event loop integration, interapp comms point for Finder (NSWorkspace) msgs,
- Services
- - one global instance (NSApp)
- - nsterm.m
-
-EmacsView : NSView <TextInput>
- - handles rendering of text and fringe, interapp comms for drag/drop
- - instance for each frame
- - child of window's content view
- - nsterm.m
-
-EmacsWindow : NSWindow
- - utility override for resize handling
-
-EmacsScroller : NSScroller
- - instance for each emacs window, renders scrollbar
- - child of window's content view
- - nsterm.m
-
-EmacsImage : NSImage
- - image rendering, toolbar icons, stippling, fringe bitmaps
- - instance for each image
- - nsimage.m
-
-EmacsMenu : NSMenu
- - menu management
- - one tree of instances for menubar, one instance for each popup menu
- - nsmenu.m
-
-EmacsToolbar : NSToolbar
- - toolbar management, one instance for each frame
- - nsmenu.m
-
-
-EmacsDialogPanel : NSPanel
- - popup dialogs, one instance for each
- - nsmenu.m
-
-EmacsTooltip : NSObject
- - tooltip popups, one instance for each
- - nsmenu.m
-
-EmacsGlyphStorage : NSObject <NSGlyphStorage>
- - utility for text rendering
- - nsfont.m
-
-EmacsPrefsController : NSObject
- - utility for preferences panel management, one global instance
- - nsterm.m
- - nextstep/Cocoa/Emacs.base/Contents/Resources/preferences.nib
- - nextstep/GNUstep/Emacs.base/Resources/preferences.gorm
-
-EmacsSavePanel : NSSavePanel
-EmacsOpenPanel : NSOpenPanel
- - utility override for panel notifications
-