ViewerClasses.mesa; Written by S. McGregor
Last Edited by: McGregor, July 21, 1983 10:41 am
Last Edited by: Maxwell, January 3, 1983 2:14 pm
DIRECTORY
Atom USING [PropList],
Cursors USING [CursorType],
Icons USING [IconFlavor],
Imager USING [Context],
Menus USING [Menu],
Rope USING [ROPE],
TIPUser USING [TIPTable];
ViewerClasses: CEDAR DEFINITIONS = BEGIN
Viewer: TYPE = REF ViewerRec;
Instance data for a viewer; Due to some compiler defaulting problems, please act as if the * entries were PRIVATE and ** entries READONLY
ViewerRec:
TYPE =
MACHINE
DEPENDENT
RECORD [
-- 35 words
class: ViewerClass ← NIL, -- static info for all Viewers of this class **
wx, wy: INTEGER ← 0, -- position of viewer frame wrt parent's client space
ww, wh: INTEGER ← 0, -- size of the viewer on the screen
cx, cy: INTEGER ← 0, -- viewer client position wrt parent **
cw, ch: INTEGER ← 0, -- size of usable space wrt client **
lock: Lock ← [NIL, 0], -- locking information used by ViewerLocks * **
tipTable: TIPUser.TIPTable ← NIL, -- mouse and keyboard events, initialised from class
name: Rope.ROPE ← NIL, -- Viewer name, displayed in caption (optional)
menu: Menus.Menu ← NIL, -- copied from class; set with ViewerOps.SetMenu
icon: Icons.IconFlavor ← unInit, -- picture to display when small, initialised from class
column: Column ← left, -- screen space algorithm used when viewer is open
scrollable: BOOL ← TRUE, -- optional scroll bar allocation
iconic: BOOL ← TRUE, -- small or large representation on screen
border: BOOL ← TRUE, -- WMgr paints a one dot black border around viewer
newVersion: BOOL ← FALSE, -- hint that the user has made new edits **
newFile: BOOL ← FALSE, -- hint that a backing file does not yet exist **
visible: BOOL ← TRUE, -- WMgr maintained hint for repaint use * **
offDeskTop: BOOL ← FALSE, -- is viewer off of the current desktop? **
destroyed: BOOL ← FALSE, -- hint that viewer has been flushed from window tree **
init: BOOL ← FALSE, -- init proc call has been completed after creation * **
saveInProgress: BOOL ← FALSE, -- the saveProc has been called but not yet returned **
inhibitDestroy: BOOL ← FALSE, -- if TRUE then window menu will not permit destroy
guardDestroy: BOOL ← FALSE, -- if TRUE then window menu will always guard destroy
clientContext: BOOL ← FALSE, -- hint that client has installed a context for this viewer * **
spare: BOOL ← FALSE, -- unused; anyone need a bit? * **
link: Viewer ← NIL, -- ring of linked viewers **
position: INTEGER ← 0, -- for window positioning primitives use * **
openHeight: INTEGER ← 0, -- "ideal" height hint for open viewer
parent: Viewer ← NIL, -- NIL if top level viewer **
sibling: Viewer ← NIL, -- sibling chain **
child: Viewer ← NIL, -- head of children chain **
props: Atom.PropList ← NIL, -- clients can associate properties with viewers **
data: REF ANY ← NIL -- data slot for Viewer Class implementor
];
Class data for a viewer:
ViewerClass: TYPE = REF ViewerClassRec;
ViewerClassRec:
TYPE =
RECORD [
flavor: ViewerFlavor ← NIL, -- name of viewer's class
notify: NotifyProc ← NIL, -- TIP input events parsed from tipTable
paint: PaintProc ← NIL, -- called whenever the Viewer should repaint its contents
modify: ModifyProc ← NIL, -- reports InputFocus changes
destroy: DestroyProc ← NIL, -- called before Viewer structures freed on destroy
copy: CopyProc ← NIL, -- copy data to new Viewer
set: SetProc ← NIL, -- set the viewer contents
get: GetProc ← NIL, -- get the viewer contents
init: InitProc ← NIL, -- called on creation or reset to init client data
save: SaveProc ← NIL, -- requests client to write contents to disk
scroll: ScrollProc ← NIL, -- document scrolling
caption: CaptionProc ← NIL, -- experimental proc for user caption display
menu: Menus.Menu ← NIL, -- template menu used for top-level viewers
tipTable: TIPUser.TIPTable ← NIL, -- table to parse mouse & keyboard events
coordSys: CoordSys ← bottom, -- coordinate system for children and mouse coords
clipChildren: BOOL ← FALSE, -- clip out children during repaint
simpleCreate: BOOL ← FALSE, -- simple creation of new instances (see below)
bltContents: BltRule ← none, -- use blt to copy screen contents (see comment below)
paintRectangles: BOOL ← FALSE, -- keep hints for the paintProc; see comment below
icon: Icons.IconFlavor ← document, -- picture to display when small
cursor: Cursors.CursorType ← textPointer -- standard cursor when mouse is in viewer
];
The bltContents rule in the class requests that the window package attempt to save some of the current screen contents of a viewer by moving the bits to the new viewer location (e.g. when the viewer is moved). These rectangles that were thus saved will show up as a paint rectangle described below with flavor=blt, as a convenience to clients that keep caches of screen contents. It does not make sense to turn this bit on without also turning the paintRectangles bit on as well. Client that scale their image to fit the viewer bounding box should not use this feature.
The paintRectangles bit in the class determines whether or not the window manager will pass a paint rectangle (as the whatChanged parameter) to the viewer when the paintProc is called. These may be used by the client to optimise painting. If NIL, then the client must assume the entire viewer is invalid. If a PaintRectangle is seen by a paintProc, then it can safely assume that it need paint only those areas with flavor=invalid.
The simpleCreate bit in the class implies that a new instances of this class can be constructed just with ViewerOps.CreateViewer[$ClassFlavor, info: [name: instanceName]].
BltRule: TYPE = { none, top, center, bottom } ;
PaintRectangle: TYPE = REF PaintRectangleRec;
PaintRectangleRec:
TYPE =
RECORD [
flavor: PaintRectangleFlavor ← invalid,
x, y, w, h: INTEGER ← 0
];
PaintRectangleFlavor: TYPE = { invalid, blt } ;
ViewerFlavor:
TYPE =
ATOM ;
ViewerFlavors predefined by the Viewer package include: $Label, $MessageWindow, $Button, $Container, $Rule. Tioga implements $Text and $Typescript.
Lock:
TYPE =
RECORD [
-- process-reentrant viewer lock
process: UNSAFE PROCESS ← NIL, -- current write process
count: CARDINAL ← 0 -- number of locks currently granted for this viewer
] ;
Column:
TYPE = {static, left, right, color} ;
Static documents, such as the message window, may not be open/closed
CoordSys:
TYPE = {bottom, top} ;
Whether mouse and nested viewer coords are relative to bottom/top of viewer
PaintProc:
TYPE =
PROC [self: Viewer, context: Imager.Context, whatChanged:
REF
ANY,
clear: BOOL] ;
Called by the window manager when the client should repaint the data on the screen. The context is clipped to the client screen area. whatChanged is just passed from the call to ViewerOps.PaintViewer, but will be NIL when the window manager requires a full repaint after moving a viewer on the screen. clear is a hint that the client background is white, so that the client can paint on the black bits if it so chooses. See comments for invalidRectangle bit in the viewer class.
NotifyProc:
TYPE =
PROC [self: Viewer, input:
LIST
OF
REF
ANY] ;
Input events from the class TIPTable. Mouse events get passed whenever the mouse is over the viewer, keyboard events get passed if the vviewer own the input focus (see the InputFocus interface). N.B. Called at Process.priorityForeground!
ModifyProc:
TYPE =
PROC [self: Viewer, change: ModifyAction] ;
ModifyAction: TYPE = {set, push, pop, kill};
Called when the input focus ownership is changing so that the client can modify things like selection feedback on the screen or private data structures and state.
DestroyProc:
TYPE =
PROC [self: Viewer] ;
Called when the viewer has been destroyed for some reason.
CopyProc:
TYPE =
PROC [self, new: Viewer] ;
Copy implementor private data structures.
The op atom for SetProc and GetProc is for private client agreements to get things like selection contents or content representations other than ropes.
SetProc: TYPE = PROC [self: Viewer, data: REF ANY, finalise: BOOL ← TRUE, op: ATOM ← NIL] ;
GetProc: TYPE = PROC [self: Viewer, op: ATOM ← NIL] RETURNS [data: REF ANY] ;
InitProc:
TYPE =
PROC [self: Viewer] ;
Called by the window manager shortly after a viewer is created so that the client can create and initialise private data structures. Also called on the "Reset" menu command.
SaveProc:
TYPE =
PROC [self: Viewer, force:
BOOL ←
FALSE] ;
Requests client to save data structures on the disk. force should only be true when called from the emergency backup code on error recovery and requests that the client consider overriding monitors or locks that might otherwise prevent saving the data.
ScrollProc:
TYPE =
PROC [self: Viewer, op: ScrollOp, amount:
INTEGER, shift, control:
BOOL ←
FALSE]
RETURNS [top, bottom: INTEGER ← LAST [INTEGER]] ;
ScrollOp: TYPE = {query, up, down, thumb};
Client scrolling and scrolling feedback. If op is 'query' the client should return the percentage of the scrollable document at the top and bottom of the screen, or default if unknown. If op is 'up' or 'down' then amount is number of pixels to glitch. If op is 'thumb' then amount is percentage into document to scroll. The shift and control information reflects the state of the shift and control keys during the up, down, and thumb ops and may be interpreted by the client as desired.
CaptionProc:
TYPE =
PROC [self: Viewer, context: Imager.Context] ;
Experimental: allows client to draw caption legend.
END.