[_CDCSL_93-16_]<1>Cedar>release>JaMImager>JaMImagerContexts.mesa

JaMImagerContexts.mesa

Last edit by Stone, January 22, 1984 6:48:49 pm PST

Tim Diebert: July 18, 1985 3:22:00 pm PDT

DIRECTORY

JaM USING [State],

Imager USING [Context];

JaMImagerContexts: CEDAR DEFINITIONS = {

State: TYPE = JaM.State;

Context: TYPE = Imager.Context;

Pick any name ie: $PD. If a context with the name already exists for that frame, AddContext will replace the old context with the new one. You must Enable the context to cause things to be displayed in it.

AddContext: PROC [state: State, context: Context, callMe: CallMe, name: ATOM, enabled: BOOLEAN ¬ TRUE];

Command: TYPE = {initdc, erase, pushdc, popdc};

CallMe: TYPE = PROC[context: Context, command: Command] RETURNS[new: Context];

generic call back procedure used to notify client of certain JaMImager commands.

If you don't want to change the context just hand it back.

The proc: callMe will be called for the following reasons

command=initdc: .initdc is called.

command=erase: .erase is called

command=pushdc: .pushdc is called. Note: the imager does not have a stack model

command=popdc: .popdc is called.

RemoveContext: PROC [state: State, name: ATOM] RETURNS [context: Context];

turns display to context on and off.

EnableContext: PROC [state: State, name: ATOM];

DisableContext: PROC [state: State, name: ATOM];

turns context in viewer on and off

EnableViewer: PROC [state: State];

DisableViewer: PROC [state: State];

NotFound: SIGNAL; --raised by RemoveContext, EnableContext and DisableContext

DCList: TYPE = REF DCRec;

DCRec: TYPE = RECORD [

next: DCList,

callMe: CallMe,

dc: Imager.Context,

enabled: BOOLEAN,

name: ATOM];

GProc: TYPE = PROC [dc: Context];

ForAllDCs: PROC [list: DCList, proc: GProc];