Class: DisplayRootView

• Inheritance
• Description
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • destroying
  • dummy
  • hotkeys
  • initialization & release
  • queries

Inheritance:

   Object
   |
   +--GraphicsMedium
      |
      +--DisplaySurface
         |
         +--DisplayRootView

Package:

stx:libview

Category:

Views-Special

Version:

rev: 1.60 date: 2022/05/30 11:21:58

user: cg

file: DisplayRootView.st directory: libview

module: stx stc-classLibrary: libview

Description:

this class describes the rootWindow (which is the background window or
desktop and can be used for drawing outside of Views 
i.e. for dragging between Views).

For historic and compatibility reasons, there is a global variable 
called 'RootView', which is bound to the default displays ('Display')
rootview. We recommend, not to access this variable, instead, get a
displays rootView via the #rootView message (sent to the device).
Otherwise, your application will not work in a multiScreen environment.

Instances of myself (i.e. these rootViews) are light-weight views; 
they do not support events, models etc.
They are pure drawing canvases and should be only used for special
applications (i.e. dragging). 
There may be display systems in which rootViews are not
supported/allowed implemented. So be VERY careful when using them.

Be aware, that the rootView is not always visible - some
windowManagers install another (pseudoRoot), into which icons and
windowManager menus are drawn. If that is the case, your paining
into the rootView may not be visible, unless you set the #noClipByChildren
option (see below).
Also, it is not guaranteed, that all devices support drawing in the
root window - especially if the device is a simulated one, such as
a remote webBrowser ...
In general, you should never use the rootView for normal applications.

To draw in the (Displays) root window:

    |rootView|

    rootView := Screen current rootView.
    rootView paint:(Color red).
    rootView fillRectangleX:10 y:10 width:100 height:100.

of course, all stuff from View and its superclasses can be used:

    |rootView|

    rootView := Screen current rootView.
    rootView paint:(Color red).
    rootView noClipByChildren.
    rootView fillRectangleX:10 y:10 width:100 height:100.

copyright
COPYRIGHT (c) 1988 by Claus Gittinger
             All Rights Reserved

This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice.   This software may not
be provided or otherwise made available to, or used by, any
other person.  No title to or ownership of the software is
hereby transferred.

Class protocol:

 onDevice: aDisplay

since there is only one RootView - catch new and return
the one and only rootView.

Instance protocol:

 model

 name

return my name - always 'RootWindow'

 subViews

return the collection of subviews - none here

 uuid

return my uuid - always the same here.
TODO: think what happens with multiple screens...

 destroy

catch destroy - some windowmanagers get confused if
we destroy the rootWindow if it's a virtual root window

 keyboardZoom: largerBoolean

ALT+/- (was: CTRL+/-) zoom action

 redrawX: x y: y width: width height: height

ignored

 addHotKeyHandler: handler forKey: aKey modifierMask: optionalModifierMaskOrNil

install a handler (which should implement keyPress:x:y:view:
and keyRelease:x:y:view: on aKey.
aKey should be a symbolic key (like #F2).
modifierMask may constraint the key to be only handled when a certain
modifier is pressed (use a bitOr combination of device ctrlModifierMask,
altModifierMask etc.) or nil, so the key is always treated as a hotkey

Usage example(s):

Display rootView sensor removeAllEventListeners. Display rootView addHotKeyHandler:[:ev | Transcript showCR:ev. ev key = 'F3' ifTrue:[ Dialog information:'YES!'. ]. false. ] forKey:'F3' modifierMask:nil

 removeHotKeyHandler: handler forKey: aKey modifierMask: optionalModifierMaskOrNil

install a handler (which should implement keyPress:x:y:view:
and keyRelease:x:y:view: on aKey.
aKey should be a symbolic key (like #F2).
modifierMask may constraint the key to be only handled when a certain
modifier is pressed (use a bitOr combination of device ctrlModifierMask,
altModifierMask etc.) or nil, so the key is always treated as a hotkey

 initialize

(comment from inherited method)
initialize defaults

 reinitialize

reinit after snapin

 canDropObjects: aCollectionOfDropObjects

return true, if aCollectionOfDropObjects can be
dropped in the receiver.
False is returned here, since nothing can be dropped on the desktop.
(for now - actually some systems do allow dropping things on the desktop
and this query should be forwarded to my display device)

 isActive

for protocol compatibility with regular views

 isComponentOf: aView

 isRootView

return true, since yes, I am a rootview

 isSameOrComponentOf: aView

return true, if I am aView or a (direct or indirect) component of aView

 isWindowManagerRunning

answer true, if a window manager is currently running.
This is done by performing an action (enabling button events of
root window), which will fail if a window manager is running.

Usage example(s):

DisplayRootView new RootView isWindowManagerRunning