Class: GraphicsDevice

• Inheritance
• Description
• Related information
• Instance protocol
  • accessing & queries
  • creating graphics contexts
  • event processing
  • misc
• Private classes

Inheritance:

   Object
   |
   +--GraphicsDevice
      |
      +--HostGraphicsDevice

Package:

stx:libview

Category:

Interface-Graphics

Version:

rev: 1.19 date: 2017/04/12 07:57:56

user: cg

file: GraphicsDevice.st directory: libview

module: stx stc-classLibrary: libview

Author:

Claus Gittinger

Description:

this abstract class was inserted to provide a home for ST-80 classes
(previously, DeviceWorkstation was directly under Object).

In ST/X, this is mostly dummy.

[instance variables:]
  displayId       <Handle>            the device handle
  screen          any                 another some device specific id
  eventListeners  <Collection> | nil  bunch of objects interested in events.
  deviceType      <Symbol>             some arbitrary symbol, used to choose windowSpecs.

Related information:

    DeviceWorkstation
    XWorkstation

Instance protocol:

 addEventListener: aListener

add a local eventListener (with new protocol - #processEvent:)
This one gets a chance to intercept all events for this device

 bePDA

 deviceType

 deviceType: aSymbol

 isPDA

 isWebServiceDevice

I am not a WebService pseude-device

 removeEventListener: aListener

remove a local eventListener (with new protocol - #processEvent:)

 supportsAlphaChannel

return true, if this device supports alpha information.
Currently none does

 newGraphicsContextFor: aGraphicsMedium

create a new graphics context.
The defaults is to use the inherited graphics context.
Subclasses may redefine this to use their own graphics context

 notifyEventListenersAbout: anEvent

notify all eventHandlers about an incoming event.
If any returns true, it is assumed to be eaten by the handler and not
enqueued (i.e. not passed to the windowGroup process)

 roundTripTime

answer the round trip time in milliseconds.
May be used to detect slow device connections.
Subclasses redefine this. Assume a fast Diplay connection
and answer 0 here

usage example(s):

Screen current roundTripTime

Private classes:

    GraphicResourceAllocationFailure