Application Sharing

Application sharing enables all conference participants to see and use any application, from a simple text editor to a spreadsheet, or complex design package. Application sharing uses an open, international standard (called T.128), which means that, for example, SunForum can view and control applications shared by other systems running Solaris, or systems running Windows (using versions of Microsoft NetMeeting earlier than 3.0, or PictureTel LiveShare Plus software).

When one person in the conference decides to share an application, all the other users in the conference see that application window on their system as if it were running locally. The window is "tagged" with the name of the user who shared the application.

Initially, only the person who shared the application can control it; everyone else can merely see the output in the shared window. If that person then collaborates, others are allowed to take control, although only one person can be in control at a time.

With the introduction of NetMeeting 3.0, the existing standard (T.128) has been extended and a different mechanism for displaying and controlling shared applications has been introduced. Sunforum supports the NetMeeting 3.0 protocol and control model through the Configuring Compatibility mode configuration option. If you want to interoperate with NetMeeting 3.0, set the compatibility mode to "NetMeeting 3". If you want to interoperate with NetMeeting 2.1 or other true T.128 products, set the compatibility mode to "T.128".

	Controlling shared applications by other people
	Using the shared desktop viewer
	Sharing applications
	Letting others work in applications you have shared
	Stopping sharing applications
	Controlling applications shared by other people
	Controlling applications when running in T.120 mode
	Controlling applications when running in NetMeeting 3 mode
	Color Resolution

Controlling shared applications

To take control of a shared application, move your mouse cursor over the application window.

	If the cursor is a simple "no-go" symbol, the person hosting the application has not collaborated, so you will not be able to take control of it.
	If the cursor is a small "no-go" symbol overlaid with an arrow, you can request control by clicking on the application window.

When you have control, you will be able to use the application with your mouse and keyboard as if it were running on your local system.

Tip: You can also take control by clicking on the Collaborate button on the SunForum toolbar, or choosing Collaborate on the Tools menu.

The Shared Desktop Viewer

When an application is shared from a system with a larger desktop than yours, SunForum enables you to view the whole of the application by automatically scrolling shared windows when the mouse cursor nears the edge of the local desktop. This feature can be disabled by unchecking the "Enable desktop scrolling" field in the Configuring Tool Settings Options.

Selecting Shared Desktop Viewer from the Tools menu of SunForum displays a window which shows the relative sizes and positions of the

Desktops of everyone in the conference

Shared application windows

You can select which of these are displayed (Desktops, Shared Windows, or both) by right-clicking with the mouse on the shared desktop viewer window, and selecting the appropriate option(s) from the popup menu.

Sharing Applications

To share an application, click the Share button on the toolbar. The mouse cursor becomes a pointing hand. Click on the window you wish to share. When shared, local applications become "tagged" with your own name.

Alternatively, you can select "Share Application" from the Tools menu. This leads to a list of currently-running applications on your system, with a check-mark next to those which are currently shared. Selecting an application which is currently not shared from the list causes that application to be shared.

Notes:

You cannot share SunForum windows (such as the whiteboard), or the root (desktop) window.

This release of SunForum is optimized for the sharing of 2D X applications. Output drawn using certain X extensions (such as Sun SME) will not be shared. Sharing of output which is drawn directly to the graphics hardware (for example, 3D applications using OpenGL) is supported, but the level of responsiveness for such applications when controlled by remote users is currently limited compared with 2D applications, unless running on very fast hardware over a high-bandwith network.

You must be running SunForum on the same system as the X server on which it is being displayed in order to share applications to other users.

After installing SunForum, you must restart your X server to enable sharing of local applications.

Letting Others Work in Applications you have Shared

Other conference participants cannot take control of applications that you have shared until you explicitly permit them to do so by collaborating. To do this, click on the Collaborate button on the SunForum toolbar, or choose the Collaborate command on the Tools menu.

When another conference participant is in control, they effectively take over your mouse and keyboard (but can only provide input to shared applications), until you request control back by pressing a key or clicking with the mouse.

To stop collaborating,

If you have control, press the collaborate button again

If someone else has control, press Escape.

In NetMeeting 3.0 compatibility mode you have more control over who can control your applications. While you are collaborating, if another person requests control, a popup is displayed asking whether you want to allow the person to take control of your shared applications. Accepting the request gives control to that person.

Selecting the "Automatically Accept Requests for Control" option on the Tools menu causes all requests for control to be accepted automatically.

In addition to receiving requests for control of your shared applications you can also grant control to another person. When collaborating, pressing the right mouse button over a person's name in the conference roster and selecting Grant Control offers control of your applications to that person.

For even tighter control of your shared applications, selecting the "Do Not Disturb with Requests for Control" option on the tools menu allows you to grant control of your applications to others but
automatically rejects any direct requests for control.

Stopping Sharing Applications

To stop sharing an application, click the Unshare button on the toolbar. The mouse cursor becomes a pointing hand. Click on the window you wish to stop sharing. The window "tag" will disappear, indicating that the window is no longer shared.

Alternatively, you can select "Share Application" from the Tools menu. This leads to a list of currently-running applications on your system, with a check-mark next to those which are currently shared. Select an application which is currently shared from the list, and it stops being shared.

Controlling applications shared by other people

The mechanism for displaying and controlling applications shared by other people is dependent on the Compatibility mode SunForum is running in.

Controlling applications shared by other people when running in T.120 compatibility mode
Controlling applications shared by other people when running in NetMeeting 3.0 compatability mode

Controlling applications when running in T.120 mode

In T.120 compatibility mode all applications shared by other people in the conference appear on the desktop as if they were running locally. The person sharing the application is indicated by a tag on the top right corner of the window.

To take control of an application that has been shared by another person in the conference, move your mouse cursor over the application window.

If the cursor is a simple "no-go" symbol, the person hosting the application has not collaborated, so you will not be able to take control of it.

If the cursor is a small "no-go" symbol overlaid with an arrow, you can take control by clicking on the application window.

When you have control, you will be able to use the application with your mouse and keyboard as if it were running on your local system.

Notes:

If you have already shared some applications, taking control of another person's application is equivalent to collaborating, and allows other people to take control of your shared applications.

In common with other standard T.128 conferencing applications (including NetMeeting version 2), SunForum can view, but cannot control, applications shared by NetMeeting version 3. SunForum can view and control applications shared by earlier versions of NetMeeting.

Tip: You can also take control by clicking on the Collaborate button on the SunForum toolbar, or choosing the Collaborate... command on the Tools menu.

Controlling applications when running in NetMeeting 3 mode

In NetMeeting 3 compatibility mode all applications shared by another person in the conference appear in their own shared application window. A shared application window is created on your machine for each remote person sharing applications in the conference.

The shared application window allows applications shared by a person to be viewed in isolation from the applications hosted by other people and your own local applications. This allows you to resize and scroll the "viewing area" to suit your own needs. In addition to the viewing area, the shared application window has a Control menu, for shared application control options, and a Window menu, for shared window selection and activation.

The title bar of the shared application window indicates the share status for that person. The title indicates who is sharing the applications, whether they are collaborating (allowing other people to control) or are actually being controlled.

Requesting Control

You can only take control of the applications shared by another person if they are collaborating. This is indicated in the title bar of the shared application window by the word "controllable".

When a person's shared applications are "controllable" you can request control of their shared applications in one of two ways.

If the cursor is a small "no-go" symbol overlaid with an arrow, you can take control by double-clicking on the application window, as in T.120 mode.
Selecting the Request Control button on the Control menu.

In addition to you requesting control, the person sharing the applications can also grant control to you. If this happens a popup appears offering you control of their shared applications. Accepting this offer gives you control.

When you have taken control of the applications shared by another person the title bar of the shared application window and the conference roster are both updated to indicate you are controlling that person's shared applications.

Controlling

When you are in control of the applications shared by another person you can then use the mouse and keyboard to control their shared applications as if they were running on your own machine.

If you cannot see a shared application, it may be hidden behind another application or be minimized. You can use the application's entry in the Window menu to restore it and/or bring it to the front.

Releasing Control

To release control of another person's applications select the Release Control button on the Control menu.

In addition to just releasing control you can also offer control to another person in the conference. Selecting a person from the Forward Control submenu under the Control menu requests that control be passed to that person. If you do this, a popup is displayed to the other person offering them control (as if the
host had granted control).

Conferencing Between Different Sized Desktops

If you are working in Netmeeting 3 compatibility mode, this section does not apply. In NetMeeting 3 compatibility mode all applications shared by other people are displayed in their own shared application window which allows you to scroll round the shared applications independently of the local desktop. Desktop scrolling is no longer required and is disabled.

When an application is shared from a system with a larger desktop than yours, you can see only part of the shared desktop area at a time. If an application window extends past the edge of the visible desktop area, SunForum automatically scrolls the desktop view when you move the mouse cursor near to the edge of the local desktop, enabling you to view the whole of the application window.

This feature can be disabled by unchecking the "Enable desktop scrolling" field in the Configuring Tool Settings options. In this case, you will see only the top left-hand corner of the larger desktop, and will not be able to access windows or parts of windows that do not fit on your display.

The Shared Desktop Viewer

If you are working in Netmeeting 3 compatibility mode, this section does not apply. In NetMeeting 3 compatibility mode all applications shared by other people are displayed in their own shared application window and so there is no "shared desktop". The Shared Desktop Viewer is disabled in NetMeeting 3 compatibility mode.

The Shared Desktop Viewer allows you to see an overview of the shared desktop, showing the relative sizes and positions of the

shared application windows
desktop areas of everyone in the conference (if different people are using different sized desktops).

To use the viewer, select the Shared Desktop Viewer command on the Tools menu. You can select which information is displayed (Shared Windows, Desktops, or both) by right-clicking with the mouse on the shared desktop viewer window, and selecting the appropriate option(s) from the popup menu.

The area displayed by the viewer represents the shared desktop. If you are displaying information on shared windows, each shared window (whether shared by you or by another person in the conference) appears as an outline showing its size and position on the desktop.

If you are displaying information on desktop areas, and if your desktop is smaller than the complete shared desktop area because an application is shared from a system with a larger desktop than yours, the viewer shows the complete shared desktop, with a smaller rectangle in a different color showing the currently visible area of your desktop. If you have enabled desktop scrolling in the SunForum configuration options, you can view a different part of the complete shared desktop by dragging this smaller rectangle to cover the desktop area you want to view.

Color Resolution

Shared output is sent to other machines in either 24-bit color depth or 8-bit color depth. 24-bit color depth is sometimes referred to as "true color" - the colors on the shadowing machines look as good as those
on the host machine. 8-bit color depth provides a good approximation, but output which uses many different colors will appear at a lower color resolution than it does on the host.

SunForum shares output at the best color depth available to all conference participants based on

the physical capabilities of each
the level of protocol supported by each
the compatibility mode in effect on each.

If any machine doesn't support 24-bit color depth output, output is sent to all machines in 8-bit format. This means that if just one machine in a conference doesn't support 24-bit colors, all machines will see lower color resolution output. This negotiation changes dynamically - if two 24-bit machines are in a conference, output is sent at 24-bit. If they are joined by an 8-bit machine, output is degraded to 8-bit. If the 8-bit machine now leaves, output resumes at 24-bit.

NetMeeting 2.x supports only 8-bit color, hence with a NetMeeting 2.x machine in the conference, image quality will always be lower.

NetMeeting 3.x supports higher color resolutions, but with a slightly different protocol from the default SunForum protocol. However, SunForum also supports the NetMeeting 3.x protocol, if the Compatibility mode is set to "NetMeeting 3".

To summarize, if you want the best possible color matching:

Use machines which support 24-bit color depth.
Use NetMeeting 3.x, or newer versions of SunForum which support the true color protocol.
If you use NetMeeting 3.x, set the Compatibility mode to "NetMeeting 3" on all copies of SunForum in the conference.
If you don't use NetMeeting 3.x, set the Compatibility mode to "T.120" on all copies of SunForum in the conference.

Or, to look at it another way, the color in a shared application will look best in the following cases.

Either, all machines in the conference

have displays capable of displaying 24-bit colors, AND
are running versions of SunForum which support true color application sharing.

have displays capable of displaying 24-bit colors, AND
are running versions of SunForum or NetMeeting which support NetMeeting true color application sharing, AND
have Compatibility mode set to "NetMeeting 3".

	Desktops of everyone in the conference
	Shared application windows

	You cannot share SunForum windows (such as the whiteboard), or the root (desktop) window.
	This release of SunForum is optimized for the sharing of 2D X applications. Output drawn using certain X extensions (such as Sun SME) will not be shared. Sharing of output which is drawn directly to the graphics hardware (for example, 3D applications using OpenGL) is supported, but the level of responsiveness for such applications when controlled by remote users is currently limited compared with 2D applications, unless running on very fast hardware over a high-bandwith network.
	You must be running SunForum on the same system as the X server on which it is being displayed in order to share applications to other users.
	After installing SunForum, you must restart your X server to enable sharing of local applications.

	If you have control, press the collaborate button again
	If someone else has control, press Escape.

	If you have already shared some applications, taking control of another person's application is equivalent to collaborating, and allows other people to take control of your shared applications.
	In common with other standard T.128 conferencing applications (including NetMeeting version 2), SunForum can view, but cannot control, applications shared by NetMeeting version 3. SunForum can view and control applications shared by earlier versions of NetMeeting.