Link Back

LinkBack is an open technology shared by several applications on OS X. It is an extension of Copy and Paste. The extended capability allows copied content to be revisited and edited at a later date, using the full capability of the originating application. This is similar to Publish and Subscribe as well as Embedded Graphic Objects on OS 9 and earlier.

LinkBack data is not itself a file or data format, rather it is additional information that accompanies the formal data formats that are transient to the system paste board. This additional information is carried with the pasted content and even saved with the hosting documents file on the hard drive. At a later date, if editing of the pasted content is required, the additional linkback information is provided to the originating application to enable a reconstitution of the content that was originally copied to the pasteboard.

LinkBack technology is provided in two components by the two cooperating applications, a Server and Client. The Server technology is provided by the application that originates the Copy to the pasteboard. The Client technology is provided by the application that Pastes from the pasteboard. Some applications implement only LinkBack Server support, others only LinkBack Client support. EazyDraw implements both Server and Client support.

LinkBack Server and Client support is enabled by checking the LinkBack options for Copy and Paste Order on the main EazyDraw Preferences window. The additional LinkBack information can be extensive, but it is provided only when requested by the destination application. Therefore there is no memory or performance penalty imposed by enabling LinkBack support when copying to applications that do not use the information.

LinkBack support is enabled on the Copy and Paste Order section of the main EazyDraw preferences panel. Checking the Copy option enables LinkBack Server support by EazyDraw. Checking the Paste option enables LinkBack Client support by EazyDraw.

No additional actions are required to provide LinkBack information to other applications when copying graphics from EazyDraw. The receiving application will normally provide an item on the Edit menu to initiate editing of the graphics in EazyDraw, and most provide double-click on the graphic as a short cut.

When EazyDraw is called to act as a Server and provide editing of previously pasted graphics, a separate drawing window is opened. This LinkBack editing drawing does not have an associated permanent file on the Hard Drive. This drawing window is used in the normal fashion to add or modify the drawing. The name of the drawing window will indicate the Client Application and hosting document.

To "send" the modified graphics back to the Client application - simply Save the drawing. So long as the LinkBack window is open and EazyDraw is running, the link to the content in the Client application remains "open". Subsequent modifications and Saves will update the content in the Client application document. This link is broken, or closed, when the corresponding EazyDraw drawing window is closed. Normally the link is closed by the Client if the Client Quits or closes the hosting document.

When pasting into EazyDraw the pasteboard is queried for LinkBack Server support and the required information which will accompany the pasted content. If LinkBack support is provided, the LinkBack badge (see below) is displayed in the lower right hand corner of the pasted content - when selected, if size permits. The other indication of LinkBack support is found on the Edit main menu, if a selected graphic has LinkBack information, the Edit menu is enabled and the menu item indicates the name of the Server application.

Editing of LinkBack content in EazyDraw is initiated by double-click on the graphic or text, or with the Edit menu, shown circled on the left.

In the Client mode, EazyDraw saves the additional LinkBack information with the drawing file. The information will remain with the drawing so long as the pasted content is present on the drawing. Edits may be initiated at any later time, even if EazyDraw has quit and relaunched, or the EazyDraw drawing was closed and saved to the hard drive.

If a drawing containing additional LinkBack information is sent to another user on another CPU a complete LinkBack edit is still possible. The receiving computer will need a working version of the originating Server application. If this application is not present, a message is provided indicating the internet web site to visit to obtain a copy of the application.

If a document that received EazyDraw LinkBack information with a pasted graphic is sent to a user that does not have EazyDraw, editing is fully supported for the receiving user, even if they are not an owner of EazyDraw. In this case when editing is attempted, a message is provided with a link to EazyDraw - free reader version. This version of EazyDraw allows editing of the graphics, but may limit adding new components.

LinkBack Server support for graphics copied from EazyDraw apply to explicit Copy menu action, and to Drag and drop of graphics from an EazyDraw drawing window. LinkBack Server support is NOT provided when using the Export Shortcut icon found in the title bar of EazyDraw drawing windows. Dropping an EazyDraw file from the Finder onto another document or application does NOT include LinkBack support.

Developers may visit the Open LinkBack project web site: linkbackproject.org for full documentation and implementation tools.