TPDFlibViewerAction
Data types, viewer interaction, actions
Description
Base class of the ready-made action components that drive a TPDFlibViewer from toolbars, menus and buttons
The action holds the target viewer in its Viewer property and keeps Enabled in sync with the document state: Update refreshes Enabled through the virtual DoUpdate, whose default implementation requires an assigned viewer with at least one page
Execute gives an assigned OnExecute the first say, mirroring standard TAction semantics; otherwise it runs the subclass command through the abstract DoExecute when DoUpdate allows
The subclasses declared in PDFlibViewerActions cover page navigation, zooming, rotation, printing, file open and save, clipboard copy and the tool modes; RegisterActions publishes them in the losLab PDF category, and CreatePDFlibViewerDefaultPopupMenu assembles the standard viewer context menu from them
When the assigned viewer is destroyed, the Notification override clears Viewer automatically
Declaration
TPDFlibViewerAction = class(TCustomAction)Key members
| Viewer | Target viewer the action drives, published so it can be wired at design time |
|---|---|
| Execute | Runs OnExecute when assigned, otherwise the subclass command |
| Update | Refreshes Enabled from DoUpdate |
| DoUpdate | Protected virtual availability check, the default requires an open document |
| DoExecute | Protected virtual abstract command the subclasses implement |
See also
TPDFlibViewerActionClass, TPDFlibViewerModeAction, TPDFlibViewer, CreatePDFlibViewerDefaultPopupMenu, InstallPDFlibViewerDefaultPopupMenu