Clipboard operations

Common Widgets provides operations to interact with the platform clipboard, which holds data to be transferred between applications. An application can copy data from Smalltalk to the clipboard, and paste data from the clipboard into Smalltalk.

Data stored in the clipboard has an associated format name, which applications use to identify the type of data. Common Widgets automatically handles two predefined formats, string and pixmap, which are mapped to the corresponding platform-specific format during clipboard operations. Applications can also work with platform-specific formats, or define new proprietary formats. The format names and corresponding buffer object classes used to represent data when working with the clipboard include the following:

STRING

String

PIXMAP

CgPixmap

All others

ByteArray

The class CgDisplay implements the clipboard operations. All operations require a CgWindow parameter, which identifies the application to the OS window system. The window can be any valid CgWindow. The available clipboard operations include the following:

clipboardStartCopy:clipLabel:itemIdReturn:

Sets up OS clipboard storage and data structures to receive data

clipboardCopy:itemId:formatName:buffer:privateId:

Copies data to the clipboard

clipboardCancelCopy:itemId:

Cancels a copy operation that has been started

clipboardEndCopy:itemId:

Ends a copy to the clipboard

clipboardInquireCount:countReturn:

Returns the number of data item formats in the clipboard

clipboardInquireFormat:index:formatNameReturn:

Returns the format of a data item

clipboardInquireLength:formatName:lengthReturn:

Returns the length of the stored data

clipboardStartRetrieve:

Starts a copy from the clipboard

clipboardRetrieve:formatName:bufferReturn:privateIdReturn:

Retrieves a data item from the clipboard

clipboardEndRetrieve:

Ends a copy from the clipboard

clipboardLock:

Locks the clipboard

clipboardUnlock:

Unlocks the clipboard

clipboardRegisterFormat:formatLength:

Registers a new format