Package org.gnome.gtk

Interface PrintOperation.PreviewCallback

All Superinterfaces:

FunctionPointer

Enclosing class:

PrintOperation

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public static interface PrintOperation.PreviewCallback
extends FunctionPointer

Functional interface declaration of the PreviewCallback callback.

See Also:

• run(org.gnome.gtk.PrintOperationPreview, org.gnome.gtk.PrintContext, org.gnome.gtk.Window)

Method Summary

Modifier and Type	Method	Description
boolean	run(@Nullable PrintOperationPreview preview, @Nullable PrintContext context, @Nullable Window parent)	Gets emitted when a preview is requested from the native dialog.
default MemorySegment	toCallback(Arena arena)	Creates a native function pointer to the upcall(java.lang.foreign.MemorySegment, java.lang.foreign.MemorySegment, java.lang.foreign.MemorySegment, java.lang.foreign.MemorySegment) method.
default int	upcall(MemorySegment sourcePrintOperation, MemorySegment preview, MemorySegment context, MemorySegment parent)	The upcall method is called from native code.

Method Details

run

boolean run(@Nullable PrintOperationPreview preview,
 @Nullable PrintContext context,
 @Nullable Window parent)

Gets emitted when a preview is requested from the native dialog.

The default handler for this signal uses an external viewer application to preview.

To implement a custom print preview, an application must return true from its handler for this signal. In order to use the provided context for the preview implementation, it must be given a suitable cairo context with PrintContext.setCairoContext(org.freedesktop.cairo.Context, double, double).

The custom preview implementation can use PrintOperationPreview.isSelected(int) and PrintOperationPreview.renderPage(int) to find pages which are selected for print and render them. The preview must be finished by calling PrintOperationPreview.endPreview() (typically in response to the user clicking a close button).

upcall

default int upcall(MemorySegment sourcePrintOperation,
 MemorySegment preview,
 MemorySegment context,
 MemorySegment parent)

The upcall method is called from native code. The parameters are marshaled and run(org.gnome.gtk.PrintOperationPreview, org.gnome.gtk.PrintContext, org.gnome.gtk.Window) is executed.

toCallback

default MemorySegment toCallback(Arena arena)

Creates a native function pointer to the upcall(java.lang.foreign.MemorySegment, java.lang.foreign.MemorySegment, java.lang.foreign.MemorySegment, java.lang.foreign.MemorySegment) method.

Specified by:

toCallback in interface FunctionPointer

Parameters:

arena - the arena in which the function pointer is allocated

Returns:

the native function pointer