Package limn.backend.lwjgl.transfer

Class MacDrag

java.lang.Object

limn.backend.lwjgl.transfer.MacDrag

public final class MacDrag
extends Object

A window's part in the system's drag and drop on macOS: it begins an NSDraggingSession from the window's view, with the pasteboard items a copy would write and the picture the scene cut for it, and it answers as a dragging destination for whatever is dragged over the view, from this program or another.

GLFW's content view already is a destination, for file URLs alone and at the drop alone. Its four destination methods are replaced on the class, once, with ours, which ask the window the view belongs to; the view is registered for every kind of data, not only for files.

Everything here runs on the main thread, which is the UI thread. AppKit tracks a drag in a loop of its own, inside the event GLFW was dispatching, as it does a window being resized: the application's loop does not turn until the drag is over, and no frame is produced by it. The destination therefore paints the window itself after each answer, or the widget that accepted would mark where the drop lands and nobody would see it (the owner: the insertion line was gone once the system drove the drag).

Over a place that refuses, the pointer is made the "not allowed" one. AppKit shows nothing for a refusal; the scene's own drag does, and the owner asked for the same here.

Method Summary

Modifier and Type	Method	Description
void	close()	Forgets a view that is going away.
static MacDrag	install(long view, UiRuntime ui, Supplier<WindowInput> input, Supplier<float[]> pointer, float toScreen, Runnable paint, BooleanSupplier animate, Runnable ownCursor)	Makes a window's view a source and a destination of the system's drags.
boolean	start(DragRequest request)	Begins the system's drag of what the scene asks.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

install

public static MacDrag install(long view,
 UiRuntime ui,
 Supplier<WindowInput> input,
 Supplier<float[]> pointer,
 float toScreen,
 Runnable paint,
 BooleanSupplier animate,
 Runnable ownCursor)

Makes a window's view a source and a destination of the system's drags. Main thread.

Parameters:

view - the window's content view

ui - the UI runtime

input - the window's input, as it is at the time of each call; may answer null

pointer - the pointer in the window's logical points, x then y

toScreen - how many of AppKit's points one logical point is

paint - paints the window now, from inside AppKit's own loop

animate - paints the frame the window is waiting for, if any, and says whether it now waits for another

ownCursor - puts the window's own pointer back, once a drag is no longer over it

Returns:

the window's drag, or null where AppKit would not have it, which is logged

close

public void close()

Forgets a view that is going away.

start

public boolean start(DragRequest request)

Begins the system's drag of what the scene asks. Main thread, while a mouse button is down.

Parameters:

request - what is dragged

Returns:

whether AppKit took it