scala swing: draggable / resizable component trait

I'm looking for a scala trait that I can mix in to a scala.swing.Component that will allow that component to be positioned and resized using mouse i开发者_如何学编程nput.

Ideally it would add little boxes as "handles" to indicate to the user that the component can be resized:

I feel like this is a fairly common task, and there should be some traits out there that support it.

---

I'm using these in my current project. You probably need to replace the Vector library with your own and add implicit defs. Or use Point/Dimension from swing. The Components need to be in a panel which allows custom positions and sizes, like NullPanel from http://dgronau.wordpress.com/2010/08/28/eine-frage-des-layouts/

trait Movable extends Component{
    var dragstart:Vec2i = null
    listenTo(mouse.clicks, mouse.moves)
    reactions += {
        case e:MouseDragged =>
            if( dragstart != null )
                peer.setLocation(location - dragstart + e.point)
        case e:MousePressed =>
            this match {
                case component:Resizable =>
                    if( component.resizestart == null )
                        dragstart = e.point
                case _ =>
                    dragstart = e.point
                     
            }
        case e:MouseReleased =>
            dragstart = null    
    }
}

trait Resizable extends Component{
    var resizestart:Vec2i = null
    var oldsize = Vec2i(0)
    def resized(delta:Vec2i) {}
    listenTo(mouse.clicks, mouse.moves)
    reactions += {
        case e:MouseDragged =>
            if( resizestart != null ){
                val delta = e.point - resizestart
                peer.setSize(max(oldsize + delta, minimumSize))

                oldsize += delta
                resizestart += delta

                resized(delta)
                revalidate
            }
        case e:MousePressed =>
            if( size.width - e.point.x < 15
             && size.height - e.point.y < 15 ){
                resizestart = e.point
                oldsize = size
            
                this match {
                    case component:Movable =>
                        component.dragstart = null
                    case _ =>
                }
            }
        case e:MouseReleased =>
            resizestart = null
    }
}

---

The only Component I know of that is Dragable and resizeable is the InternalFrame on the JDesktop. here is an example:

import swing._
import event._

import javax.swing.{UIManager,JComponent}
import javax.swing.KeyStroke.getKeyStroke
import java.awt.{Graphics2D,Graphics}

object InternalFrameDemo extends SimpleSwingApplication{
    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName)

    val top = new MainFrame{
        title = "InternalFrameDemo"
        preferredSize = new Dimension(640,480)
        val desktop = new javax.swing.JDesktopPane

        val jc = new JComponent{
            override def paint(g:Graphics){
                import g._
                drawLine(0,0,20,20)
                drawLine(0,20,20,0)
                println("yay draw")
            }

            setVisible(true)
        }

        desktop add jc

        contents = Component.wrap(desktop)

        menuBar = new MenuBar{
            contents += new Menu("Document"){
                mnemonic = Key.D

                contents += new MenuItem("New"){
                    mnemonic = Key.N
                    action = new Action("new"){
                        def apply = createFrame
                        accelerator = Some(getKeyStroke("alt N"))
                    }
                }

                contents += new MenuItem("Quit"){
                    mnemonic = Key.Q
                    action = new Action("quit"){
                        def apply(){
                            quit()
                        }
                        accelerator = Some(getKeyStroke("alt Q"))
                    }
                }
            }
        }

        def createFrame{
            val newFrame = MyInternalFrame()
            newFrame setVisible true
            desktop add newFrame
            newFrame setSelected true

        }
    }
}

import javax.swing.{JDesktopPane,JInternalFrame}
import collection.mutable.ArrayBuffer

object MyInternalFrame{
    var openFrameCount = 0;
    val xOffset, yOffset = 30;

    def apply() = {
        openFrameCount += 1
        val jframe = new javax.swing.JInternalFrame("Document #" + openFrameCount,true,true,true,true)

        jframe.setSize(300,300)
        jframe.setLocation(xOffset*openFrameCount,yOffset*openFrameCount)

        jframe //Component.wrap(jframe)
    }
}

but both JInternalFrame and JDesktop are not integrated in the scala swing package and need to be wrapped manually.