src/Pure/GUI/gui.scala

uniform focus traversal via TAB / Shift-TAB for all fields, in contrast to Java defaults, but in accordance to occasional jEdit practice;

/*  Title:      Pure/GUI/gui.scala
    Module:     PIDE-GUI
    Author:     Makarius

Basic GUI tools (for AWT/Swing).
*/

package isabelle


import java.lang.{ClassLoader, ClassNotFoundException, NoSuchMethodException}
import java.awt.{Image, Component, Container, Toolkit, Window, Font, KeyboardFocusManager}
import java.awt.font.{TextAttribute, TransformAttribute, FontRenderContext, LineMetrics}
import java.awt.geom.AffineTransform
import javax.swing.{ImageIcon, JOptionPane, UIManager, JLayeredPane, JFrame, JWindow, JButton}

import scala.collection.convert.WrapAsJava
import scala.swing.{ComboBox, TextArea, ScrollPane}
import scala.swing.event.SelectionChanged


object GUI
{
  /* Swing look-and-feel */

  def get_laf(): String =
  {
    if (Platform.is_windows || Platform.is_macos)
      UIManager.getSystemLookAndFeelClassName()
    else
      UIManager.getInstalledLookAndFeels().find(_.getName == "Nimbus").map(_.getClassName)
        .getOrElse(UIManager.getCrossPlatformLookAndFeelClassName())
  }

  def init_laf(): Unit = UIManager.setLookAndFeel(get_laf())

  def is_macos_laf(): Boolean =
    Platform.is_macos &&
    UIManager.getSystemLookAndFeelClassName() == UIManager.getLookAndFeel.getClass.getName


  /* plain focus traversal, notably for text fields */

  def plain_focus_traversal(component: Component)
  {
    val dummy_button = new JButton
    def apply(id: Int): Unit =
      component.setFocusTraversalKeys(id, dummy_button.getFocusTraversalKeys(id))
    apply(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS)
    apply(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS)
  }


  /* X11 window manager */

  def window_manager(): Option[String] =
  {
    if (Platform.is_windows || Platform.is_macos) None
    else
      try {
        val XWM = Class.forName("sun.awt.X11.XWM", true, ClassLoader.getSystemClassLoader)
        val getWM = XWM.getDeclaredMethod("getWM")
        getWM.setAccessible(true)
        getWM.invoke(null) match {
          case null => None
          case wm => Some(wm.toString)
        }
      }
      catch {
        case _: ClassNotFoundException => None
        case _: NoSuchMethodException => None
      }
  }


  /* simple dialogs */

  def scrollable_text(txt: String, width: Int = 60, height: Int = 20, editable: Boolean = false)
    : ScrollPane =
  {
    val text = new TextArea(txt)
    if (width > 0) text.columns = width
    if (height > 0 && split_lines(txt).length > height) text.rows = height
    text.editable = editable
    new ScrollPane(text)
  }

  private def simple_dialog(kind: Int, default_title: String,
    parent: Component, title: String, message: Seq[Any])
  {
    Swing_Thread.now {
      val java_message = message map { case x: scala.swing.Component => x.peer case x => x }
      JOptionPane.showMessageDialog(parent,
        java_message.toArray.asInstanceOf[Array[AnyRef]],
        if (title == null) default_title else title, kind)
    }
  }

  def dialog(parent: Component, title: String, message: Any*) =
    simple_dialog(JOptionPane.PLAIN_MESSAGE, null, parent, title, message)

  def warning_dialog(parent: Component, title: String, message: Any*) =
    simple_dialog(JOptionPane.WARNING_MESSAGE, "Warning", parent, title, message)

  def error_dialog(parent: Component, title: String, message: Any*) =
    simple_dialog(JOptionPane.ERROR_MESSAGE, "Error", parent, title, message)

  def confirm_dialog(parent: Component, title: String, option_type: Int, message: Any*): Int =
    Swing_Thread.now {
      val java_message = message map { case x: scala.swing.Component => x.peer case x => x }
      JOptionPane.showConfirmDialog(parent,
        java_message.toArray.asInstanceOf[Array[AnyRef]], title,
          option_type, JOptionPane.QUESTION_MESSAGE)
    }


  /* zoom box */

  class Zoom_Box(apply_factor: Int => Unit) extends ComboBox[String](
    List("50%", "70%", "85%", "100%", "125%", "150%", "175%", "200%", "300%", "400%"))
  {
    val Factor = "([0-9]+)%?".r
    def parse(text: String): Int =
      text match {
        case Factor(s) =>
          val i = Integer.parseInt(s)
          if (10 <= i && i <= 1000) i else 100
        case _ => 100
      }

    def print(i: Int): String = i.toString + "%"

    def set_item(i: Int) {
      peer.getEditor match {
        case null =>
        case editor => editor.setItem(print(i))
      }
    }

    makeEditable()(c => new ComboBox.BuiltInEditor(c)(text => print(parse(text)), x => x))
    reactions += {
      case SelectionChanged(_) => apply_factor(parse(selection.item))
    }
    listenTo(selection)
    selection.index = 3
    prototypeDisplayValue = Some("00000%")
  }


  /* tooltip with multi-line support */

  def tooltip_lines(text: String): String =
    if (text == null || text == "") null
    else "<html>" + HTML.encode(text) + "</html>"


  /* screen resolution */

  def resolution_scale(): Double = Toolkit.getDefaultToolkit.getScreenResolution.toDouble / 72
  def resolution_scale(i: Int): Int = (i.toDouble * resolution_scale()).round.toInt


  /* icon */

  def isabelle_icon(): ImageIcon =
    new ImageIcon(getClass.getClassLoader.getResource("isabelle/isabelle_transparent-32.gif"))

  def isabelle_icons(): List[ImageIcon] =
    for (icon <- List("isabelle/isabelle_transparent-32.gif", "isabelle/isabelle_transparent.gif"))
      yield new ImageIcon(getClass.getClassLoader.getResource(icon))

  def isabelle_image(): Image = isabelle_icon().getImage

  def isabelle_images(): java.util.List[Image] =
    WrapAsJava.seqAsJavaList(isabelle_icons.map(_.getImage))


  /* component hierachy */

  def get_parent(component: Component): Option[Container] =
    component.getParent match {
      case null => None
      case parent => Some(parent)
    }

  def ancestors(component: Component): Iterator[Container] = new Iterator[Container] {
    private var next_elem = get_parent(component)
    def hasNext(): Boolean = next_elem.isDefined
    def next(): Container =
      next_elem match {
        case Some(parent) =>
          next_elem = get_parent(parent)
          parent
        case None => Iterator.empty.next()
      }
  }

  def parent_window(component: Component): Option[Window] =
    ancestors(component).collectFirst({ case x: Window => x })

  def layered_pane(component: Component): Option[JLayeredPane] =
    parent_window(component) match {
      case Some(window: JWindow) => Some(window.getLayeredPane)
      case Some(frame: JFrame) => Some(frame.getLayeredPane)
      case _ => None
    }


  /* font operations */

  def font_metrics(font: Font): LineMetrics =
    font.getLineMetrics("", new FontRenderContext(null, false, false))

  def imitate_font(family: String, font: Font, scale: Double = 1.0): Font =
  {
    val font1 = new Font(family, font.getStyle, font.getSize)
    val size = scale * (font_metrics(font).getAscent / font_metrics(font1).getAscent * font.getSize)
    font1.deriveFont(size.round.toInt)
  }

  def transform_font(font: Font, transform: AffineTransform): Font =
  {
    import scala.collection.JavaConversions._
    font.deriveFont(Map(TextAttribute.TRANSFORM -> new TransformAttribute(transform)))
  }
}