src/Tools/jEdit/src/syntax_style.scala

clarified modules;

/*  Title:      Tools/jEdit/src/syntax_style.scala
    Author:     Makarius

Support for extended syntax styles: subscript, superscript, bold, user fonts.
*/

package isabelle.jedit


import isabelle._

import java.awt.{Font, Color}
import java.awt.font.TextAttribute
import java.awt.geom.AffineTransform

import org.gjt.sp.util.SyntaxUtilities
import org.gjt.sp.jedit.syntax.{Token => JEditToken, SyntaxStyle}


object Syntax_Style
{
  private val plain_range: Int = JEditToken.ID_COUNT
  private val full_range = 6 * plain_range + 1
  private def check_range(i: Int) { require(0 <= i && i < plain_range) }

  def subscript(i: Byte): Byte = { check_range(i); (i + plain_range).toByte }
  def superscript(i: Byte): Byte = { check_range(i); (i + 2 * plain_range).toByte }
  def bold(i: Byte): Byte = { check_range(i); (i + 3 * plain_range).toByte }
  def user_font(idx: Int, i: Byte): Byte = { check_range(i); (i + (4 + idx) * plain_range).toByte }
  val hidden: Byte = (6 * plain_range).toByte

  private def font_style(style: SyntaxStyle, f: Font => Font): SyntaxStyle =
    new SyntaxStyle(style.getForegroundColor, style.getBackgroundColor, f(style.getFont))

  private def script_style(style: SyntaxStyle, i: Int): SyntaxStyle =
  {
    font_style(style, font0 =>
      {
        import scala.collection.JavaConversions._
        val font1 = font0.deriveFont(Map(TextAttribute.SUPERSCRIPT -> new java.lang.Integer(i)))

        def shift(y: Float): Font =
          GUI.transform_font(font1, AffineTransform.getTranslateInstance(0.0, y.toDouble))

        val m0 = GUI.line_metrics(font0)
        val m1 = GUI.line_metrics(font1)
        val a = m1.getAscent - m0.getAscent
        val b = (m1.getDescent + m1.getLeading) - (m0.getDescent + m0.getLeading)
        if (a > 0.0f) shift(a)
        else if (b > 0.0f) shift(- b)
        else font1
      })
  }

  private def bold_style(style: SyntaxStyle): SyntaxStyle =
    font_style(style, font => font.deriveFont(if (font.isBold) Font.PLAIN else Font.BOLD))

  val hidden_color: Color = new Color(255, 255, 255, 0)

  class Extender extends SyntaxUtilities.StyleExtender
  {
    val max_user_fonts = 2
    if (Symbol.font_names.length > max_user_fonts)
      error("Too many user symbol fonts (" + max_user_fonts + " permitted): " +
        Symbol.font_names.mkString(", "))

    override def extendStyles(styles: Array[SyntaxStyle]): Array[SyntaxStyle] =
    {
      val new_styles = new Array[SyntaxStyle](full_range)
      for (i <- 0 until plain_range) {
        val style = styles(i)
        new_styles(i) = style
        new_styles(subscript(i.toByte)) = script_style(style, -1)
        new_styles(superscript(i.toByte)) = script_style(style, 1)
        new_styles(bold(i.toByte)) = bold_style(style)
        for (idx <- 0 until max_user_fonts)
          new_styles(user_font(idx, i.toByte)) = style
        for ((family, idx) <- Symbol.font_index)
          new_styles(user_font(idx, i.toByte)) = font_style(style, GUI.imitate_font(_, family))
      }
      new_styles(hidden) =
        new SyntaxStyle(hidden_color, null,
          { val font = styles(0).getFont
            GUI.transform_font(new Font(font.getFamily, 0, 1),
              AffineTransform.getScaleInstance(1.0, font.getSize.toDouble)) })
      new_styles
    }
  }

  def extended(text: CharSequence): Map[Text.Offset, Byte => Byte] =
  {
    // FIXME Symbol.bsub_decoded etc.
    def control_style(sym: String): Option[Byte => Byte] =
      if (sym == Symbol.sub_decoded) Some(subscript(_))
      else if (sym == Symbol.sup_decoded) Some(superscript(_))
      else if (sym == Symbol.bold_decoded) Some(bold(_))
      else None

    var result = Map[Text.Offset, Byte => Byte]()
    def mark(start: Text.Offset, stop: Text.Offset, style: Byte => Byte)
    {
      for (i <- start until stop) result += (i -> style)
    }
    var offset = 0
    var control = ""
    for (sym <- Symbol.iterator(text)) {
      if (control_style(sym).isDefined) control = sym
      else if (control != "") {
        if (Symbol.is_controllable(sym) && sym != "\"" && !Symbol.fonts.isDefinedAt(sym)) {
          mark(offset - control.length, offset, _ => hidden)
          mark(offset, offset + sym.length, control_style(control).get)
        }
        control = ""
      }
      Symbol.lookup_font(sym) match {
        case Some(idx) => mark(offset, offset + sym.length, user_font(idx, _))
        case _ =>
      }
      offset += sym.length
    }
    result
  }
}