src/Tools/jEdit/src/text_area_painter.scala

ignore empty gfx_range;
tuned;

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

Painter setup for main jEdit text area.
*/

package isabelle.jedit


import isabelle._

import java.awt.{Graphics2D, Shape}
import java.awt.font.TextAttribute
import java.text.AttributedString
import java.util.ArrayList

import org.gjt.sp.jedit.Debug
import org.gjt.sp.jedit.syntax.{DisplayTokenHandler, Chunk}
import org.gjt.sp.jedit.textarea.{TextAreaExtension, TextAreaPainter, JEditTextArea}


class Text_Area_Painter(doc_view: Document_View)
{
  private val model = doc_view.model
  private val buffer = model.buffer
  private val text_area = doc_view.text_area


  /* text area ranges */

  private class Gfx_Range(val x: Int, val y: Int, val length: Int)

  private def gfx_range(range: Text.Range): Option[Gfx_Range] =
  {
    val p = text_area.offsetToXY(range.start)
    val q = text_area.offsetToXY(range.stop)
    if (p != null && q != null && p.x < q.x && p.y == q.y)
      Some(new Gfx_Range(p.x, p.y, q.x - p.x))
    else None
  }


  /* original painters */

  private def pick_extension(name: String): TextAreaExtension =
  {
    text_area.getPainter.getExtensions.iterator.filter(x => x.getClass.getName == name).toList
    match {
      case List(x) => x
      case _ => error("Expected exactly one " + name)
    }
  }

  private val orig_text_painter =
    pick_extension("org.gjt.sp.jedit.textarea.TextAreaPainter$PaintText")


  /* common painter state */

  @volatile private var painter_snapshot: Document.Snapshot = null
  @volatile private var painter_clip: Shape = null

  private val set_state = new TextAreaExtension
  {
    override def paintScreenLineRange(gfx: Graphics2D,
      first_line: Int, last_line: Int, physical_lines: Array[Int],
      start: Array[Int], end: Array[Int], y: Int, line_height: Int)
    {
      doc_view.robust_body(()) {
        painter_snapshot = doc_view.update_snapshot()
        painter_clip = gfx.getClip
      }
    }
  }

  private val reset_state = new TextAreaExtension
  {
    override def paintScreenLineRange(gfx: Graphics2D,
      first_line: Int, last_line: Int, physical_lines: Array[Int],
      start: Array[Int], end: Array[Int], y: Int, line_height: Int)
    {
      doc_view.robust_body(()) {
        painter_snapshot = null
        painter_clip = null
      }
    }
  }


  /* text background */

  private val background_painter = new TextAreaExtension
  {
    override def paintScreenLineRange(gfx: Graphics2D,
      first_line: Int, last_line: Int, physical_lines: Array[Int],
      start: Array[Int], end: Array[Int], y: Int, line_height: Int)
    {
      doc_view.robust_body(()) {
        val snapshot = painter_snapshot
        val ascent = text_area.getPainter.getFontMetrics.getAscent

        for (i <- 0 until physical_lines.length) {
          if (physical_lines(i) != -1) {
            val line_range = doc_view.proper_line_range(start(i), end(i))

            // background color (1)
            for {
              Text.Info(range, color) <- Isabelle_Rendering.background1(snapshot, line_range)
              r <- gfx_range(range)
            } {
              gfx.setColor(color)
              gfx.fillRect(r.x, y + i * line_height, r.length, line_height)
            }

            // background color (2)
            for {
              Text.Info(range, color) <- Isabelle_Rendering.background2(snapshot, line_range)
              r <- gfx_range(range)
            } {
              gfx.setColor(color)
              gfx.fillRect(r.x + 2, y + i * line_height + 2, r.length - 4, line_height - 4)
            }

            // squiggly underline
            for {
              Text.Info(range, color) <- Isabelle_Rendering.message_color(snapshot, line_range)
              r <- gfx_range(range)
            } {
              gfx.setColor(color)
              val x0 = (r.x / 2) * 2
              val y0 = r.y + ascent + 1
              for (x1 <- Range(x0, x0 + r.length, 2)) {
                val y1 = if (x1 % 4 < 2) y0 else y0 + 1
                gfx.drawLine(x1, y1, x1 + 1, y1)
              }
            }
          }
        }
      }
    }
  }


  /* text */

  def char_width(): Int =
  {
    val painter = text_area.getPainter
    val font = painter.getFont
    val font_context = painter.getFontRenderContext
    font.getStringBounds(" ", font_context).getWidth.round.toInt
  }

  private def line_infos(physical_lines: Iterator[Int]): Map[Text.Offset, Chunk] =
  {
    val painter = text_area.getPainter
    val font = painter.getFont
    val font_context = painter.getFontRenderContext

    // see org.gjt.sp.jedit.textarea.TextArea.propertiesChanged
    // see org.gjt.sp.jedit.textarea.TextArea.setMaxLineLength
    val margin =
      if (buffer.getStringProperty("wrap") != "soft") 0.0f
      else {
        val max = buffer.getIntegerProperty("maxLineLen", 0)
        if (max > 0) font.getStringBounds(" " * max, font_context).getWidth.toInt
        else painter.getWidth - char_width() * 3
      }.toFloat

    val out = new ArrayList[Chunk]
    val handler = new DisplayTokenHandler

    var result = Map[Text.Offset, Chunk]()
    for (line <- physical_lines) {
      out.clear
      handler.init(painter.getStyles, font_context, painter, out, margin)
      buffer.markTokens(line, handler)

      val line_start = buffer.getLineStartOffset(line)
      for (i <- 0 until out.size) {
        val chunk = out.get(i)
        result += (line_start + chunk.offset -> chunk)
      }
    }
    result
  }

  private def paint_chunk_list(
    gfx: Graphics2D, line_start: Text.Offset, head: Chunk, x: Float, y: Float): Float =
  {
    val clip_rect = gfx.getClipBounds
    val painter = text_area.getPainter
    val font_context = painter.getFontRenderContext

    var w = 0.0f
    var chunk = head
    while (chunk != null) {
      val chunk_offset = line_start + chunk.offset
      if (x + w + chunk.width > clip_rect.x &&
          x + w < clip_rect.x + clip_rect.width && chunk.accessable)
      {
        val chunk_range = Text.Range(chunk_offset, chunk_offset + chunk.length)
        val chunk_str = if (chunk.str == null) " " * chunk.length else chunk.str
        val chunk_font = chunk.style.getFont
        val chunk_color = chunk.style.getForegroundColor

        def string_width(s: String): Float =
          if (s.isEmpty) 0.0f
          else chunk_font.getStringBounds(s, font_context).getWidth.toFloat

        val caret_range =
          if (text_area.hasFocus) doc_view.caret_range()
          else Text.Range(-1)

        val markup =
          for {
            r1 <- Isabelle_Rendering.text_color(painter_snapshot, chunk_range, chunk_color)
            r2 <- r1.try_restrict(chunk_range)
          } yield r2

        val padded_markup =
          if (markup.isEmpty)
            Iterator(Text.Info(chunk_range, chunk_color))
          else
            Iterator(
              Text.Info(Text.Range(chunk_range.start, markup.head.range.start), chunk_color)) ++
            markup.iterator ++
            Iterator(Text.Info(Text.Range(markup.last.range.stop, chunk_range.stop), chunk_color))

        var x1 = x + w
        gfx.setFont(chunk_font)
        for (Text.Info(range, color) <- padded_markup if !range.is_singularity) {
          val str = chunk_str.substring(range.start - chunk_offset, range.stop - chunk_offset)
          gfx.setColor(color)

          range.try_restrict(caret_range) match {
            case Some(r) if !r.is_singularity =>
              val i = r.start - range.start
              val j = r.stop - range.start
              val s1 = str.substring(0, i)
              val s2 = str.substring(i, j)
              val s3 = str.substring(j)

              if (!s1.isEmpty) gfx.drawString(s1, x1, y)

              val astr = new AttributedString(s2)
              astr.addAttribute(TextAttribute.FONT, chunk_font)
              astr.addAttribute(TextAttribute.FOREGROUND, painter.getCaretColor)
              astr.addAttribute(TextAttribute.SWAP_COLORS, TextAttribute.SWAP_COLORS_ON)
              gfx.drawString(astr.getIterator, x1 + string_width(s1), y)

              if (!s3.isEmpty)
                gfx.drawString(s3, x1 + string_width(str.substring(0, j)), y)

            case _ =>
              gfx.drawString(str, x1, y)
          }
          x1 += string_width(str)
        }
      }
      w += chunk.width
      chunk = chunk.next.asInstanceOf[Chunk]
    }
    w
  }

  private val text_painter = new TextAreaExtension
  {
    override def paintScreenLineRange(gfx: Graphics2D,
      first_line: Int, last_line: Int, physical_lines: Array[Int],
      start: Array[Int], end: Array[Int], y: Int, line_height: Int)
    {
      doc_view.robust_body(()) {
        val clip = gfx.getClip
        val x0 = text_area.getHorizontalOffset
        val fm = text_area.getPainter.getFontMetrics
        var y0 = y + fm.getHeight - (fm.getLeading + 1) - fm.getDescent

        val infos = line_infos(physical_lines.iterator.filter(i => i != -1))
        for (i <- 0 until physical_lines.length) {
          if (physical_lines(i) != -1) {
            val x1 =
              infos.get(start(i)) match {
                case None => x0
                case Some(chunk) =>
                  gfx.clipRect(x0, y + line_height * i, Integer.MAX_VALUE, line_height)
                  val w = paint_chunk_list(gfx, start(i), chunk, x0, y0).toInt
                  x0 + w.toInt
              }
            gfx.clipRect(x1, 0, Integer.MAX_VALUE, Integer.MAX_VALUE)
            orig_text_painter.paintValidLine(gfx,
              first_line + i, physical_lines(i), start(i), end(i), y + line_height * i)
            gfx.setClip(clip)
          }
          y0 += line_height
        }
      }
    }
  }


  /* foreground */

  private val foreground_painter = new TextAreaExtension
  {
    override def paintScreenLineRange(gfx: Graphics2D,
      first_line: Int, last_line: Int, physical_lines: Array[Int],
      start: Array[Int], end: Array[Int], y: Int, line_height: Int)
    {
      doc_view.robust_body(()) {
        val snapshot = painter_snapshot

        for (i <- 0 until physical_lines.length) {
          if (physical_lines(i) != -1) {
            val line_range = doc_view.proper_line_range(start(i), end(i))

            // foreground color
            for {
              Text.Info(range, color) <- Isabelle_Rendering.foreground(snapshot, line_range)
              r <- gfx_range(range)
            } {
              gfx.setColor(color)
              gfx.fillRect(r.x, y + i * line_height, r.length, line_height)
            }

            // highlighted range -- potentially from other snapshot
            for {
              info <- doc_view.highlight_range()
              Text.Info(range, color) <- info.try_restrict(line_range)
              r <- gfx_range(range)
            } {
              gfx.setColor(color)
              gfx.fillRect(r.x, y + i * line_height, r.length, line_height)
            }
          }
        }
      }
    }
  }


  /* caret -- outside of text range */

  private class Caret_Painter(before: Boolean) extends TextAreaExtension
  {
    override def paintValidLine(gfx: Graphics2D,
      screen_line: Int, physical_line: Int, start: Int, end: Int, y: Int)
    {
      doc_view.robust_body(()) {
        if (before) gfx.clipRect(0, 0, 0, 0)
        else gfx.setClip(painter_clip)
      }
    }
  }

  private val before_caret_painter1 = new Caret_Painter(true)
  private val after_caret_painter1 = new Caret_Painter(false)
  private val before_caret_painter2 = new Caret_Painter(true)
  private val after_caret_painter2 = new Caret_Painter(false)

  private val caret_painter = new TextAreaExtension
  {
    override def paintValidLine(gfx: Graphics2D,
      screen_line: Int, physical_line: Int, start: Int, end: Int, y: Int)
    {
      doc_view.robust_body(()) {
        if (text_area.hasFocus) {
          val caret = text_area.getCaretPosition
          if (start <= caret && caret == end - 1) {
            val painter = text_area.getPainter
            val fm = painter.getFontMetrics

            val offset = caret - text_area.getLineStartOffset(physical_line)
            val x = text_area.offsetToXY(physical_line, offset).x
            gfx.setColor(painter.getCaretColor)
            gfx.drawRect(x, y, char_width() - 1, fm.getHeight - 1)
          }
        }
      }
    }
  }


  /* activation */

  def activate()
  {
    val painter = text_area.getPainter
    painter.addExtension(TextAreaPainter.LOWEST_LAYER, set_state)
    painter.addExtension(TextAreaPainter.LINE_BACKGROUND_LAYER + 1, background_painter)
    painter.addExtension(TextAreaPainter.TEXT_LAYER, text_painter)
    painter.addExtension(TextAreaPainter.CARET_LAYER - 1, before_caret_painter1)
    painter.addExtension(TextAreaPainter.CARET_LAYER + 1, after_caret_painter1)
    painter.addExtension(TextAreaPainter.BLOCK_CARET_LAYER - 1, before_caret_painter2)
    painter.addExtension(TextAreaPainter.BLOCK_CARET_LAYER + 1, after_caret_painter2)
    painter.addExtension(TextAreaPainter.BLOCK_CARET_LAYER + 2, caret_painter)
    painter.addExtension(500, foreground_painter)
    painter.addExtension(TextAreaPainter.HIGHEST_LAYER, reset_state)
    painter.removeExtension(orig_text_painter)
  }

  def deactivate()
  {
    val painter = text_area.getPainter
    painter.addExtension(TextAreaPainter.TEXT_LAYER, orig_text_painter)
    painter.removeExtension(reset_state)
    painter.removeExtension(foreground_painter)
    painter.removeExtension(caret_painter)
    painter.removeExtension(after_caret_painter2)
    painter.removeExtension(before_caret_painter2)
    painter.removeExtension(after_caret_painter1)
    painter.removeExtension(before_caret_painter1)
    painter.removeExtension(text_painter)
    painter.removeExtension(background_painter)
    painter.removeExtension(set_state)
  }
}