Improve terminal escape handling

copret/src/slides.scala

@@ -6,6 +6,7 @@ import syntax._
 case class Presentation(slides: Vector[Slide], meta: Map[String, String] = Map.empty):
   def start(using keymap: Keymap = Keymap.default) =
     Terminal.enterRawMode()
+    Terminal.hideCursor()
     run()
 
   import Presentation._
@@ -34,7 +35,12 @@ case class Presentation(slides: Vector[Slide], meta: Map[String, String] = Map.e
           else
             rec(p, pos, waitkey)
         case Interactive(cmd, path) =>
-          %(cmd)(path)
+          Terminal.showCursor()
+          try
+            %(cmd)(path)
+          catch case _ => ()
+          Terminal.hideCursor()
+          Terminal.clear()
           rec(p, pos - 1, QuickNext)
         case Goto(target) =>
           for i <- 0 until target
@@ -57,11 +63,12 @@ case class Presentation(slides: Vector[Slide], meta: Map[String, String] = Map.e
 object Presentation:
   def executeSlide(p: Presentation, pos: Int)(slide: Slide = p.slides(pos)): Unit = slide match
     case Paragraph(contents) => println(contents)
-    case Clear => print("\u001b[2J\u001b[;H")
+    case Clear => Terminal.clear()
     case PauseKey => waitkey(using Keymap.empty)
     case Pause(msec) => Thread.sleep(msec)
     case incMd @ IncludeMarkdown(_) => println(incMd.markdownBlock())
-    case Image(file, width, height, keepAspect) => print(Terminal.showImage(file, width, height, keepAspect))
+    case Image(file, None) => Terminal.showImage(file)
+    case Image(file, Some(ImageSize(w, h, aspect))) => Terminal.showImageScaled(file, w, h, aspect)
     case cmd: TypedCommand[_] => cmd.show()
     case Silent(actions) => actions()
     case Group(slides) => slides.foreach(executeSlide(p, pos))
@@ -80,16 +87,32 @@ object Presentation:
     case cmd: TypedCommand[_] => cmd.force()
     case Group(slides) => slides.foreach(executeSilent(p, pos))
     case lios @ LazyIOSlide(_, display) => executeSilent(p, pos)(lios.genSlide())
-    case Paragraph(_) | Image(_,_,_,_) | Clear | IncludeMarkdown(_) | Meta(_) => ()
+    case Paragraph(_) | Image(_,_) | Clear | IncludeMarkdown(_) | Meta(_) => ()
     case _ => executeQuick(p, pos)(slide)
 
 
+case class ImageSize(width: Double, height: Double, keepAspect: Boolean)
+
 sealed trait Slide
-case class Paragraph(contents: fansi.Str) extends Slide
+case class Paragraph(contents: String) extends Slide:
+  def centerVertical(height: Int): Paragraph =
+    val lines = contents.toString.count(_ == '\n') + 1
+    val pad = "\n" * ((height - lines) / 2)
+    Paragraph(pad + contents + pad)
+
+object Paragraph:
+  def apply(str: fansi.Str): Paragraph = Paragraph(str.toString)
+
 case class IncludeMarkdown(path: Path) extends Slide:
   def markdownBlock() =
     %%%("/usr/bin/mdcat", "--columns", (columns * 0.8).toInt.toString, path.toString)(using ImplicitWd.implicitCwd).block
-case class Image(path: Path, width: String = "100%", height: String = "100%", keepAspect: Boolean = true) extends Slide
+
+case class Image(path: Path, sizing: Option[ImageSize]) extends Slide
+object Image:
+  def apply(path: Path) = new Image(path, None)
+  def scaled(path: Path, width: Double, height: Double, keepAspect: Boolean) =
+    Image(path, Some(ImageSize(width, height, keepAspect)))
+
 case object Clear extends Slide
 case class Pause(millisec: Long) extends Slide
 case object PauseKey extends Slide
@@ -103,8 +126,10 @@ case class TypedCommand[T](exec: T => String, display: String, cmd: T) extends S
 
   def show() =
     prompt()
+    Terminal.showCursor()
     typeCmd()
     print(output)
+    Terminal.hideCursor()
 
   def quickShow() =
     prompt()

copret/src/terminal.scala

@@ -14,9 +14,15 @@ object Terminal:
     %%("sh", "-c", "stty -icanon min 1 < /dev/tty")(pwd)
     %%("sh", "-c", "stty -echo < /dev/tty")(pwd)
 
+  extension (percent: Double)
+    def toPercent: String = s"${(percent * 100).toInt}%"
+
   private[copret] lazy val jterm = org.jline.terminal.TerminalBuilder.terminal()
   private[copret] lazy val lineReader = LineReaderBuilder.builder().terminal(jterm).build()
 
+  def height = jterm.getSize.getRows
+  def width = jterm.getSize.getColumns
+
   def waitkey(using keymap: Keymap): SlideAction =
     // ignore keypresses done during slide animations
     while Console.in.ready() do Console.in.read
@@ -42,22 +48,40 @@ object Terminal:
 
   def isTmux = sys.env.contains("TMUX") || term.startsWith("screen")
 
-  def osc = if isTmux then "\u001bPtmux\u001b\u001b]" else "\u001b]"
+  def osc(code: String) = (if isTmux then "\u001bPtmux\u001b\u001b]" else "\u001b]") + code + st
   def st = if isTmux then "\u0007\u001b\\" else "\u0007"
+  def csi(code: String) = "\u001b[" + code
 
-  def showImage(img: Path, width: String = "100%", height: String = "100%", keepAspect: Boolean = true) =
+  def hideCursor() = print(csi("?25l"))
-    if term == "xterm-kitty" then showImageKitty(img)
+  def showCursor() = print(csi("?25h"))
-    else showImageIterm(img, width, height, keepAspect)
+  def cursorTo(row: Int, col: Int) = print(csi(s"${row};${col}H"))
+  def clear() = print(csi("2J") + csi(";H"))
 
-  def showImageIterm(img: Path, width: String = "100%", height: String = "100%", keepAspect: Boolean = true) =
+  def showImage(img: Path): Unit =
+    print(
+      if term == "xterm-kitty" then showImageKitty(img)
+      else showImageIterm(img, "100%", "100%", true)
+    )
+
+  def showImageScaled(img: Path, width: Double, height: Double, keepAspect: Boolean): Unit =
+    print(
+      if term == "xterm-kitty" then
+        val cols = (jterm.getSize.getColumns * width).toInt
+        val rows = (jterm.getSize.getRows * height).toInt
+        showImageKitty(img) // TODO
+      else
+        showImageIterm(img, width.toPercent, height.toPercent, keepAspect)
+    )
+
+  def showImageIterm(img: Path, width: String, height: String, keepAspect: Boolean = true): String =
     import java.util.Base64
     val image = Base64.getEncoder.encodeToString(read.bytes(img))
     val aspect = if keepAspect then 1 else 0
-    s"${osc}1337;File=inline=1;width=$width;height=$height;preserveAspectRatio=$aspect:$image$st"
+    osc(s"1337;File=inline=1;width=$width;height=$height;preserveAspectRatio=$aspect:$image")
 
-  def showImageKitty(img: Path, width: String = "100%", height: String = "100%", keepAspect: Boolean = true) =
+  def showImageKitty(img: Path): String =
     import java.util.Base64
-    s"\u001b_Gf=100,t=f,a=T;${Base64.getEncoder.encodeToString(img.toString.toCharArray.map(_.toByte))}\u001b\\"
+    s"\u001b_Gf=100,t=f,a=T,C=1;${Base64.getEncoder.encodeToString(img.toString.toCharArray.map(_.toByte))}\u001b\\"
 
 private[copret] trait TerminalSyntax:
   import Terminal._