From f864b5a4731e5ab5148b5fe20533e71691cf6955 Mon Sep 17 00:00:00 2001
From: Jason Woofenden <jason@jasonwoof.com>
Date: Thu, 31 Jan 2013 16:43:29 -0500
Subject: [PATCH] add csi_r (scrolling region)

---
 client.coffee   |    2 ++
 server.coffee   |    2 +-
 terminal.coffee |   51 ++++++++++++++++++++++++++++++++++++++++++---------
 3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/client.coffee b/client.coffee
index 14e5a6f..3cc8c87 100644
--- a/client.coffee
+++ b/client.coffee
@@ -147,4 +147,6 @@ $ ->
 		term.text = v.text
 		term.attributes = v.attributes
 		term.cursor_visible = v.cursor_visible
+		term.scroll_top = v.scroll_top
+		term.scroll_bottom = v.scroll_bottom
 		redraw()
diff --git a/server.coffee b/server.coffee
index 7adfc69..5d5ca35 100644
--- a/server.coffee
+++ b/server.coffee
@@ -49,7 +49,7 @@ io.sockets.on 'connection', (socket) ->
 				sockets.splice i, 1
 				return
 
-	socket.emit 'init', width: term.width, height: term.height, x: term.x, y: term.y, a: term.a, text: term.text, attributes: term.attributes, cursor_visible: term.cursor_visible
+	socket.emit 'init', width: term.width, height: term.height, x: term.x, y: term.y, a: term.a, text: term.text, attributes: term.attributes, cursor_visible: term.cursor_visible, scroll_top: term.scroll_top, scroll_bottom: term.scroll_bottom
 
 process.stdin.resume()
 process.stdin.setEncoding 'utf8'
diff --git a/terminal.coffee b/terminal.coffee
index d371476..721ed80 100644
--- a/terminal.coffee
+++ b/terminal.coffee
@@ -20,10 +20,13 @@ class Terminal
 		@partial = ''
 		@saved_normal_screen = null
 		@cursor_visible = true
+		@scroll_top = 0
+		@scroll_bottom = height - 1
 		@resize width, height
 
 	resize: (width, height) ->
 		# FIXME: write a version that retains some of the data
+		# FIXME: clamp variables (eg x, y, saved.*, scrolling region) if getting smaller
 		@width = width
 		@height = height
 		@text = []
@@ -54,20 +57,30 @@ class Terminal
 		return
 
 	add_new_line: ->
-		# clear top line
+		# clear the line at the top of the scrolling region
 		for i in [0...@width]
-			@text[0][i] = ' '
-			@attributes[0][i] = 0x07
-		# move (newly cleared) top line to the bottom
-		tmp = @text.shift()
-		@text.push(tmp)
-		tmp = @attributes.shift()
-		@attributes.push(tmp)
+			@text[@scroll_top][i] = ' '
+			@attributes[@scroll_top][i] = 0x07
+
+		# move (newly cleared) top line to the bottom of the scrolling region
+		@text = [
+			@text[0...@scroll_top]..., # up to but not including scroll top
+			@text[@scroll_top + 1 .. @scroll_bottom]..., # scroll region except top line of it
+			@text[@scroll_top], # top line of scroll region (already cleared)
+			@text[@scroll_bottom + 1 ... @height]... # rest of screen
+		]
+		@attributes = [
+			@attributes[0...@scroll_top]..., # up to but not including scroll top
+			@attributes[@scroll_top + 1 .. @scroll_bottom]..., # scroll region except top line of it
+			@attributes[@scroll_top], # top line of scroll region (already cleared)
+			@attributes[@scroll_bottom + 1 ... @height]... # rest of screen
+		]
+
 		# slide cursor up with rest of text
 		@y -= 1
 
 	wrap_to_next_line: ->
-		if @y is @height - 1
+		if @y is @scroll_bottom
 			@add_new_line()
 		@y += 1
 		@x = 0
@@ -121,6 +134,7 @@ class Terminal
 		@y -= lines
 		if @y < 0
 			@y = 0
+		return
 
 	# move cursor down
 	csi_B: (lines) ->
@@ -128,6 +142,7 @@ class Terminal
 		@y += lines
 		if @y >= @height
 			@y = @height - 1
+		return
 
 	# move cursor right
 	csi_C: (cols) ->
@@ -135,6 +150,7 @@ class Terminal
 		@x += cols
 		if @x >= @width
 			@x = @width - 1
+		return
 
 	# move cursor left
 	csi_D: (cols) ->
@@ -142,6 +158,7 @@ class Terminal
 		@x -= cols
 		if @x < 0
 			@x = 0
+		return
 
 	# set cursor position (one based)
 	csi_H: (row, column) ->
@@ -162,6 +179,7 @@ class Terminal
 		#move the cursor
 		@x = column
 		@y = row
+		return
 
 	# clear to screen edge(es)
 	csi_J: (direction) ->
@@ -238,6 +256,8 @@ class Terminal
 							@attributes[y].push 0x07
 				else
 					console.log "confusing arg for csiq_h: #{arg}"
+		return
+
 	# unmisc
 	csiq_l: ->
 		args = []
@@ -257,6 +277,7 @@ class Terminal
 					@saved_normal_screen = null
 				else
 					console.log "confusing arg for csiq_l: #{arg}"
+		return
 
 	# set color, bold, underline, etc
 	csi_m: ->
@@ -398,6 +419,18 @@ class Terminal
 					@a = 0
 		return
 
+	# set scrolling region
+	csi_r: (top, bottom) ->
+		top = -1 + parseInt @fix_esc_arg top, '1'
+		bottom = -1 + parseInt @fix_esc_arg bottom, '10000'
+		if top < 0
+			top = 0
+		if bottom >= @height
+			bottom = @height - 1
+		@scroll_top = top
+		@scroll_bottom = bottom
+		return
+
 	# str is the whole escape sequence (minus the esc[ prefix)
 	update_sequence: (str) ->
 		prefix = 'csi_'
-- 
1.7.10.4