Vttest 2 (#190)

* added Tab Stops support

* added support for Screen Mode (DECSCNM) -- reverse colors

* bug fix: cursor rendition in Origin Mode

* bug fix: SGR parameters handling

* Save/Restore Cursor updates. Partial charset implementation.

buffer/buffer.go

@@ -14,11 +14,14 @@ type Buffer struct {
 	displayChangeHandlers []chan bool
 	savedX                uint16
 	savedY                uint16
+	savedCursorAttr       *CellAttributes
 	dirty                 bool
 	selectionStart        *Position
 	selectionEnd          *Position
 	selectionComplete     bool // whether the selected text can update or whether it is final
 	terminalState         *TerminalState
+	savedCharsets         []*map[rune]rune
+	savedCurrentCharset   int
 }
 
 type Position struct {
@@ -355,13 +358,27 @@ func (buffer *Buffer) ScrollToEnd() {
 }
 
 func (buffer *Buffer) SaveCursor() {
+	copiedAttr := buffer.terminalState.CursorAttr
+	buffer.savedCursorAttr = &copiedAttr
 	buffer.savedX = buffer.terminalState.cursorX
 	buffer.savedY = buffer.terminalState.cursorY
+	buffer.savedCharsets = make([]*map[rune]rune, len(buffer.terminalState.Charsets))
+	copy(buffer.savedCharsets, buffer.terminalState.Charsets)
+	buffer.savedCurrentCharset = buffer.terminalState.CurrentCharset
 }
 
 func (buffer *Buffer) RestoreCursor() {
+	if buffer.savedCursorAttr != nil {
+		copiedAttr := *buffer.savedCursorAttr
+		buffer.terminalState.CursorAttr = copiedAttr // @todo ignore colors?
+	}
 	buffer.terminalState.cursorX = buffer.savedX
 	buffer.terminalState.cursorY = buffer.savedY
+	if buffer.savedCharsets != nil {
+		buffer.terminalState.Charsets = make([]*map[rune]rune, len(buffer.savedCharsets))
+		copy(buffer.terminalState.Charsets, buffer.savedCharsets)
+		buffer.terminalState.CurrentCharset = buffer.savedCurrentCharset
+	}
 }
 
 func (buffer *Buffer) CursorAttr() *CellAttributes {

buffer/terminal_state.go

@@ -16,6 +16,8 @@ type TerminalState struct {
 	AutoWrap              bool
 	maxLines              uint64
 	tabStops              map[uint16]struct{}
+	Charsets              []*map[rune]rune // array of 2 charsets, nil means ASCII (no conversion)
+	CurrentCharset        int              // active charset index in Charsets array, valid values are 0 or 1
 }
 
 // NewTerminalMode creates a new terminal state
@@ -30,6 +32,7 @@ func NewTerminalState(viewCols uint16, viewLines uint16, attr CellAttributes, ma
 		viewHeight:   viewLines,
 		topMargin:    0,
 		bottomMargin: uint(viewLines - 1),
+		Charsets:     []*map[rune]rune{nil, nil},
 		LineFeedMode: true,
 	}
 	b.TabReset()

terminal/ansi.go

@@ -17,8 +17,8 @@ var ansiSequenceMap = map[rune]escapeSequenceHandler{
 	'P': sixelHandler,
 	'c': risHandler, //RIS
 	'#': screenStateHandler,
-	'(': swallowHandler(1), // character set bullshit
+	'(': scs0Handler,       // select character set into G0
-	')': swallowHandler(1), // character set bullshit
+	')': scs1Handler,       // select character set into G1
 	'*': swallowHandler(1), // character set bullshit
 	'+': swallowHandler(1), // character set bullshit
 	'>': swallowHandler(0), // numeric char selection  //@todo

terminal/charset.go

@@ -0,0 +1,65 @@
+package terminal
+
+import "fmt"
+
+var charSets = map[rune]*map[rune]rune{
+	'0': &decSpecGraphics,
+	'B': nil, // ASCII
+	// @todo 1,2,A
+}
+
+var decSpecGraphics = map[rune]rune{
+	0x5f: 0x00A0, // NO-BREAK SPACE
+	0x60: 0x25C6, // BLACK DIAMOND
+	0x61: 0x2592, // MEDIUM SHADE
+	0x62: 0x2409, // SYMBOL FOR HORIZONTAL TABULATION
+	0x63: 0x240C, // SYMBOL FOR FORM FEED
+	0x64: 0x240D, // SYMBOL FOR CARRIAGE RETURN
+	0x65: 0x240A, // SYMBOL FOR LINE FEED
+	0x66: 0x00B0, // DEGREE SIGN
+	0x67: 0x00B1, // PLUS-MINUS SIGN
+	0x68: 0x2424, // SYMBOL FOR NEWLINE
+	0x69: 0x240B, // SYMBOL FOR VERTICAL TABULATION
+	0x6a: 0x2518, // BOX DRAWINGS LIGHT UP AND LEFT
+	0x6b: 0x2510, // BOX DRAWINGS LIGHT DOWN AND LEFT
+	0x6c: 0x250C, // BOX DRAWINGS LIGHT DOWN AND RIGHT
+	0x6d: 0x2514, // BOX DRAWINGS LIGHT UP AND RIGHT
+	0x6e: 0x253C, // BOX DRAWINGS LIGHT VERTICAL AND HORIZONTAL
+	0x6f: 0x23BA, // HORIZONTAL SCAN LINE-1
+	0x70: 0x23BB, // HORIZONTAL SCAN LINE-3
+	0x71: 0x2500, // BOX DRAWINGS LIGHT HORIZONTAL
+	0x72: 0x23BC, // HORIZONTAL SCAN LINE-7
+	0x73: 0x23BD, // HORIZONTAL SCAN LINE-9
+	0x74: 0x251C, // BOX DRAWINGS LIGHT VERTICAL AND RIGHT
+	0x75: 0x2524, // BOX DRAWINGS LIGHT VERTICAL AND LEFT
+	0x76: 0x2534, // BOX DRAWINGS LIGHT UP AND HORIZONTAL
+	0x77: 0x252C, // BOX DRAWINGS LIGHT DOWN AND HORIZONTAL
+	0x78: 0x2502, // BOX DRAWINGS LIGHT VERTICAL
+	0x79: 0x2264, // LESS-THAN OR EQUAL TO
+	0x7a: 0x2265, // GREATER-THAN OR EQUAL TO
+	0x7b: 0x03C0, // GREEK SMALL LETTER PI
+	0x7c: 0x2260, // NOT EQUAL TO
+	0x7d: 0x00A3, // POUND SIGN
+	0x7e: 0x00B7, // MIDDLE DOT
+}
+
+func scs0Handler(pty chan rune, terminal *Terminal) error {
+	return scsHandler(pty, terminal, 0)
+}
+
+func scs1Handler(pty chan rune, terminal *Terminal) error {
+	return scsHandler(pty, terminal, 1)
+}
+
+func scsHandler(pty chan rune, terminal *Terminal, which int) error {
+	b := <-pty
+
+	cs, ok := charSets[b]
+	if ok {
+		terminal.logger.Debugf("Selected charset %v into G%v", string(b), which)
+		terminal.terminalState.Charsets[which] = cs
+		return nil
+	}
+	terminal.terminalState.Charsets[which] = nil
+	return fmt.Errorf("Unknown SCS charset code: 0x%02X [%v]", b, string(b))
+}

terminal/output.go

@@ -61,12 +61,14 @@ func enqHandler(terminal *Terminal) error {
 }
 
 func shiftOutHandler(terminal *Terminal) error {
-	terminal.logger.Errorf("Received shift out")
+	terminal.logger.Debugf("Received shift out")
+	terminal.terminalState.CurrentCharset = 1
 	return nil
 }
 
 func shiftInHandler(terminal *Terminal) error {
-	terminal.logger.Errorf("Received shift in")
+	terminal.logger.Debugf("Received shift in")
+	terminal.terminalState.CurrentCharset = 0
 	return nil
 }
 
@@ -79,10 +81,22 @@ func (terminal *Terminal) processRune(b rune) {
 		return
 	}
 	//terminal.logger.Debugf("Received character 0x%X: %q", b, string(b))
-	terminal.ActiveBuffer().Write(b)
+	terminal.ActiveBuffer().Write(terminal.translateRune(b))
 	terminal.isDirty = true
 }
 
+func (terminal *Terminal) translateRune(b rune) rune {
+	table := terminal.terminalState.Charsets[terminal.terminalState.CurrentCharset]
+	if table == nil {
+		return b
+	}
+	chr, ok := (*table)[b]
+	if ok {
+		return chr
+	}
+	return b
+}
+
 func (terminal *Terminal) processInput(pty chan rune) {
 
 	// https://en.wikipedia.org/wiki/ANSI_escape_code

terminal/sgr.go

@@ -20,7 +20,7 @@ func sgrSequenceHandler(params []string, terminal *Terminal) error {
 		p := strings.Replace(strings.Replace(params[i], "[", "", -1), "]", "", -1)
 
 		switch p {
-		case "00", "0":
+		case "00", "0", "":
 			attr := terminal.ActiveBuffer().CursorAttr()
 			*attr = buffer.CellAttributes{
 				FgColour: terminal.config.ColourScheme.Foreground,