| 1 | """ |
| 2 | yterm: a simple, standalone interface library for VT100-like terminals on UNIX. |
| 3 | Written by Jacob Welsh for yrc, March 2017. |
| 4 | Tested with Python 2.7 (should support at least 2.4). |
| 5 | """ |
| 6 | |
| 7 | __version__ = '9 Kelvin' |
| 8 | |
| 9 | from sys import stdout |
| 10 | from fcntl import ioctl |
| 11 | from struct import unpack |
| 12 | import termios as t |
| 13 | |
| 14 | NUL = chr(0) |
| 15 | BS = chr(8) |
| 16 | HT = chr(9) |
| 17 | LF = chr(10) |
| 18 | CR = chr(13) |
| 19 | SO = chr(14) |
| 20 | SI = chr(15) |
| 21 | ESC = chr(27) |
| 22 | |
| 23 | # VT100 http://vt100.net/docs/vt100-ug/chapter3.html |
| 24 | RESET = ESC + 'c' |
| 25 | CURSOR_SAVE = ESC + '7' |
| 26 | CURSOR_RESTORE = ESC + '8' |
| 27 | KEYPAD_APP = ESC + '=' # keypad produces escape sequences |
| 28 | KEYPAD_NUM = ESC + '>' # keypad produces numbers/symbols |
| 29 | select_g0 = lambda c: ESC + '(' + c |
| 30 | select_g1 = lambda c: ESC + ')' + c |
| 31 | SELECT_G0_ASCII = select_g0('B') |
| 32 | SELECT_G1_SPECIAL = select_g1('0') |
| 33 | CSI = ESC + '[' |
| 34 | cseq = lambda code, *params: ''.join((CSI, ';'.join(map(str, params)), code)) |
| 35 | # 1-based coordinates, from origin downward |
| 36 | cursor_pos = lambda row, col: cseq('H', row, col) |
| 37 | CURSOR_HOME = cseq('H') |
| 38 | cursor_up = lambda n: cseq('A', n) |
| 39 | CURSOR_UP1 = cseq('A') |
| 40 | cursor_down = lambda n: cseq('B', n) |
| 41 | CURSOR_DOWN1 = cseq('B') |
| 42 | cursor_back = lambda n: cseq('D', n) |
| 43 | CURSOR_BACK1 = cseq('D') |
| 44 | cursor_forward = lambda n: cseq('C', n) |
| 45 | CURSOR_FORWARD1 = cseq('C') |
| 46 | # Top/bottom margins of scrolling region |
| 47 | margins = lambda top, bot: cseq('r', top, bot) |
| 48 | MARGINS_NONE = cseq('r') |
| 49 | set_mode = lambda m: cseq('h', m) |
| 50 | rst_mode = lambda m: cseq('l', m) |
| 51 | set_priv_mode = lambda m: set_mode('?' + str(m)) |
| 52 | rst_priv_mode = lambda m: rst_mode('?' + str(m)) |
| 53 | LINEFEED_ON = set_mode(20) # LF moves to first column of next row |
| 54 | LINEFEED_OFF = rst_mode(20) # LF moves down only |
| 55 | CURSOR_APP = set_priv_mode(1) # DECCKM |
| 56 | CURSOR_ANSI = rst_priv_mode(1) # implied by KEYPAD_NUM |
| 57 | SCROLL_SMOOTH = set_priv_mode(4) # DECSCLM |
| 58 | SCROLL_JUMP = rst_priv_mode(4) |
| 59 | ORIGIN_MARGIN = set_priv_mode(6) # DECOM: row 1 at top margin, cursor confined |
| 60 | # to scrolling region |
| 61 | ORIGIN_SCREEN = rst_priv_mode(6) # row 1 at top of screen |
| 62 | ERASE_TO_END = cseq('J') |
| 63 | ERASE_FROM_START = cseq('J', 1) |
| 64 | ERASE_FULL = cseq('J', 2) |
| 65 | ERASE_LINE_TO_END = cseq('K') |
| 66 | ERASE_LINE_FROM_START = cseq('K', 1) |
| 67 | ERASE_LINE_FULL = cseq('K', 2) |
| 68 | attrs = lambda *args: cseq('m', *args) |
| 69 | A_NONE = 0 |
| 70 | A_BOLD = 1 |
| 71 | A_ULINE = 4 |
| 72 | A_BLINK = 5 |
| 73 | A_REVERSE = 7 |
| 74 | ATTR_NONE = attrs() |
| 75 | ATTR_BOLD = attrs(A_BOLD) |
| 76 | ATTR_ULINE = attrs(A_ULINE) |
| 77 | ATTR_BLINK = attrs(A_BLINK) |
| 78 | ATTR_REVERSE = attrs(A_REVERSE) |
| 79 | |
| 80 | # DEC special graphics characters http://vt100.net/docs/vt100-ug/table3-9.html |
| 81 | SGC_BLANK = '_' |
| 82 | SGC_DIAMOND = '`' |
| 83 | SGC_CHECKER = 'a' |
| 84 | SGC_HT = 'b' |
| 85 | SGC_FF = 'c' |
| 86 | SGC_CR = 'd' |
| 87 | SGC_LF = 'e' |
| 88 | SGC_DEGREE = 'f' |
| 89 | SGC_PLUSMINUS = 'g' |
| 90 | SGC_NL = 'h' |
| 91 | SGC_VT = 'i' # ACS_LANTERN in ncurses, unclear where that comes from |
| 92 | SGC_LRCORNER = 'j' |
| 93 | SGC_URCORNER = 'k' |
| 94 | SGC_ULCORNER = 'l' |
| 95 | SGC_LLCORNER = 'm' |
| 96 | SGC_CROSSING = 'n' |
| 97 | SGC_HLINE1 = 'o' |
| 98 | SGC_HLINE3 = 'p' |
| 99 | SGC_HLINE5 = 'q' |
| 100 | SGC_HLINE7 = 'r' |
| 101 | SGC_HLINE9 = 's' |
| 102 | SGC_LTEE = 't' |
| 103 | SGC_RTEE = 'u' |
| 104 | SGC_BTEE = 'v' |
| 105 | SGC_TTEE = 'w' |
| 106 | SGC_VBAR = 'x' |
| 107 | SGC_LEQ = 'y' |
| 108 | SGC_GEQ = 'z' |
| 109 | SGC_PI = '{' |
| 110 | SGC_NEQ = '|' |
| 111 | SGC_STERLING = '}' |
| 112 | SGC_CENTERDOT = '~' |
| 113 | |
| 114 | # XTerm http://invisible-island.net/xterm/ctlseqs/ctlseqs.html |
| 115 | ALT_SCREEN_ON = set_priv_mode(47) |
| 116 | ALT_SCREEN_OFF = rst_priv_mode(47) |
| 117 | BRACKETED_PASTE_ON = set_priv_mode(2004) |
| 118 | BRACKETED_PASTE_OFF = rst_priv_mode(2004) |
| 119 | BRACKETED_PASTE_START = cseq('~', 200) |
| 120 | BRACKETED_PASTE_END = cseq('~', 201) |
| 121 | |
| 122 | def init(term_file=stdout, nonblock_read=False): |
| 123 | """ |
| 124 | Initialize the terminal for full-screen graphics and raw input, |
| 125 | returning a cleanup function to be called to restore it at exit. |
| 126 | |
| 127 | Parameters: |
| 128 | term_file -- file object representing the terminal, default stdout (must |
| 129 | support write, flush, and fileno methods) |
| 130 | nonblock_read -- if false (default), reading from the terminal is blocking |
| 131 | and returns at least one character (except on EOF); otherwise it is |
| 132 | nonblocking and may return no characters. |
| 133 | |
| 134 | Details: |
| 135 | - Sets terminal driver attributes for raw input: no line buffering; no flow |
| 136 | control (^S/^Q), signal (^C etc.), or EOF (^D) characters; no CR/LF |
| 137 | translation; 8-bit character size; no echo |
| 138 | - Saves terminal cursor, attribute, and character set state (DECSC) |
| 139 | - Initializes terminal character sets: G0 to ASCII and G1 to the DEC |
| 140 | special graphics characters, initially selecting G0 (SI selects G0; SO |
| 141 | selects G1) |
| 142 | - Selects the alternate screen (to preserve XTerm scrollback) |
| 143 | - Initializes terminal modes: standard linefeed handling (LNM); keypad |
| 144 | produces ASCII characters (DECKPNM); jump scrolling (DECSCLM); no scroll |
| 145 | margins (DECSTBM); no character attributes |
| 146 | |
| 147 | Cleanup details: |
| 148 | - Selects G0 character set |
| 149 | - Disables the alternate screen |
| 150 | - Restores terminal cursor, attribute, and character set state (DECRC) |
| 151 | - Restores original terminal driver state |
| 152 | """ |
| 153 | old_attrs = t.tcgetattr(term_file.fileno()) |
| 154 | # "It's a bad idea to simply initialize a struct termios structure to a |
| 155 | # chosen set of attributes and pass it directly to tcsetattr. Your program |
| 156 | # may be run years from now, on systems that support members not |
| 157 | # documented in this manual. The way to avoid setting these members to |
| 158 | # unreasonable values is to avoid changing them." |
| 159 | # -- glibc manual |
| 160 | # |
| 161 | # Nope. It's 2017; we don't need new pheaturez in termios. If forcing them |
| 162 | # to zero does something "unreasonable", then blindly accepting prior state |
| 163 | # is worse as it could just as well do the same, but unpredictably. |
| 164 | iflag = oflag = lflag = 0 |
| 165 | cflag = t.CS8 | t.CREAD |
| 166 | ispeed, ospeed = old_attrs[4:6] |
| 167 | cc = [NUL]*t.NCCS |
| 168 | if nonblock_read: |
| 169 | cc[t.VMIN] = 0 |
| 170 | else: |
| 171 | cc[t.VMIN] = 1 |
| 172 | cc[t.VTIME] = 0 |
| 173 | t.tcsetattr(term_file.fileno(), t.TCSANOW, |
| 174 | [iflag, oflag, cflag, lflag, ispeed, ospeed, cc]) |
| 175 | term_file.write(''.join(( |
| 176 | CURSOR_SAVE, ALT_SCREEN_ON, |
| 177 | SELECT_G0_ASCII, SI, SELECT_G1_SPECIAL, |
| 178 | LINEFEED_OFF, KEYPAD_NUM, SCROLL_JUMP, |
| 179 | ATTR_NONE, MARGINS_NONE, ERASE_FULL, |
| 180 | ))) |
| 181 | term_file.flush() |
| 182 | def cleanup(): |
| 183 | term_file.write(''.join(( |
| 184 | SI, ALT_SCREEN_OFF, CURSOR_RESTORE, |
| 185 | ))) |
| 186 | term_file.flush() |
| 187 | t.tcsetattr(term_file.fileno(), t.TCSANOW, old_attrs) |
| 188 | return cleanup |
| 189 | |
| 190 | def screen_size(term_file=stdout): |
| 191 | """ |
| 192 | Return the screen size (rows, columns) of the given terminal as reported by |
| 193 | the driver. |
| 194 | """ |
| 195 | rows, cols = unpack('HH', ioctl(term_file.fileno(), t.TIOCGWINSZ, ' '*4)) |
| 196 | return rows, cols |
| 197 | |
| 198 | def render(tree, stack=None): |
| 199 | """ |
| 200 | Render a text attribute tree to a single string with escape sequences. |
| 201 | |
| 202 | A node is either: |
| 203 | - a string, or |
| 204 | - a sequence of attribute code followed by zero or more child nodes |
| 205 | |
| 206 | An attribute code is an integer (e.g. the A_* constants). |
| 207 | |
| 208 | Example: |
| 209 | >>> t = (A_NONE, 'normal, ', |
| 210 | ... (A_REVERSE, 'reverse, ', (A_BOLD, 'bold reverse,'), |
| 211 | ... ' reverse again,'), |
| 212 | ... ' and back to normal.') |
| 213 | >>> print render(t) |
| 214 | """ |
| 215 | if isinstance(tree, str): |
| 216 | return tree |
| 217 | if stack is None: |
| 218 | stack = [A_NONE] |
| 219 | tag, children = tree[0], tree[1:] |
| 220 | stack.append(tag) |
| 221 | body = ''.join(render(c, stack) for c in children) |
| 222 | stack.pop() |
| 223 | return ''.join((attrs(tag), body, attrs(*stack))) |