517 lines
15 KiB
C
517 lines
15 KiB
C
/**
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* sixdraw.c - draw on your terminal
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*
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* Requires sixel graphics and 1016 mouse mode to run on your terminal.
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* These features are not widely supported.
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* To save yourself from trouble, use a latest version of XTerm or mintty.
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*
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* Before 1016 mode was introduced in XTerm patch #359, it is also possible
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* to report mouse position in pixels using DEC locator (which is also rarely
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* implemented). However, it is not used in this example.
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*
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* Copyright (C) 2020,2021 CismonX <admin@cismon.net>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif // HAVE_CONFIG_H
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#include <errno.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <getopt.h>
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#include <sys/ioctl.h>
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#include <termios.h>
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#include <unistd.h>
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#include <ctlseqs.h>
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#ifndef DEFAULT_TIMEOUT_MILLIS
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# define DEFAULT_TIMEOUT_MILLIS 500
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#endif // !DEFAULT_TIMEOUT_MILLIS
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#define DECRQM_SET 1
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#define DECRQM_RST 2
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#define DECTCEM 25
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#define DECSDM 80
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#define BTN_EVENT_TRACKING 1002
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#define SGR_MOUSE_PIXELMODE 1016
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#define ALT_SCRBUF 1049
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#define SIXEL_SEQ_HEAD CTLSEQS_DCS "0;1q\"1;1;"
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static char sixel_seq[4096] = SIXEL_SEQ_HEAD;
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struct sixdraw_ctx {
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struct termios termios;
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union ctlseqs_value result[64];
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char const *prog_name;
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FILE* out_file;
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FILE* err_file;
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struct ctlseqs_matcher *matcher;
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struct ctlseqs_reader *reader;
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bool has_termios;
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bool hide_cursor;
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bool alt_scrbuf;
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bool btnev_tracking;
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bool legacy_xterm;
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bool sgr_pixelmode;
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bool sixel_scroll;
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int in_fd;
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int out_fd;
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int timeout;
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unsigned rows;
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unsigned canvas_width;
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unsigned canvas_height;
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unsigned ch_width;
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unsigned ch_height;
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unsigned line_color;
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unsigned sixel_init_size;
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};
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static inline void
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print_error(
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struct sixdraw_ctx const *ctx,
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char const *format,
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...
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) {
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char msg[1024];
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va_list args;
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va_start(args, format);
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vsnprintf(msg, 1024, format, args);
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va_end(args);
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fprintf(ctx->err_file, "%s: [error] %s.\n", ctx->prog_name, msg);
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}
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static void
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terminate(
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struct sixdraw_ctx *ctx
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) {
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ctlseqs_matcher_free(ctx->matcher);
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ctlseqs_reader_free(ctx->reader);
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// Restore normal screen buffer.
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if (ctx->alt_scrbuf) {
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fprintf(ctx->out_file, CTLSEQS_DECRST("%d"), ALT_SCRBUF);
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}
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// Restore original mouse modes.
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if (ctx->btnev_tracking) {
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fprintf(ctx->out_file, CTLSEQS_DECRST("%d"), BTN_EVENT_TRACKING);
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}
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if (ctx->sgr_pixelmode) {
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fprintf(ctx->out_file, CTLSEQS_DECRST("%d"), SGR_MOUSE_PIXELMODE);
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}
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// Restore cursor status.
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if (ctx->hide_cursor) {
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fprintf(ctx->out_file, CTLSEQS_DECSET("%d"), DECTCEM);
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}
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// Restore original sixel mode.
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if (ctx->sixel_scroll) {
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fprintf(
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ctx->out_file,
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ctx->legacy_xterm ? CTLSEQS_DECRST("%d") : CTLSEQS_DECSET("%d"),
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DECSDM
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);
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}
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// Restore original terminal modes.
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if (ctx->has_termios) {
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tcsetattr(ctx->in_fd, TCSANOW, &ctx->termios);
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}
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}
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static bool
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get_winsize(
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struct sixdraw_ctx *ctx
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) {
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struct winsize ws = { 0 };
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if (ioctl(ctx->in_fd, TIOCGWINSZ, &ws) != 0) {
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print_error(ctx, "failed to get terminal window size");
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return false;
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}
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if (ws.ws_xpixel == 0 || ws.ws_ypixel == 0) {
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print_error(ctx, "failed to get terminal window size (in pixels)");
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return false;
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}
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ctx->rows = ws.ws_row;
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ctx->ch_width = ws.ws_xpixel / ws.ws_col;
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ctx->ch_height = ws.ws_ypixel / ws.ws_row;
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ctx->canvas_width = ctx->ch_width * ws.ws_col;
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ctx->canvas_height = ctx->ch_height * ws.ws_row - ctx->ch_height * 2;
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return true;
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}
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static bool
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decrqm(
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struct sixdraw_ctx *ctx,
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unsigned mode,
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char const *name
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) {
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ssize_t retval;
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union ctlseqs_value *result = ctx->result;
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fprintf(ctx->out_file, CTLSEQS_DECRQM("%d"), mode);
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do {
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retval = ctlseqs_read(ctx->reader, ctx->matcher, ctx->timeout);
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} while (retval == CTLSEQS_PARTIAL);
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if (retval != 1) {
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print_error(ctx, "failed to get %s status", name);
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return false;
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}
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int mode_value = result[1].num;
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if ( result[0].num != mode
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|| (mode_value != DECRQM_SET && mode_value != DECRQM_RST)
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) {
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print_error(ctx, "%s status (%d) not recognizable", name, mode_value);
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return false;
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}
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return true;
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}
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static long
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xtversion(
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struct sixdraw_ctx *ctx
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) {
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ssize_t retval;
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union ctlseqs_value *result = ctx->result;
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fprintf(ctx->out_file, CTLSEQS_XTVERSION());
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do {
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retval = ctlseqs_read(ctx->reader, ctx->matcher, ctx->timeout);
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} while (retval == CTLSEQS_PARTIAL);
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if (retval != 3) {
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// Terminal emulator does not recognize XTVERSION;
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return -1;
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}
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char const *xtversion = result[1].str;
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if (result[0].len < sizeof("XTerm(")) {
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return -2;
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}
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if (strncmp(xtversion, "XTerm(", sizeof("XTerm(") - 1) != 0) {
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// Terminal emulator is not XTerm.
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return -2;
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}
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errno = 0;
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long version_num = strtol(xtversion + (sizeof("XTerm(") - 1), NULL, 10);
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if (errno) {
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return -3;
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}
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return version_num;
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}
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static void
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print_sixel_dot(
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struct sixdraw_ctx *ctx,
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unsigned x,
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unsigned y
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) {
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if (x >= ctx->canvas_width || y >= ctx->canvas_height) {
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return;
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}
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// Move cursor.
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unsigned row = y / ctx->ch_height + 1;
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unsigned col = x / ctx->ch_width + 1;
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fprintf(ctx->out_file, CTLSEQS_CUP("%d", "%d"), row, col);
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// Build sixel sequence.
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row = y % ctx->ch_height;
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col = x % ctx->ch_width;
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unsigned seq_size = ctx->sixel_init_size;
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seq_size += sprintf(
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sixel_seq + seq_size,
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"%.*s!%u?%c" CTLSEQS_ST,
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row / 6, "------------------------", col, (1 << row % 6) + 0x3F
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);
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fwrite(sixel_seq, seq_size, 1, ctx->out_file);
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}
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static bool
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init(
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struct sixdraw_ctx *ctx,
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int argc,
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char *argv[]
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) {
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*ctx = (struct sixdraw_ctx) {
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.prog_name = argc > 0 ? argv[0] : "sixdraw",
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.out_file = stdout,
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.err_file = stderr,
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.in_fd = STDIN_FILENO,
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.out_fd = STDOUT_FILENO,
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.timeout = DEFAULT_TIMEOUT_MILLIS,
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.line_color = 0x00FF00
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};
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// Process command line arguments.
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int opt;
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while (-1 != (opt = getopt(argc, argv, "t:c:"))) {
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switch (opt) {
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case 't':
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ctx->timeout = atoi(optarg);
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break;
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case 'c':
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ctx->line_color = strtoul(optarg, NULL, 16);
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break;
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case '?':
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default:
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fprintf(ctx->out_file, "%s\n",
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"Usage: sixdraw [-t timeout] [-c line-color]");
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return false;
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}
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}
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// Initialize control sequence matcher.
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ctx->matcher = ctlseqs_matcher_init();
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if (ctx->matcher == NULL) {
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print_error(ctx, "failed to initialize matcher");
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return false;
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}
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char const *patterns[] = {
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CTLSEQS_RESP_PRIMARY_DA(CTLSEQS_PH_NUMS),
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CTLSEQS_RESP_DECRQM(CTLSEQS_PH_NUM, CTLSEQS_PH_NUM),
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CTLSEQS_RESP_SGR_MOUSE(
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CTLSEQS_PH_NUM, CTLSEQS_PH_NUM, CTLSEQS_PH_NUM, "M"),
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CTLSEQS_RESP_XTVERSION(CTLSEQS_PH_STR),
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};
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struct ctlseqs_matcher_options matcher_options = {
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.patterns = patterns,
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.npatterns = sizeof(patterns) / sizeof(char const *),
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};
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if (ctlseqs_matcher_config(ctx->matcher, &matcher_options) != 0) {
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print_error(ctx, "failed to set matcher options");
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return false;
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}
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// Initialize control sequence reader.
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ctx->reader = ctlseqs_reader_init();
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if (ctx->reader == NULL) {
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print_error(ctx, "failed to initialize reader");
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return false;
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}
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struct ctlseqs_reader_options reader_options = {
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.result = ctx->result,
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.fd = ctx->in_fd,
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.maxlen = 4096,
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};
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if (CTLSEQS_OK != ctlseqs_reader_config(ctx->reader, &reader_options)) {
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print_error(ctx, "failed to set reader options");
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return false;
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}
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return true;
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}
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static bool
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prepare(
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struct sixdraw_ctx *ctx
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) {
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// Check whether we're running on a terminal.
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if (!isatty(ctx->in_fd) || !isatty(ctx->out_fd)) {
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print_error(ctx, "this program can only run in a terminal");
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return false;
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}
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// Set terminal to noncanonical mode.
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if (tcgetattr(ctx->in_fd, &ctx->termios) != 0) {
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print_error(ctx, "failed to get terminal attributes");
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return false;
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}
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struct termios termios = ctx->termios;
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termios.c_cc[VMIN] = 0;
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termios.c_cc[VTIME] = 0;
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termios.c_lflag &= ~(ICANON | ISIG | ECHO);
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if (tcsetattr(ctx->in_fd, TCSANOW, &termios) != 0) {
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print_error(ctx, "failed to set terminal attributes");
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return false;
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}
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ctx->has_termios = true;
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// Set STDIN flags to nonblocking, and disable output buffering.
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int flags = fcntl(ctx->in_fd, F_GETFL);
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if (flags == -1) {
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print_error(ctx, "failed to get file status flags");
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return false;
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}
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if (fcntl(ctx->in_fd, F_SETFL, flags | O_NONBLOCK) == -1) {
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print_error(ctx, "failed to set file status flags");
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return false;
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}
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if (setvbuf(stdout, NULL, _IONBF, 0) != 0) {
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print_error(ctx, "failed to disable output buffering");
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return false;
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}
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// Get initial terminal window size.
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if (!get_winsize(ctx)) {
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return false;
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}
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// Check terminal support for sixel graphics.
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fprintf(ctx->out_file, CTLSEQS_PRIMARY_DA());
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ssize_t retval;
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do {
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retval = ctlseqs_read(ctx->reader, ctx->matcher, ctx->timeout);
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} while (retval == CTLSEQS_PARTIAL);
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if (retval != 0) {
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print_error(ctx, "failed to get terminal features");
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return false;
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}
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bool has_sixel = false;
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union ctlseqs_value *result = ctx->result;
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for (size_t i = 1; i <= result[0].len; ++i) {
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if (result[i].num == 4) {
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has_sixel = true;
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}
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}
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if (!has_sixel) {
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print_error(ctx, "terminal does not support sixel graphics");
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return false;
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}
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// Hide cursor.
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if (!decrqm(ctx, DECTCEM, "cursor")) {
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return false;
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}
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ctx->hide_cursor = result[1].num == DECRQM_SET;
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if (ctx->hide_cursor) {
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fprintf(ctx->out_file, CTLSEQS_DECRST("%d"), DECTCEM);
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}
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// Check terminal name and version.
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long xterm_version = xtversion(ctx);
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if (xterm_version >= 0 && xterm_version < 369) {
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ctx->legacy_xterm = true;
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} else {
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ctx->legacy_xterm = false;
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}
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// Enable sixel scrolling.
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if (!decrqm(ctx, DECSDM, "sixel scrolling")) {
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return false;
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}
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// Before patch #369, XTerm implemented DECSDM incorrectly.
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// See https://invisible-island.net/xterm/xterm.log.html#xterm_369
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ctx->sixel_scroll
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= result[1].num == (ctx->legacy_xterm ? DECRQM_RST : DECRQM_SET);
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if (ctx->sixel_scroll) {
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fprintf(
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ctx->out_file,
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ctx->legacy_xterm ? CTLSEQS_DECSET("%d") : CTLSEQS_DECRST("%d"),
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DECSDM
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);
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}
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// Enable button event tracking mode.
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if (!decrqm(ctx, BTN_EVENT_TRACKING, "button event tracking mode")) {
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return false;
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}
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ctx->btnev_tracking = result[1].num == DECRQM_RST;
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if (ctx->btnev_tracking) {
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fprintf(ctx->out_file, CTLSEQS_DECSET("%d"), BTN_EVENT_TRACKING);
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}
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// Enable SGR mouse pixel mode.
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if (!decrqm(ctx, SGR_MOUSE_PIXELMODE, "SGR mouse pixel mode")) {
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return false;
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}
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ctx->sgr_pixelmode = result[1].num == DECRQM_RST;
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if (ctx->sgr_pixelmode) {
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fprintf(ctx->out_file, CTLSEQS_DECSET("%d"), SGR_MOUSE_PIXELMODE);
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}
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// Switch to alternate screen buffer.
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if (!decrqm(ctx, ALT_SCRBUF, "screen buffer")) {
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return false;
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}
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ctx->alt_scrbuf = result[1].num == DECRQM_RST;
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if (ctx->alt_scrbuf) {
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fprintf(ctx->out_file, CTLSEQS_DECSET("%d"), ALT_SCRBUF);
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}
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// Build the immutable part of sixel sequence.
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ctx->sixel_init_size = sizeof(SIXEL_SEQ_HEAD) - 1;
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ctx->sixel_init_size += sprintf(
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sixel_seq + ctx->sixel_init_size,
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"%u;%u#0;2;%d;%d;%d#0",
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ctx->ch_width, ctx->ch_height,
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((ctx->line_color >> 16) & 0xFF) * 100 / 0xFF,
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((ctx->line_color >> 8) & 0xFF) * 100 / 0xFF,
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((ctx->line_color >> 0) & 0xFF) * 100 / 0xFF
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);
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return true;
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}
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static bool
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draw(
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struct sixdraw_ctx *ctx
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) {
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fprintf(
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ctx->out_file,
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CTLSEQS_CUP("%d", "1") "Canvas size: %ux%u. Line color: #%06X.",
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ctx->rows - 1, ctx->canvas_width, ctx->canvas_height, ctx->line_color
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);
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fprintf(
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ctx->out_file,
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CTLSEQS_CUP("%d", "1") "Usage: Draw with mouse. Press Ctrl+C to exit.",
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ctx->rows
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);
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union ctlseqs_value *result = ctx->result;
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while (true) {
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switch (ctlseqs_read(ctx->reader, ctx->matcher, -1)) {
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case 2: // CTLSEQS_RESP_SGR_MOUSE
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// Pixel coordinates start at 1 instead of 0.
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print_sixel_dot(ctx, result[1].num - 1, result[2].num - 1);
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break;
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case CTLSEQS_NOSEQ:
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// Press Ctrl+C to exit.
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if (result[1].str[0] == 0x03) {
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return true;
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}
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break;
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case CTLSEQS_ERROR:
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case CTLSEQS_NOMEM:
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case CTLSEQS_EOF:
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return false;
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}
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}
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}
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int
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main(
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int argc,
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char *argv[]
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) {
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int status;
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struct sixdraw_ctx ctx;
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if (init(&ctx, argc, argv) && prepare(&ctx)) {
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status = draw(&ctx) ? 0 : -1;
|
|
} else {
|
|
status = -1;
|
|
}
|
|
terminate(&ctx);
|
|
return status;
|
|
}
|