move (invisible) cursor to the active grid cell

This is especially useful for blind people using braille displays.

A braille display is a device with mechanical dots representing the
content of the screen in braille with the aid of a software package
such as BRLTTY. Those displays are made of a single line with a variable
number of rows depending on the model, usually 40 or 80. This is
effectively a 1x40 window view of the screen.

By default, the braille window moves with the position of the screen
cursor. It doesn't track attributes such as reverse color as this is
too unreliable. Finding the actual active cell manually is a daunting
task.

This patch makes sc-im locate the cursor in the active cell when
navigating around so the braille window can automatically be located
on the active cell, or on the input field when active, or on the last
status message, hugely improving the user experience.

1 files changed, 32 insertions, 0 deletions

diff --git a/src/tui.c b/src/tui.c
index 25eafbb..6ae8d7c 100644
--- a/src/tui.c
+++ b/src/tui.c
@@ -104,6 +104,9 @@ WINDOW * input_win;
 SCREEN * sstderr;
 SCREEN * sstdout;
 
+int status_line_empty;
+int curwinrow, curwincol;
+
 /**
  * \brief Called to start UI
  *
@@ -118,6 +121,7 @@ void ui_start_screen() {
 
     main_win = newwin(LINES - RESROW, COLS, atoi(get_conf_value("input_bar_bottom")) ? 0 : RESROW, 0);
     input_win = newwin(RESROW, COLS, atoi(get_conf_value("input_bar_bottom")) ? LINES-RESROW : 0, 0);
+    status_line_empty = 1;
 
     #ifdef USECOLORS
     if (has_colors()) {
@@ -247,6 +251,8 @@ void ui_sc_msg(char * s, int type, ...) {
 #endif
         mvwprintw(input_win, 1, 0, "%s", t);
         wclrtoeol(input_win);
+        wmove(input_win, 1, 0);
+        status_line_empty = 0;
 
         if (type == DEBUG_MSG || (loading && type == ERROR_MSG)) {
             wtimeout(input_win, -1);
@@ -343,6 +349,12 @@ void ui_do_welcome() {
         }
     }
     wrefresh(main_win);
+
+    /* land cursor next to the help line */
+    curwinrow = LINES/2;
+    curwincol = COLS/2-strlen(msg_help)/2-1;
+    status_line_empty = 1;
+
     return;
 }
 
@@ -376,6 +388,7 @@ void ui_update(int header) {
         // comment this to prevent info message to be erased
         //wmove(input_win, 0, 0);
         //wclrtobot(input_win);
+        //status_line_empty = 1;
         ui_show_celldetails(); // always before ui_print_mode
         ui_print_mode();
     }
@@ -419,6 +432,10 @@ void ui_update(int header) {
     // Show sc_row headings: 0, 1, 2, 3..
     ui_show_sc_row_headings(main_win, mxrow);
 
+    // Leave cursor on selected cell when no status message
+    if (status_line_empty)
+        wmove(main_win, curwinrow, curwincol);
+
     // Refresh curses windows
     wrefresh(main_win);
 
@@ -506,6 +523,12 @@ void ui_print_mult_pend() {
     // Return cursor to previous position
     wmove(input_win, row_orig, col_orig);
     wrefresh(input_win);
+
+    if (status_line_empty && curmode != EDIT_MODE) {
+        // Leave cursor on selected cell when no status message
+        wmove(main_win, curwinrow, curwincol);
+        wrefresh(main_win);
+    }
 }
 
 /**
@@ -560,6 +583,8 @@ void ui_clr_header(int i) {
     // Return cursor to previous position
     wmove(input_win, row_orig, col_orig);
 
+    if (i == 1) status_line_empty = 1;
+
     return;
 }
 
@@ -1013,6 +1038,11 @@ void ui_show_content(WINDOW * win, int mxrow, int mxcol) {
                 wclrtoeol(win);
             }
 
+            if (currow == row && curcol == col) {
+                curwinrow = row + 1 - offscr_sc_rows - q_row_hidden;
+                curwincol = c + ((align == 1) ? (fieldlen - 1) : 0);
+            }
+
             // clean format
             #ifndef USECOLORS
             wattroff(win, A_REVERSE);
@@ -1262,6 +1292,7 @@ void ui_bail(lua_State *L, char * msg) {
     set_term(sstderr);
     move(0, 0);
     clrtobot();
+    status_line_empty = 1;
     clearok(stdscr, TRUE);
     mvprintw(0, 0, "%s", stderr_buffer);
     stderr_buffer[0]='\0';
@@ -1370,6 +1401,7 @@ char * ui_query(char * initial_msg) {
     wclrtoeol(input_win);
     wmove(input_win, 1,0);
     wclrtoeol(input_win);
+    status_line_empty = 1;
     wrefresh(input_win);
     return hline;
 }