terminal: Scroll margins

Implement scroll margins and related escape codes.

Signed-off-by: Callum Lowcay <callum@callumscode.com>

diff --git a/clients/terminal.c b/clients/terminal.c
index 26f8c9d..e900298 100644 (file)
--- a/clients/terminal.c
+++ b/clients/terminal.c
@@ -187,7 +187,9 @@ struct terminal {
        union utf8_char *data;
        struct attr *data_attr;
        struct attr curr_attr;
+       char origin_mode;
        union utf8_char last_char;
+       int margin_top, margin_bottom;
        int data_pitch, attr_pitch;  /* The width in bytes of a line */
        int width, height, start, row, column;
        int fd, master;
@@ -211,6 +213,7 @@ static void
 terminal_init(struct terminal *terminal)
 {
        terminal->curr_attr = terminal->color_scheme->default_attr;
+       terminal->origin_mode = 0;
 
        terminal->row = 0;
        terminal->column = 0;
@@ -266,6 +269,94 @@ terminal_get_attr(struct terminal *terminal, int row, int col) {
 }
 
 static void
+terminal_scroll_buffer(struct terminal *terminal, int d)
+{
+       int i;
+
+       d = d % (terminal->height + 1);
+       terminal->start = (terminal->start + d) % terminal->height;
+       if (terminal->start < 0) terminal->start = terminal->height + terminal->start;
+       if(d < 0) {
+               d = 0 - d;
+               for(i = 0; i < d; i++) {
+                       memset(terminal_get_row(terminal, i), 0, terminal->data_pitch);
+                       attr_init(terminal_get_attr_row(terminal, i),
+                           terminal->curr_attr, terminal->width);
+               }
+       } else {
+               for(i = terminal->height - d; i < terminal->height; i++) {
+                       memset(terminal_get_row(terminal, i), 0, terminal->data_pitch);
+                       attr_init(terminal_get_attr_row(terminal, i),
+                           terminal->curr_attr, terminal->width);
+               }
+       }
+}
+
+static void
+terminal_scroll_window(struct terminal *terminal, int d)
+{
+       int i;
+       int window_height;
+       int from_row, to_row;
+       struct attr *dup_attr;
+       
+       // scrolling range is inclusive
+       window_height = terminal->margin_bottom - terminal->margin_top + 1;
+       d = d % (window_height + 1);
+       if(d < 0) {
+               d = 0 - d;
+               to_row = terminal->margin_bottom;
+               from_row = terminal->margin_bottom - d;
+               
+               for (i = 0; i < (window_height - d); i++) {
+                       memcpy(terminal_get_row(terminal, to_row - i),
+                              terminal_get_row(terminal, from_row - i),
+                              terminal->data_pitch);
+                       memcpy(terminal_get_attr_row(terminal, to_row - i),
+                              terminal_get_attr_row(terminal, from_row - i),
+                              terminal->attr_pitch);
+               }
+               dup_attr = terminal_get_attr_row(terminal, terminal->margin_top);
+               for (i = terminal->margin_top; i < (terminal->margin_top + d); i++) {
+                       memset(terminal_get_row(terminal, i), 0, terminal->data_pitch);
+                       if (i > terminal->margin_top) {
+                               memcpy(terminal_get_attr_row(terminal, i),
+                                      dup_attr, terminal->attr_pitch);
+                       }
+               }
+       } else {
+               to_row = terminal->margin_top;
+               from_row = terminal->margin_top + d;
+               
+               for (i = 0; i < (window_height - d); i++) {
+                       memcpy(terminal_get_row(terminal, to_row + i),
+                              terminal_get_row(terminal, from_row + i),
+                              terminal->data_pitch);
+                       memcpy(terminal_get_attr_row(terminal, to_row + i),
+                              terminal_get_attr_row(terminal, from_row + i),
+                              terminal->attr_pitch);
+               }
+               dup_attr = terminal_get_attr_row(terminal, terminal->margin_bottom);
+               for (i = terminal->margin_bottom - d + 1; i <= terminal->margin_bottom; i++) {
+                       memset(terminal_get_row(terminal, i), 0, terminal->data_pitch);
+                       if (i < terminal->margin_bottom) {
+                               memcpy(terminal_get_attr_row(terminal, i),
+                                      dup_attr, terminal->attr_pitch);
+                       }
+               }
+       }
+}
+
+static void
+terminal_scroll(struct terminal *terminal, int d)
+{
+       if(terminal->margin_top == 0 && terminal->margin_bottom == terminal->height - 1)
+               terminal_scroll_buffer(terminal, d);
+       else
+               terminal_scroll_window(terminal, d);
+}
+
+static void
 terminal_resize(struct terminal *terminal, int width, int height)
 {
        size_t size;
@@ -317,6 +408,8 @@ terminal_resize(struct terminal *terminal, int width, int height)
        terminal->attr_pitch = attr_pitch;
        terminal->width = width;
        terminal->height = height;
+       if(terminal->margin_bottom >= terminal->height)
+               terminal->margin_bottom = terminal->height - 1;
        terminal->data = data;
        terminal->data_attr = data_attr;
 
@@ -531,12 +624,38 @@ static void
 handle_sgr(struct terminal *terminal, int code);
 
 static void
+handle_term_parameter(struct terminal *terminal, int code, int sr)
+{
+       if (terminal->qmark_flag) {
+               switch(code) {
+               case 6:  /* DECOM */
+                       terminal->origin_mode = sr;
+                       if (terminal->origin_mode)
+                               terminal->row = terminal->margin_top;
+                       else
+                               terminal->row = 0;
+                       terminal->column = 0;
+                       break;
+               default:
+                       fprintf(stderr, "Unknown parameter: ?%d\n", code);
+                       break;
+               }
+       } else {
+               switch(code) {
+               default:
+                       fprintf(stderr, "Unknown parameter: %d\n", code);
+                       break;
+               }
+       }
+}
+
+static void
 handle_escape(struct terminal *terminal)
 {
        union utf8_char *row;
        struct attr *attr_row;
        char *p;
-       int i, count;
+       int i, count, top, bottom;
        int args[10], set[10] = { 0, };
 
        terminal->escape[terminal->escape_length++] = '\0';
@@ -610,6 +729,22 @@ handle_escape(struct terminal *terminal)
                memset(&row[terminal->column], 0, (terminal->width - terminal->column) * sizeof(union utf8_char));
                attr_init(&attr_row[terminal->column], terminal->curr_attr, (terminal->width - terminal->column));
                break;
+       case 'S':    /* SU */
+               terminal_scroll(terminal, set[0] ? args[0] : 1);
+               break;
+       case 'T':    /* SD */
+               terminal_scroll(terminal, 0 - (set[0] ? args[0] : 1));
+               break;
+       case 'h':    /* SM */
+               for(i = 0; i < 10 && set[i]; i++) {
+                       handle_term_parameter(terminal, args[i], 1);
+               }
+               break;
+       case 'l':    /* RM */
+               for(i = 0; i < 10 && set[i]; i++) {
+                       handle_term_parameter(terminal, args[i], 0);
+               }
+               break;
        case 'm':    /* SGR */
                if (set[0] && set[1] && set[2] && args[1] == 5) {
                        if (args[0] == 38) {
@@ -631,11 +766,31 @@ handle_escape(struct terminal *terminal)
                        }
                }
                break;
-       case '?':
-               if (strcmp(p, "?25l") == 0) {
-                       /* hide cursor */
-               } else if (strcmp(p, "?25h") == 0) {
-                       /* show cursor */
+       case 'r':
+               if(!set[0]) {
+                       terminal->margin_top = 0;
+                       terminal->margin_bottom = terminal->height-1;
+                       terminal->row = 0;
+                       terminal->column = 0;
+               } else {
+                       top = (set[0] ? args[0] : 1) - 1;
+                       top = top < 0 ? 0 :
+                             (top >= terminal->height ? terminal->height - 1 : top);
+                       bottom = (set[1] ? args[1] : 1) - 1;
+                       bottom = bottom < 0 ? 0 :
+                                (bottom >= terminal->height ? terminal->height - 1 : bottom);
+                       if(bottom > top) {
+                               terminal->margin_top = top;
+                               terminal->margin_bottom = bottom;
+                       } else {
+                               terminal->margin_top = 0;
+                               terminal->margin_bottom = terminal->height-1;
+                       }
+                       if(terminal->origin_mode)
+                               terminal->row = terminal->margin_top;
+                       else
+                               terminal->row = 0;
+                       terminal->column = 0;
                }
                break;
        default:
@@ -647,6 +802,28 @@ handle_escape(struct terminal *terminal)
 static void
 handle_non_csi_escape(struct terminal *terminal, char code)
 {
+       switch(code) {
+       case 'M':    /* RI */
+               terminal->row -= 1;
+               if(terminal->row < terminal->margin_top) {
+                       terminal->row = terminal->margin_top;
+                       terminal_scroll(terminal, -1);
+               }
+               break;
+       case 'E':    /* NEL */
+               terminal->column = 0;
+               // fallthrough
+       case 'D':    /* IND */
+               terminal->row += 1;
+               if(terminal->row > terminal->margin_bottom) {
+                       terminal->row = terminal->margin_bottom;
+                       terminal_scroll(terminal, +1);
+               }
+               break;
+       default:
+               fprintf(stderr, "Unknown escape code: %c\n", code);
+               break;
+       }
 }
 
 static void
@@ -735,16 +912,10 @@ handle_special_char(struct terminal *terminal, char c)
                /* fallthrough */
        case '\v':
        case '\f':
-               if (terminal->row + 1 < terminal->height) {
-                       terminal->row++;
-               } else {
-                       terminal->start++;
-                       if (terminal->start == terminal->height)
-                               terminal->start = 0;
-                       memset(terminal_get_row(terminal, terminal->row),
-                              0, terminal->width * sizeof(union utf8_char));
-                       attr_init(terminal_get_attr_row(terminal, terminal->row),
-                                 terminal->curr_attr, terminal->width);
+               terminal->row++;
+               if(terminal->row > terminal->margin_bottom) {
+                       terminal->row = terminal->margin_bottom;
+                       terminal_scroll(terminal, +1);
                }
 
                break;
@@ -969,6 +1140,9 @@ terminal_create(struct display *display, int fullscreen)
        terminal->fullscreen = fullscreen;
        terminal->color_scheme = &DEFAULT_COLORS;
        terminal_init(terminal);
+       terminal->margin_top = 0;
+       terminal->margin_bottom = 10000;  /* much too large, will be trimmed down
+                                          * by terminal_resize */
        terminal->window = window_create(display, "Wayland Terminal",
                                         500, 400);