Add support for BCE (background colour erase). This makes various escape

sequences (notable EL and ED but also IL, DL, ICH, DCH) create blank cells using the current background colour rather than the default colour. On modern systems BCE doesn't really have many benefits, but most other terminals now support it, some (lazy) applications rely on it, and it is not hard to include now that we have pane background colours anyway. Mostly written by Sean Haugh.

Author: nicm

grid-view.c

@@ -47,7 +47,7 @@ grid_view_set_cell(struct grid *gd, u_int px, u_int py,
 
 /* Clear into history. */
 void
-grid_view_clear_history(struct grid *gd)
+grid_view_clear_history(struct grid *gd, u_int bg)
 {
 struct grid_line*gl;
 u_int yy, last;
@@ -56,38 +56,43 @@ grid_view_clear_history(struct grid *gd)
 last = 0;
 for (yy = 0; yy < gd->sy; yy++) {
 gl = &gd->linedata[grid_view_y(gd, yy)];
-if (gl->cellsize != 0)
+if (gl->cellused != 0)
 last = yy + 1;
 }
-if (last == 0)
+if (last == 0) {
+grid_view_clear(gd, 0, 0, gd->sx, gd->sy, bg);
 return;
+}
 
 /* Scroll the lines into the history. */
 for (yy = 0; yy < last; yy++) {
-grid_collect_history(gd);
-grid_scroll_history(gd);
+grid_collect_history(gd, bg);
+grid_scroll_history(gd, bg);
 }
+if (last < gd->sy)
+grid_view_clear(gd, 0, 0, gd->sx, gd->sy - last, bg);
 gd->hscrolled = 0;
 }
 
 /* Clear area. */
 void
-grid_view_clear(struct grid *gd, u_int px, u_int py, u_int nx, u_int ny)
+grid_view_clear(struct grid *gd, u_int px, u_int py, u_int nx, u_int ny,
+ u_int bg)
 {
 px = grid_view_x(gd, px);
 py = grid_view_y(gd, py);
 
-grid_clear(gd, px, py, nx, ny);
+grid_clear(gd, px, py, nx, ny, bg);
 }
 
 /* Scroll region up. */
 void
 grid_view_scroll_region_up(struct grid *gd, u_int rupper, u_int rlower)
 {
 if (gd->flags & GRID_HISTORY) {
-grid_collect_history(gd);
+grid_collect_history(gd, 8);
 if (rupper == 0 && rlower == gd->sy - 1)
-grid_scroll_history(gd);
+grid_scroll_history(gd, 8);
 else {
 rupper = grid_view_y(gd, rupper);
 rlower = grid_view_y(gd, rlower);
@@ -96,7 +101,7 @@ grid_view_scroll_region_up(struct grid *gd, u_int rupper, u_int rlower)
 } else {
 rupper = grid_view_y(gd, rupper);
 rlower = grid_view_y(gd, rlower);
-grid_move_lines(gd, rupper, rupper + 1, rlower - rupper);
+grid_move_lines(gd, rupper, rupper + 1, rlower - rupper, 8);
 }
 }
 
@@ -107,26 +112,26 @@ grid_view_scroll_region_down(struct grid *gd, u_int rupper, u_int rlower)
 rupper = grid_view_y(gd, rupper);
 rlower = grid_view_y(gd, rlower);
 
-grid_move_lines(gd, rupper + 1, rupper, rlower - rupper);
+grid_move_lines(gd, rupper + 1, rupper, rlower - rupper, 8);
 }
 
 /* Insert lines. */
 void
-grid_view_insert_lines(struct grid *gd, u_int py, u_int ny)
+grid_view_insert_lines(struct grid *gd, u_int py, u_int ny, u_int bg)
 {
 u_intsy;
 
 py = grid_view_y(gd, py);
 
 sy = grid_view_y(gd, gd->sy);
 
-grid_move_lines(gd, py + ny, py, sy - py - ny);
+grid_move_lines(gd, py + ny, py, sy - py - ny, bg);
 }
 
 /* Insert lines in region. */
 void
 grid_view_insert_lines_region(struct grid *gd, u_int rlower, u_int py,
- u_int ny)
+ u_int ny, u_int bg)
 {
 u_intny2;
 
@@ -135,28 +140,28 @@ grid_view_insert_lines_region(struct grid *gd, u_int rlower, u_int py,
 py = grid_view_y(gd, py);
 
 ny2 = rlower + 1 - py - ny;
-grid_move_lines(gd, rlower + 1 - ny2, py, ny2);
-grid_clear(gd, 0, py + ny2, gd->sx, ny - ny2);
+grid_move_lines(gd, rlower + 1 - ny2, py, ny2, bg);
+grid_clear(gd, 0, py + ny2, gd->sx, ny - ny2, bg);
 }
 
 /* Delete lines. */
 void
-grid_view_delete_lines(struct grid *gd, u_int py, u_int ny)
+grid_view_delete_lines(struct grid *gd, u_int py, u_int ny, u_int bg)
 {
 u_intsy;
 
 py = grid_view_y(gd, py);
 
 sy = grid_view_y(gd, gd->sy);
 
-grid_move_lines(gd, py, py + ny, sy - py - ny);
-grid_clear(gd, 0, sy - ny, gd->sx, py + ny - (sy - ny));
+grid_move_lines(gd, py, py + ny, sy - py - ny, bg);
+grid_clear(gd, 0, sy - ny, gd->sx, py + ny - (sy - ny), bg);
 }
 
 /* Delete lines inside scroll region. */
 void
 grid_view_delete_lines_region(struct grid *gd, u_int rlower, u_int py,
- u_int ny)
+ u_int ny, u_int bg)
 {
 u_intny2;
 
@@ -165,13 +170,13 @@ grid_view_delete_lines_region(struct grid *gd, u_int rlower, u_int py,
 py = grid_view_y(gd, py);
 
 ny2 = rlower + 1 - py - ny;
-grid_move_lines(gd, py, py + ny, ny2);
-grid_clear(gd, 0, py + ny2, gd->sx, ny - ny2);
+grid_move_lines(gd, py, py + ny, ny2, bg);
+grid_clear(gd, 0, py + ny2, gd->sx, ny - ny2, bg);
 }
 
 /* Insert characters. */
 void
-grid_view_insert_cells(struct grid *gd, u_int px, u_int py, u_int nx)
+grid_view_insert_cells(struct grid *gd, u_int px, u_int py, u_int nx, u_int bg)
 {
 u_intsx;
 
@@ -181,14 +186,14 @@ grid_view_insert_cells(struct grid *gd, u_int px, u_int py, u_int nx)
 sx = grid_view_x(gd, gd->sx);
 
 if (px == sx - 1)
-grid_clear(gd, px, py, 1, 1);
+grid_clear(gd, px, py, 1, 1, bg);
 else
-grid_move_cells(gd, px + nx, px, py, sx - px - nx);
+grid_move_cells(gd, px + nx, px, py, sx - px - nx, bg);
 }
 
 /* Delete characters. */
 void
-grid_view_delete_cells(struct grid *gd, u_int px, u_int py, u_int nx)
+grid_view_delete_cells(struct grid *gd, u_int px, u_int py, u_int nx, u_int bg)
 {
 u_intsx;
 
@@ -197,8 +202,8 @@ grid_view_delete_cells(struct grid *gd, u_int px, u_int py, u_int nx)
 
 sx = grid_view_x(gd, gd->sx);
 
-grid_move_cells(gd, px, px + nx, py, sx - px - nx);
-grid_clear(gd, sx - nx, py, px + nx - (sx - nx), 1);
+grid_move_cells(gd, px, px + nx, py, sx - px - nx, bg);
+grid_clear(gd, sx - nx, py, px + nx - (sx - nx), 1, bg);
 }
 
 /* Convert cells into a string. */