Retain scrollback position when resizing #143

Manually merged
dnkl merged 3 commits from reflow-retain-scrollback-position into master 1 year ago
  1. 2
      CHANGELOG.md
  2. 27
      grid.c

2
CHANGELOG.md

@ -27,6 +27,8 @@
(https://codeberg.org/dnkl/foot/issues/146).
* Color flashes when changing the color palette with OSC 4,10,11
(https://codeberg.org/dnkl/foot/issues/141).
* Scrollback position is now retained when resizing the window
(https://codeberg.org/dnkl/foot/issues/142).
### Security

27
grid.c

@ -6,6 +6,7 @@
#define LOG_MODULE "grid"
#define LOG_ENABLE_DBG 0
#include "log.h"
#include "macros.h"
#include "sixel.h"
#include "util.h"
#include "xmalloc.h"
@ -65,6 +66,9 @@ grid_reflow(struct grid *grid, int new_rows, int new_cols,
const int old_rows = grid->num_rows;
const int old_cols = grid->num_cols;
/* Is viewpoint tracking current grid offset? */
const bool view_follows = grid->view == grid->offset;
int new_col_idx = 0;
int new_row_idx = 0;
@ -97,9 +101,14 @@ grid_reflow(struct grid *grid, int new_rows, int new_cols,
tll_push_back(tracking_points, &cursor);
tll_push_back(tracking_points, &saved_cursor);
struct coord viewport = {0, grid->view};
if (!view_follows)
tll_push_back(tracking_points, &viewport);
for (size_t i = 0; i < tracking_points_count; i++)
tll_push_back(tracking_points, _tracking_points[i]);
/*
* Walk the old grid
*/
@ -308,7 +317,6 @@ grid_reflow(struct grid *grid, int new_rows, int new_cols,
grid->offset += new_rows;
while (new_grid[grid->offset] == NULL)
grid->offset = (grid->offset + 1) & (new_rows - 1);
grid->view = grid->offset;
/* Ensure all visible rows have been allocated */
for (int r = 0; r < new_screen_rows; r++) {
@ -317,6 +325,23 @@ grid_reflow(struct grid *grid, int new_rows, int new_cols,
new_grid[idx] = grid_row_alloc(new_cols, true);
}
grid->view = view_follows ? grid->offset : viewport.row;
/* If enlarging the window, the old viewport may be too far down,
* with unallocated rows. Make sure this cannot happen */
while (true) {
int idx = (grid->view + new_screen_rows - 1) & (new_rows - 1);
if (new_grid[idx] != NULL)
break;
grid->view--;
if (grid->view < 0)
grid->view += new_rows;
}
for (size_t r = 0; r < new_screen_rows; r++) {
int UNUSED idx = (grid->view + r) & (new_rows - 1);
assert(new_grid[idx] != NULL);
}
/* Free old grid */
for (int r = 0; r < grid->num_rows; r++)
grid_row_free(old_grid[r]);

Loading…
Cancel
Save