Merge branch 'scroll-up-down-while-selecting' into master

Closes #149

CHANGELOG.md

@@ -37,6 +37,10 @@
 * **csd.preferred** can now be set to `none` to disable window
   decorations. Note that some compositors will render SSDs despite
   this option being used (https://codeberg.org/dnkl/foot/issues/163).
+* Terminal content is now auto-scrolled when moving the mouse above or
+  below the window while selecting
+  (https://codeberg.org/dnkl/foot/issues/149).
+
 
 ### Changed
 ### Deprecated

input.c

@@ -1325,10 +1325,46 @@ wl_pointer_motion(void *data, struct wl_pointer *wl_pointer,
             = old_col != seat->mouse.col || old_row != seat->mouse.row;
 
         /* Cursor is inside the grid, i.e. *not* in the margins */
-        bool cursor_is_on_grid = seat->mouse.col >= 0 && seat->mouse.row >= 0;
+        const bool cursor_is_on_grid = seat->mouse.col >= 0 && seat->mouse.row >= 0;
+
+        enum selection_scroll_direction auto_scroll_direction
+            = y < term->margins.top ? SELECTION_SCROLL_UP
+            : y > term->height - term->margins.bottom ? SELECTION_SCROLL_DOWN
+            : SELECTION_SCROLL_NOT;
+
+        if (auto_scroll_direction == SELECTION_SCROLL_NOT)
+            selection_stop_scroll_timer(term);
 
         /* Update selection */
         if (!term->is_searching) {
+            if (auto_scroll_direction != SELECTION_SCROLL_NOT) {
+                /*
+                 * Start ‘selection auto-scrolling’
+                 *
+                 * The speed of the scrolling is proportional to the
+                 * distance between the mouse and the grid; the
+                 * further away the mouse is, the faster we scroll.
+                 *
+                 * Note that the speed is measured in ‘intervals (in
+                 * ns) between each timed scroll of a single line’.
+                 *
+                 * Thus, the further away the mouse is, the smaller
+                 * interval value we use.
+                 */
+
+                int distance = auto_scroll_direction == SELECTION_SCROLL_UP
+                    ? term->margins.top - y
+                    : y - (term->height - term->margins.bottom);
+
+                assert(distance > 0);
+                int divisor
+                    = distance * term->conf->scrollback.multiplier / term->scale;
+
+                selection_start_scroll_timer(
+                    term, 400000000 / (divisor > 0 ? divisor : 1),
+                    auto_scroll_direction, selection_col);
+            }
+
             if (cursor_is_on_new_cell || term->selection.end.row < 0)
                 selection_update(term, selection_col, selection_row);
         }

selection.c

@@ -15,6 +15,7 @@
 #include "log.h"
 
 #include "async.h"
+#include "commands.h"
 #include "config.h"
 #include "extract.h"
 #include "grid.h"
@@ -619,6 +620,7 @@ selection_finalize(struct seat *seat, struct terminal *term, uint32_t serial)
     if (!term->selection.ongoing)
         return;
 
+    selection_stop_scroll_timer(term);
     term->selection.ongoing = false;
 
     if (term->selection.start.row < 0 || term->selection.end.row < 0)
@@ -647,6 +649,7 @@ selection_cancel(struct terminal *term)
             term->selection.start.row, term->selection.start.col,
             term->selection.end.row, term->selection.end.col);
 
+    selection_stop_scroll_timer(term);
 
     if (term->selection.start.row >= 0 && term->selection.end.row >= 0) {
         foreach_selected(
@@ -789,6 +792,108 @@ selection_mark_row(
     selection_finalize(seat, term, serial);
 }
 
+static bool
+fdm_scroll_timer(struct fdm *fdm, int fd, int events, void *data)
+{
+    if (events & EPOLLHUP)
+        return false;
+
+    struct terminal *term = data;
+
+    uint64_t expiration_count;
+    ssize_t ret = read(
+        term->selection.auto_scroll.fd,
+        &expiration_count, sizeof(expiration_count));
+
+    if (ret < 0) {
+        if (errno == EAGAIN)
+            return true;
+
+        LOG_ERRNO("failed to read selection scroll timer");
+        return false;
+    }
+
+    switch (term->selection.auto_scroll.direction) {
+    case SELECTION_SCROLL_NOT:
+        return true;
+
+    case SELECTION_SCROLL_UP:
+        cmd_scrollback_up(term, expiration_count);
+        selection_update(term, term->selection.auto_scroll.col, 0);
+        break;
+
+    case SELECTION_SCROLL_DOWN:
+        cmd_scrollback_down(term, expiration_count);
+        selection_update(term, term->selection.auto_scroll.col, term->rows - 1);
+        break;
+    }
+
+
+    return true;
+}
+
+void
+selection_start_scroll_timer(struct terminal *term, int interval_ns,
+                             enum selection_scroll_direction direction, int col)
+{
+    assert(direction != SELECTION_SCROLL_NOT);
+
+    if (!term->selection.ongoing)
+        return;
+
+    if (term->selection.auto_scroll.fd < 0) {
+        int fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | TFD_NONBLOCK);
+        if (fd < 0) {
+            LOG_ERRNO("failed to create selection scroll timer");
+            goto err;
+        }
+
+        if (!fdm_add(term->fdm, fd, EPOLLIN, &fdm_scroll_timer, term)) {
+            close(fd);
+            return;
+        }
+
+        term->selection.auto_scroll.fd = fd;
+    }
+
+    struct itimerspec timer;
+    if (timerfd_gettime(term->selection.auto_scroll.fd, &timer) < 0) {
+        LOG_ERRNO("failed to get current selection scroll timer value");
+        goto err;
+    }
+
+    if (timer.it_value.tv_sec == 0 && timer.it_value.tv_nsec == 0)
+        timer.it_value.tv_nsec = 1;
+
+    timer.it_interval.tv_sec = interval_ns / 1000000000;
+    timer.it_interval.tv_nsec = interval_ns % 1000000000;
+
+    if (timerfd_settime(term->selection.auto_scroll.fd, 0, &timer, NULL) < 0) {
+        LOG_ERRNO("failed to set new selection scroll timer value");
+        goto err;
+    }
+
+    term->selection.auto_scroll.direction = direction;
+    term->selection.auto_scroll.col = col;
+    return;
+
+err:
+    selection_stop_scroll_timer(term);
+    return;
+}
+
+void
+selection_stop_scroll_timer(struct terminal *term)
+{
+    if (term->selection.auto_scroll.fd < 0) {
+        assert(term->selection.auto_scroll.direction == SELECTION_SCROLL_NOT);
+        return;
+    }
+
+    fdm_del(term->fdm, term->selection.auto_scroll.fd);
+    term->selection.auto_scroll.fd = -1;
+    term->selection.auto_scroll.direction = SELECTION_SCROLL_NOT;
+}
 
 static void
 target(void *data, struct wl_data_source *wl_data_source, const char *mime_type)

selection.h

@@ -74,3 +74,8 @@ void text_from_primary(
     struct seat *seat, struct terminal *term,
     void (*cb)(const char *data, size_t size, void *user),
     void (*dont)(void *user), void *user);
+
+void selection_start_scroll_timer(
+    struct terminal *term, int interval_ns,
+    enum selection_scroll_direction direction, int col);
+void selection_stop_scroll_timer(struct terminal *term);

terminal.c

@@ -985,6 +985,9 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
         .selection = {
             .start = {-1, -1},
             .end = {-1, -1},
+            .auto_scroll = {
+                .fd = -1,
+            },
         },
         .normal = {.scroll_damage = tll_init(), .sixel_images = tll_init()},
         .alt = {.scroll_damage = tll_init(), .sixel_images = tll_init()},
@@ -1164,6 +1167,7 @@ term_shutdown(struct terminal *term)
 
     term_cursor_blink_disable(term);
 
+    fdm_del(term->fdm, term->selection.auto_scroll.fd);
     fdm_del(term->fdm, term->render.app_sync_updates.timer_fd);
     fdm_del(term->fdm, term->delayed_render_timer.lower_fd);
     fdm_del(term->fdm, term->delayed_render_timer.upper_fd);
@@ -1176,6 +1180,7 @@ term_shutdown(struct terminal *term)
     else
         close(term->ptmx);
 
+    term->selection.auto_scroll.fd = -1;
     term->render.app_sync_updates.timer_fd = -1;
     term->delayed_render_timer.lower_fd = -1;
     term->delayed_render_timer.upper_fd = -1;
@@ -1226,6 +1231,7 @@ term_destroy(struct terminal *term)
         }
     }
 
+    fdm_del(term->fdm, term->selection.auto_scroll.fd);
     fdm_del(term->fdm, term->render.app_sync_updates.timer_fd);
     fdm_del(term->fdm, term->delayed_render_timer.lower_fd);
     fdm_del(term->fdm, term->delayed_render_timer.upper_fd);

terminal.h

@@ -182,6 +182,7 @@ enum cursor_style { CURSOR_BLOCK, CURSOR_UNDERLINE, CURSOR_BAR };
 
 enum selection_kind { SELECTION_NONE, SELECTION_NORMAL, SELECTION_BLOCK };
 enum selection_direction {SELECTION_UNDIR, SELECTION_LEFT, SELECTION_RIGHT};
+enum selection_scroll_direction {SELECTION_SCROLL_NOT, SELECTION_SCROLL_UP, SELECTION_SCROLL_DOWN};
 
 struct ptmx_buffer {
     void *data;
@@ -349,6 +350,12 @@ struct terminal {
         struct coord start;
         struct coord end;
         bool ongoing;
+
+        struct {
+            int fd;
+            int col;
+            enum selection_scroll_direction direction;
+        } auto_scroll;
     } selection;
 
     bool is_searching;