Implement keyboard shortcuts for scrolling

kitty/boss.py

@@ -281,4 +281,15 @@ class Boss(Thread):
         text = subprocess.check_output(['xsel'])
         self.paste(text)
 
+    def scroll_line_up(self):
+        self.queue_action(self.char_grid.scroll, 'line', True)
+
+    def scroll_line_down(self):
+        self.queue_action(self.char_grid.scroll, 'line', False)
+
+    def scroll_page_up(self):
+        self.queue_action(self.char_grid.scroll, 'page', True)
+
+    def scroll_page_down(self):
+        self.queue_action(self.char_grid.scroll, 'page', False)
     # }}}

kitty/char_grid.py

@@ -218,15 +218,25 @@ class CharGrid:
             self.render_queue.put(RenderData(clear_color=self.default_bg))
             self.clear_count = 4
 
+    def scroll(self, amt, upwards=True):
+        amt = 1 if amt == 'line' else self.screen.lines - 1 if amt == 'page' else max(0, min(int(amt), self.screen.lines - 1))
+        if not upwards:
+            amt *= -1
+        y = max(0, min(self.scrolled_by + amt, self.screen.historybuf.count))
+        if y != self.scrolled_by:
+            self.scrolled_by = y
+            self.update_cell_data()
+
     def update_cell_data(self, add_viewport_data=False):
-        rd = RenderData(sprite_layout=self.sprites.layout)
+        rd = RenderData(sprite_layout=self.sprites.layout, cell_data_changed=True)
         if add_viewport_data:
             rd.viewport = Size(self.width, self.height)
             rd.screen_geometry = self.screen_geometry
         with self.sprites_lock:
-            cursor_changed = self.screen.update_cell_data(
+            cursor_changed, history_line_added_count = self.screen.update_cell_data(
                 self.sprites.backend, self.color_profile, addressof(self.main_sprite_map), self.default_fg, self.default_bg, add_viewport_data)
             if self.scrolled_by:
+                self.scrolled_by = min(self.scrolled_by + history_line_added_count, self.screen.historybuf.count)
                 self.screen.set_scroll_cell_data(
                     self.sprites.backend, self.color_profile, addressof(self.main_sprite_map), self.default_fg, self.default_bg,
                     self.scrolled_by, addressof(self.scroll_sprite_map))
@@ -234,7 +244,6 @@ class CharGrid:
         data = self.scroll_sprite_map if self.scrolled_by else self.main_sprite_map
         with self.buffer_lock:
             memmove(self.render_buf, data, sizeof(type(data)))
-        rd.cell_data_changed = True
         if cursor_changed:
             c = self.screen.cursor
             rd.cursor = Cursor(c.x, c.y, c.hidden, c.shape, c.color, c.blink)

kitty/data-types.h

@@ -323,6 +323,7 @@ unsigned int linebuf_char_width_at(LineBuf *self, index_type x, index_type y);
 bool historybuf_resize(HistoryBuf *self, index_type lines);
 void historybuf_add_line(HistoryBuf *self, const Line *line);
 void historybuf_rewrap(HistoryBuf *self, HistoryBuf *other);
+void historybuf_init_line(HistoryBuf *self, index_type num, Line *l);
 
 void screen_restore_cursor(Screen *);
 void screen_save_cursor(Screen *);

kitty/history.c

@@ -70,6 +70,10 @@ static inline void init_line(HistoryBuf *self, index_type num, Line *l) {
     l->combining_chars = (combining_type*)(l->decoration_fg + self->xnum);
 }
 
+void historybuf_init_line(HistoryBuf *self, index_type lnum, Line *l) {
+    init_line(self, index_of(self, lnum), l);
+}
+
 static inline index_type historybuf_push(HistoryBuf *self) {
     index_type idx = (self->start_of_data + self->count) % self->ynum;
     init_line(self, idx, self->line);

kitty/screen.c

@@ -1029,11 +1029,40 @@ screen_update_cell_data(Screen *self, PyObject *args) {
     if (!PyArg_ParseTuple(args, "O!O!O!kkp", &SpriteMap_Type, &spm, &ColorProfile_Type, &color_profile, &PyLong_Type, &dp, &default_fg, &default_bg, &force_screen_refresh)) return NULL;
     data = PyLong_AsVoidPtr(dp);
     PyObject *cursor_changed = self->change_tracker->cursor_changed ? Py_True : Py_False;
+    unsigned int history_line_added_count = self->change_tracker->history_line_added_count;
+
     if (!tracker_update_cell_data(self->change_tracker, self->linebuf, spm, color_profile, data, default_fg, default_bg, (bool)force_screen_refresh)) return NULL;
-    Py_INCREF(cursor_changed);
+    return Py_BuildValue("OI", cursor_changed, history_line_added_count);
-    return cursor_changed;
 }
 
+static PyObject*
+set_scroll_cell_data(Screen *self, PyObject *args) {
+    SpriteMap *spm;
+    ColorProfile *color_profile;
+    PyObject *dp, *sp;
+    unsigned int *data, *src, scrolled_by;
+    unsigned long default_bg, default_fg;
+    if (!PyArg_ParseTuple(args, "O!O!O!kkIO", &SpriteMap_Type, &spm, &ColorProfile_Type, &color_profile, &PyLong_Type, &sp, &default_fg, &default_bg, &scrolled_by, &dp)) return NULL;
+    data = PyLong_AsVoidPtr(dp);
+    src = PyLong_AsVoidPtr(sp);
+    unsigned int line_size = 9 * self->columns;
+
+    scrolled_by = MIN(self->historybuf->count, scrolled_by);
+
+    for (index_type y = 0; y < MIN(self->lines, scrolled_by); y++) {
+        historybuf_init_line(self->historybuf, scrolled_by - y, self->historybuf->line);
+        self->historybuf->line->ynum = y;
+        if (!update_cell_range_data(spm, self->historybuf->line, 0, self->columns - 1, color_profile, default_bg, default_fg, data)) return NULL;
+    }
+    if (scrolled_by < self->lines) {
+        // Less than a full screen has been scrolled, copy some lines from the screen buffer to the scroll buffer
+        index_type num_to_copy = self->lines - scrolled_by;
+        index_type offset = line_size * scrolled_by;
+        memcpy(data + offset, src, line_size * num_to_copy * sizeof(unsigned int));
+    }
+    Py_RETURN_NONE;
+}
+ 
 static PyObject* is_dirty(Screen *self) {
     PyObject *ans = self->change_tracker->dirty ? Py_True : Py_False;
     Py_INCREF(ans);
@@ -1096,6 +1125,7 @@ static PyMethodDef methods[] = {
     MND(reverse_index, METH_NOARGS)
     MND(is_dirty, METH_NOARGS)
     MND(resize, METH_VARARGS)
+    MND(set_scroll_cell_data, METH_VARARGS)
     {"update_cell_data", (PyCFunction)screen_update_cell_data, METH_VARARGS, ""},
 
     {NULL}  /* Sentinel */