Add PAGE_UP, PAGE_DOWN, KEY_HOME, and KEY_END support in ScrollMenu

[pkazmier]

ScrollMenu only supports moving up and down by a single line at a time. When a scroll menu contains hundreds and hundreds of items, navigating in this manner is too slow. It would be great to add support for PAGE_UP, PAGE_DOWN, KEY_HOME, and KEY_END.

[jwlodek]

I think this would be worthwhile. I guess pageup, pagedown can move a set number of positions, and home/end moves to the top or bottom of the menu

[pkazmier]

No time to submit a PR, but here are the implementations I used for page up and page down in my custom ScrollMenu widget:

    def page_up(self):
        shift_by = self.height - (2 * self.pady) - 3

        new_top_view = self.top_view - shift_by
        new_selected_item = self.selected_item - shift_by

        self.top_view = 0 if new_top_view < 0 else new_top_view
        self.selected_item = 0 if new_selected_item < 0 else new_selected_item

    def page_down(self):
        shift_by = self.height - (2 * self.pady) - 3
        last_item_idx = len(self.view_items) - 1

        new_top_view = self.top_view + shift_by
        new_selected_item = self.selected_item + shift_by

        self.top_view = (
            new_top_view - shift_by if new_top_view > last_item_idx else new_top_view
        )
        self.selected_item = (
            last_item_idx if new_selected_item > last_item_idx else new_selected_item
        )

[jwlodek]

This feature has been added to the v0.1.1-develop branch, and seems to work OK on my end. Unit tests still need to be expanded to account for this change.

[wdog]

I've implemented directly on the custom ScrollMenu PAGE_UP PAGE_DOWN this way

    def _handle_key_press(self, key_pressed):
        super()._handle_key_press(key_pressed)

        if key_pressed == curses.KEY_NPAGE:
            # if next jump is on the groud
            if self._selected_item + self._height - 2 < len(self._view_items):
                self._selected_item += self._height - 2
                self._top_view = self._selected_item
               
        if key_pressed == curses.KEY_PPAGE:
            self._selected_item -= self._height - 2
            self._top_view = self._selected_item
            if self._selected_item < 0:
                self._selected_item = 0

maybe helps mybe not 🎮

[jwlodek]

Closing, included in new py_cui release