Source code for simvx.ide.panels.scroll_mixin

"""Reusable scroll mixin for IDE panels with vertical scrolling."""


from __future__ import annotations

import logging

log = logging.getLogger(__name__)



class ScrollableMixin:
    """Mixin providing scroll_y tracking, key handling, and row-at-y mapping.

    Panels using this mixin should call ``_handle_scroll(key, content_height, visible_height)``
    from their ``_on_gui_input`` and ``_row_at_y(py, content_top, row_height)`` for click mapping.
    """

    _scroll_y: float = 0.0
    _scroll_step: float = 20.0

    def _handle_scroll(self, key: str, content_height: float, visible_height: float) -> bool:
        """Handle scroll_up/scroll_down keys, clamping to valid range. Returns True if handled."""
        if key == "scroll_up":
            self._scroll_y = max(0.0, self._scroll_y - self._scroll_step)
            return True
        if key == "scroll_down":
            max_scroll = max(0.0, content_height - visible_height)
            self._scroll_y = min(max_scroll, self._scroll_y + self._scroll_step)
            return True
        return False

    def _row_at_y(self, py: float, content_top: float, row_height: float) -> int:
        """Map a screen Y coordinate to a row index accounting for scroll offset."""
        return int((py - content_top + self._scroll_y) / row_height)

    def _clamp_scroll(self, content_height: float, visible_height: float) -> None:
        """Clamp current scroll_y to valid range (useful after content changes)."""
        max_scroll = max(0.0, content_height - visible_height)
        self._scroll_y = max(0.0, min(self._scroll_y, max_scroll))