Function UpdateGUIZoom

src/gfx.cpp:1790–1810

* Resolve GUI zoom level, if auto-suggestion is requested. */

 * Resolve GUI zoom level, if auto-suggestion is requested.
 */
void UpdateGUIZoom()
{
	/* Determine real GUI zoom to use. */
	if (_gui_scale_cfg == -1) {
		/* Minimum design size of the game is 640x480. */
		float xs = _screen.width / 640.f;
		float ys = _screen.height / 480.f;
		int scale = std::min(xs, ys) * 100;
		/* Round down scaling to 25% increments and clamp to limits. */
		_gui_scale = Clamp((scale / 25) * 25, MIN_INTERFACE_SCALE, MAX_INTERFACE_SCALE);
	} else {
		_gui_scale = Clamp(_gui_scale_cfg, MIN_INTERFACE_SCALE, MAX_INTERFACE_SCALE);
	}

	ZoomLevel new_zoom = ScaleGUITrad(1) <= 1 ? ZoomLevel::Normal : ScaleGUITrad(1) >= 4 ? ZoomLevel::In4x : ZoomLevel::In2x;
	/* Font glyphs should not be clamped to min/max zoom. */
	_font_zoom = new_zoom;
	/* Ensure the gui_zoom is clamped between min/max. */
	new_zoom = Clamp(new_zoom, _settings_client.gui.zoom_min, _settings_client.gui.zoom_max);
	_gui_zoom = new_zoom;
}

/**
 * Resolve GUI zoom level and adjust GUI to new zoom, if auto-suggestion is requested.