Function PreventHiding

src/window.cpp:2022–2053

* Do not allow hiding of the rectangle with base coordinates \a nx and \a ny behind window \a v. * If needed, move the window base coordinates to keep it visible. * @param nx Base horizontal coordinate of the rectangle. * @param ny Base vertical coordinate of the rectangle. * @param rect Rectangle that must stay visible (horizontally, vertically, or both) * @param v Window lying in fro

 * @param dir  If no room horizontally, move the rectangle to the indicated position.
 */
static void PreventHiding(int *nx, int *ny, const Rect &rect, const Window *v, int px, PreventHideDirection dir)
{
	if (v == nullptr) return;

	const int min_visible = rect.Height();

	int v_bottom = v->top + v->height - 1;
	int v_right = v->left + v->width - 1;
	int safe_y = (dir == PHD_UP) ? (v->top - min_visible - rect.top) : (v_bottom + min_visible - rect.bottom); // Compute safe vertical position.

	if (*ny + rect.top <= v->top - min_visible) return; // Above v is enough space
	if (*ny + rect.bottom >= v_bottom + min_visible) return; // Below v is enough space

	/* Vertically, the rectangle is hidden behind v. */
	if (*nx + rect.left + min_visible < v->left) { // At left of v.
		if (v->left < min_visible) *ny = safe_y; // But enough room, force it to a safe position.
		return;
	}
	if (*nx + rect.right - min_visible > v_right) { // At right of v.
		if (v_right > _screen.width - min_visible) *ny = safe_y; // Not enough room, force it to a safe position.
		return;
	}

	/* Horizontally also hidden, force movement to a safe area. */
	if (px + rect.left < v->left && v->left >= min_visible) { // Coming from the left, and enough room there.
		*nx = v->left - min_visible - rect.left;
	} else if (px + rect.right > v_right && v_right <= _screen.width - min_visible) { // Coming from the right, and enough room there.
		*nx = v_right + min_visible - rect.right;
	} else {
		*ny = safe_y;
	}
}

/**
 * Make sure at least a part of the caption bar is still visible by moving