Function ResizeWindow

src/window.cpp:2099–2132

* Resize the window. * Update all the widgets of a window based on their resize flags * Both the areas of the old window and the new sized window are set dirty * ensuring proper redrawing. * @param w Window to resize * @param delta_x Delta x-size of changed window (positive if larger, etc.) * @param delta_y Delta y-size of changed window * @param clamp_to_screen Whether to make sure t

 * @param clamp_to_screen Whether to make sure the whole window stays visible
 */
void ResizeWindow(Window *w, int delta_x, int delta_y, bool clamp_to_screen, bool schedule_resize)
{
	if (delta_x != 0 || delta_y != 0) {
		if (clamp_to_screen) {
			/* Determine the new right/bottom position. If that is outside of the bounds of
			 * the resolution clamp it in such a manner that it stays within the bounds. */
			int new_right  = w->left + w->width  + delta_x;
			int new_bottom = w->top  + w->height + delta_y;
			if (new_right  >= (int)_screen.width)  delta_x -= Ceil(new_right  - _screen.width,  std::max(1U, w->nested_root->resize_x));
			if (new_bottom >= (int)_screen.height) delta_y -= Ceil(new_bottom - _screen.height, std::max(1U, w->nested_root->resize_y));
		}

		w->SetDirty();

		uint new_xinc = std::max(0, (w->nested_root->resize_x == 0) ? 0 : (int)(w->nested_root->current_x - w->nested_root->smallest_x) + delta_x);
		uint new_yinc = std::max(0, (w->nested_root->resize_y == 0) ? 0 : (int)(w->nested_root->current_y - w->nested_root->smallest_y) + delta_y);
		assert(w->nested_root->resize_x == 0 || new_xinc % w->nested_root->resize_x == 0);
		assert(w->nested_root->resize_y == 0 || new_yinc % w->nested_root->resize_y == 0);

		w->nested_root->AssignSizePosition(ST_RESIZE, 0, 0, w->nested_root->smallest_x + new_xinc, w->nested_root->smallest_y + new_yinc, _current_text_dir == TD_RTL);
		w->width  = w->nested_root->current_x;
		w->height = w->nested_root->current_y;
	}

	EnsureVisibleCaption(w, w->left, w->top);

	/* Schedule OnResize to make sure everything is initialised correctly if it needs to be. */
	if (schedule_resize) {
		w->ScheduleResize();
	} else {
		w->OnResize();
	}
	w->SetDirty();
}

/**
 * Return the top of the main view available for general use.