Method SetSelection

src/audio_display.cpp:202–206

	}

	void SetSelection(int new_start, int new_length)
	{
		sel_start = (int64_t)new_start * bounds.width / data_length;
		sel_length = (int64_t)new_length * bounds.width / data_length;
	}

	void ChangeLengths(int new_data_length, int new_page_length)
	{