Method get_image_handle_at

src/animation.cpp:156–209

display::image_handle animation::get_image_handle_at(animation_position const &p_animation_position)
{
	// Check if the position is beyond the list of parts
	if (p_animation_position.m_part_nr >= m_parts.size())
	{
		LOG_MSG(warning, "animation position (" << p_animation_position << ") has invalid part nr");
		return display::invalid_image_handle;
	}

	animation::part const &part = m_parts[p_animation_position.m_part_nr];

	// Check if the position is beyond the list of frames inside the part
	if (p_animation_position.m_frame_nr_in_part >= part.m_frames.size())
	{
		LOG_MSG(warning, "animation position (" << p_animation_position << ") has invalid frame nr");
		return display::invalid_image_handle;
	}

	display::image_handle * cached_handle = m_image_handle_cache.get_entry(p_animation_position);
	if (cached_handle == nullptr)
	{
		LOG_MSG(trace, "no frame at position " << p_animation_position << " in LRU cache - loading");

		// Get the zip archive entry for the current position
		zip_archive::entry const &p_entry = *(part.m_frames[p_animation_position.m_frame_nr_in_part]);

		image frame = load_png(m_zip_archive.uncompress_data(p_entry));
		if (!is_valid(frame))
		{
			LOG_MSG(error, "could not load PNG \"" << p_entry.m_filename << "\"");
			return display::invalid_image_handle;
		}

		// Create a display image_handle for each frame
		display::image_handle handle = m_display.load_image(std::move(frame));
		if (handle != display::invalid_image_handle)
		{
			LOG_MSG(trace, "loaded frame \"" << p_entry.m_filename << "\"");

			cached_handle = &(m_image_handle_cache.add_entry(p_animation_position, std::move(handle)));
		}
		else
		{
			LOG_MSG(error, "could not load frame \"" << p_entry.m_filename << "\" into display");
			return display::invalid_image_handle;
		}
	}
	else
	{
		LOG_MSG(trace, "retrieved frame at position " << p_animation_position << " from LRU cache");
	}

	return *cached_handle;
}