Method updateMapCache

src/gui/map/map_widget.cpp:1348–1408

}

void MapWidget::updateMapCache(bool use_background)
{
	if (map_cache.isNull())
	{
		// Lazy allocation of cache image
		map_cache = QImage(size(), QImage::Format_ARGB32_Premultiplied);
		map_cache_dirty_rect = rect();
	}
	else
	{
		// Make sure not to use a bigger draw rect than necessary
		map_cache_dirty_rect = map_cache_dirty_rect.intersected(rect());
	}
	
	// Start drawing
	QPainter painter;
	painter.begin(&map_cache);
	painter.setClipRect(map_cache_dirty_rect);
	
	// Fill with background color (TODO: make configurable)
	if (use_background)
	{
		painter.fillRect(map_cache_dirty_rect, Qt::white);
	}
	else
	{
		QPainter::CompositionMode mode = painter.compositionMode();
		painter.setCompositionMode(QPainter::CompositionMode_Clear);
		painter.fillRect(map_cache_dirty_rect, Qt::transparent);
		painter.setCompositionMode(mode);
	}
	
	RenderConfig::Options options(RenderConfig::Screen | RenderConfig::HelperSymbols);
	bool use_antialiasing = force_antialiasing || Settings::getInstance().getSettingCached(Settings::MapDisplay_Antialiasing).toBool();
	if (use_antialiasing)
		painter.setRenderHint(QPainter::Antialiasing);
	else
		options |= RenderConfig::DisableAntialiasing | RenderConfig::ForceMinSize;
		
	Map* map = view->getMap();
	QRectF map_view_rect = view->calculateViewedRect(viewportToView(map_cache_dirty_rect));

	RenderConfig config = { *map, map_view_rect, view->calculateFinalZoomFactor(), options, 1.0 };
	
	painter.translate(width() / 2.0, height() / 2.0);
	painter.setWorldTransform(view->worldTransform(), true);
#ifndef Q_OS_ANDROID
	if (view->isOverprintingSimulationEnabled())
		map->drawOverprintingSimulation(&painter, config);
	else
#endif
		map->draw(&painter, config);
	
	if (view->isGridVisible())
		map->drawGrid(&painter, map_view_rect);
	
	// Finish drawing
	painter.end();