[rviz_common] fix loading of icon resources

[wjwwood]

See:

• rviz/rviz_common/src/rviz_common/load_resource.cpp

  Lines 45 to 62 in ca8f42e

  	// TODO(wjwwood): replace this with ROS 2 and boost-free version
  	// boost::filesystem::path getPath(QString url)
  	// {
  	// boost::filesystem::path path;
  	// if (url.indexOf("package://", 0, Qt::CaseInsensitive) == 0) {
  	// QString package_name = url.section('/', 2, 2);
  	// QString file_name = url.section('/', 3);
  	// path = ros::package::getPath(package_name.toStdString());
  	// path = path / file_name.toStdString();
  	// } else if (url.indexOf("file://", 0, Qt::CaseInsensitive) == 0) {
  	// path = url.section('/', 2).toStdString();
  	// } else {
  	// ROS_ERROR("Invalid or unsupported URL: '%s'", url.toStdString().c_str() );
  	// }
  	// return path;
  	// }

• rviz/rviz_common/src/rviz_common/load_resource.cpp

  Lines 69 to 91 in ca8f42e

  	// TODO(wjwwood): reenable this, or in the meantime add a placeholder pixmap
  	Q_UNUSED(url);
  	Q_UNUSED(fill_cache);
  	// RVIZ_COMMON_LOG_WARNING_STREAM("did not load pixmap at " << url.toStdString());
  	// // if it's in the cache, no need to locate
  	// if (QPixmapCache::find(url, &pixmap) ) {
  	// return pixmap;
  	// }
  	// boost::filesystem::path path = getPath(url);
  	// // If something goes wrong here, we go on and store the empty pixmap,
  	// // so the error won't appear again anytime soon.
  	// if (boost::filesystem::exists(path) ) {
  	// ROS_DEBUG_NAMED("load_resource", "Loading '%s'", path.string().c_str() );
  	// if (!pixmap.load(QString::fromStdString(path.string() ) ) ) {
  	// ROS_ERROR("Could not load pixmap '%s'", path.string().c_str() );
  	// }
  	// }
  	// if (fill_cache) {
  	// QPixmapCache::insert(url, pixmap);
  	// }

• rviz/rviz_common/src/rviz_common/load_resource.cpp

  Lines 104 to 118 in ca8f42e

  	// TODO(wjwwood): reenable this
  	Q_UNUSED(url);
  	Q_UNUSED(fill_cache);
  	// RVIZ_COMMON_LOG_WARNING_STREAM("did not load icon as cursor at " << url.toStdString());
  	return QCursor(Qt::ArrowCursor);
  	#if 0
  	QPixmap icon = loadPixmap(url, fill_cache);
  	if (icon.width() == 0 || icon.height() == 0) {
  	ROS_ERROR("Could not load pixmap '%s' -- using default cursor instead.",
  	url.toStdString().c_str() );
  	return getDefaultCursor();
  	}
  	QString cache_key = url + ".cursor";
  	return makeIconCursor(icon, cache_key, fill_cache);
  	#endif

• rviz/rviz_common/src/rviz_common/load_resource.cpp

  Lines 123 to 165 in ca8f42e

  	// TODO(wjwwood): reenable this
  	Q_UNUSED(icon);
  	Q_UNUSED(cache_key);
  	Q_UNUSED(fill_cache);
  	// RVIZ_COMMON_LOG_WARNING_STREAM("did not make icon into cursor at " << cache_key.toStdString());
  	return QCursor(Qt::ArrowCursor);
  	#if 0
  	// if it's in the cache, no need to locate
  	QPixmap cursor_img;
  	if (QPixmapCache::find(cache_key, &cursor_img) ) {
  	return QCursor(cursor_img, 0, 0);
  	}
  	QPixmap base_cursor = loadPixmap("package://rviz/icons/cursor.svg", fill_cache);
  	const int cursor_size = 32;
  	cursor_img = QPixmap(cursor_size, cursor_size);
  	cursor_img.fill(QColor(0, 0, 0, 0) );
  	// copy base cursor & icon into one image
  	QPainter painter(&cursor_img);
  	int draw_x = 12;
  	int draw_y = 16;
  	// if the icon is too large, move it to the left
  	if (draw_x + icon.width() > cursor_size) {
  	draw_x = cursor_size - icon.width();
  	}
  	if (draw_y + icon.height() > cursor_size) {
  	draw_y = cursor_size - icon.height();
  	}
  	painter.drawPixmap(0, 0, base_cursor);
  	painter.drawPixmap(draw_x, draw_y, icon);
  	if (fill_cache) {
  	QPixmapCache::insert(cache_key, cursor_img);
  	}
  	return QCursor(cursor_img, 1, 1);
  	#endif

This will probably be solved with a combination of either ament_index_cpp (to have a relocatable solution to finding the files at runtime) and QDir/QFile/QFileInfo to replace boost::filesystem.

[greimela-si]

Will this use the resource_retriever from #51 or should ament_index_cpp be used directly?

[wjwwood]

Will this use the resource_retriever from #51 or should ament_index_cpp be used directly?

We should use resource_retriever if possible. If resource_retriever gives us a file:// back from a package:// then we can use that directly. Otherwise we'll have to let resource_retriever open the file and see if QPixmap has a version of .load() that takes a buffer/file-like object instead of a path.

[wjwwood]

This should be reevaluated after #123 was merged.