libcamera: Use the Size class through libcamera

Several of our structures include width and height fields that model a
size while we have a Size class for that purpose. Use the Size class
through libcamera, and give it a toString() method like other geometry
and format classes.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/libcamera/geometry.cpp

@@ -107,6 +107,15 @@ bool operator==(const Rectangle &lhs, const Rectangle &rhs)
  * \brief The Size height
  */
 
+/**
+ * \brief Assemble and return a string describing the size
+ * \return A string describing the size
+ */
+const std::string Size::toString() const
+{
+	return std::to_string(width) + "x" + std::to_string(height);
+}
+
 /**
  * \brief Compare sizes for equality
  * \return True if the two sizes are equal, false otherwise