Text: use Math::join() on ranges instead of custom code.

It does the same in a shorter and less error-prone way.

src/Magnum/Text/AbstractFont.cpp

@@ -340,11 +340,9 @@ Containers::Pair<Range2D, Range2D> AbstractLayouter::renderGlyph(const UnsignedI
     /* Move the quad to cursor */
     const Range2D quadPosition = quadPositionTextureCoordinatesAdvance.first().translated(cursorPosition);
 
-    /* Extend rectangle with current quad bounds. If zero size, replace it. */
-    if(!rectangle.size().isZero()) {
-        rectangle.bottomLeft() = Math::min(rectangle.bottomLeft(), quadPosition.bottomLeft());
-        rectangle.topRight() = Math::max(rectangle.topRight(), quadPosition.topRight());
-    } else rectangle = quadPosition;
+    /* Extend the rectangle with current quad bounds. If the original is zero
+       size, it gets replaced. */
+    rectangle = Math::join(rectangle, quadPosition);
 
     /* Advance cursor position to next character */
     cursorPosition += quadPositionTextureCoordinatesAdvance.third();

src/Magnum/Text/Renderer.cpp

@@ -150,11 +150,9 @@ std::tuple<std::vector<Vertex>, Range2D> renderVerticesInternal(AbstractFont& fo
         for(auto it = vertices.begin()+lastLineLastVertex; it != vertices.end(); ++it)
             it->position.x() += alignmentOffsetX;
 
-        /* Add final line bounds to total bounds, similarly to AbstractFont::renderGlyph() */
-        if(!rectangle.size().isZero()) {
-            rectangle.bottomLeft() = Math::min(rectangle.bottomLeft(), lineRectangle.bottomLeft());
-            rectangle.topRight() = Math::max(rectangle.topRight(), lineRectangle.topRight());
-        } else rectangle = lineRectangle;
+        /* Extend the rectangle with final line bounds, similarly to
+           AbstractFont::renderGlyph() */
+        rectangle = Math::join(rectangle, lineRectangle);
 
     /* Move to next line */
     } while(prevPos = pos+1,