1. A method comprising: receiving data that defines a first layout specifying a fixed graphical placement for rendering of graphical content portions contained within the data; identifying graphical placement relationships between the graphical content portions in the first layout, and defining a sort order for the graphical content portions in the first layout based on the graphical placement relationships; generating an ordered tree structure for the graphical content portions based on the sort order, the ordered tree structure comprising a plurality of nodes, each node identifying one of the graphical content portions, the plurality of nodes arranged in the ordered tree structure such that an in-order traversal of each node of the ordered tree structure maintains a presentation order of the graphical content portions in the first layout, the ordered tree structure allowing graphical placement of the graphical content portions in a second layout in accordance with the presentation order based on the in-order traversal of each node of the ordered tree structure, the second layout different than the first layout; and providing the ordered tree structure to allow rendering of the graphical content portions in accordance with the second layout.
1. A method comprising: receiving data that defines a first layout specifying a fixed graphical placement for rendering of graphical content portions contained within the data; identifying graphical placement relationships between the graphical content portions in the first layout, and defining a sort order for the graphical content portions in the first layout based on the graphical placement relationships; generating an ordered tree structure for the graphical content portions based on the sort order, the ordered tree structure comprising a plurality of nodes, each node identifying one of the graphical content portions, the plurality of nodes arranged in the ordered tree structure such that an in-order traversal of each node of the ordered tree structure maintains a presentation order of the graphical content portions in the first layout, the ordered tree structure allowing graphical placement of the graphical content portions in a second layout in accordance with the presentation order based on the in-order traversal of each node of the ordered tree structure, the second layout different than the first layout; and providing the ordered tree structure to allow rendering of the graphical content portions in accordance with the second layout. 5. The method of claim 1 , wherein the ordered tree structure comprises a binary tree, and wherein generating the ordered tree structure for the graphical content portions comprises: comparing graphical locations of the graphical content portions from the sort order with graphical locations of the graphical content portions in the first layout; recursively inserting the graphical content portions into the binary tree as nodes; and responsive to evaluating a current graphical content portion to insert into the binary tree, the current graphical content portion graphically spanning a first previously inserted graphical content portion in a current branch of the binary tree and graphically spanning a second previously inserted graphical content portion in a right branch of the binary tree, preventing an association of additional nodes to the current branch of the binary tree.