[webkit-dev] Can someone explain tx/ty?

[Eric Seidel]

I believe int tx, int ty -- which we see sprinkled around the
rendering tree -- are the offset from the top left corner of the
current renderer's parent to the containing block.  Is that correct?

In SVG we use IntSize containingBlockOffset in the rare places we have
to deal with this RenderBoxModelObject-only concept.

I've long considered fixing renders to use IntPoint and IntSize
instead of x, y, tx, ty, but to do that, I need to make sure I
understand what tx, ty are, and what name they should have as an
IntSize.

-eric