spec/css3-box: edited

Author: aprowse

spec/css3-box.txt

@@ -100,6 +100,26 @@ If the definition of principal box is modified so that an inline element generat
 
 Editorially, it's be helpful to have a name for "fix-up boxes" introduced into the formatting structure in order to ensure that the rules of each formatting context are met.  Perhaps the term "anonymous box" could be used for this purpose?  Need to define fix-up box: perhaps say that it's a box which cannot be distinguished by its property values and characteristics from a box generated by some hypothetical document element.  Implications: column boxes and probably certain ruby boxes would *not* be anonymous, since no hypothetical document element could create them.  A misparented table cell can result in the creation of an anonymous/fix-up table wrapper box, but is it reasonable to call the table box anonymous?  Is the table box a fix-up, really, or is the wrapper box the fix up and the table box the natural consequence of the wrapper box?
 
+=====Flow roots, flows and formatting contexts=====
+
+Terminology crisis!
+
+CSS has "normal flow", "in-flow" and "out of flow", but never really explains what the/a normal flow is.
+
+===Relevant quotes===
+
+From CSS21:
+  * "normal flow includes block formatting of block-level boxes, inline formatting of inline-level boxes"
+  * "An element is called out of flow if it is floated, absolutely positioned, or is the root element. An element is called in-flow if it is not out-of-flow."
+  * "The flow of an element A is the set consisting of A and all in-flow elements whose nearest out-of-flow ancestor is A." ...hence the flow of an in-flow element is the singleton consisting of itself.
+  * "Boxes in the normal flow belong to a formatting context, which in CSS 2.1 may be table, block or inline. In future levels of CSS, other types of formatting context will be introduced. Block-level boxes participate in a block formatting context. Inline-level boxes participate in an inline formatting context." (wording taken from errata)
+  * "The baseline of an 'inline-block' is the baseline of its last line box in the normal flow, unless it has either no in-flow line boxes or [...]"
+  * "User Agents must apply these properties to block-level elements in the normal flow of the root element" ('page-break-*')
+
+
+[Note: according to CSS21 9.3, the root element is out of flow.  Is this correct?  Surely it participates in the block formatting context established by the initial containing block.]
+
+
 
 ====== Spec Issues ======