ooo-build r14871 - trunk/doc

[michael svn gnome org]

Author: michael
Date: Tue Dec 16 13:40:17 2008
New Revision: 14871
URL: http://svn.gnome.org/viewvc/ooo-build?rev=14871&view=rev

Log:
more work


Modified:
   trunk/doc/sw.txt

Modified: trunk/doc/sw.txt
==============================================================================
--- trunk/doc/sw.txt	(original)
+++ trunk/doc/sw.txt	Tue Dec 16 13:40:17 2008
@@ -1,4 +1,5 @@
-How to understand the writer core:
+*** How to understand the writer core ***
+
 
 * What does a document look like ?
 
@@ -40,7 +41,7 @@
 		+ inserts tripples : this automatically merges sub-'Hints'
 
 
--------------------------- problems --------------------------
+-------------------------- more detail --------------------------
 
 * 65k - for para length.
 	+ problems with line breaks. <shift>Enter
@@ -89,22 +90,181 @@
 		+ this stores pointers to the underlying paragraphs
 		  for rows / columns.
 
-	+ 
-
-
-
-* Red-lining ...
-	+ have a copy of the document; 
-		+ the problem - splitting paragraphs; track that we split
-		  a paragraph
-		+ 
+	+ cell merging, vert / horiz now possible;
+		+ previously - you could split cells
+			+ but couldn't display every table from merge model.
+			+ "Table too complex" / export same problem.
+			+ need to know widths of rows to do this export.
+	+ the merge thing is now implemented;
+		+ only impl. for ODF; not yet in the doc import/export.
+		+ CWS not yet complete.
+			+ all the old documents still have this model.
+			+ can mix models.
+
+	+ no real red-lining support for tables:
+		+ was there a row deleted / cell inserted ?
+		+ serious problem +
+
+
+* SwPaM (point and mark) (inc/pam.hxx)
+	+ can be a selection, or a cursor position.
+	+ most famous: "insert-unicode character"
+		+ used in import filters:
+			+ as if you type it in.
+
+
+
+Q. why can't we skip nodes in layout ?
+	+ how hard-coded is all that ? - just a flat piece-table like
+	  representation etc. ?
+
+
+-------------------------- layout --------------------------
+
+* Everything in layout is measured in TWIPS
+	+ 1440 twip/inch. or 567 / cm.  [ cumul error ? ]
+		+ so ~250k page limit.
+	+ DPI neceessary to do layout; used to use printer
+	  resolution; re-layout with a different printer.
+	+ nowadays - layout is done at:
+		+ 8640 DPI (usually) used for fonts.
+		+ then convert to TWIPS & loose resolution.
+	+ using device-independaent layout;
+		+ metrics & char widths used from high res,
+		+ looses lots of fidelity / wastes the work
+		  of the artists, doing lower-res tweaking.
+
+* Everything derived from SwFrm
+	+ source/core/inc/frame.hxx
+		+ (SwRectFnCollection)
+	+ class SwFrm:
+		SwRect aFrm; - absolute document position
+		SwRect aPrt; - same rectangle relative to parent
+	+ SwRect (long X,Y,Width,Height)
+	+ 'SwRootFrame' (source/core/inc/rootfrm.hxx)
+		+ children of that - are pages.
+		+ 5000 pages; 
+
+	+ Root frame
+		+ Page Frame
+			+ Header
+			+ Body
+				+ Paragraph |
+				+ Table frame |
+				+ Column frame
+			+ Footer 
+
+	* first time you want to do layout:
+		+ create a root frame, call "make all"
+			+ called recusively in a timer loop,
+			  every <N> milliseconds.
+			+ creates all the children ?
+		+ walk tree / is there a difference ?
+			+ insert a new para or not.
+			+ lots of difference detection.
+
+	* every few ms - layout calls 'make all'
+
+	* create an SwDoc, insert a new character; trigger make all
+		+ run through whole tree
+			- try to skip as much as possible
+		+ modify the current layout.
+		+ OLPC - has issues; open a writer document
+			+ don't do anything - watch battery go down
+			+ idle loop, kicks in regularly.
+
+	* Beware while debugging:
+		+ if you 'continue' - can come back into breakpoints
+		  via the timer ... / makes life hard.
+
+	* layout loops / debugging:
+		+ nightmares with absolute positioned objects
+			+ Paragraph lays itself out; places an object
+			  somewhere, starts to re-layout.
+			+ no single control loop,
+				+ any object can ping - (ie. force relayout)
+				  of any other object.
+
+	* frame.hxx (ShrinkFrm, GrowFrm) - called lots
+		+ eg. footnote example, push footnote off - ShrinkFrm
+		  pushes para to next page, 
+		+ previous page - GrowFrm - to fit next next para.
+
+	* Layout loops - 10 man year a hole, trying to understand the issues
+
+	* Loop free layout:
+		* an example:
+			+ source/core/layout/calcmove.cxx (SwCntntFrm::MakeAll)
+			+ #define STOP_FLY_FORMAT 10
+			+ eg.:
+// --> OD 2006-09-25 #b6448963# - loop prevention
+const int cnStopFormat = 15;
+// <--
+            // --> OD 2006-01-23 #i59341#
+            // Workaround for inadequate layout algorithm:
+            // suppress invalidation and calculation of position, if paragraph
+            // has formatted itself at least STOP_FLY_FORMAT times and
+            // has anchored objects.
+            // Thus, the anchored objects get the possibility to format itself
+            // and this probably solve the layout loop.
+
+		* 'StackHack' - is a framek already invalidated [etc.]
+			+ try not to re-invalidate it.
+			+ does loop detection
+
+		* improvement - hit pause in the debugger, add a loop
+		  catch repeat.
+
+	* Macros to detect it:
+
+    // NEW: Looping Louie (Light). Should not be applied in balanced sections.
+    // Should only be applied if there is no better solution!
+    LOOPING_LOUIE_LIGHT( bMovedFwd && bMovedBwd && !IsInBalancedSection() &&
+
+	* The MS layout algorithm is -much- simpler.
+		+ lots of features, this layout supports, we don't need to
+		  be interoperable.
+		+ the answer - throw away stuff.
+
+
+
+-------------------------- misc --------------------------
+
+* most functions - designed to respond to user input.
+
+* the legacy Word import filter:
+	+ fills out internal structures, etc.
+
+* Import issues:
+	+ Doc import currently:
+		+ type text in, go back, create selection,
+		  apply attributes etc.
+		+ as if you would type it.
+	+ UNO API: wrapper around SwDoc, again as if you were typing.
+		+ can't front-load attributes as we push them.
+		+ InsertAttr -> import filters; append attributes.
+		+ extra space & empty para at the end.
+			+ clean new style info.
+			+ new 'Filter' API ...
+	+ lots of additional tricks to overcome these problems.
+		+ consider the issues +
+		+ "<b>Hello</b>\nWorld"
+			+ as you type 'World' it becomes bold, so you
+			  have to overcome this by misc. evil. tricks.
+	+ as you debug import:
+		+ see lots of additional spaces / paras being inserted
+		  and subsequently removed ...
+			+ someone forgot to cleanup artificial paragraph.
+
+* MS do things differently
+	+ piece-table, formatting codes etc.
+	+ OTOH - word can't do nested sections (yet)
+		+ entirely different concepts +
+		+ word section - more like a "Master Page" / "Page style"
+			+ except for 1 thing:
+			+ Word sections, can be balanced.
 
 
--------------------------- problems --------------------------
 
 
 
-		+ BigPtrArray
-			+ 'SwNode' / 'SwDoc'
-			+ sw/inc/node.hxx -> sw/source/core/docnode/node.cxx
-			+ sw/inc/doc.hxx ->