[Gzz-commits] alph/doc alph.rst

[Tuomas J. Lukka]

CVSROOT:        /cvsroot/alph
Module name:    alph
Changes by:     Tuomas J. Lukka <address@hidden>        03/05/26 04:26:52

Modified files:
        doc            : alph.rst 

Log message:
        more

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/alph/alph/doc/alph.rst.diff?tr1=1.1&tr2=1.2&r1=text&r2=text

Patches:
Index: alph/doc/alph.rst
diff -u alph/doc/alph.rst:1.1 alph/doc/alph.rst:1.2
--- alph/doc/alph.rst:1.1       Mon May 26 04:06:16 2003
+++ alph/doc/alph.rst   Mon May 26 04:26:52 2003
@@ -5,9 +5,17 @@
 Alph is an implementation of xanalogical hypertext (see e.g. Nelson's
 writings). The fundamental point in xanalogical hypertext is that
 each smallest unit of media has a unique identity.
-Alph does not use the tumbler model in previous implementations,
-but is rather based on *scrollblocks* - fixed units
-of fluid media. This allows Alph to exist on top of Storm.
+
+Spans and Media types
+=====================
+
+The most user-visible objects in Alph are spans. A span
+is a contiguous block of permanent media, e.g. "the 5 characters
+'xyahb' typed on 5 May 2003 by Janne V. Kujala" or 
+"the 23x12 block of pixels in a particular photo snapshot of a custom
+controller built from lego bricks by Asko Soukka".
+Spans are operated on much as any immutable media objects,
+like Java's own ``String``s.
 
 The media types handled by Alph are
 
@@ -82,4 +90,56 @@
 Note: Spans are immutable objects - the ``append()`` method returns
 a new span, if the the object and the parameter were consecutive
 in the right order.
+
+Manipulating text: Enfilades, Span makers
+=========================================
+
+
+Scrollblocks
+============
+
+Alph does not use the tumbler model in previous implementations,
+but is rather based on *scrollblocks* - fixed units
+of fluid media. This allows Alph to exist on top of Storm.
+
+Each span can contain media only inside one scrollblock:
+
+..  UML:: alph_scrollblock
+
+    class Span "interface"
+
+    class ScrollBlock
+       assoc multi(1) - multi(*) Span
+       methods
+           String getContentType()
+           Span getCurrent()
+           boolean isMutable()
+           String getID()
+           Object getBlockId()
+           
+
+
+
+The scrollblock model assumes that given a span it is possible
+to access all the fluid media units inside the same block.
+However, this is not always true:
+there are some span types that do not have a real scroll block - 
+``FakeTextSpan`` and ``URN5TextSpan``.
+
+
+Access to the original media: block files
+=========================================
+
+Alph does not currently provide access methods
+for data in images and pagespans. This is because the 
+programs may use their own methods for accessing these -
+e.g. Fenfire uses either Java AWT *or* the Libvob OpenGL 
+system implemented in C++. Forcing access using AWT images
+would make things inefficient for the OpenGL system.
+
+Because of this, Alph provides direct access to the underlying
+block:
+
+
+