\b On platforms such as MacOS X and PalmOS, which build all the
puzzles into a single monolithic binary, the game structure in each
back end must have a different name, and there's a helper module
-\c{list.c} which contains a complete list of those game structures.
+\c{list.c} (constructed automatically by the same Perl script that
+builds the \cw{Makefile}s) which contains a complete list of those
+game structures.
On the latter type of platform, source files may assume that the
preprocessor symbol \c{COMBINED} has been defined. Thus, the usual
each game. On the rare occasion that animated solve moves are
actually required, you can set this flag.
+\dt \cw{REQUIRE_RBUTTON}
+
+\dd This flag indicates that the puzzle cannot be usefully played
+without the use of mouse buttons other than the left one. On some
+PDA platforms, this flag is used by the front end to enable
+right-button emulation through an appropriate gesture. Note that a
+puzzle is not required to set this just because it \e{uses} the
+right button, but only if its use of the right button is critical to
+playing the game. (Slant, for example, uses the right button to
+cycle through the three square states in the opposite order from the
+left button, and hence can manage fine without it.)
+
+\dt \cw{REQUIRE_NUMPAD}
+
+\dd This flag indicates that the puzzle cannot be usefully played
+without the use of number-key input. On some PDA platforms it causes
+an emulated number pad to appear on the screen. Similarly to
+\cw{REQUIRE_RBUTTON}, a puzzle need not specify this simply if its
+use of the number keys is not critical.
+
\H{backend-initiative} Things a back end may do on its own initiative
This section describes a couple of things that a back end may choose
\c void (*draw_update)(void *handle, int x, int y, int w, int h);
-This function behaves exactly like the back end \cw{draw_text()}
-function; see \k{drawing-draw-text}.
+This function behaves exactly like the back end \cw{draw_update()}
+function; see \k{drawing-draw-update}.
An implementation of this API which only supports printing is
permitted to define this function pointer to be \cw{NULL} rather
Similarly, \c{ym} and \c{yc} specify the vertical position of the
puzzle as a function of the page height: the page height times
-\c{xm}, plus \c{xc} millimetres, equals the desired distance from
+\c{ym}, plus \c{yc} millimetres, equals the desired distance from
the top of the page to the top of the puzzle.
(This unwieldy mechanism is required because not all printing
\c extern const int gamecount;
\c{gamelist} will be an array of \c{gamecount} game structures,
-declared in the source module \c{list.c}. The application should
-search that array for the game it wants, probably by reaching into
-each game structure and looking at its \c{name} field.
+declared in the automatically constructed source module \c{list.c}.
+The application should search that array for the game it wants,
+probably by reaching into each game structure and looking at its
+\c{name} field.
}