Do some cleanup; now we pass a struct with the layout algorithm's state

1998-10-08  Federico Mena Quintero  <federico@nuclecu.unam.mx>

	* layout.c: Do some cleanup; now we pass a struct with the layout
	algorithm's state instead of passing a trillion parameters around.

	* gncal-full-day.c (layout_children): Use the new generic layout
	engine.
	(child_compare): Sort keys are start time then end time, not just
	start time.  This produces somewhat nicer results for the layout
	algorithm.

	The new layout code uses a partition of the time range occupied by
	the events, rather than using a fixed time granularity.  This is
	better since the different parts of the program that use the
	layout module will have different semantics regarding snapping the
	event bounds to a fixed "time grid".

svn path=/trunk/; revision=434

1 files changed, 16 insertions, 4 deletions

diff --git a/calendar/layout.h b/calendar/layout.h
index b87cf7e36b..734b720b8b 100644
--- a/calendar/layout.h
+++ b/calendar/layout.h
@@ -9,17 +9,29 @@
 #ifndef LAYOUT_H
 #define LAYOUT_H
 
-#include "calendar.h"
+#include <glib.h>
+#include <time.h>
 
 
-/* This is the main layout function for overlapping events.  You pass in a list of CalendarObject
- * structures and it will calculate a nice non-overlapping layout for them.
+/* Functions of this type must translate the list item into two time_t values for the start and end
+ * of an event.
+ */
+typedef void (* LayoutQueryTimeFunc) (GList *event, time_t *start, time_t *end);
+
+
+/* This is the main layout function for overlapping events.  You pass in a list of (presumably)
+ * events and a function that should take a list element and return the start and end times for the
+ * event corresponding to that list element.
  *
  * It returns the number of slots ("columns") that you need to take into account when actually
  * painting the events, the array of the first slot index that each event occupies, and the array of
  * number of slots that each event occupies.  You have to free both arrays.
+ *
+ * You will get somewhat better-looking results if the list of events is sorted by using the start
+ * time as the primary sort key and the end time as the secondary sort key -- so that "longer"
+ * events go first in the list.
  */
-void layout_events (GList *events, int *num_slots, int **allocations, int **slots);
+void layout_events (GList *events, LayoutQueryTimeFunc func, int *num_slots, int **allocations, int **slots);
 
 
 #endif