Changes between Version 4 and Version 5 of img2twit Tweet

Timestamp:

05/22/2009 01:43:45 AM (16 years ago)

Author:

Sam Hocevar

Comment:

--

img2twit

@@ -45 +45 @@
 Whether to use a palette or to encode colour information into the picture elements is undecided yet. We'll cover both options.
 
-== Storing a palette ==
+== Strategy 1: colour information in picture elements ==
 
-''To do.''
+Each picture element will hold data for:
+ * coordinates
+ * colour information
+ * additional control information
+
+Coordinates could be absolute (therefore requiring 16 or 14 bits, maybe 12) or relative. I would favour a coordinate system relative to predefined image cells because there is a good chance that each cell will hold a point. Assuming at least 8 horizontal and vertical subdivisions, 6 bits can be gained this way. The final coordinate bit allocation is now 10, 8 or 6. We'll pick 8 to be safe for now: 16 X values and 16 Y values.
+
+Using 7 bits per colour allows for the following options:
+ * full bit range usage: 4 red values, 8 green values, 4 blue values
+ * almost full bit range usage: 5 red values, 5 green values, 5 blue values
+
+Finally, a weight value could be added, using a final bit.
+
+The proposed allocation is then 16, allowing 144 points to be stored in the following configurations:
+ * 12×12
+ * 10×14 (losing 4 points)
+ * 9×16
+ * 8×18
+ * 7×20 (losig 4 points)
+ * 6×24
 
 == Not storing a palette ==