Sunday 23 June 2002

categories: Computationally Minded

I am trying to figure out how to set up a Smalltalk infinite Form. Not an InfiniteForm, which is a sibling class (inherits from DisplayMedium as well), but which fills up an entire field with a single Form repeated over and over, but a Form of inifinite extent. I need a Form that can expand on demand and yet keep a small memory footprint. I figure something along the lines of a sparse matrix, with empty Points not being represented. Perhaps a Form with an on-demand Bitmap, that expands whenever a Point is accessed outside the current bounds? But allocating a bigger Bitmap on each bounds miss will probably cause a performance hit :.). How about a collection of smaller Bitmaps that are already allocated and are assigned a particular offset when needed, then, when time permits, are rolled into a larger Bitmap? Or when called to BitBlt, perhaps alter the message to BitBlt every used Bitmap—that is, use the Composite design pattern? 8:38:41 PM    comment []