[plt-scheme] 2htdp/image

From: Stephen Bloch (sbloch at adelphi.edu)
Date: Mon Jan 11 15:45:06 EST 2010

On Jan 11, 2010, at 3:28 PM, Matthias Felleisen wrote:

> We are still in the experimentation stage with 2htdp/image and its use in conjunction with 2htdp/universe. I do not expect this combination to stabilize before August. -- Matthias

Ouch.  Well, I'll deal with it.  I guess this means using universe with htdp/image, which means I have to talk about scenes vs. pictures.

Here's a quick fix that would make things easier until 2htdp/image is ready: could we redefine "scene" from "image whose pinhole must be at (0,0)" to "image which is treated as though its pinhole were at (0,0)"?  For example, "place-image" would ignore the pinhole in its background argument, and draw-handlers would be allowed to return any picture, without worrying about its pinhole.  This wouldn't break any existing legal world or universe programs, but would allow us to teach animations without talking about pinholes (which are going away shortly anyway).

This is what sb-world has done for at least a year.

Stephen Bloch
sbloch at adelphi.edu

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