Transparency and Turtle Shapes

[James Steiner]

When the color of a turtle is set to an RGBA color, not only does the "color that changes" become transparent, but ALL the individual drawing objects that make up the shape become individually transparent to the same degree.

While it is debatable whether making the entire shape transparent when the "color" property has transparency is a feature or a bug (seems like a feature to me),  I think it is less desirable for transparency to apply to individual drawing objects, rather than to the shape as a whole. While most shapes remain mostly intelligible, they certainly look weird. 

Ideally, the shape should be rendered opaquely, then the alpha value applied to the final rendered shape. I expect this may add a lot of complexity or time to the shape display, so it would also be perfectly fine to keep it as is, but perhaps this behavior could be documented in the latter part of the description of the COLOR primitive.

Of course, an author that intends to use transparent shapes can carefully craft shapes that work will with transparency as implemented.

~~James

www.turtlezero.com