not sure if this has been reported before, or even if it's a bug at all:
When I was playing around with the 'set size to ___%' block and filled in '50' I noticed that Scratch changed the area of my sprite's costume actually not just to 50%, but to 25 % by reducing *both* x and y dimensions to 50 %.
I'm no math genius but I found this behavior rather confusing. Also, I think it misleads children using Scratch for 2D geometry projects into using and coming up with actually 'incorrect' formulas (at least as far as geometry conventions used in school are concerned).
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Size isn't an exact mathematical descriptive word like length, width and volume.
Much easier for Scratch writers to interpret it as changing x and y dimensions rather than trying to work out the volume or circumference of the object and changing that by the specified amount :-)
regards
Simon
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Simon, I understand the need to simplify the idea of scaling a 2D image by using just one argument (%) instead of both x and y dimensions. I would, however, expect Scratch to scale a sprite's bounding box (which is always a rectangle, even when the costume resembles something else), and to do so correctly. Consider e.g. growth models or scaling something as simple as a rectangular image. While size may not be a mathematically unique term I did understand it as the 'playfield real estate' covered by a sprite's costume.
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Scaling is traditionally by length, not by area or volume. I think that the Scratch team did the right thing here, both mathematically and intuitively for most users. (Sorry, Jens, but I think that your expectation that *area* would be scaled is not the most common expectation.)
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