(x position) is more precise than in 2.0

[mrjacobbloom]

Expected Behavior

For perfect compatibility, (x position) should round to 8 decimal places

Actual Behavior

It looks like (x position) is rounding to 16 decimal places

Steps to Reproduce

https://llk.github.io/scratch-gui/develop/compatibility-testing.html#223591096

This project breaks in 3.0: https://llk.github.io/scratch-gui/develop/#117386152/

Operating System and Browser

MacOS 10.12.4, Chrome 66.0.3359.139 (64-bit)

[mrjacobbloom]

Note: I'm all for more precision in 3.0, but I thought I'd report the incompatibility

[mrjacobbloom]

There aren't a lot of great uses for fractional coordinates at all, I can only really think of one: pen transparency. This is less important now that pen colors can have alpha, and would only be useful for challenges like the one above. Either way, I don't think you need more than a digits or two of precision for that.

In fact, in many cases it's probably more confusing than beneficial to have fractional coordinates at all. Consider the following script:

the sprite will head toward the mouse pointer, but once it's reached the mouse the script won't terminate as expected because it's still a fractional distance away.

[MsBlockCat]

Maybe something could be mentioned in the help section for the coordinate blocks about using the round block to round the coordinates in the code?

[apple502j]

scratchfoundation/scratch-gui#1372

Similar problem

[thisandagain]

Wow. Great catch. Thanks @mrjacobbloom

[thisandagain]

I'm marking this as "help wanted". It should be fairly simple to resolve by looking at the block implementation.

[mrjacobbloom]

confirmed the project works correctly in the VM playground! 🙌