mRNA text jittering as ribosome makes mRNA

[ghost]

Test device:

MacBook Air (13-inch, Early 2015)

Operating System:

macOS Sierra Version 10.12.6 (16G29)

Browser:

Google Chrome Version 62.0.3202.75 (Official Build) (64-bit)

Problem description:

Somewhat difficult to reproduce, but the mRNA text will jitter as the ribosome makes mRNA. This only works if you attach the ribosome to the fairly quickly. I think this happens because the protein and the mRNA text overlap. This is for phetsims/QA#58.

Steps to reproduce:

1. Go to the third gene in the expression screen.
2. Attach positive transcription factors.
3. Attach polymerase.
4. Attach ribosome fairly quickly, but not too quickly. (You don't want #94 to occur.)

Screenshots:

Troubleshooting information (do not edit):

Name: ‪Gene Expression Essentials‬ URL: https://www.colorado.edu/physics/phet/dev/html/gene-expression-essentials/1.0.0-dev.13/gene-expression-essentials_en.html Version: 1.0.0-dev.13 2017-10-25 21:56:59 UTC Features missing: touch User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.75 Safari/537.36 Language: en-US Window: 1438x700 Pixel Ratio: 1/1 WebGL: WebGL 1.0 (OpenGL ES 2.0 Chromium) GLSL: WebGL GLSL ES 1.0 (OpenGL ES GLSL ES 1.0 Chromium) Vendor: WebKit (WebKit WebGL) Vertex: attribs: 16 varying: 15 uniform: 1024 Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 80) Max viewport: 16384x16384 OES_texture_float: true Dependencies JSON: {"assert":{"sha":"928741cf","branch":"master"},"axon":{"sha":"80b60293","branch":"master"},"babel":{"sha":"ce29f350","branch":"master"},"brand":{"sha":"cfca902d","branch":"master"},"chipper":{"sha":"6b338220","branch":"master"},"dot":{"sha":"85ef2bbf","branch":"master"},"gene-expression-essentials":{"sha":"a8b7efc7","branch":"master"},"joist":{"sha":"eb3a1951","branch":"master"},"kite":{"sha":"2c921cba","branch":"master"},"phet-core":{"sha":"c30d15ed","branch":"master"},"phetcommon":{"sha":"b13138d2","branch":"master"},"query-string-machine":{"sha":"c74e454e","branch":"master"},"scenery":{"sha":"92a2872d","branch":"master"},"scenery-phet":{"sha":"d394b9df","branch":"master"},"sherpa":{"sha":"0d590744","branch":"master"},"sun":{"sha":"99a0abef","branch":"master"},"tandem":{"sha":"c1e98f69","branch":"master"}}

[jbphet]

This problem is caused by the ribosome consuming the mRNA more rapidly that it is being produced, so its bounds end up changing radically while it is being synthesized. The bounds are used to position the caption, hence the jumpiness. This was addressed by https://github.com/phetsims/gene-expression-essentials/commit/ba4c80578664d112cad8863723e00fffcccfcb23, which as done for issue #94. I've tested after the update, and the motion isn't perfectly smooth, but it is much improved and is as good as it was in the Java version.

[jbphet]

Should be fixed, will unassign and have it verified on the next dev or RC release.

[brroberts1231]

For phetsims/QA#68 Seems improved for genes 2 and 3, but gene 1 now looks noticeably worse than the other two. Tested on Dirac, OS X 10.9.5, Safari

[ghost]

Tested on several devices/browsers. Seems to be fixed.