resource usage line chart categorical colors insufficiently contrasty

[Eoghan Glynn]

The line charts use d3.scale.category20() to allocate colors to the per-tenant trend lines.

However these colors are arranged in alternating dark-light pairs (darker blue, lighter blue, darker orange, lighter orange, ...):

  https://github.com/mbostock/d3/wiki/Ordinal-Scales#wiki-category20

The result is that as new tenants are created, the color rendered for every second new tenant is hard to distinguish visually from the previous one.

The resource usage panel should instead either use the narrower but more contrasty d3.scale.category10():

  https://github.com/mbostock/d3/wiki/Ordinal-Scales#wiki-category10

or else construct it's own wider and more contrasty ordinal scale.

[Ladislav Smola (lsmola)]

agree

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/54890

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/54890
Committed: http://github.com/openstack/horizon/commit/59266cba1953d51b4eca80560c8d1568b1d8dd14
Submitter: Jenkins
Branch: master

commit 59266cba1953d51b4eca80560c8d1568b1d8dd14
Author: sayalilunkad <email address hidden>
Date: Fri Nov 1 14:31:28 2013 +0530

    Presents color contrast in resource usage charts

    This makes use of d3.scale.category10() to allocate colors to per tenant
    trend lines as opposed to d3.scale.category20().
    This makes it easy to distinguish the color rendered for each new tenant as
    d3.scale.category10() is a more contrasty.

    Closes-Bug: #1243747

    Change-Id: I6ac2bcd4fa831944dfb10944eb620d333e1f3644