Overlay blend mode

[njsmith]

No time to put together a PR just now (I need to check out of this hotel!) but while skimming colors.py I just noticed:

        blend_mode : {'hsv', 'overlay', 'soft'} or callable, optional
            The type of blending used to combine the colormapped data values
            with the illumination intensity.  For backwards compatibility, this
            defaults to "hsv". Note that for most topographic surfaces,
            "overlay" or "soft" appear more visually realistic. If a

Sounds like a good candidate for a 2.0 change to me. AFAIK the HSV space is never the best option for pretty much anything :-).

[WeatherGod]

We would need to make that controlable via rcparams for 1.5.

On Wed, Jul 15, 2015 at 11:59 AM, Nathaniel J. Smith <
notifications@github.com> wrote:

No time to put together a PR just now (I need to check out of this hotel!)
but while skimming colors.py I just noticed:

    blend_mode : {'hsv', 'overlay', 'soft'} or callable, optional
        The type of blending used to combine the colormapped data values
        with the illumination intensity.  For backwards compatibility, this
        defaults to "hsv". Note that for most topographic surfaces,
        "overlay" or "soft" appear more visually realistic. If a

Sounds like a good candidate for a 2.0 change to me. AFAIK the HSV space
is never the best option for pretty much anything :-).

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#4700.

[jenshnielsen]

The new overlay modes were AFAIK introduced by @joferkington but are yet not in a release. Usually we wait a bit before chancing the default. It we change this we should make it an rcparam for 1.5 and add a warning that the default will change.

[WeatherGod]

We don't even really need a warning. It would be a part of the 2.0 style
changes. We just need to make sure we get the rcparam in for 1.5 so that
there is no new code for 2.0, just config changes.

On Wed, Jul 15, 2015 at 7:15 PM, Jens Hedegaard Nielsen <
notifications@github.com> wrote:

The new overlay modes were AFAIK introduced by @joferkington
https://github.com/joferkington but are yet not in a release. Usually
we wait a bit before chancing the default. It we change this we should make
it an rcparam for 1.5 and add a warning that the default will change.

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#4700 (comment)
.

[mdboom]

Which of 'overlay' or 'soft' would be the best default?

[joferkington]

"overlay" is a better default than "soft", i.m.o.

I've never seen a surface where overlay blending the hillshade looks terribly bad. Sometimes it's less than ideal, but it's never awful. By contrast, soft light blending hillshades can yield a result that's almost unnoticeable in many cases.

From a purely qualitative standpoint, "soft" blending (which is Pegtop soft light blending, by the way) provides a very subtle hillshade effect. It's too subtle for "smooth" surfaces. "overlay" essentially gives more contrast to the hillshade effect.

Just my $0.02, at any rate.