minOpacity is actually minValue

[nhamer]

See attached screenshot, of simpleheat demo, with minOpacity set to 1

[nhamer]

PR adds an opacity slider to the demo - it's more correct in some sense, but it's not actually prettier, so the right fix might be just to rename minOpacity

[yannbriancon]

@tristangbn deployed a npm package with a fix https://www.npmjs.com/package/simpleheat-gradient-opacity.

In his package, the opacity depends on the colors in the gradient option. To have transparent data up to 0.4, you can use a gradient like the one below:

heat.gradient({
    0.4: 'transparent',
    0.65: 'lime',
    1: 'red'
})

[MajorSquirrelTVS]

Hi! Is it possible to take a look at @tristangbn work?