Bug. Warning: max(): Array must contain at least one element

[Ne-Lexa]

An array of colors can be empty when there are no colors in the image.
In the function max and min, you can not pass an empty array, otherwise the function will return false and throw warning.

Stacktrace:

Warning: max(): Array must contain at least one element

Exception trace:
 () at vendor/marijnvdwerf/material-palette/src/ColorCutQuantizer.php:101
 marijnvdwerf\palette\Vbox->getVolume() at vendor/marijnvdwerf/material-palette/src/ColorCutQuantizer.php:39
 marijnvdwerf\palette\ColorCutQuantizer->quantize() at vendor/marijnvdwerf/material-palette/src/PaletteGenerator.php:47
 marijnvdwerf\palette\PaletteGenerator->generate() at vendor/marijnvdwerf/material-palette/src/Palette.php:59

Sample code

$manager = new ImageManager();
$image = $manager->make('filename');
$palette = Palette::generate($image);
$palette->getVibrantSwatch()->getColor();

Problem image

[on2]

I've taken a look at this and I can only replicate the error when using the problem image. If I try to recreate the image the recreated image works fine. I note as well that I couldn't load the problem image in MacOS's Preview application so I'm thinking it might be the image at fault.

That said, the findSplitPoint() method in the ColorCutQuantizer class returns 0 for this image at some point during the processing:

material-palette-php/src/ColorCutQuantizer.php

Lines 121 to 137 in 7c937f0

	private function findSplitPoint()
	{
	$longestDimension = $this->getLongestColorDimension();
	usort($this->swatches, self::sortSwatchesByComponent($longestDimension));
	$dimensionMidpoint = $this->midPoint($longestDimension);
	for ($i = 0; $i < count($this->swatches); $i++) {
	$swatch = $this->swatches[$i];
	if ($swatch->getColor()->asRGBColor()->$longestDimension >= $dimensionMidpoint) {
	return $i;
	}
	}
	return 0;
	}

When Vbox::split() is called later the first section contains no swatches which causes the error as the array is empty.