/**
* Checks if the image is a logo, by checking if the outer pixels all have the same color
* This method returns true when:
* - The image is a png or gif
* - The colors of the outermost pixels are the same color
* @param string $path
* @return bool
*/
public static function IsLogo($path)
{
if (!file_exists($path)) {
return false;
}
try {
$info = getimagesize($path);
$img = null;
$transparent = false;
switch ($info[2]) {
case IMAGETYPE_GIF:
case IMAGETYPE_PNG:
$img = $info[2] == IMAGETYPE_GIF ? imagecreatefromgif($path) : imagecreatefrompng($path);
$rgba = imagecolorat($img, 0, 0);
$alpha = ($rgba & 0x7f000000) >> 24;
$transparent = $alpha == 127;
break;
case IMAGETYPE_JPEG:
case IMAGETYPE_JPEG2000:
$img = imagecreatefromjpeg($path);
break;
default:
// Unknown image type
throw new \Exception("invalid image");
}
$sameColor = 0;
$totalPixels = $info[0] * 2 + $info[1] * 2 - 4;
if ($transparent) {
// Image has transparency, logo for sure
return true;
} else {
$color = ColorUtils::dec2hex(imagecolorat($img, 0, 0));
// Check top and bottom line for color differences,
for ($x = 0; $x < $info[0]; $x++) {
if (ColorUtils::compareColors($color, ColorUtils::dec2hex(imagecolorat($img, $x, 0)), 10, $x, 0)) {
$sameColor++;
}
if (ColorUtils::compareColors($color, ColorUtils::dec2hex(imagecolorat($img, $x, $info[1] - 1)), 10, $x, $info[1] - 1)) {
$sameColor++;
}
}
// Check left and right line for color differences,
for ($y = 0; $y < $info[1]; $y++) {
if (ColorUtils::compareColors($color, ColorUtils::dec2hex(imagecolorat($img, 0, $y)), 10, 0, $y)) {
$sameColor++;
}
if (ColorUtils::compareColors($color, ColorUtils::dec2hex(imagecolorat($img, $info[0] - 1, $y)), 10, $info[0] - 1, $y)) {
$sameColor++;
}
}
}
imagedestroy($img);
// 90% of the outer pixels are the same color
return $sameColor / $totalPixels > 0.9;
} catch (\Exception $e) {
}
return false;
}
