Get the index of the color of a pixel
Syntax
imagecolorat(
GdImage $image,
int $x,
int $y
): int|falseParameters
imageA GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().
xx-coordinate of the point.
yy-coordinate of the point.
Return
Returns the index of the color or false on failure.
Warning: This function may return Boolean false, but may also return a non-Boolean value which evaluates to false. Use the === operator for testing the return value of this function.
Examples
1 · return
<? $width = 100; $height = 100; $image = imagecreatetruecolor($width, $height); $x = 0; $y = 0; $return = imagecolorat($image, $x, $y); var_export($return); ?>
0
2 · >>
<? $width = 100; $height = 100; $image = imagecreatetruecolor($width, $height); $red = 255; $green = 128; $blue = 0; $alpha = 64; $background = imagecolorallocatealpha($image, $red, $green, $blue, $alpha); $x = 0; $y = 0; imagefill($image, $x, $y, $background); $x = 0; $y = 0; $color = imagecolorat($image, $x, $y); $r = 0xff & ($color >> 16); $g = 0xff & ($color >> 8); $b = 0xff & $color; $a = 0xff & ($color >> 24); var_dump($r, $g, $b, $a); ?>
int(255) int(128) int(0) int(64)
