Same as PHP's imagecopymerge() function, except preserves alpha-transparency in 24-bit PNGs
| public static imageCopyMergeAlpha ( mixed $dstImg, mixed $srcImg, array $dist, array $src, array $srcSizes, integer $opacity ) | ||
| $dstImg | mixed | Dist image resource |
| $srcImg | mixed | Source image resource |
| $dist | array | Left and Top offset of dist |
| $src | array | Left and Top offset of source |
| $srcSizes | array | Width and Height of source |
| $opacity | integer | |
/**
* Changes the opacity level of the image
*
* @param resource $image Image GD resource
* @param float|int $opacity 0-1 or 0-100
*
* @return mixed
*/
public static function opacity($image, $opacity)
{
// Determine opacity
$opacity = Helper::opacity($opacity);
$width = imagesx($image);
$height = imagesy($image);
$newImage = imagecreatetruecolor($width, $height);
// Set a White & Transparent Background Color
$bg = imagecolorallocatealpha($newImage, 0, 0, 0, 127);
imagefill($newImage, 0, 0, $bg);
// Copy and merge
Helper::imageCopyMergeAlpha($newImage, $image, array(0, 0), array(0, 0), array($width, $height), $opacity);
imagedestroy($image);
return $newImage;
}
/**
* Overlay an image on top of another, works with 24-bit PNG alpha-transparency
*
* @param string|Image $overlay An image filename or a Image object
* @param string $position center|top|left|bottom|right|top left|top right|bottom left|bottom right
* @param float|int $opacity Overlay opacity 0-1 or 0-100
* @param int $globOffsetX Horizontal offset in pixels
* @param int $globOffsetY Vertical offset in pixels
*
* @return $this
* @throws Exception
*/
public function overlay($overlay, $position = 'bottom right', $opacity = 0.4, $globOffsetX = 0, $globOffsetY = 0)
{
// Load overlay image
if (!$overlay instanceof self) {
$overlay = new self($overlay);
}
// Convert opacity
$opacity = Helper::opacity($opacity);
$globOffsetX = VarFilter::int($globOffsetX);
$globOffsetY = VarFilter::int($globOffsetY);
// Determine position
list($xOffset, $yOffset) = Helper::getInnerCoords($position, array($this->_width, $this->_height), array($overlay->getWidth(), $overlay->getHeight()), array($globOffsetX, $globOffsetY));
// Perform the overlay
Helper::imageCopyMergeAlpha($this->_image, $overlay->getImage(), array($xOffset, $yOffset), array(0, 0), array($overlay->getWidth(), $overlay->getHeight()), $opacity);
return $this;
}
