<?php
namespace HeroQR\Customs;
use Endroid\QrCode\Color\ColorInterface;
/**
* Handles overlaying a cursor image on a background image
* Provides methods to save, output, or get the image as a Base64 string
*/
class ImageOverlay
{
private ?string $backgroundPath;
private ?string $overlayPath;
/**
* Constructor to initialize background and overlay paths
*/
public function __construct($background, $overlay)
{
$this->overlayPath = CursorPaths::getValueByKey($overlay);
$this->backgroundPath = MarkerPaths::getValueByKey($background);
}
/**
* Saves the generated image to the specified output path
*
* @param string $outputPath
* @param ColorInterface|null $overlayColor
* @return void
* @throws \Exception
*/
public function saveImage(string $outputPath, ?ColorInterface $overlayColor = null): void
{
$result = $this->createCenteredImage($overlayColor);
imagepng($result, $outputPath);
imagedestroy($result);
}
/**
* Returns the image as a base64-encoded URI
*
* @param ColorInterface|null $overlayColor
* @return string
* @throws \Exception
*/
public function getUriImage(?ColorInterface $overlayColor = null): string
{
return $this->getImageAsBase64(true, $overlayColor);
}
/**
* Returns the image as a string
*
* @param ColorInterface|null $overlayColor
* @return string
* @throws \Exception
*/
public function getImageAsString(?ColorInterface $overlayColor = null): string
{
return $this->getImageAsBase64(false, $overlayColor);
}
/**
* Returns the generated image as a GdImage instance
*
* @param ColorInterface|null $overlayColor
* @return \GdImage
* @throws \Exception
*/
public function getImage(?ColorInterface $overlayColor = null): \GdImage
{
return $this->createCenteredImage($overlayColor);
}
/**
* Outputs the image directly to the browser
*
* @param ColorInterface|null $overlayColor
* @return void
* @throws \Exception
*/
public function outputImage(?ColorInterface $overlayColor = null): void
{
$result = $this->createCenteredImage($overlayColor);
header('Content-Type: image/png');
imagepng($result);
imagedestroy($result);
}
/**
* Creates a centered image by overlaying one image on another
*/
private function createCenteredImage(?ColorInterface $color = null): \GdImage
{
$this->validatePaths();
$background = $this->createImageResource($this->backgroundPath);
$overlay = $this->createImageResource($this->overlayPath);
if ($color !== null) {
$background = $this->recolorImage($background, $color);
$overlay = $this->recolorImage($overlay, $color);
}
$bgWidth = imagesx($background);
$bgHeight = imagesy($background);
$overlayWidth = (int)(imagesx($overlay) / 3.1);
$overlayHeight = (int)(imagesy($overlay) / 3.1);
$x = (int)(($bgWidth - $overlayWidth) / 2);
$y = (int)(($bgHeight - $overlayHeight) / 2);
imagealphablending($background, true);
imagesavealpha($background, true);
imagecopyresampled(
$background, $overlay,
$x, $y, 0, 0,
$overlayWidth, $overlayHeight,
imagesx($overlay), imagesy($overlay)
);
imagedestroy($overlay);
return $background;
}
/**
* Helper method to generate base64 image output
*/
private function getImageAsBase64(bool $uri = true, ?ColorInterface $overlayColor = null): string
{
$image = $this->createCenteredImage($overlayColor);
ob_start();
imagepng($image);
$data = ob_get_clean();
imagedestroy($image);
return $uri ? 'data:image/png;base64,' . base64_encode($data) : $data;
}
/**
* Tints an image with a specific color while preserving transparency
*/
private function recolorImage(\GdImage $image, ColorInterface $color): \GdImage
{
[$width, $height] = [imagesx($image), imagesy($image)];
$tinted = imagecreatetruecolor($width, $height);
imagealphablending($tinted, false);
imagesavealpha($tinted, true);
$newColorIndex = imagecolorallocatealpha(
$tinted,
$color->getRed(),
$color->getGreen(),
$color->getBlue(),
$color->getAlpha()
);
$transparentColor = imagecolorallocatealpha($tinted, 0, 0, 0, 127);
for ($x = 0; $x < $width; $x++) {
for ($y = 0; $y < $height; $y++) {
$pixelIndex = imagecolorat($image, $x, $y);
$pixelColor = imagecolorsforindex($image, $pixelIndex);
if ($pixelColor['alpha'] < 127) {
imagesetpixel($tinted, $x, $y, $newColorIndex);
} else {
imagesetpixel($tinted, $x, $y, $transparentColor);
}
}
}
return $tinted;
}
/**
* Creates an image resource from a file path
*/
private function createImageResource(string $path): \GdImage
{
if (!file_exists($path)) {
throw new \Exception("File not found: {$path}");
}
$image = imagecreatefrompng($path);
if (!$image) {
throw new \Exception("Failed to load image from: {$path}");
}
imagealphablending($image, false);
imagesavealpha($image, true);
return $image;
}
/**
* Validates the paths for background and overlay
*
*/
private function validatePaths(): void
{
if (!file_exists($this->backgroundPath) || !file_exists($this->overlayPath)) {
throw new \Exception('Invalid file paths for background or overlay images.');
}
}
}
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