PHP: Can't get semitransparent overly over the image-CodePudding

I'm trying to darken the image with PHP. Have tried this code, but it doesn't work. Have searched all over the Net and can't find any working solution. Please help.

$img = imagecreatefromjpeg($imgage_path);
$size=getimagesize($imgage_path); 
$w=(int)$size[0]; 
$h=(int)$size[1]; 

$stamp = imagecreatetruecolor(100, 100);
$black = imagecolorallocate($stamp, 0, 0, 0);
imagefilledrectangle($stamp, 0, 0, $w, $h, $black);

imagecopymerge($img, $stamp, $w, $h, 0, 0, $w, $h, 50);

CodePudding user response：

Perhaps the following might help - there are 10 successive layers of the dark overlay applied ~ the opacity of the overlay remains constant but you will observe a definite darkening of the source image. Each layer and text is offset to show the effect clearer.

This is done by using imagecolorallocatealpha for the overlay

<?php

    $imgsrc='https://a.ltrbxd.com/resized/sm/upload/wi/cl/t4/l0/barbarella-1200-1200-675-675-crop-000000.jpg';
    $text='It\'s getting darker...';

    $img=imagecreatefromjpeg( $imgsrc );
    list( $w, $h, $t, $a )=getimagesize( $imgsrc );

    $opacity=99;
    $fontsize=15;
    
    $x=0;
    $y=0;
    $dx=50;
    $dy=50;
    
    
    $overlay = imagecolorallocatealpha( $img, 0, 0, 0, $opacity );
    $colour = imagecolorallocate( $img, 255, 255, 255 );
    $font = sprintf('%s/arial.ttf',__DIR__);
    
    
    # add layers of overlays to show the darkening effect
    for( $i=1; $i <= 10; $i  ){
        $x =$dx;
        $y =$dy;
        
        $text=$i > 2 ? 'and darker' : $text;
        $text=$i==10 ? 'and noticably darker now!' : $text;
        $msg=$i==1 ? 'Original' : $text;
        
        imagefilledrectangle( $img, $x, $y, $w, $h, $overlay );
        imagefttext( $img, $fontsize, 0, $x, $y - $fontsize, $colour, $font, sprintf( '[%d] %s', $i, $msg ) );
    }
    
    header('Content-Type: image/jpeg');
    imagejpeg($img);
    imagedestroy($img);
?>

CodePudding user response：

People at other site suggested me much simpler solution that works:

imagefilter($img, IMG_FILTER_BRIGHTNESS, -100);