如何在QRCode图像中添加透明徽标

Question

这是我必须使用的代码：

    // Start DRAWING LOGO IN QRCODE

    $QR = imagecreatefrompng($filepath);

    // START TO DRAW THE IMAGE ON THE QR CODE
    $logo = imagecreatefromstring(file_get_contents($logopath));

    imagecolortransparent($logo , imagecolorallocatealpha($logo , 0, 0, 0, 127));
    imagealphablending($logo , false);
    imagesavealpha($logo , true);

    $QR_width = imagesx($QR);
    $QR_height = imagesy($QR);

    $logo_width = imagesx($logo);
    $logo_height = imagesy($logo);

    // Scale logo to fit in the QR Code
    $logo_qr_width = $QR_width/3;
    $scale = $logo_width/$logo_qr_width;
    $logo_qr_height = $logo_height/$scale;

    imagecopyresampled($QR, $logo, $QR_width/3, $QR_height/3, 0, 0, $logo_qr_width, $logo_qr_height, $logo_width, $logo_height);

    // Save QR code again, but with logo on it
    imagepng($QR,$filepath);

在QRCode图像的中心添加了徽标，但是透明区域填充了白色。

任何人都可以检查并更新给我。

Answer 1

我对问题采取了稍微不同的方法，之前曾遇到过一两次问题。下面将创建一个新的透明PNG图像，在其上添加QR码和徽标。

<?php


    /* 
        to output directly to the browser set as false,
        to save set as true
    */
    $save=false;

    $filepath='c:/wwwroot/images/qrcodes/4e9550be3c5ce4649ef00a70c9d6fb92bda09752.png';
    $logopath='c:/wwwroot/images/ict_cmyk_jigsaw_1.png';


    $source = imagecreatefrompng( $filepath );  # QR-Code
    $logo = imagecreatefrompng( $logopath );    # Overlay

    $sw = intval( imagesx( $source ) );
    $sh = intval( imagesy( $source ) );
    $lw = intval( imagesx( $logo ) );
    $lh = intval( imagesy( $logo ) );




    /* Create a new image onto which we will copy images & assign transparency */
    $target = imagecreatetruecolor( $sw, $sh );
    imagesavealpha( $target , true );

    /* common divisor for overlay image size calculations */
    $divisor = 3;

    /* image size calculations */
    $clw = $sw / $divisor;      #   calculated width
    $scale = $lw / $clw;        #   calculated ratio
    $clh = $lh / $scale;        #   calculated height



    /* allocate a transparent colour for the new image */
    $transparent = imagecolorallocatealpha( $target, 0, 0, 0, 127 );
    imagefill( $target,0, 0, $transparent );



    /* copy the QR-Code to the new image */
    imagecopy( $target, $source, 0, 0, 0, 0, $sw, $sh );

    /* Determine position of overlay image using divisor */
    $px=$sw/$divisor;
    $py=$sh/$divisor;

    /* add the overlay */
    imagecopyresampled( $target, $logo, $px, $py, 0, 0, $clw, $clh, $lw, $lh );



    /* output or save image */
    header( 'Content-Type: image/png' );
    imagepng( $target, $save ? $filepath : null );



    /* clean up */
    imagedestroy( $target );
    imagedestroy( $source );
    imagedestroy( $logo );
?>

原始QR码

源透明徽标

结果