phpqrcode transparent background

问题

Is there a way to get the background of generated qr codes transparent when using phpqrcode?

I am generating a PNG to disk.

I found this but I think it is way outdated:

The line suggested in that forum is

ImageColorTransparent($target_image, $col);

however it is not clear to me where it should go, if it is even meant to work with this current version of the code.

<?php
/*
 * PHP QR Code encoder
 *
 * Image output of code using GD2
 *
 * PHP QR Code is distributed under LGPL 3
 * Copyright (C) 2010 Dominik Dzienia <deltalab at poczta dot fm>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

    define('QR_IMAGE', true);

    class QRimage {

    //----------------------------------------------------------------------
    public static function png($frame, $filename = false, $pixelPerPoint = 4, $outerFrame = 4,$saveandprint=FALSE) 
    {
        $image = self::image($frame, $pixelPerPoint, $outerFrame);

        if ($filename === false) {
            Header("Content-type: image/png");
            ImagePng($image);
        } else {
            if($saveandprint===TRUE){
                ImagePng($image, $filename);
                header("Content-type: image/png");
                ImagePng($image);
            }else{
                ImagePng($image, $filename);
            }
        }

        ImageDestroy($image);
    }

    //----------------------------------------------------------------------
    public static function jpg($frame, $filename = false, $pixelPerPoint = 8, $outerFrame = 4, $q = 85) 
    {
        $image = self::image($frame, $pixelPerPoint, $outerFrame);

        if ($filename === false) {
            Header("Content-type: image/jpeg");
            ImageJpeg($image, null, $q);
        } else {
            ImageJpeg($image, $filename, $q);            
        }

        ImageDestroy($image);
    }

    //----------------------------------------------------------------------
    private static function image($frame, $pixelPerPoint = 4, $outerFrame = 4) 
    {
        $h = count($frame);
        $w = strlen($frame[0]);

        $imgW = $w + 2*$outerFrame;
        $imgH = $h + 2*$outerFrame;

        $base_image =ImageCreate($imgW, $imgH);

        $col[0] = ImageColorAllocate($base_image,255,255,255);
        $col[1] = ImageColorAllocate($base_image,0,0,0);


        imagefill($base_image, 0, 0, $col[0]);

        for($y=0; $y<$h; $y++) {
            for($x=0; $x<$w; $x++) {
                if ($frame[$y][$x] == '1') {
                    ImageSetPixel($base_image,$x+$outerFrame,$y+$outerFrame,$col[1]); 
                }
            }
        }

        $target_image =ImageCreate($imgW * $pixelPerPoint, $imgH * $pixelPerPoint);
        ImageCopyResized($target_image, $base_image, 0, 0, 0, 0, $imgW * $pixelPerPoint, $imgH * $pixelPerPoint, $imgW, $imgH);
        ImageDestroy($base_image);

        return $target_image;
    }
    }

回答1:

in qrimage.php, insert the following line:

ImageColorTransparent($target_image, $col[0]);

as shown below:

That will result fix it for you.

ImageCopyResized($target_image, $base_image, 0, 0, 0, 0, $imgW * $pixelPerPoint, $imgH * $pixelPerPoint, $imgW, $imgH);
ImageColorTransparent($target_image, $col[0]);
ImageDestroy($base_image);

来源：https://stackoverflow.com/questions/17969645/phpqrcode-transparent-background