Performance issue on ZendPdf\Resource\Image\Png with Alpha filter

[bastnic]

Hi,

I encounter very serious performance trouble with this file : https://github.com/zendframework/ZendPdf/blob/master/library/ZendPdf/Resource/Image/Png.php#L233

            case self::PNG_CHANNEL_RGB_ALPHA:
                /*
                 * To decode PNG's with alpha data we must create two images from one. One image will contain the RGB data
                 * the other will contain the Gray transparency overlay data. The former will become the object data and the latter
                 * will become the Shadow Mask (SMask).
                 */
[…]
                //Iterate every pixel and copy out rgb data and alpha channel (this will be slow)
                for($pixel = 0, $pixelcount = ($width * $height); $pixel < $pixelcount; $pixel++) {
                    $imageDataTmp .= $pngDataRawDecoded[($pixel*4)+0] . $pngDataRawDecoded[($pixel*4)+1] . $pngDataRawDecoded[($pixel*4)+2];
                    $smaskData .= $pngDataRawDecoded[($pixel*4)+3];
                }

I found two mentions on the great internet:

• http://framework.zend.com/issues/browse/ZF-3392
• https://github.com/psliwa/PHPPdf#known-limitations

In the first article there is a mention of parsers being recoded. 6 years later and no trace of that change. Is there any plan on this bug?

See ya. Thanks.