jpg文件上的php gd image png watermark会产生奇怪的结果

Question

Trying to add a transparent PNG watermark to jpg images get's me different results either if i'm on localhost or production server.

Here's the results...

On my localhost (PHP Version 5.6.24)

On production server (PHP Version 5.5.9-1ubuntu4.21)

I don't even know what to call this problem of the blue color turning pink and the logo doesn't get correctly rendered...

The code is this:

function getBrightness($gdHandle) {
$width = imagesx($gdHandle);
$height = imagesy($gdHandle);

$totalBrightness = 0;

for ($x = 0; $x < $width; $x++) {
    for ($y = 0; $y < $height; $y++) {
        $rgb = imagecolorat($gdHandle, $x, $y);

        $red = ($rgb >> 16) & 0xFF;
        $green = ($rgb >> 8) & 0xFF;
        $blue = $rgb & 0xFF;

        $totalBrightness += (max($red, $green, $blue) + min($red, $green, $blue)) / 2;
    }
}

  //  imagedestroy($gdHandle);

return ($totalBrightness / ($width * $height)) / 2.55;
}

function render_text_on_gd_image(&$source_gd_image, $text, $font, $size, $color, $opacity, $rotation, $bpx, $bpy, $wnewx) {

$source_width = imagesx($source_gd_image);
$source_height = imagesy($source_gd_image);
$bb = imagettfbbox($size, $rotation, $font, $text);
$x0 = min($bb[0], $bb[2], $bb[4], $bb[6]);
$x1 = max($bb[0], $bb[2], $bb[4], $bb[6]);
$y0 = min($bb[1], $bb[3], $bb[5], $bb[7]);
$y1 = max($bb[1], $bb[3], $bb[5], $bb[7]);
$bb_width = abs($x1 - $x0);
$bb_height = abs($y1 - $y0);

$alpha_color = imagecolorallocatealpha(
    $source_gd_image,
    hexdec(substr($color, 0, 2)),
    hexdec(substr($color, 2, 2)),
    hexdec(substr($color, 4, 2)),
    127 * (100 - $opacity) / 100
);
return imagettftext($source_gd_image, $size, $rotation, $bpx + $wnewx/2 - $bb_width/2 , $bpy, $alpha_color, $font, $text);
}


$val = array();

//$val["displayName"] = "Administrador";
$val["displayName"] = "Afonso Ferreira Gomes";

$val["relFile"] = "imagem.jpg";

list($val["width_original"], $val["height_original"]) = getimagesize($val["relFile"]);

if ($val["width_original"] > $val["height_original"] && $val["width_original"] >= 1200) {

    $val["height_resized"] = $val["height_original"] * (1200/$val["width_original"]);
    $val["width_resized"]  = 1200;

}  elseif ($val["height_original"] > $val["width_original"] && $val["height_original"] >= 1200) {

    $val["height_resized"] = 1200;
    $val["width_resized"]  = (1200/$val["height_original"]) * $val["width_original"];

} else {

    $val["height_resized"] = $val["height_original"];
    $val["width_resized"]  = $val["width_original"];

}

$i = imagecreatefromjpeg($val["relFile"]);

$i = imagescale($i, $val["width_resized"], $val["height_resized"]);

$val["width_new"] = imagesx($i);

$val["height_new"] = imagesy($i);


if ($val["width_new"] < $val["height_new"]) {

    $val["portait"] = true;
    $val["smallest"] = $val["width_new"];

} else {

    $val["portait"] = false;
    $val["smallest"] = $val["height_new"];

}


/* GERAR WATERMARK LOGOTIPO */
$val["racio"] = 0.20;
$val["marLeft"] = 40;
$val["marBottom"] = 40;
$val["bright"] = getBrightness($i);


if ($val["bright"] < 30) {

    $val["opacidade"] = 20;

} else {

    $val["opacidade"] = 40;

}

$w = imagecreatefrompng("jbw_260_40.png");

if ($val["portait"]) {

    $val["water_width"] = $val["width_new"] * $val["racio"];
    $val["water_height"] = $val["width_new"] * $val["racio"];

} else {

    $val["water_width"] = $val["height_new"] * $val["racio"];
    $val["water_height"] = $val["height_new"] * $val["racio"];

}

$wnew = imagescale($w, $val["water_width"], $val["water_height"]);

$val["water_width"] = imagesx($wnew);
$val["water_height"] = imagesy($wnew);

/* GERAR WATERMARK TEXTO AUTOR */
if ($val["displayName"] == "Administrador") {
    $val["autor"] = "";
    $val["marBottom"] = 20;
    $val["marLeft"] = 20;
} else {
    $val["autor"] = $val["displayName"];
}


// PRIMEIRO E ULTIMO NOME SÓ!!
$autorNomes = explode(" ", $val["autor"]);

if (count($autorNomes) >= 2) {
    $val["autor"] = $autorNomes[0] . " " . $autorNomes[count($autorNomes) - 1];
} else {
    $val["autor"] = $autorNomes[0];
}

$font = "../font/Montserrat.ttf";
$color = "FFFFFF";

$flagSize = false;

$val["fontSize"] = 12;

for ($size = 7; $size <= 50; $size += 0.5) {

    $bb = imagettfbbox($size, 0, $font, $val["autor"]);
    $x0 = min($bb[0], $bb[2], $bb[4], $bb[6]);
    $x1 = max($bb[0], $bb[2], $bb[4], $bb[6]);
    $y0 = min($bb[1], $bb[3], $bb[5], $bb[7]);
    $y1 = max($bb[1], $bb[3], $bb[5], $bb[7]);

    $val["bbox_width"] = abs($x1 - $x0);
    $val["bbox_height"] = abs($y1 - $y0);

    if (($val["bbox_width"] >= $val["water_width"] && !$flagSize) || $size == 50) {
        $val["fontSize"] = $size;
        $flagSize = true;
        break;
    }
}

$val["posY_water"] = $val["height_new"] - $val["water_height"] - $val["marBottom"];
$val["posY_text"] = $val["height_new"] - $val["marBottom"] + $val["bbox_height"] - 5;

imagecopy($i, $wnew, $val["marLeft"],  $val["posY_water"] , 0, 0, $val["water_width"], $val["water_height"]);

render_text_on_gd_image($i, $val["autor"], $font, $val["fontSize"], $color, $val["opacidade"] ,0 , $val["marLeft"]  , $val["posY_text"], $val["water_width"]);


// echo "<pre>"; print_r($val); echo "</pre>"; die;

/* OUTPUT IMAGEM E LIMPA BUFFER */
header('Content-type: image/png');

imagepng($i);
imagedestroy($i);
imagedestroy($w);

And this are the gd section of phpinfo for localhost and production server

What am I missing? this is driving me insane!

Answer 1

Those issues almost always object to the alpha channel of either the source or destination not beeing preserved or the output not really beeing true color.

Try using the imagesavealpha() function and search for "alpha" in the comments of the PHP documentation because there are many people having solutions to similiar issues.

This comment might be helpful and is kinda what Esko said:

http://php.net/manual/en/function.imagecreatefrompng.php#90364

Basically it copies an image to a buffer using imagecreatetruecolor() .

Answer 2

I'm having the same issue. The imageScale function in Ubuntu seems to turn greens and blues to pink. Solution could be to use imagecopyresampled and imagecreatetruecolor. However this solution is way slower.