douji0073
douji0073
2018-09-13 20:56
浏览 38
已采纳

当我尝试在PHP + GD库中添加图像时,文本正在消失

I'm trying to create a PNG with some text and a scaled picture in it. Here is the code for just the text, it works fine:

<?php
session_start();
error_reporting(E_ALL);

$label = imagecreate(500, 500);
imagecolorallocate($label, 0, 0, 0);

// up text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 150, $color, "arial.ttf", "UP UP UP");

// down text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 350, $color, "assets/fonts/arial.ttf", "DOWN DOWN DOWN");

header('Content-type: image/png');
imagepng($label);
imagedestroy($label);
die();
?>

With the code above you get the following picture, which is correct:

enter image description here

Now I'm trying to have a small picture in it, So I'm loading the picture from a JPEG file (adidas.jpg). Here's the code

<?php
session_start();
error_reporting(E_ALL);


$label = imagecreate(500, 500);
imagecolorallocate($label, 0, 0, 0);


// up text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 150, $color, "arial.ttf", "UP UP UP");

// image
$src = imagecreatefromjpeg("adidas.jpg");
$pic = imagecreatetruecolor(500, 500);
imagecopyresampled($label, $src, 0, 0, 0, 0, 150, 150, imagesx($src), imagesy($src));
$white = imagecolorallocate($pic, 255, 255, 255);
imagefill($label,0,0,$white);
imagedestroy($pic);


// down text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 350, $color, "arial.ttf", "DOWN DOWN DOWN");

header('Content-type: image/png');
imagepng($label);
imagedestroy($label);
die();
?>

And this is what I get:

enter image description here

To my surprise the "down" text disappeared. Why is that? The text added before the picture is fine, the text added after it turns to black for some reason

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1条回答 默认 最新

  • duanlu0559
    duanlu0559 2018-09-13 22:00
    已采纳

    Your code is bit messy, "DOWN.." text will appear if you remove second:

    $color = imagecolorallocate($label, 255, 255, 255);
    

    You dont fill the original image, you try it later but with wrong color ($white is from $pic, not $label). I cleaned it up:

    <?php
    session_start();
    error_reporting(E_ALL);
    
    $label = imagecreate(500, 500);
    $black = imagecolorallocate($label, 0, 0, 0);
    $white = imagecolorallocate($label, 255, 255, 255);
    imagefill($label, 0, 0, $black);
    
    imagettftext($label, 50, 0, 0, 150, $white, "arial.ttf", "UP UP UP");
    
    $src = imagecreatefromjpeg("adidas.jpg");
    $pic = imagecreatetruecolor(500, 500);
    imagecopyresampled($label, $src, 0, 0, 0, 0, 150, 150, imagesx($src), imagesy($src));
    $white2 = imagecolorallocate($pic, 255, 255, 255);
    
    imagettftext($label, 50, 0, 0, 350, $white, "arial.ttf", "DOWN DOWN DOWN");
    
    ob_end_clean();
    header('Content-type: image/png');
    imagepng($label);
    
    imagedestroy($src);
    imagedestroy($pic);
    imagedestroy($label);
    die();
    ?>
    
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