PHP GD自由文本渲染與pixilation

Question

這是問題的文字覆蓋在圖像和漸變周圍有一些奇怪的圖像周圍的文字，但我不知道爲什麼。

- >

下面的代碼：

<?php 
function hex2rgb($hex) { 
    $rgb[0] = hexdec(substr($hex, 0, 2)); 
    $rgb[1] = hexdec(substr($hex, 2, 2)); 
    $rgb[2] = hexdec(substr($hex, 4, 2)); 
    return $rgb; 
} 

$sourceImage = imagecreatefromstring(file_get_contents("source.jpg")); 

$imagePadding = 10; 

$height = imagesy($sourceImage); 
$width = imagesx($sourceImage); 

$baseImage = imagecreatetruecolor($width, $height); 

$backgroundColor = imagecolorallocate($baseImage, 0, 0, 0); 
imagefill($baseImage, 0, 0, $backgroundColor); 

imagecopyresampled($baseImage, $sourceImage, 0, 0, 0, 0, $width, $height, $width, $height); 

//==== GRADIENT ====// 
// Modified from: http://stackoverflow.com/questions/14684622/blend-transparent-gradient-with-an-image-using-php-gd-library 
$gradientCanvas = imagecreatetruecolor($width, $height); 
$transColor = imagecolorallocatealpha($gradientCanvas, 0, 0, 0, 127); 

imagefill($gradientCanvas, 0, 0, $transColor); 

$color = hex2rgb("000000"); 
$start = -40; 
$stop = 120; 
$range = $stop - $start; 

for ($y = 0; $y < $height; ++$y) { 
    $alpha = $y <= $start ? 0 : round(min(($y - $start)/$range, 1) * 127); 
    $newColor = imagecolorallocatealpha($gradientCanvas, $color[0], $color[1], $color[2], $alpha); 
    imageline($gradientCanvas, 0, $y, $width, $y, $newColor); 
} 

imagecopyresampled($baseImage, $gradientCanvas, 0, 0, 0, 0, $width, $height, $width, $height); 

//==== TEXT ====// 
putenv('GDFONTPATH=.'); 
$font = "HelveticaNeueBold.ttf"; 


$white = imagecolorallocate($baseImage, 255, 255, 255); 
imagettftext($baseImage, 14, 0, $imagePadding, $imagePadding + 16, $white, $font, "Foobar"); 

header('Content-Type: image/jpeg'); 
imagejpeg($baseImage); 
imagedestroy($baseImage); 
imagedestroy($sourceImage); 
?> 

Answer 1

的imagejpeghttp://php.net/manual/en/function.imagejpeg.php的默認質量爲〜75％，你會想將它設置爲100

imagejpeg($baseImage, null, 100); 

Answer 2

主要的原因 - 你正在使用JPG作爲輸出和輸入圖像。編輯JPG圖像通常會導致圖像失真。嘗試使用PNG圖像作爲源。 或者嘗試imagejpeg（）的「質量」參數設置爲100