Question

我有这个PHP脚本，可以将图像大小调整为50％（或任何预设的百分比）

$filename = 'test.jpg';
$percent = 0.5;

// Content type
header('Content-Type: image/jpeg');

// Get new dimensions
list($width, $height) = getimagesize($filename);
$new_width = $width * $percent;
$new_height = $height * $percent;

// Resample
$image_p = imagecreatetruecolor($new_width, $new_height);
$image = imagecreatefromjpeg($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

// Output
imagejpeg($image_p, null, 100);

现在如果我想将$ new_width指定为1200（px）并告诉$ new_height自动计算保持宽高比并将新图像的名称设置为“test-2.jpg”

$filename = 'test.jpg';

// Content type
header('Content-Type: image/jpeg');

// Get new dimensions
list($width, $height) = getimagesize($filename);
$new_width = 1200;
$new_height = // MUST BE AUTO;

// Resample
$image_p = imagecreatetruecolor($new_width, $new_height);
$image = imagecreatefromjpeg($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

// Output
imagejpeg($image_p, null, 100);

Answer 1

这是你的意思吗？

// Get new dimensions
list($width, $height) = getimagesize($filename);
$new_width = 1200;
$new_height = ($height/$width)*$new_width;

Answer 2

＆＃34;保持宽高比＆＃34;意味着必须遵循以下等式：

$new_height / $new_width == $height / $width

因此，计算新高度的等式是：

$new_height = ceil($height * ($new_width/$width));

请注意ceil确保新高度为整数值且至少为1（假设新宽度和旧宽度+高度均为正值）。

PHP图像使用宽高比调整大小

2 个答案: