Imagick::scaleImage()

(PECL imagick 2.0.0)

Scales the size of an image

说明

Imagick::scaleImage(int $cols,int $rows[,bool $bestfit= FALSE[,bool $legacy= FALSE]]): bool

Scales the size of an image to the given dimensions. The other parameter will be calculated if 0 is passed as either param.

Note:参数$bestfit的特性在 Imagick 3.0.0 中已改变。在此版本以前，当目标尺寸设为 400x400 时，原尺寸为 200x150 的图像将不会被改变。自 Imagick 3.0.0 起，源图像将会被放大到 400x300 因为这将更好的适合目标尺寸。当使用参数$bestfit时，必须同时给出宽度和高度。

参数

$cols

$rows

$bestfit

返回值

成功时返回TRUE。

错误／异常

错误时抛出 ImagickException。

更新日志

范例

Example #1 Imagick::scaleImage()

<?php
function scaleImage($imagePath) {
    $imagick = new \Imagick(realpath($imagePath));
    $imagick->scaleImage(150, 150, true);
    header("Content-Type: image/jpg");
    echo $imagick->getImageBlob();
}
?>

If anyone finds "The other parameter will be calculated if 0 is passed as either param. " to be a bit confusing, it means approximately this:
<?php
$im = new Imagick('example.jpg');
$im->scaleImage(300, 0);
?>
This scales the image such that it is now 300 pixels wide, and automatically calculates the height to keep the image at the same aspect ratio.
<?php
$im = new Imagick('example.jpg');
$im->scaleImage(0, 300);
?>
Similarly, this example scales the image to make it 300 pixels tall, and the method automatically recalculates the image's height to maintain the aspect ratio.

Warning: this will blur your edges in possibly unexpected ways. For better control, use resizeImage, instead.

Here is an easy way to resize an animated gif : 
$picture = new Imagick('animated_gif.gif');
foreach($picture as $frame){
  $frame->scaleImage($width, $height);
}

When using the "fit = true" option, the image will only scale down, but never scale up:
<?php
$im = new Imagick('1600x1200.jpg');
$im->scaleImage(2000, 1500, true); // => 1600x1200
$im->scaleImage(1000, 500, true); // => 666x500
?>

Need to resize portrait and landscape images (and convert to 72ppi)? These will fit an area of 800x600 without distorting, no matter how tall or wide.
<?php
  $img = new Imagick($img_loc.$file);
  $img->setImageResolution(72,72); 
  $img->resampleImage(72,72,imagick::FILTER_UNDEFINED,1);
  $img->scaleImage(800,0);
  $d = $img->getImageGeometry(); 
  $h = $d['height']; 
  if($h > 600) {
  $img->scaleImage(0,600);
  $img->writeImage($resized_loc.$file);
  } else {
  $img->writeImage($resized_loc.$file);
  }
  $img->destroy();
?>

If using the fit-parameter this function sometimes seems not to work when one of the two sizes (width or height) is the same size as the image has. For example:
<?php
$image = new Imagick('800x480.jpg');
$image->scaleImage(640, 480, true);
// $image is still 800x480
?>
You have to calculate the new sizes yourself and use false for $fit in this case.