# Imagick::linearStretchImage

(PECL imagick 2, PECL imagick 3)

Imagick::linearStretchImage — Stretches with saturation the image intensity

### 说明

public Imagick::linearStretchImage(float `$blackPoint`, float `$whitePoint`): bool

Stretches with saturation the image intensity.

### 参数

`blackPoint`

  The image black point

`whitePoint`

  The image white point

### 返回值

成功时返回 `true`。

### 示例

示例 #1 Imagick::linearStretchImage()

`<?php
function linearStretchImage($imagePath, $blackThreshold, $whiteThreshold) {
$imagick = new \Imagick(realpath($imagePath));
$pixels = $imagick->getImageWidth() * $imagick->getImageHeight();
$imagick->linearStretchImage($blackThreshold * $pixels, $whiteThreshold * $pixels);
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>`
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