# Imagick::whiteThresholdImage

(PECL imagick 2, PECL imagick 3)

Imagick::whiteThresholdImage — Force all pixels above the threshold into white

### 说明

public Imagick::whiteThresholdImage(mixed `$threshold`): bool

Is like Imagick::ThresholdImage() but force all pixels above the threshold into white while leaving all pixels below the threshold unchanged.

### 参数

`threshold`

### 返回值

成功时返回 `true`。

### 更新日志

版本 | 说明
--- | ---
PECL imagick 2.1.0 | Now allows a string representing the color as a parameter. Previous versions allow only an ImagickPixel object.

### 示例

示例 #1 Imagick::whiteThresholdImage()

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