Change the brightness and/or contrast of an image

# Imagick::brightnessContrastImage

(PECL imagick 3 >= 3.3.0)

Imagick::brightnessContrastImage — Change the brightness and/or contrast of an image

### 说明

public function Imagick::brightnessContrastImage(float `$brightness`, float `$contrast`, int `$channel` = Imagick::CHANNEL_DEFAULT): bool

Change the brightness and/or contrast of an image. It converts the brightness and contrast parameters into slope and intercept and calls a polynomial function to apply to the image.

### 参数

`brightness`

`contrast`

`channel`

### 返回值

成功时返回 `true`。

### 示例

示例 #1 Imagick::brightnessContrastImage()

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

    ?>

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