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PHP Gmagick setimagechanneldepth()用法及代码示例


Gmagick::setimagechanneldepth()函数是PHP中的内置函数,用于设置特定通道图像的深度。

用法:

Gmagick Gmagick::setimagechanneldepth( $channel , $depth )

参数:该函数接受上述和以下描述的两个参数:


  • $channel:此参数用于指定通道常数。以下是固定频道列表:
    CHANNEL constants:
    • Gmagick::CHANNEL_UNDEFINED
    • Gmagick::CHANNEL_RED
    • Gmagick::CHANNEL_GRAY
    • Gmagick::CHANNEL_CYAN
    • Gmagick::CHANNEL_GREEN
    • Gmagick::CHANNEL_MAGENTA
    • Gmagick::CHANNEL_BLUE
    • Gmagick::CHANNEL_YELLOW
    • Gmagick::CHANNEL_ALPHA
    • Gmagick::CHANNEL_OPACITY
    • Gmagick::CHANNEL_MATTE
    • Gmagick::CHANNEL_BLACK
    • Gmagick::CHANNEL_INDEX
    • Gmagick::CHANNEL_ALL
    • Gmagick::CHANNEL_DEFAULT
  • $depth:此参数用于指定要为Gmagick对象设置的深度。

返回值:成功时,此函数返回Gmagick对象。

以下示例程序旨在说明PHP中的Gmagick::setimagechanneldepth()函数:

示例1:
原始图片:
https://media.geeksforgeeks.org/wp-content/uploads/geeks-21.png

<?php 
   
// Create new Gmagick object 
$im = new Gmagick( 
'https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-15.png'); 
   
// Using getImageChannelDepth function 
// with red channel 
echo "Before Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(Gmagick::CHANNEL_RED) . "</br>"; 
   
// Set channel Depth of CYAN and GREEN Channel 
$im->setimagechanneldepth(Gmagick::CHANNEL_RED, 4); 
   
echo "After Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(Gmagick::CHANNEL_RED) . "</br>"; 
  
?>

输出:

Before Set Channel depth:
8
After Set Channel depth:
4

示例2:
原始图片:
https://media.geeksforgeeks.org/wp-content/uploads/Screenshot-from-2018-10-16-23-23-54.png

<?php  
   
$string = "Computer Science portal for Geeks!";  
   
// Creating new image of above String  
// and add color 
$im = new Gmagick();  
$draw = new GmagickDraw();  
   
// Fill the color in image  
$draw->setFillColor(new GmagickPixel('green'));  
   
// Set the text font size  
$draw->setFontSize(50);  
   
$metrix = $im->queryFontMetrics($draw, $string);  
$draw->annotation(0, 40, $string);  
$im->newImage($metrix['textWidth'], $metrix['textHeight'],  
        new GmagickPixel('white'));  
   
// Draw the image          
$im->drawImage($draw);  
$im->setImageFormat('jpeg');  
   
// Using getImageChannelDepth function 
// with red channel 
echo "Before Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(Gmagick::CHANNEL_GREEN) . "</br>"; 
   
// Set channel Depth of Green Channel 
$im->setimagechanneldepth(Gmagick::CHANNEL_GREEN, 8); 
   
echo "After Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(Gmagick::CHANNEL_GREEN) . "</br>"; 
  
?>

输出:

Before Set Channel depth:
16
After Set Channel depth:
8

参考: http://php.net/manual/en/gmagick.setimagechanneldepth.php



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注:本文由纯净天空筛选整理自R_Raj大神的英文原创作品 PHP | Gmagick setimagechanneldepth() Function。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。