我用下面的代码创建一个带阴影的png样本(使用FPDF动态插入PDF文件)
$shadowSwatch = $pm->clone() ;
$shadowSwatch->setImageBackgroundColor('#000000') ;
//Angle & Offset of Drop Shadow based on photoshop settings
$angle = deg2rad(45) ;
$xOffset = round(sin($angle) * 18, 0) ;
$yOffset = round(cos($angle) * 18, 0) ;
//Shadow Image seems to take extra time
ini_set('max_execution_time', 300) ;
$shadowSwatch->shadowImage(8, 8, $xOffset, $yOffset) ;
//Overlay original image on its shadow
$shadowSwatch->compositeImage($pm, Imagick::COMPOSITE_OVER, 0, 0) ;
//Attempts at forcing consistent output
$shadowSwatch->flattenImages();
$shadowSwatch->setImageColorspace(13);
$shadowSwatch->setImageDepth(32);
$shadowSwatch->setImageFormat('PNG32');
//Save Swatch
$shadowSwatch->writeImage($swatchDestination) ;
我的问题是，我需要让它始终如一地输出相同的位深度writeImage…事实并非如此。有时候，当FPDF只能处理32位(每个RGBA 8个)时，它输出64位png。
任何关于从Imagick png中获得一致位深度的建议将非常感谢!
我找到了答案。使用imagick replace在png中提供一致的位深度:
$shadowSwatch->setColorspace(13);
$shadowSwatch->setImageDepth(32);
:
$shadowSwatch->setOption('png:color-type', 6);
$shadowSwatch->setOption('png:bit-depth', 8);