把一张图片（根据指定的RGB颜色范围）透明化。但是实际处理当中，下面的代码值移除了白色，请教是怎么回事？
$o_pic = '1.jpg';//要处理的色阶起始值$begin_r = 215;$begin_g = 215;$begin_b = 215;list($src_w,$src_h,$src_type) = getimagesize($o_pic);// 获取原图像信息$file_ext = get_ext($o_pic);//获取扩展名$target_im = imagecreatetruecolor($src_w,$src_h);//新图if($file_ext == 'jpg') //转换JPG 开始{ $src_im = ImageCreateFromJPEG($o_pic); imagecopymerge($target_im,$src_im,0,0,0,0,$src_w,$src_h,100); for($x = 0; $x < $src_w; $x++) { for($y = 0; $y < $src_h; $y++) { $rgb = imagecolorat($src_im, $x, $y); $r = ($rgb >> 16) & 0xFF; $g = ($rgb >> 8) & 0xFF; $b = $rgb & 0xFF; if($r > $begin_r && $g > $begin_g && $b > $begin_b ){ imagecolortransparent($target_im, imagecolorallocate($target_im,$r, $g, $b)); } } }}解决方案
时隔4年，我来贡献一个面向对象的。哈哈
/** * Created by PhpStorm. * User: shellus * Date: 2016-12-01 * Time: 23:12 */require 'vendor/autoload.php';// import the Intervention Image Manager Classuse Intervention\Image\ImageManager;// create an image manager instance with favored driver$manager = new ImageManager(array('driver' => 'gd'));$img = $manager->make('1.jpg');for ($y = 0; $y < $img->height(); $y++){ for ($x = 0; $x < $img->width(); $x++) { $c = $img -> pickColor($x, $y, 'array'); if(abs($c[0] - 205) < 50 && abs($c[1] - 223) < 50 && abs($c[2] - 211) < 50 ){ $c[0] = $c[1] = $c[2] = 255; $img -> pixel($c, $x, $y); } }}$img -> save();