在GD IMG_FILTER_COLORIZE之后对PNG透明图像应用背景

Question

我有透明的png图像(它是单色的)，我应用了彩色的php GD滤镜。所以现在它是彩色的，但我在应用白色背景来摆脱透明度时遇到了麻烦。

    list($r,$g,$b) = array_map('hexdec',str_split($ColourPrimary,2));
    $r = $r - 52;
    $g = $g - 52;
    $b = $b - 52;

    imagesavealpha($im, true);
    imagefilter($im, IMG_FILTER_COLORIZE, $r, $g, $b);

    $bw  = imagesx($im);
    $bh = imagesy($im);
    $background = imagecreatetruecolor($bw,$bh);
    $bkwhite = imagecolorallocate($background, 255, 255, 255);
    imagefill($background,0,0,$bkwhite);
    imagecopy($background, $im, 0, 0, 0, 0, $bw, $bh);

Answer 1

睡了个好觉后，我意识到我是在倒退。我首先应用了背景，并在顶部复制了图像。

    list($r,$g,$b) = array_map('hexdec',str_split($ColourPrimary,2));
    $r = $r - 52;
    $g = $g - 52;
    $b = $b - 52;

    $imfore = imagecreatefrompng(FILELOCATION);
    imagesavealpha($imfore, true);
    imagefilter($imfore, IMG_FILTER_COLORIZE, $r, $g, $b);
    $bw  = imagesx($imfore);
    $bh = imagesy($imfore);

    $im = imagecreatetruecolor($bw,$bh);
    $bkwhite = imagecolorallocate($im, 255, 255, 255);
    imagefill($im,0,0,$bkwhite);
    imagecopy($im, $imfore, 0, 0, 0, 0,$bw,$bh);