protected function addImagePngAlpha($file, $x, $y, $w, $h, $byte)
{
// generate images
$img = imagecreatefrompng($file);
if ($img === false) {
return;
}
// FIXME The pixel transformation doesn't work well with 8bit PNGs
$eight_bit = ($byte & 4) !== 4;
$wpx = imagesx($img);
$hpx = imagesy($img);
imagesavealpha($img, false);
// create temp alpha file
$tempfile_alpha = tempnam($this->tmp, "cpdf_img_");
@unlink($tempfile_alpha);
$tempfile_alpha = "{$tempfile_alpha}.png";
// create temp plain file
$tempfile_plain = tempnam($this->tmp, "cpdf_img_");
@unlink($tempfile_plain);
$tempfile_plain = "{$tempfile_plain}.png";
$imgalpha = imagecreate($wpx, $hpx);
imagesavealpha($imgalpha, false);
// generate gray scale palette (0 -> 255)
for ($c = 0; $c < 256; ++$c) {
imagecolorallocate($imgalpha, $c, $c, $c);
}
// Use PECL gmagick + Graphics Magic to process transparent PNG images
if (extension_loaded("gmagick")) {
$gmagick = new Gmagick($file);
$gmagick->setimageformat('png');
// Get opacity channel (negative of alpha channel)
$alpha_channel_neg = clone $gmagick;
$alpha_channel_neg->separateimagechannel(Gmagick::CHANNEL_OPACITY);
// Negate opacity channel
$alpha_channel = new Gmagick();
$alpha_channel->newimage($wpx, $hpx, "#FFFFFF", "png");
$alpha_channel->compositeimage($alpha_channel_neg, Gmagick::COMPOSITE_DIFFERENCE, 0, 0);
$alpha_channel->separateimagechannel(Gmagick::CHANNEL_RED);
$alpha_channel->writeimage($tempfile_alpha);
// Cast to 8bit+palette
$imgalpha_ = imagecreatefrompng($tempfile_alpha);
imagecopy($imgalpha, $imgalpha_, 0, 0, 0, 0, $wpx, $hpx);
imagedestroy($imgalpha_);
imagepng($imgalpha, $tempfile_alpha);
// Make opaque image
$color_channels = new Gmagick();
$color_channels->newimage($wpx, $hpx, "#FFFFFF", "png");
$color_channels->compositeimage($gmagick, Gmagick::COMPOSITE_COPYRED, 0, 0);
$color_channels->compositeimage($gmagick, Gmagick::COMPOSITE_COPYGREEN, 0, 0);
$color_channels->compositeimage($gmagick, Gmagick::COMPOSITE_COPYBLUE, 0, 0);
$color_channels->writeimage($tempfile_plain);
$imgplain = imagecreatefrompng($tempfile_plain);
} elseif (extension_loaded("imagick")) {
$imagick = new Imagick($file);
$imagick->setFormat('png');
// Get opacity channel (negative of alpha channel)
$alpha_channel = clone $imagick;
$alpha_channel->separateImageChannel(Imagick::CHANNEL_ALPHA);
$alpha_channel->negateImage(true);
$alpha_channel->writeImage($tempfile_alpha);
// Cast to 8bit+palette
$imgalpha_ = imagecreatefrompng($tempfile_alpha);
imagecopy($imgalpha, $imgalpha_, 0, 0, 0, 0, $wpx, $hpx);
imagedestroy($imgalpha_);
imagepng($imgalpha, $tempfile_alpha);
// Make opaque image
$color_channels = new Imagick();
$color_channels->newImage($wpx, $hpx, "#FFFFFF", "png");
$color_channels->compositeImage($imagick, Imagick::COMPOSITE_COPYRED, 0, 0);
$color_channels->compositeImage($imagick, Imagick::COMPOSITE_COPYGREEN, 0, 0);
$color_channels->compositeImage($imagick, Imagick::COMPOSITE_COPYBLUE, 0, 0);
$color_channels->writeImage($tempfile_plain);
$imgplain = imagecreatefrompng($tempfile_plain);
} else {
// allocated colors cache
$allocated_colors = array();
// extract alpha channel
for ($xpx = 0; $xpx < $wpx; ++$xpx) {
for ($ypx = 0; $ypx < $hpx; ++$ypx) {
$color = imagecolorat($img, $xpx, $ypx);
$col = imagecolorsforindex($img, $color);
$alpha = $col['alpha'];
if ($eight_bit) {
// with gamma correction
$gammacorr = 2.2;
$pixel = pow((127 - $alpha) * 255 / 127 / 255, $gammacorr) * 255;
} else {
// without gamma correction
$pixel = (127 - $alpha) * 2;
$key = $col['red'] . $col['green'] . $col['blue'];
if (!isset($allocated_colors[$key])) {
$pixel_img = imagecolorallocate($img, $col['red'], $col['green'], $col['blue']);
$allocated_colors[$key] = $pixel_img;
} else {
$pixel_img = $allocated_colors[$key];
}
imagesetpixel($img, $xpx, $ypx, $pixel_img);
}
imagesetpixel($imgalpha, $xpx, $ypx, $pixel);
}
}
// extract image without alpha channel
$imgplain = imagecreatetruecolor($wpx, $hpx);
imagecopy($imgplain, $img, 0, 0, 0, 0, $wpx, $hpx);
imagedestroy($img);
imagepng($imgalpha, $tempfile_alpha);
imagepng($imgplain, $tempfile_plain);
}
// embed mask image
$this->addImagePng($tempfile_alpha, $x, $y, $w, $h, $imgalpha, true);
imagedestroy($imgalpha);
// embed image, masked with previously embedded mask
$this->addImagePng($tempfile_plain, $x, $y, $w, $h, $imgplain, false, true);
imagedestroy($imgplain);
// remove temp files
unlink($tempfile_alpha);
unlink($tempfile_plain);
}
protected function addImagePngAlpha($file, $x, $y, $w, $h, $byte)
{
$img = imagecreatefrompng($file);
if ($img === false) {
return;
}
$eight_bit = ($byte & 4) !== 4;
$wpx = imagesx($img);
$hpx = imagesy($img);
imagesavealpha($img, false);
$tempfile_alpha = tempnam($this->tmp, "cpdf_img_");
@unlink($tempfile_alpha);
$tempfile_alpha = "{$tempfile_alpha}.png";
$tempfile_plain = tempnam($this->tmp, "cpdf_img_");
@unlink($tempfile_plain);
$tempfile_plain = "{$tempfile_plain}.png";
$imgalpha = imagecreate($wpx, $hpx);
imagesavealpha($imgalpha, false);
for ($c = 0; $c < 256; ++$c) {
imagecolorallocate($imgalpha, $c, $c, $c);
}
if (extension_loaded("gmagick")) {
$gmagick = new Gmagick($file);
$gmagick->setimageformat('png');
$alpha_channel_neg = clone $gmagick;
$alpha_channel_neg->separateimagechannel(Gmagick::CHANNEL_OPACITY);
$alpha_channel = new Gmagick();
$alpha_channel->newimage($wpx, $hpx, "#FFFFFF", "png");
$alpha_channel->compositeimage($alpha_channel_neg, Gmagick::COMPOSITE_DIFFERENCE, 0, 0);
$alpha_channel->separateimagechannel(Gmagick::CHANNEL_RED);
$alpha_channel->writeimage($tempfile_alpha);
$imgalpha_ = imagecreatefrompng($tempfile_alpha);
imagecopy($imgalpha, $imgalpha_, 0, 0, 0, 0, $wpx, $hpx);
imagedestroy($imgalpha_);
imagepng($imgalpha, $tempfile_alpha);
$color_channels = new Gmagick();
$color_channels->newimage($wpx, $hpx, "#FFFFFF", "png");
$color_channels->compositeimage($gmagick, Gmagick::COMPOSITE_COPYRED, 0, 0);
$color_channels->compositeimage($gmagick, Gmagick::COMPOSITE_COPYGREEN, 0, 0);
$color_channels->compositeimage($gmagick, Gmagick::COMPOSITE_COPYBLUE, 0, 0);
$color_channels->writeimage($tempfile_plain);
$imgplain = imagecreatefrompng($tempfile_plain);
} elseif (extension_loaded("imagick")) {
$imagick = new Imagick($file);
$imagick->setFormat('png');
$alpha_channel = clone $imagick;
$alpha_channel->separateImageChannel(Imagick::CHANNEL_ALPHA);
$alpha_channel->negateImage(true);
$alpha_channel->writeImage($tempfile_alpha);
$imgalpha_ = imagecreatefrompng($tempfile_alpha);
imagecopy($imgalpha, $imgalpha_, 0, 0, 0, 0, $wpx, $hpx);
imagedestroy($imgalpha_);
imagepng($imgalpha, $tempfile_alpha);
$color_channels = new Imagick();
$color_channels->newImage($wpx, $hpx, "#FFFFFF", "png");
$color_channels->compositeImage($imagick, Imagick::COMPOSITE_COPYRED, 0, 0);
$color_channels->compositeImage($imagick, Imagick::COMPOSITE_COPYGREEN, 0, 0);
$color_channels->compositeImage($imagick, Imagick::COMPOSITE_COPYBLUE, 0, 0);
$color_channels->writeImage($tempfile_plain);
$imgplain = imagecreatefrompng($tempfile_plain);
} else {
$allocated_colors = array();
for ($xpx = 0; $xpx < $wpx; ++$xpx) {
for ($ypx = 0; $ypx < $hpx; ++$ypx) {
$color = imagecolorat($img, $xpx, $ypx);
$col = imagecolorsforindex($img, $color);
$alpha = $col['alpha'];
if ($eight_bit) {
$gammacorr = 2.2;
$pixel = pow((127 - $alpha) * 255 / 127 / 255, $gammacorr) * 255;
} else {
$pixel = (127 - $alpha) * 2;
$key = $col['red'] . $col['green'] . $col['blue'];
if (!isset($allocated_colors[$key])) {
$pixel_img = imagecolorallocate($img, $col['red'], $col['green'], $col['blue']);
$allocated_colors[$key] = $pixel_img;
} else {
$pixel_img = $allocated_colors[$key];
}
imagesetpixel($img, $xpx, $ypx, $pixel_img);
}
imagesetpixel($imgalpha, $xpx, $ypx, $pixel);
}
}
$imgplain = imagecreatetruecolor($wpx, $hpx);
imagecopy($imgplain, $img, 0, 0, 0, 0, $wpx, $hpx);
imagedestroy($img);
imagepng($imgalpha, $tempfile_alpha);
imagepng($imgplain, $tempfile_plain);
}
$this->addImagePng($tempfile_alpha, $x, $y, $w, $h, $imgalpha, true);
imagedestroy($imgalpha);
$this->addImagePng($tempfile_plain, $x, $y, $w, $h, $imgplain, false, true);
imagedestroy($imgplain);
unlink($tempfile_alpha);
unlink($tempfile_plain);
}
