279 lines
12 KiB
PHP
279 lines
12 KiB
PHP
<?php
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// Simple .ICO parsing. The ICO format is insanely complex and this may
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// fail to correctly handle some technically valid files, but it works
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// on the majority I've found.
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//
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// jimIcon was written in 2013 by Jim Paris <jim@jtan.com> and is
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// released under the terms of the CC0:
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//
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// To the extent possible under law, the author(s) have dedicated all
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// copyright and related and neighboring rights to this software to
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// the public domain worldwide. This software is distributed without
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// any arranty.
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//
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// You may have received a copy of the CC0 Public Domain Dedication
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// along with this software. If not, see
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// http://creativecommons.org/publicdomain/zero/1.0/
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class jimIcon {
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// Get an image color from a string
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function get_color($str, $img) {
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$b = ord($str[0]);
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$g = ord($str[1]);
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$r = ord($str[2]);
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if (strlen($str) > 3) {
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$a = 127 - (ord($str[3]) / 2);
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if ($a != 0 && $a != 127)
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$this->had_alpha = 1;
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} else {
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$a = 0;
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}
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if ($a != 127)
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$this->all_transaprent = 0;
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return imagecolorallocatealpha($img, $r, $g, $b, (int) $a);
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}
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// Given a string with the contents of an .ICO,
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// return a GD image of the icon, or false on error.
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function fromiconstring($ico) {
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$this->error = "(unknown error)";
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$this->had_alpha = 0;
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// Read header
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if (strlen($ico) < 6) {
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$this->error = "too short";
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return false;
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}
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$h = unpack("vzero/vtype/vnum", $ico);
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// Must be ICO format with at least one image
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if ($h["zero"] != 0 || $h["type"] != 1 || $h["num"] == 0) {
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// See if we can just parse it with GD directly
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// if it's not ICO format; maybe it was a mislabeled
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// PNG or something.
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$i = @imagecreatefromstring($ico);
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if ($i) {
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imagesavealpha($i, true);
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return $i;
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}
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$this->error = "not ICO or other image";
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return false;
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}
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// Read directory entries to find the biggest image
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$most_pixels = 0;
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for ($i = 0; $i < $h["num"]; $i++) {
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$entry = substr($ico, 6 + 16 * $i, 16);
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if (!$entry || strlen($entry) < 16)
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continue;
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$e = unpack("Cwidth/" .
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"Cheight/" .
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"Ccolors/" .
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"Czero/" .
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"vplanes/" .
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"vbpp/" .
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"Vsize/" .
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"Voffset/",
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$entry);
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if ($e["width"] == 0)
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$e["width"] = 256;
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if ($e["height"] == 0)
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$e["height"] = 256;
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if ($e["zero"] != 0) {
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$this->error = "nonzero reserved field";
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return false;
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}
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$pixels = $e["width"] * $e["height"];
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if ($pixels > $most_pixels) {
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$most_pixels = $pixels;
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$most = $e;
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}
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}
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if ($most_pixels == 0) {
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$this->error = "no pixels";
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return false;
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}
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$e = $most;
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// Extract image data
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$data = substr($ico, $e["offset"], $e["size"]);
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if (!$data || strlen($data) != $e["size"]) {
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$this->error = "bad image data";
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return false;
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}
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// See if we can parse it (might be PNG format here)
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if (self::has_parsable_image_type($data)) {
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if ($i = @imagecreatefromstring($data)) {
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imagesavealpha($i, true);
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return $i;
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}
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}
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// Must be a BMP. Parse it ourselves.
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$img = imagecreatetruecolor($e["width"], $e["height"]);
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imagesavealpha($img, true);
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$bg = imagecolorallocatealpha($img, 255, 0, 0, 127);
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imagefill($img, 0, 0, $bg);
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// Skip over the BITMAPCOREHEADER or BITMAPINFOHEADER;
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// we'll just assume the palette and pixel data follow
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// in the most obvious format as described by the icon
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// directory entry.
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$bitmapinfo = unpack("Vsize", $data);
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if ($bitmapinfo["size"] == 40) {
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$info = unpack("Vsize/" .
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"Vwidth/" .
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"Vheight/" .
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"vplanes/" .
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"vbpp/" .
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"Vcompress/" .
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"Vsize/" .
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"Vxres/" .
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"Vyres/" .
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"Vpalcolors/" .
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"Vimpcolors/", $data);
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if ($e["bpp"] == 0) {
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$e["bpp"] = $info["bpp"];
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}
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}
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$data = substr($data, $bitmapinfo["size"]);
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$height = $e["height"];
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$width = $e["width"];
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$bpp = $e["bpp"];
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// For indexed images, we only support 1, 4, or 8 BPP
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switch ($bpp) {
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case 1:
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case 4:
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case 8:
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$indexed = 1;
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break;
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case 24:
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case 32:
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$indexed = 0;
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break;
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default:
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$this->error = "bad BPP $bpp";
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return false;
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}
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$offset = 0;
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if ($indexed) {
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$palette = array();
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$this->all_transparent = 1;
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for ($i = 0; $i < (1 << $bpp); $i++) {
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$entry = substr($data, $i * 4, 4);
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$palette[$i] = $this->get_color($entry, $img);
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}
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$offset = $i * 4;
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// Hack for some icons: if everything was transparent,
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// discard alpha channel.
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if ($this->all_transparent) {
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for ($i = 0; $i < (1 << $bpp); $i++) {
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$palette[$i] &= 0xffffff;
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}
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}
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}
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// Assume image data follows in bottom-up order.
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// First the "XOR" image
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if ((strlen($data) - $offset) < ($bpp * $height * $width / 8)) {
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$this->error = "short data";
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return false;
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}
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$XOR = array();
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for ($y = $height - 1; $y >= 0; $y--) {
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$x = 0;
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while ($x < $width) {
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if (!$indexed) {
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$bytes = $bpp / 8;
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$entry = substr($data, $offset, $bytes);
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$pixel = $this->get_color($entry, $img);
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$XOR[$y][$x] = $pixel;
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$x++;
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$offset += $bytes;
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} elseif ($bpp == 1) {
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$p = ord($data[$offset]);
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for ($b = 0x80; $b > 0; $b >>= 1) {
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if ($p & $b) {
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$pixel = $palette[1];
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} else {
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$pixel = $palette[0];
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}
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$XOR[$y][$x] = $pixel;
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$x++;
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}
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$offset++;
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} elseif ($bpp == 4) {
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$p = ord($data[$offset]);
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$pixel1 = $palette[$p >> 4];
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$pixel2 = $palette[$p & 0x0f];
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$XOR[$y][$x] = $pixel1;
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$XOR[$y][$x+1] = $pixel2;
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$x += 2;
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$offset++;
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} elseif ($bpp == 8) {
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$pixel = $palette[ord($data[$offset])];
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$XOR[$y][$x] = $pixel;
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$x += 1;
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$offset++;
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} else {
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$this->error = "bad BPP";
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return false;
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}
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}
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// End of row padding
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while ($offset & 3)
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$offset++;
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}
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// Now the "AND" image, which is 1 bit per pixel. Ignore
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// if some of our image data already had alpha values,
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// or if there isn't enough data left.
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if ($this->had_alpha ||
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((strlen($data) - $offset) < ($height * $width / 8))) {
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// Just return what we've got
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for ($y = 0; $y < $height; $y++) {
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for ($x = 0; $x < $width; $x++) {
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imagesetpixel($img, $x, $y,
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$XOR[$y][$x]);
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}
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}
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return $img;
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}
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// Mask what we have with the "AND" image
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for ($y = $height - 1; $y >= 0; $y--) {
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$x = 0;
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while ($x < $width) {
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for ($b = 0x80;
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$b > 0 && $x < $width; $b >>= 1) {
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if (!(ord($data[$offset]) & $b)) {
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imagesetpixel($img, $x, $y,
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$XOR[$y][$x]);
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}
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$x++;
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}
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$offset++;
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}
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// End of row padding
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while ($offset & 3)
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$offset++;
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}
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return $img;
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}
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// Checks whether the data is a type parsable by imagecreatefromstring()
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private function has_parsable_image_type($image_data) {
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$size = getimagesizefromstring($image_data);
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return $size && in_array($size[2],
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[IMAGETYPE_JPEG, IMAGETYPE_PNG, IMAGETYPE_GIF, IMAGETYPE_BMP, IMAGETYPE_WBMP, IMAGETYPE_WEBP]);
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}
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}
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?>
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