summaryrefslogtreecommitdiff
path: root/includes/media/XCF.php
blob: 806db73cd7a107c1e7fe54d23c3ed0976fab83fd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
<?php
/**
 * Handler for the Gimp's native file format (XCF)
 *
 * Overview:
 *   http://en.wikipedia.org/wiki/XCF_(file_format)
 * Specification in Gnome repository:
 *   http://svn.gnome.org/viewvc/gimp/trunk/devel-docs/xcf.txt?view=markup
 *
 * @file
 * @ingroup Media
 */

/**
 * Handler for the Gimp's native file format; getimagesize() doesn't
 * support these files
 *
 * @ingroup Media
 */
class XCFHandler extends BitmapHandler {

	/**
	 * @param $file
	 * @return bool
	 */
	function mustRender( $file ) {
		return true;
	}

	/**
	 * Render files as PNG
	 *
	 * @param $ext
	 * @param $mime
	 * @param $params
	 * @return array
	 */
	function getThumbType( $ext, $mime, $params = null ) {
		return array( 'png', 'image/png' );
	}

	/**
	 * Get width and height from the XCF header.
	 *
	 * @param $image
	 * @param $filename
	 * @return array
	 */
	function getImageSize( $image, $filename ) {
		return self::getXCFMetaData( $filename );
	}

	/**
	 * Metadata for a given XCF file
	 *
	 * Will return false if file magic signature is not recognized
	 * @author Hexmode
	 * @author Hashar
	 *
	 * @param $filename String Full path to a XCF file
	 * @return false|metadata array just like PHP getimagesize()
	 */
	static function getXCFMetaData( $filename ) {
		# Decode master structure
		$f = fopen( $filename, 'rb' );
		if( !$f ) {
			return false;
		}
		# The image structure always starts at offset 0 in the XCF file.
		# So we just read it :-)
		$binaryHeader = fread( $f, 26 );
		fclose($f);

		# Master image structure:
		#
		# byte[9] "gimp xcf "  File type magic
		# byte[4] version      XCF version
		#                        "file" - version 0
		#                        "v001" - version 1
		#                        "v002" - version 2
		# byte    0            Zero-terminator for version tag
		# uint32  width        With of canvas
		# uint32  height       Height of canvas
		# uint32  base_type    Color mode of the image; one of
		#                         0: RGB color
		#                         1: Grayscale
		#                         2: Indexed color
		#        (enum GimpImageBaseType in libgimpbase/gimpbaseenums.h)
		try {
			$header = wfUnpack(
				  "A9magic"     # A: space padded
				. "/a5version"  # a: zero padded
				. "/Nwidth"     # \
				. "/Nheight"    # N: unsigned long 32bit big endian
				. "/Nbase_type" # /
			, $binaryHeader
			);
		} catch( MWException $mwe ) {
			return false;
		}

		# Check values
		if( $header['magic'] !== 'gimp xcf' ) {
			wfDebug( __METHOD__ . " '$filename' has invalid magic signature.\n" );
			return false;
		}
		# TODO: we might want to check for sane values of width and height

		wfDebug( __METHOD__ . ": canvas size of '$filename' is {$header['width']} x {$header['height']} px\n" );

		# Forge a return array containing metadata information just like getimagesize()
		# See PHP documentation at: http://www.php.net/getimagesize
		$metadata = array();
		$metadata[0] = $header['width'];
		$metadata[1] = $header['height'];
		$metadata[2] = null;   # IMAGETYPE constant, none exist for XCF.
		$metadata[3] = sprintf(
			'height="%s" width="%s"', $header['height'], $header['width']
		);
		$metadata['mime'] = 'image/x-xcf';
		$metadata['channels'] = null;
		$metadata['bits'] = 8;  # Always 8-bits per color

		assert( '7 == count($metadata); # return array must contains 7 elements just like getimagesize() return' );

		return $metadata;
	}

	/**
	 * Must use "im" for XCF
	 *
	 * @return string
	 */
	protected static function getScalerType( $dstPath, $checkDstPath = true ) {
		return "im";
	}
}