bmp-to-image-object.php — Admin and Site Enhancements (ASE) 6.2.2

admin-site-enhancements / includes / bmp-to-image-object.php

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bmp-to-image-object.php

182 lines

1	<?php
2
3	/**
4	* Converts BMP to JPG
5	*
6	* @link https://github.com/dompdf/dompdf/blob/master/src/Helpers.php
7	* @link http://www.programmierer-forum.de/function-imagecreatefrombmp-welche-variante-laeuft-t143137.htm
8	* @since 4.3.0
9	*/
10	function bmp_to_image_object( $filename, $context = null ) {
11
12	if (!function_exists("imagecreatetruecolor")) {
13	trigger_error("The PHP GD extension is required, but is not installed.", E_ERROR);
14	return false;
15	}
16
17	// version 1.00
18	if (!($fh = fopen($filename, 'rb'))) {
19	trigger_error('imagecreatefrombmp: Can not open ' . $filename, E_USER_WARNING);
20	return false;
21	}
22
23	$bytes_read = 0;
24
25	// read file header
26	$meta = unpack('vtype/Vfilesize/Vreserved/Voffset', fread($fh, 14));
27
28	// check for bitmap
29	if ($meta['type'] != 19778) {
30	trigger_error('imagecreatefrombmp: ' . $filename . ' is not a bitmap!', E_USER_WARNING);
31	return false;
32	}
33
34	// read image header
35	$meta += unpack('Vheadersize/Vwidth/Vheight/vplanes/vbits/Vcompression/Vimagesize/Vxres/Vyres/Vcolors/Vimportant', fread($fh, 40));
36	$bytes_read += 40;
37
38	// read additional bitfield header
39	if ($meta['compression'] == 3) {
40	$meta += unpack('VrMask/VgMask/VbMask', fread($fh, 12));
41	$bytes_read += 12;
42	}
43
44	// set bytes and padding
45	$meta['bytes'] = $meta['bits'] / 8;
46	$meta['decal'] = 4 - (4 * (($meta['width'] * $meta['bytes'] / 4) - floor($meta['width'] * $meta['bytes'] / 4)));
47	if ($meta['decal'] == 4) {
48	$meta['decal'] = 0;
49	}
50
51	// obtain imagesize
52	if ($meta['imagesize'] < 1) {
53	$meta['imagesize'] = $meta['filesize'] - $meta['offset'];
54	// in rare cases filesize is equal to offset so we need to read physical size
55	if ($meta['imagesize'] < 1) {
56	$meta['imagesize'] = @filesize($filename) - $meta['offset'];
57	if ($meta['imagesize'] < 1) {
58	trigger_error('imagecreatefrombmp: Can not obtain filesize of ' . $filename . '!', E_USER_WARNING);
59	return false;
60	}
61	}
62	}
63
64	// calculate colors
65	$meta['colors'] = !$meta['colors'] ? pow(2, $meta['bits']) : $meta['colors'];
66
67	// read color palette
68	$palette = [];
69	if ($meta['bits'] < 16) {
70	$palette = unpack('l' . $meta['colors'], fread($fh, $meta['colors'] * 4));
71	// in rare cases the color value is signed
72	if ($palette[1] < 0) {
73	foreach ($palette as $i => $color) {
74	$palette[$i] = $color + 16777216;
75	}
76	}
77	}
78
79	// ignore extra bitmap headers
80	if ($meta['headersize'] > $bytes_read) {
81	fread($fh, $meta['headersize'] - $bytes_read);
82	}
83
84	// create gd image
85	$im = imagecreatetruecolor($meta['width'], $meta['height']);
86	$data = fread($fh, $meta['imagesize']);
87
88	// uncompress data
89	switch ($meta['compression']) {
90	case 1:
91	$data = Helpers::rle8_decode($data, $meta['width']);
92	break;
93	case 2:
94	$data = Helpers::rle4_decode($data, $meta['width']);
95	break;
96	}
97
98	$p = 0;
99	$vide = chr(0);
100	$y = $meta['height'] - 1;
101	$error = 'imagecreatefrombmp: ' . $filename . ' has not enough data!';
102
103	// loop through the image data beginning with the lower left corner
104	while ($y >= 0) {
105	$x = 0;
106	while ($x < $meta['width']) {
107	switch ($meta['bits']) {
108	case 32:
109	case 24:
110	if (!($part = substr($data, $p, 3 /$meta['bytes']/))) {
111	trigger_error($error, E_USER_WARNING);
112	return $im;
113	}
114	$color = unpack('V', $part . $vide);
115	break;
116	case 16:
117	if (!($part = substr($data, $p, 2 /$meta['bytes']/))) {
118	trigger_error($error, E_USER_WARNING);
119	return $im;
120	}
121	$color = unpack('v', $part);
122
123	if (empty($meta['rMask']) \|\| $meta['rMask'] != 0xf800) {
124	$color[1] = (($color[1] & 0x7c00) >> 7) * 65536 + (($color[1] & 0x03e0) >> 2) * 256 + (($color[1] & 0x001f) << 3); // 555
125	} else {
126	$color[1] = (($color[1] & 0xf800) >> 8) * 65536 + (($color[1] & 0x07e0) >> 3) * 256 + (($color[1] & 0x001f) << 3); // 565
127	}
128	break;
129	case 8:
130	$color = unpack('n', $vide . substr($data, $p, 1));
131	$color[1] = $palette[$color[1] + 1];
132	break;
133	case 4:
134	$color = unpack('n', $vide . substr($data, floor($p), 1));
135	$color[1] = ($p * 2) % 2 == 0 ? $color[1] >> 4 : $color[1] & 0x0F;
136	$color[1] = $palette[$color[1] + 1];
137	break;
138	case 1:
139	$color = unpack('n', $vide . substr($data, floor($p), 1));
140	switch (($p * 8) % 8) {
141	case 0:
142	$color[1] = $color[1] >> 7;
143	break;
144	case 1:
145	$color[1] = ($color[1] & 0x40) >> 6;
146	break;
147	case 2:
148	$color[1] = ($color[1] & 0x20) >> 5;
149	break;
150	case 3:
151	$color[1] = ($color[1] & 0x10) >> 4;
152	break;
153	case 4:
154	$color[1] = ($color[1] & 0x8) >> 3;
155	break;
156	case 5:
157	$color[1] = ($color[1] & 0x4) >> 2;
158	break;
159	case 6:
160	$color[1] = ($color[1] & 0x2) >> 1;
161	break;
162	case 7:
163	$color[1] = ($color[1] & 0x1);
164	break;
165	}
166	$color[1] = $palette[$color[1] + 1];
167	break;
168	default:
169	trigger_error('imagecreatefrombmp: ' . $filename . ' has ' . $meta['bits'] . ' bits and this is not supported!', E_USER_WARNING);
170	return false;
171	}
172	imagesetpixel($im, $x, $y, $color[1]);
173	$x++;
174	$p += $meta['bytes'];
175	}
176	$y--;
177	$p += $meta['decal'];
178	}
179	fclose($fh);
180	return $im;
181
182	}