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107 lines
3.6 KiB
107 lines
3.6 KiB
package Display::Image;
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use base qw(Exporter);
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our @EXPORT_OK = qw(image_size image_markup);
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=item image_size
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Returns (width, height) of a variety of image files. Called by icon_markup and
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line_parse. Uses Image::Size if available, otherwise uses a couple of built-in
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routines munged together from pngsize and jpegsize in wwwis, by Alex Knowles
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and Andrew Tong.
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=cut
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# needs to call wwwis routine below if we don't have Image::Size...
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my $has_imgsize = eval 'use Image::Size;';
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sub image_size {
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my ($image_file) = shift;
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my ($x, $y, $type);
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if ($has_imgsize) {
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($x, $y, $type) = imgsize($image_file);
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}
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else {
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($x, $y) = wwwis($image_file);
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}
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return ($x, $y);
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}
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sub wwwis {
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my ($image_file) = shift;
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my ($head, $if);
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if ( ! open $if, '<', $image_file ) {
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print STDERR "can't open IMG $image_file";
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return (0, 0);
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} else {
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binmode $if;
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if ($image_file =~ m/\.png$/) { # it's a PNG
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my ($a, $b, $c, $d, $e, $f, $g, $h) = 0;
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if (defined($image_file)
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&& read($if, $head, 8) == 8
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&& ($head eq "\x8a\x4d\x4e\x47\x0d\x0a\x1a\x0a" ||
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$head eq "\x89\x50\x4e\x47\x0d\x0a\x1a\x0a")
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&& read($if, $head, 4) == 4
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&& read($if, $head, 4) == 4
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&& ($head eq "MHDR" || $head eq "IHDR")
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&& read($if, $head, 8) == 8) {
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# ($x, $y) = unpack("I"x2, $head);
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# doesn't work on little-endian machines
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# return ($x,$y);
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($a,$b,$c,$d,$e,$f,$g,$h) = unpack ("C"x8, $head);
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return ($a<<24|$b<<16|$c<<8|$d, $e<<24|$f<<16|$g<<8|$h);
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}
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} elsif ($image_file =~ m/\.jpe?g$/) { # it's a JPEG
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my($done) = 0;
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my($c1,$c2,$ch,$s,$length, $dummy) = (0,0,0,0,0,0);
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my($a,$b,$c,$d);
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if (defined($image_file)
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&& read($if, $c1, 1)
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&& read($if, $c2, 1)
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&& ord($c1) == 0xFF
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&& ord($c2) == 0xD8) {
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while (ord($ch) != 0xDA && !$done) {
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# Find next marker (JPEG markers begin with 0xFF)
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# This can hang the program!!
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while (ord($ch) != 0xFF) {
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return(0,0) unless read($if, $ch, 1);
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}
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# JPEG markers can be padded with unlimited 0xFF's
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while (ord($ch) == 0xFF) {
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return(0,0) unless read($if, $ch, 1);
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}
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# Now, $ch contains the value of the marker.
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if ((ord($ch) >= 0xC0) && (ord($ch) <= 0xC3)) {
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return(0,0) unless read ($if, $dummy, 3);
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return(0,0) unless read($if, $s, 4);
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($a,$b,$c,$d)=unpack("C"x4,$s);
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return ($c<<8|$d, $a<<8|$b );
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} else {
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# We **MUST** skip variables, since FF's within
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# variable names are NOT valid JPEG markers
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return(0,0) unless read ($if, $s, 2);
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($c1, $c2) = unpack("C"x2,$s);
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$length = $c1<<8|$c2;
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last if (!defined($length) || $length < 2);
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read($if, $dummy, $length-2);
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}
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}
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}
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}
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return (0,0);
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}
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}
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1;
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