--- /dev/null
+#!/usr/bin/perl
+
+# Take a collection of input image files and convert them into a
+# multi-resolution Windows .ICO icon file.
+#
+# The input images can be treated as having four different colour
+# depths:
+#
+# - 24-bit true colour
+# - 8-bit with custom palette
+# - 4-bit using the Windows 16-colour palette (see comment below
+# for details)
+# - 1-bit using black and white only.
+#
+# The images can be supplied in any input format acceptable to
+# ImageMagick, but their actual colour usage must already be
+# appropriate for the specified mode; this script will not do any
+# substantive conversion. So if an image intended to be used in 4-
+# or 1-bit mode contains any colour not in the appropriate fixed
+# palette, that's a fatal error; if an image to be used in 8-bit
+# mode contains more than 256 distinct colours, that's also a fatal
+# error.
+#
+# Command-line syntax is:
+#
+# icon.pl -depth imagefile [imagefile...] [-depth imagefile [imagefile...]]
+#
+# where `-depth' is one of `-24', `-8', `-4' or `-1', and tells the
+# script how to treat all the image files given after that option
+# until the next depth option. For example, you might execute
+#
+# icon.pl -24 48x48x24.png 32x32x24.png -8 32x32x8.png -1 monochrome.png
+#
+# to build an icon file containing two differently sized 24-bit
+# images, one 8-bit image and one black and white image.
+#
+# Windows .ICO files support a 1-bit alpha channel on all these
+# image types. That is, any pixel can be either opaque or fully
+# transparent, but not partially transparent. The alpha channel is
+# separate from the main image data, meaning that `transparent' is
+# not required to take up a palette entry. (So an 8-bit image can
+# have 256 distinct _opaque_ colours, plus transparent pixels as
+# well.) If the input images have alpha channels, they will be used
+# to determine which pixels of the icon are transparent, by simple
+# quantisation half way up (e.g. in a PNG image with an 8-bit alpha
+# channel, alpha values of 00-7F will be mapped to transparent
+# pixels, and 80-FF will become opaque).
+
+# The Windows 16-colour palette consists of:
+# - the eight corners of the colour cube (000000, 0000FF, 00FF00,
+# 00FFFF, FF0000, FF00FF, FFFF00, FFFFFF)
+# - dim versions of the seven non-black corners, at 128/255 of the
+# brightness (000080, 008000, 008080, 800000, 800080, 808000,
+# 808080)
+# - light grey at 192/255 of full brightness (C0C0C0).
+%win16pal = (
+ "\x00\x00\x00\x00" => 0,
+ "\x00\x00\x80\x00" => 1,
+ "\x00\x80\x00\x00" => 2,
+ "\x00\x80\x80\x00" => 3,
+ "\x80\x00\x00\x00" => 4,
+ "\x80\x00\x80\x00" => 5,
+ "\x80\x80\x00\x00" => 6,
+ "\xC0\xC0\xC0\x00" => 7,
+ "\x80\x80\x80\x00" => 8,
+ "\x00\x00\xFF\x00" => 9,
+ "\x00\xFF\x00\x00" => 10,
+ "\x00\xFF\xFF\x00" => 11,
+ "\xFF\x00\x00\x00" => 12,
+ "\xFF\x00\xFF\x00" => 13,
+ "\xFF\xFF\x00\x00" => 14,
+ "\xFF\xFF\xFF\x00" => 15,
+);
+@win16pal = sort { $win16pal{$a} <=> $win16pal{$b} } keys %win16pal;
+
+# The black and white palette consists of black (000000) and white
+# (FFFFFF), obviously.
+%win2pal = (
+ "\x00\x00\x00\x00" => 0,
+ "\xFF\xFF\xFF\x00" => 1,
+);
+@win2pal = sort { $win16pal{$a} <=> $win2pal{$b} } keys %win2pal;
+
+@hdr = ();
+@dat = ();
+
+$depth = undef;
+foreach $_ (@ARGV) {
+ if (/^-(24|8|4|1)$/) {
+ $depth = $1;
+ } elsif (defined $depth) {
+ &readicon($_, $depth);
+ } else {
+ $usage = 1;
+ }
+}
+if ($usage || length @hdr == 0) {
+ print "usage: icon.pl ( -24 | -8 | -4 | -1 ) image [image...]\n";
+ print " [ ( -24 | -8 | -4 | -1 ) image [image...] ...]\n";
+ exit 0;
+}
+
+# Now write out the output icon file.
+print pack "vvv", 0, 1, scalar @hdr; # file-level header
+$filepos = 6 + 16 * scalar @hdr;
+for ($i = 0; $i < scalar @hdr; $i++) {
+ print $hdr[$i];
+ print pack "V", $filepos;
+ $filepos += length($dat[$i]);
+}
+for ($i = 0; $i < scalar @hdr; $i++) {
+ print $dat[$i];
+}
+
+sub readicon {
+ my $filename = shift @_;
+ my $depth = shift @_;
+ my $pix;
+ my $i;
+ my %pal;
+
+ # Determine the icon's width and height.
+ my $w = `identify -format %w $filename`;
+ my $h = `identify -format %h $filename`;
+
+ # Read the file in as RGBA data. We flip vertically at this
+ # point, to avoid having to do it ourselves (.BMP and hence
+ # .ICO are bottom-up).
+ my $data = [];
+ open IDATA, "convert -flip -depth 8 $filename rgba:- |";
+ push @$data, $rgb while (read IDATA,$rgb,4,0) == 4;
+ close IDATA;
+ # Check we have the right amount of data.
+ $xl = $w * $h;
+ $al = scalar @$data;
+ die "wrong amount of image data ($al, expected $xl) from $filename\n"
+ unless $al == $xl;
+
+ # Build the alpha channel now, so we can exclude transparent
+ # pixels from the palette analysis. We replace transparent
+ # pixels with undef in the data array.
+ #
+ # We quantise the alpha channel half way up, so that alpha of
+ # 0x80 or more is taken to be fully opaque and 0x7F or less is
+ # fully transparent. Nasty, but the best we can do without
+ # dithering (and don't even suggest we do that!).
+ my $x;
+ my $y;
+ my $alpha = "";
+
+ for ($y = 0; $y < $h; $y++) {
+ my $currbyte = 0, $currbits = 0;
+ for ($x = 0; $x < (($w+31)|31)-31; $x++) {
+ $pix = ($x < $w ? $data->[$y*$w+$x] : "\x00\x00\x00\xFF");
+ my @rgba = unpack "CCCC", $pix;
+ $currbyte <<= 1;
+ $currbits++;
+ if ($rgba[3] < 0x80) {
+ if ($x < $w) {
+ $data->[$y*$w+$x] = undef;
+ }
+ $currbyte |= 1; # MS has the alpha channel inverted :-)
+ } else {
+ # Might as well flip RGBA into BGR0 while we're here.
+ if ($x < $w) {
+ $data->[$y*$w+$x] = pack "CCCC",
+ $rgba[2], $rgba[1], $rgba[0], 0;
+ }
+ }
+ if ($currbits >= 8) {
+ $alpha .= pack "C", $currbyte;
+ $currbits -= 8;
+ }
+ }
+ }
+
+ # For an 8-bit image, check we have at most 256 distinct
+ # colours, and build the palette.
+ %pal = ();
+ if ($depth == 8) {
+ my $palindex = 0;
+ foreach $pix (@$data) {
+ next unless defined $pix;
+ $pal{$pix} = $palindex++ unless defined $pal{$pix};
+ }
+ die "too many colours in 8-bit image $filename\n" unless $palindex <= 256;
+ } elsif ($depth == 4) {
+ %pal = %win16pal;
+ } elsif ($depth == 1) {
+ %pal = %win2pal;
+ }
+
+ my $raster = "";
+ if ($depth < 24) {
+ # For a non-24-bit image, flatten the image into one palette
+ # index per pixel.
+ $pad = 32 / $depth; # number of pixels to pad scanline to 4-byte align
+ $pmask = $pad-1;
+ for ($y = 0; $y < $h; $y++) {
+ my $currbyte = 0, $currbits = 0;
+ for ($x = 0; $x < (($w+$pmask)|$pmask)-$pmask; $x++) {
+ $currbyte <<= $depth;
+ $currbits += $depth;
+ if ($x < $w && defined ($pix = $data->[$y*$w+$x])) {
+ if (!defined $pal{$pix}) {
+ die "illegal colour value $pix at pixel $i in $filename\n";
+ }
+ $currbyte |= $pal{$pix};
+ }
+ if ($currbits >= 8) {
+ $raster .= pack "C", $currbyte;
+ $currbits -= 8;
+ }
+ }
+ }
+ } else {
+ # For a 24-bit image, reverse the order of the R,G,B values
+ # and stick a padding zero on the end.
+ #
+ # (In this loop we don't need to bother padding the
+ # scanline out to a multiple of four bytes, because every
+ # pixel takes four whole bytes anyway.)
+ for ($i = 0; $i < scalar @$data; $i++) {
+ if (defined $data->[$i]) {
+ $raster .= $data->[$i];
+ } else {
+ $raster .= "\x00\x00\x00\x00";
+ }
+ }
+ $depth = 32; # and adjust this
+ }
+
+ # Prepare the icon data. First the header...
+ my $data = pack "VVVvvVVVVVV",
+ 40, # size of bitmap info header
+ $w, # icon width
+ $h*2, # icon height (x2 to indicate the subsequent alpha channel)
+ 1, # 1 plane (common to all MS image formats)
+ $depth, # bits per pixel
+ 0, # no compression
+ length $raster, # image size
+ 0, 0, 0, 0; # resolution, colours used, colours important (ignored)
+ # ... then the palette ...
+ if ($depth <= 8) {
+ my $ncols = (1 << $depth);
+ my $palette = "\x00\x00\x00\x00" x $ncols;
+ foreach $i (keys %pal) {
+ substr($palette, $pal{$i}*4, 4) = $i;
+ }
+ $data .= $palette;
+ }
+ # ... the raster data we already had ready ...
+ $data .= $raster;
+ # ... and the alpha channel we already had as well.
+ $data .= $alpha;
+
+ # Prepare the header which will represent this image in the
+ # icon file.
+ my $header = pack "CCCCvvV",
+ $w, $h, # width and height (this time the real height)
+ 1 << $depth, # number of colours, if less than 256
+ 0, # reserved
+ 1, # planes
+ $depth, # bits per pixel
+ length $data; # size of real icon data
+
+ push @hdr, $header;
+ push @dat, $data;
+}
projects / PuTTY.git / blobdiff