src/cygicons/README

   1 Provenance, licensing, and resolution, Oh My!
   2
   3 Windows .ICO file format
   4 ========================================================================
   5 Windows icons come in many flavors: size, number of colors, transparency
   6 mechanism, etc.
   7
   8 The format of a single .ico image:
   9 ----------------------------------
  10 Each image contains (among other things)
  11   o an indication of its size in pixels
  12   o an indication of the bit depth: 1,4,8,24,32
  13   o [optional]: a palette, containing
  14     * N entries, where N = 2 ^ bitdepth
  15     * each entry contains a 32bit record, consisting
  16       of an 8bit R, G, B triple and a reserve byte
  17       (no, it's not used for alpha)
  18   o an "AND" mask containing (most of) the pixel
  19     data.  This is an MxM raster (LL->LR, ... UL->UR)
  20     of pixels, where each pixel is represented by
  21     1, 4, 8, 24, or 32 bits.  If 4 or 8, then the
  22     values represent indices into the palette. If
  23     1, the values represent black/white.  If 24,
  24     the values represent 24bit RGB data.  If 32,
  25     the values represent 24bit RGB data + 8bit alpha.
  26   o [optional]: an "XOR" maks containing (more) pixel
  27     data.  This is an MxM raster (LL->LR, ... UL->UR)
  28     of pixels, where each pixel is represent by
  29     1 bit.  This is used to create transparency (and
  30     other effects) for 1, 4, 8, and 24 bit icons.
  31     32bit icons have a built-in alpha channel in the
  32     "AND" mask, which provides all the transparency
  33     effects it needs.
  34
  35 One-bit transparency:
  36 ---------------------
  37 Applies to 1,4,8, and 24 bit icon images.
  38
  39 As mentioned above, each icon image actually contains two
  40 MxM pixel data arrays.  The first is called the "AND mask"
  41 and uses N bits per pixel (where N is 1,4,8,24,or 32, although
  42 32 bit icons use a different mechanism for transparency). The
  43 second data array is called the "XOR mask" and is one bit per
  44 pixel.
  45
  46 The XOR mask allows a few fancy effects: transparency, but
  47 also "inverting" the background.  For transparency to work,
  48 you have to choose one of your 16 (or 256, or 16M) colors
  49 as the "transparent" color, and then make sure the XOR mask
  50 has 1's everywhere the transparent color is used in the AND
  51 mask, and 0's everywhere else.
  52    For all the nitty-gritty, see
  53    http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/dnargdi/html/msdn_transblt.asp
  54 By setting up places in the image where the XOR mask has 1's,
  55 but the transparent color is not used in the AND mask at that
  56 location, you get color-inversion at those locations.
  57
  58 Most icon editors simplify this process: you don't deal with
  59 the XOR mask directly. Instead, you pick a color to be the
  60 "transparent" one, and the editor figures out how to construct
  61 the XOR mask from that.  (Thus, color-inversion effects are
  62 hard to achieve with most icon editors).
  63
  64 The point is this: you get N colors (where N=2 ^ bitdepth, so
  65 16 for 4bit, 256 for 8bit, 16M for 24bit) and NO transparency,
  66 or you get N-1 colors and transparency.
  67
  68 Main icon format types:
  69 -----------------------
  70    16 color: icons which contain only 16 colors
  71              chosen from a specific palette (not
  72              just ANY 16 colors).  This palette
  73              is the EGA 16:
  74                     0   0    0   black
  75                   128   0    0   dark red
  76                     0 128    0   dark green
  77                   128 128    0   brown
  78                     0   0  128   dark blue
  79                   128   0  128   purple
  80                     0 128  128   teal
  81                   128 128  128   grey
  82                   192 192  192   light grey
  83                   255   0    0   red
  84                     0 255    0   green
  85                   255 255    0   yellow
  86                     0   0  255   blue
  87                   255   0  255   magenta
  88                     0 255  255   cyan
  89                   255 255  255   white
  90
  91              Additionally, one of these 16 colors
  92              can be designated the "transparent"
  93              color, given 15 "real" colors and
  94              1-bit transparency.
  95
  96              "1-bit" transparency means no alpha,
  97              and no anti-aliasing.
  98
  99    256color: icons which contain only 256 colors
 100              the palette can specify 256 unique
 101              colors chosen from the universe of
 102              16M 24bit RGB values.  Many 256color
 103              icons use a standard palette (the
 104              so-called web-safe 216, plus 40 others
 105              chosen somehow).
 106
 107              Again, one of these 256 colors can be
 108              designated the "transparent" color.
 109              Windows XP style guidelines say that
 110              magenta (#ff00ff) should be used for
 111              this.
 112
 113              "1-bit" transparency means no alpha,
 114              and no anti-aliasing.
 115
 116    24bit   : 16M colors, but you have to give up
 117              one of them if you want transparency.
 118              No alpha, no anti-aliasing.
 119
 120    32bit   : 16M colors, with full 8bit alpha
 121              support and anti-aliasing.
 122
 123 Main icon sizes:
 124 ----------------
 125    16x16    : used on the TaskBar
 126    24x24    : uncommon. used on the left half of
 127               the Start Menu in Windows XP.
 128    32x32    : default icon size for desktop icons
 129    48x48    : DisplayProperties->Appearance->Advanced,
 130               Item=Icon, set size.  Not often used.
 131    64x64    : New icon size for Vista.
 132    256x256  : New icon size for Vista. Stored in compressed
 133               PNG format within the .ico file; completely
 134               violates all the rules described above.
 135
 136 Icons in this package:
 137 ========================================================================
 138 Provenance, licensing, and resolution information.
 139
 140
 141 ==================================================
 142 cygwin.ico
 143     License    : GPL
 144     Author     : unknown
 145     Provenance : setup module on cygwin-apps repository
 146                  cvs -d:pserver:anoncvs@sources.redhat.com:/cvs/cygwin-apps co setup
 147                  subdir: setup/cygwin.ico
 148     Comments   :
 149     Contents   :
 150       48x48 16 color
 151       32x32 16 color
 152       16x16 16 color
 153
 154 ==================================================
 155 cygwinred.ico
 156 cygwinblue.ico
 157 cygwincyan.ico
 158 cygwinpurple.ico
 159 cygwinyellow.ico
 160     License   : GPL
 161     Author    : Charles Wilson
 162     Provenance: cygutils module on cygwin-apps repository
 163                 cvs -d:pserver:anoncvs@sources.redhat.com:/cvs/cygwin-apps co cygutils
 164                 subdir: cygutils/src/cygicons/
 165     Comments  : simple derived works, derived from cygwin.ico
 166     Contents  :
 167       48x48 16 color
 168       32x32 16 color
 169       16x16 16 color
 170
 171 ==================================================
 172 cygwinshiny.ico
 173     License   : GPL (assumed)
 174     Author    : Nicky H.
 175     Provenance: posted to cygwin mailing list
 176                 http://cygwin.com/ml/cygwin/2004-10/msg00549.html
 177     Comments  : was posted with the express hope that it
 178                 be incorporated into the setup.exe source
 179                 code, which would require GPL.  Note that
 180                 this version has been modified from the
 181                 original, 32bit-only contribution: I added
 182                 256color and 16color versions.
 183     Contents  :
 184       48x48 16 color
 185       32x32 16 color
 186       16x16 16 color
 187       48x48 256 color
 188       32x32 256 color
 189       16x16 256 color
 190       48x48 32bit
 191       32x32 32bit
 192       16x16 32bit
 193
 194 ==================================================
 195 cygwing.ico
 196     License   : Public Domain (assumed)
 197     Author    : August Mayer
 198     Provenance: posted to cygwin mailing list
 199                 http://cygwin.com/ml/cygwin/2001-07/msg01099.html
 200     Comments  : While I'm not a graphic designer or the like,
 201                 I have created a slightly improved version of
 202                 the Cygwin icon. Enjoy! -- A. Mayer
 203     Contents  :
 204       32x32 16 color
 205       16x16 16 color
 206       32x32 256 color
 207
 208 ==================================================
 209 cygwings.ico
 210     License   : Public Domain (assumed)
 211     Author    : August Mayer
 212     Provenance: posted to cygwin mailing list
 213                 http://cygwin.com/ml/cygwin/2001-07/msg01151.html
 214     Comments  : Similar to cygwing.ico, but with better anti-aliasing
 215     Contents  :
 216       32x32 16 color
 217       16x16 16 color
 218       32x32 256 color
 219
 220 ==================================================
 221 cygwin-kdelook.ico
 222     License   : GPL
 223     Author    : FBL
 224     Provenance: submitted to kde-look.org
 225                 http://www.kde-look.org/content/show.php?content=36393
 226     Comments  :
 227     Contents  :
 228       96x96 256 color
 229       72x72 256 color
 230       64x64 256 color
 231       48x48 256 color
 232       32x32 256 color
 233       16x16 256 color
 234       96x96 24bit
 235       72x72 24bit
 236       64x64 24bit
 237       48x48 24bit
 238       32x32 24bit
 239       16x16 24bit
 240       96x96 32bit
 241       72x72 32bit
 242       64x64 32bit
 243       48x48 32bit
 244       32x32 32bit
 245       16x16 32bit
 246
 247
 248 ==================================================
 249 hippo.ico
 250     License   : CC-BY-SA 3.0
 251     Author    : Charles Wilson
 252     Provenance: derived from public domain, Michal Pecyna
 253                 http://openclipart.org/media/files/TheStructorr/1751
 254     Comments  :
 255     Contents  :
 256       48x48 16 color
 257       32x32 16 color
 258       24x24 16 color
 259       16x16 16 color
 260       48x48 256 color
 261       32x32 256 color
 262       24x24 256 color
 263       16x16 256 color
 264       64x64 32bit
 265       48x48 32bit
 266       32x32 32bit
 267       24x24 32bit
 268       16x16 32bit
 269       256x256 32bit PNG
 270
 271 <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/us/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-sa/3.0/us/88x31.png" /></a><br /><span xmlns:dc="http://purl.org/dc/elements/1.1/" href="http://purl.org/dc/dcmitype/StillImage" property="dc:title" rel="dc:type">hippo.ico</span> by <span xmlns:cc="http://creativecommons.org/ns#" property="cc:attributionName">Charles Wilson</span> is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/us/">Creative Commons Attribution-Share Alike 3.0 United States License</a>.<br />Based on a work at <a xmlns:dc="http://purl.org/dc/elements/1.1/" href=" http://openclipart.org/media/files/TheStructorr/1751" rel="dc:source"> http://openclipart.org/media/files/TheStructorr/1751</a>.
 272