[cygwin-apps/cygutils.git] / src / cygicons / README

Provenance, licensing, and resolution, Oh My!

Windows .ICO file format
========================================================================
Windows icons come in many flavors: size, number of colors, transparency
mechanism, etc.

The format of a single .ico image:
----------------------------------
Each image contains (among other things)
  o an indication of its size in pixels
  o an indication of the bit depth: 1,4,8,24,32
  o [optional]: a palette, containing
    * N entries, where N = 2 ^ bitdepth
    * each entry contains a 32bit record, consisting
      of an 8bit R, G, B triple and a reserve byte
      (no, it's not used for alpha)
  o an "AND" mask containing (most of) the pixel
    data.  This is an MxM raster (LL->LR, ... UL->UR)
    of pixels, where each pixel is represented by 
    1, 4, 8, 24, or 32 bits.  If 4 or 8, then the
    values represent indices into the palette. If
    1, the values represent black/white.  If 24,
    the values represent 24bit RGB data.  If 32,
    the values represent 24bit RGB data + 8bit alpha.
  o [optional]: an "XOR" maks containing (more) pixel
    data.  This is an MxM raster (LL->LR, ... UL->UR)
    of pixels, where each pixel is represent by
    1 bit.  This is used to create transparency (and
    other effects) for 1, 4, 8, and 24 bit icons.
    32bit icons have a built-in alpha channel in the
    "AND" mask, which provides all the transparency 
    effects it needs.    

One-bit transparency:
---------------------
Applies to 1,4,8, and 24 bit icon images.

As mentioned above, each icon image actually contains two
MxM pixel data arrays.  The first is called the "AND mask"
and uses N bits per pixel (where N is 1,4,8,24,or 32, although
32 bit icons use a different mechanism for transparency). The
second data array is called the "XOR mask" and is one bit per
pixel.

The XOR mask allows a few fancy effects: transparency, but
also "inverting" the background.  For transparency to work,
you have to choose one of your 16 (or 256, or 16M) colors
as the "transparent" color, and then make sure the XOR mask
has 1's everywhere the transparent color is used in the AND
mask, and 0's everywhere else.
   For all the nitty-gritty, see
   http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/dnargdi/html/msdn_transblt.asp
By setting up places in the image where the XOR mask has 1's,
but the transparent color is not used in the AND mask at that
location, you get color-inversion at those locations.

Most icon editors simplify this process: you don't deal with
the XOR mask directly. Instead, you pick a color to be the
"transparent" one, and the editor figures out how to construct
the XOR mask from that.  (Thus, color-inversion effects are
hard to achieve with most icon editors).

The point is this: you get N colors (where N=2 ^ bitdepth, so
16 for 4bit, 256 for 8bit, 16M for 24bit) and NO transparency,
or you get N-1 colors and transparency.

Main icon format types:
-----------------------
   16 color: icons which contain only 16 colors
             chosen from a specific palette (not
             just ANY 16 colors).  This palette
             is the EGA 16:
                    0   0    0   black
                  128   0    0   dark red
                    0 128    0   dark green
                  128 128    0   brown
                    0   0  128   dark blue
                  128   0  128   purple
                    0 128  128   teal
                  128 128  128   grey
                  192 192  192   light grey
                  255   0    0   red
                    0 255    0   green
                  255 255    0   yellow
                    0   0  255   blue
                  255   0  255   magenta
                    0 255  255   cyan
                  255 255  255   white

             Additionally, one of these 16 colors
             can be designated the "transparent"
             color, given 15 "real" colors and
             1-bit transparency.

             "1-bit" transparency means no alpha,
             and no anti-aliasing.

   256color: icons which contain only 256 colors
             the palette can specify 256 unique
             colors chosen from the universe of
             16M 24bit RGB values.  Many 256color
             icons use a standard palette (the
             so-called web-safe 216, plus 40 others
             chosen somehow).

             Again, one of these 256 colors can be
             designated the "transparent" color. 
             Windows XP style guidelines say that
             magenta (#ff00ff) should be used for
             this.

             "1-bit" transparency means no alpha,
             and no anti-aliasing.

   24bit   : 16M colors, but you have to give up
             one of them if you want transparency.
             No alpha, no anti-aliasing.

   32bit   : 16M colors, with full 8bit alpha
             support and anti-aliasing.

Main icon sizes:
----------------
   16x16    : used on the TaskBar
   24x24    : uncommon. used on the left half of
              the Start Menu in Windows XP.
   32x32    : default icon size for desktop icons
   48x48    : DisplayProperties->Appearance->Advanced,
              Item=Icon, set size.  Not often used.
   64x64    : New icon size for Vista.
   256x256  : New icon size for Vista. Stored in compressed
              PNG format within the .ico file; completely
              violates all the rules described above.

Icons in this package:
========================================================================
Provenance, licensing, and resolution information.


==================================================
cygwin.ico
    License    : GPL
    Author     : unknown
    Provenance : setup module on cygwin-apps repository
                 cvs -d:pserver:anoncvs@sources.redhat.com:/cvs/cygwin-apps co setup
                 subdir: setup/cygwin.ico
    Comments   :
    Contents   :
      48x48 16 color
      32x32 16 color
      16x16 16 color

==================================================
cygwinred.ico
cygwinblue.ico
cygwincyan.ico
cygwinpurple.ico
cygwinyellow.ico
    License   : GPL
    Author    : Charles Wilson
    Provenance: cygutils module on cygwin-apps repository
                cvs -d:pserver:anoncvs@sources.redhat.com:/cvs/cygwin-apps co cygutils
                subdir: cygutils/src/cygicons/
    Comments  : simple derived works, derived from cygwin.ico
    Contents  :
      48x48 16 color
      32x32 16 color
      16x16 16 color

==================================================
cygwinshiny.ico
    License   : GPL (assumed)
    Author    : Nicky H.
    Provenance: posted to cygwin mailing list
                http://cygwin.com/ml/cygwin/2004-10/msg00549.html
    Comments  : was posted with the express hope that it
                be incorporated into the setup.exe source
                code, which would require GPL.  Note that
                this version has been modified from the
                original, 32bit-only contribution: I added
                256color and 16color versions.
    Contents  :
      48x48 16 color
      32x32 16 color
      16x16 16 color
      48x48 256 color
      32x32 256 color
      16x16 256 color
      48x48 32bit
      32x32 32bit
      16x16 32bit

==================================================
cygwing.ico
    License   : Public Domain (assumed)
    Author    : August Mayer
    Provenance: posted to cygwin mailing list
                http://cygwin.com/ml/cygwin/2001-07/msg01099.html
    Comments  : While I'm not a graphic designer or the like,
                I have created a slightly improved version of
                the Cygwin icon. Enjoy! -- A. Mayer
    Contents  :
      32x32 16 color
      16x16 16 color
      32x32 256 color

==================================================
cygwings.ico
    License   : Public Domain (assumed)
    Author    : August Mayer
    Provenance: posted to cygwin mailing list
                http://cygwin.com/ml/cygwin/2001-07/msg01151.html
    Comments  : Similar to cygwing.ico, but with better anti-aliasing
    Contents  :
      32x32 16 color
      16x16 16 color
      32x32 256 color

==================================================
cygwin-kdelook.ico
    License   : GPL
    Author    : FBL
    Provenance: submitted to kde-look.org
                http://www.kde-look.org/content/show.php?content=36393
    Comments  :
    Contents  :
      96x96 256 color
      72x72 256 color
      64x64 256 color
      48x48 256 color
      32x32 256 color
      16x16 256 color
      96x96 24bit
      72x72 24bit
      64x64 24bit
      48x48 24bit
      32x32 24bit
      16x16 24bit
      96x96 32bit
      72x72 32bit
      64x64 32bit
      48x48 32bit
      32x32 32bit
      16x16 32bit


==================================================
hippo.ico
    License   : CC-BY-SA 3.0
    Author    : Charles Wilson
    Provenance: derived from public domain, Michal Pecyna
                http://openclipart.org/media/files/TheStructorr/1751
    Comments  :
    Contents  :
      48x48 16 color
      32x32 16 color
      24x24 16 color
      16x16 16 color
      48x48 256 color
      32x32 256 color
      24x24 256 color
      16x16 256 color
      64x64 32bit 
      48x48 32bit
      32x32 32bit
      24x24 32bit
      16x16 32bit
      256x256 32bit PNG

<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>.
Commit	Line	Data
65b579cb CW	1	Provenance, licensing, and resolution, Oh My!
65b579cb CW	2
7b4dda32 CW	3	Windows .ICO file format
	4	========================================================================
	5	Windows icons come in many flavors: size, number of colors, transparency
	6	mechanism, etc.
65b579cb CW	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,
6492d64c CW	48	you have to choose one of your 16 (or 256, or 16M) colors
6492d64c CW	49	as the "transparent" color, and then make sure the XOR mask
65b579cb	50	has 1's everywhere the transparent color is used in the AND
6492d64c	51	mask, and 0's everywhere else.
65b579cb CW	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.
7b4dda32	131	64x64 : New icon size for Vista.
65b579cb CW	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:
7b4dda32 CW	137	========================================================================
	138	Provenance, licensing, and resolution information.
	139
	140
65b579cb CW	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
6492d64c CW	200	Comments : While I'm not a graphic designer or the like,
6492d64c CW	201	I have created a slightly improved version of
65b579cb CW	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
7b4dda32 CW	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