[projectaon] Re: PNGout
- From: "Robert Wellock" <xhtmlcoder@xxxxxxxxx>
- To: projectaon@xxxxxxxxxxxxx
- Date: Thu, 24 Apr 2008 11:24:02 +0100
To clarify; GIF does NOT support truecolor images, alpha channels, or
gamma correction in the first place.
PNGOUTWin doesn't affect the "Standard Chunks" by 'Default' it only
concerns itself with the "Ancillary Chunks", for example:
bKGD - background color - specifies a default background colour to
present the image against.
pHYs - encodes the absolute or relative dimensions of pixels, e.g. aspect ratio.
gAMA - specifies the gamma of the camera (or simulated camera).
cHRM - is allowed in all PNG files, although it is of little value for
greyscale images.
iCCP - ICC profile.
sRGB - cross system colour fidelity.
sBIT - sample depths.
sPLT - suggested-palette chunk.
hIST - histogram is nothing more than a frequency-of-occurrence table.
tiME - timestamp.
iTXt - international text Annotations.
tEXt - textual data, keyword or the text string.
zTXt - compressed textual data.
As you can see most of them would be overkill in PNG-8, e.g. bKGD,
tiME, iTXt, tEXt, zTXt for the Internet Editions. The "equivalents"
weren't already present in the GIF specifications anyway so all-in-all
if it weren't there it cannot have been lost.
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