How To Make PNG
This page explains how to create pictures with all emulators that
support rerecording, in PNG, Portable Network Graphics, format as small file as possible.
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Snapshots when using Windows
Famtasia
Go to FILE menu, then NEW ->Save BMP.
Now choose a directory and a name.
VirtuaNES
Press Ctrl+P and the picture(s), in BMP format,
should be created in a directory named snapshot.
That one is in VirtuaNES default path.
FCE Ultra
Press F12 and the picture(s), in PNG format,
should be created in a directory named snaps.
That one is in FCE Ultra default path.
Snes9x
Simply press F12 during gameplay and the picture(s),
in PNG format, should be in your rom(s)
directory or Snes9x default path.
Gens
Press Shift+Backspace and the picture(s), in BMP format,
should be in Gens default path.
FB Alpha
Simply press F12 during gameplay and the picture(s),
in PNG format, should be created in a directory
named screenshots. That one is in
FB Alpha default path.
Snapshots when using Linux
In Linux, when you install Imagemagick, you can use
import to
take screenshots of any window. Example:
import tmp.png
Then click the window to take screenshot from, and it beeps twice
when the file is ready.
You can also select a region from screen by pressing the button
somewhere and dragging the cursor to mark the corners of the region.
If you use KDE, there is a program which comes with most KDE installs called KSnapshot. It can take images from any window or area, take images on a timer, and remove window decorations automatically. Simply open it, and have it take a snapshot of the active window with the remove decorations box checked.
If your snapshots contains menubars and other irrelevant things,
use an image manipulation program such as
The GIMP
to remove them.
Also ensure that your image is 8-bit, because
avdpng
can only handle 8-bit images.
You can do the conversion with Imagemagick
with a command line such as this:
convert tmp.png -colors 256 -depth 8 +dither tmp2.png
or you can use an image manipulation program to do it.
Ps: The programs mentioned in this chapter
can be used in Windows too.
Minimizing the file size
Firstly, pictures in BMP format should be converted into PNG format.
You can use
bmp2png downloadable at:
http://hp.vector.co.jp/authors/VA010446/b2p-home/index.html.
Or, you can use an image manipulation program such as
The GIMP.
Now, you need AdvanceCOMP. You can download it at:
http://advancemame.sourceforge.net/comp-download.html
AdvanceCOMP consists of 4 or more utilities. The one
that recompresses PNG files is called AdvPNG.
For more information on how to use it, read the
documentation included with it.
Example of command line:
advpng.exe -z -4 *.png
After this, all supported PNG images in the
current directory are optimized.
There exists also another program,
pngcrush, to minimize png files. While in most cases advpng makes a better job than pngcrush, there are certain few cases where pngcrush actually produces smaller files. If maximum possible compression is desired, it may be a good idea to try both.
There exists also a program called
PNGOUT.
I tried it and it seems to outperform AdvPNG in almost all cases.
I'll use it from now on.
Unfortunately though, it's not
free.
It is only
free as in price, which is nice
as long as you don't mind being limited to the options given to you. -
Bisqwit
Yet another program that can be used is
optipng, which is similar to pngcrush.
DeflOpt is a program which should be run last on PNGs, and it can typically reduce the filesize of images produced by pngcrush and other PNG optimizers by 3-3,000 bytes.
There exists a
tutorial about PNGOUT
for Windows users. Note: Do
not drag and drop the image file onto the pngout executable, because it uses RGB compression, when we want palette compression. Do this as follows:
- In the same folder as pngout.exe, write a .bat file with the following text: start /wait pngout.exe /c3 zz.png (all on one line).
- Name your .png file zz.png and place it in the same folder as pngout.exe.
- Run the .bat file.
zz.png should be replaced by the compressed file.
Example of PNGOUT command line in Linux:
for s in *.png;do ./pngout* -c3 -b0 -v "$s" tmp.png && mv -f tmp.png "$s";done
This handles all PNG files in the current directory. To handle
a single file, do
./pngout* -c3 -b0 -v file.png. This creates
file_.png.
Note that PNGOUT can read BMP files directly. You don't need to convert them first.
But the input should be made 8-bit for best compression, as shown before.
Note that in some cases PNGOUT produces PNG files that don't work on all platforms
(due to broken zlib implementations on those platforms).


HowToMakePNG last edited by ccfreak2k on 2008-06-01 03:03:03
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