1. == PngOptimizer Changelog ==
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2012-09-09 (2.2)
- new: support of the ".apng" file extension
- fixed: only lower case file extensions were managed. The extension case is not
relevant anymore.
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2012-06-09 (2.1)
- new: option to keep or force pixel physical dimensions (pHYs chunk)
- new: better compatibility for old Windows versions (NT based)
- new: Windows Seven taskbar icon now shows progression of an optimization
- new: better automatic dialogs placement when near screen borders, near taskbar
or with multiple monitors
- new: the list is now scrollable with the keyboard
- new: "Done" written at the end of multiple files optimization
- new: screenshot directory dialog can be resized
-----------------
2011-04-25 (2.0)
- new: support for APNG for both optimization and conversion (animated GIFs)
- new: x64 version
- new: PNG options moved to their own dialog window
- new: option to ignore animated GIFs
- new: option to keep original file date and time
- new: option to force background color (bkGD chunk)
- new: option to keep or force textual information (tEXt chunk)
- new: always on top option for the main window in the contextual menu
- new: suggested screenshot filename now keeps leading "0" for file number (file
001.png, file 002.png...)
- new: suggested screenshot filename now accepts "-" as a number separator
(file-01.png file-02.png...)
- change: AvoidGreyWithSimpleTransparency is now disabled by default (was for
IE6 compatibility)
- change: keyboard shortcut to clear the list is slightly less complicated:
Ctrl+Delete instead of Ctrl+Shift+Delete
- misc: better results with some cases of indexed color images
- misc: updated ZLib 1.2.3 to 1.2.5 (compression library)
- fixed: bad % reported for large files
- fixed: hangs at startup when loading an empty configuration file
(PngOptimizer.ini)
- fixed: could not load GIFs containing non-Netscape application extensions
blocks
(like XMP data from Photoshop CS)
- fixed: could not load GIFs with a compressed block ending with a terminator
instead of an end-of-information code
-----------------
2009-12-13 (1.9)
Internal version
-----------------
2008-11-02 (1.8)
- new: uses Windows XP and Windows Vista theme on those platforms
- new: uses a lot less memory when optimizing

2. - new: when asking for a screenshot file name: does not select the .png part of
the file name
- new: when asking for a screenshot file name: proposes a new file name based on
the previous file name
- corrected: freezes on Windows Vista
- corrected: better anti-aliased text in the list
-----------------
2008-09-11 (1.7)
Private release by Paul Higginbottom
-----------------
2007-04-22 (1.6.1)
- corrected : more robust clipboard code to avoid crash whith strange bitmap
data (MSN messenger, again)
-----------------
2007-04-16 (1.6)
- new: optimization engine improved
- new: dump of a clean copy of the source PNG file if the compression cannot be
improved
- new: directories accepted for drag-and-drop (with recursive optimization)
- new: TGA files accepted
- new: more BMP formats accepted
- new: added an option to optimize screenshots
- new: added an option to ask for the file name of a screenshot
- new: settings stored in a configuration file instead of the registry
- corrected: bug for 32 bits images converted to palette images that contained
more than one fully transparent color
- corrected: could not load 24 bits BMP with a colorcount set to 16777216
(expected 0 for the colorcount)
- corrected: bug when decoding a transparent GIF with a local palette
- corrected: screenshot drag-and-drop could not be done to some applications
- corrected: PngOptimizer was complaining when the source file was read-only
even when a new file was created
- corrected: no blocking anymore when optimizing files given through the command
line
- internal: use of the chustd framework instead of the dkstd
- internal: improved software architecture
- misc: PngOptimizer is now Open Source software
- misc: dropped support for Windows 98/Me
-----------------
2006-01-09 (1.5.4 aka 1.54)
- uneeded bKGD chunk inserted when the « Keep background color » option was set.
-----------------
2006-01-07 (1.5.3 aka 1.53)
- Use of critical section to avoid potential conflict between the user interface
and the working thread.
- Corrected 24 bits & 32 bits BMP decoding errors.
- Support for 16 bits BMPs.
- "Clear" option in the context menu to clear the list.
- Better previous window positionning :

3. - When PngOptimizer was minimized then closed, the window was unreachable at
relaunch.
- When other instances of PngOptimizer are running, the window is now
offseted respectively to the previous
instance window.
-----------------
2005-11-20 (1.5.2 aka 1.52)
- Use of the latest zlib (v1.2.3 ; 2005-07-18) instead of the zlib++ based on
v1.1.4
- Further compression for 24 bits images :
Checking size without filtering : slower optimization but improves file size
(no more +50% increase)
- Further compression for 32 bits images :
Checking size without filtering (same method than for 24 bits images).
A 32 bits image which could be converted to a 24 bits image was then stored
to the disk.
Now PngOptimizer feeds the 24 bits image to the 24 bits optimizer (which can
lead to a palette image).
- Improved general compression by changing the ZLib compression strategy :
Filtered images are stored with the Z_FILTERED strategy, otherwise
Z_DEFAULT_STRATEGY is used.
For 32 bits images, both strategy are used and compared, as Z_FILTERED does
not always give
the best results for 32 bits filtered pictures.
- Warning when converting animated GIF
2005-08-15 (1.5.1 aka 1.51)
- BMP decoder crash with 32 bits BMPs
- Crashed when a fake bitmap was stored in the clipboard :
IsClipboardFormatAvailable(CF_BITMAP) returned true,
GetClipboardData(CF_BITMAP) returned NULL
Case found when copying & pasting MSN Messenger smileys
-----------------
2005-03-11 (1.5)
- Full Unicode support (except for PngOptimizerCL).
- Corrected two memory leaks when decoding BMP and GIF files.
- Added an option to keep the background color (bKGD). Please note that the
background color is
not kept with indexed (palette mode) pictures. This option only works with
true-color or grey
pictures.
- PngOptimizer remembers the last window position and size.
- The main text window has been enhanced. Printing is faster in some cases. You
can now scroll
inside with the keyboard and the mouse wheel. The scrolling position is not
lost anymore when
you resize the window.
- For the first time in PngOptimizer history, introducing multithreading :) You
can now move
the interface while PngOptimizer is working.
- Support for compressed BMP added.

4. - Support for bitmap stored in the clipboard. Primary used for screenshots, but
can be used
for any bitmap stored in the clipboard.
.:: More Info
1) Take a screenshot with the "Print Screen" key or Alt+"Print Screen" for the
current window only.
2) Press Ctrl+V or Shift+Insert in the PngOptimizer window, or right-click in
PngOptimizer and
choose "Paste screenshot"
3) PngOptimizer creates a PNG file from your screenshot, and prints the
filename in its window.
4) You can drag the file name out of the PngOptimizer window in any
application which accepts
dragged files.
5) You can also double-click on the file name to display your picture in your
favorite picture
viewer.
By default, those files are stored in your Temp directory in your Windows
profile. For example :
C:Documents and SettingsYourNameLocal SettingsTemp
In Windows 98, the default storage location is located in the global Temp
directory. For example :
C:WINDOWSTEMP
You can change the storage location : Right click in PngOptimizer and
select "Change screenshots directory". A dialog box will allow you to select
the screenshots location.
You can view the content of the screenshots directory by right-clicking in the
PngOptimizer window
and choose "Show screenshots directory".
Those PNG files are compressed with a medium ratio (zlib compression 6), in
order to reduce
the creation time. If you want to reduce the size a bit more, you can drag
them from a file
explorer to the PngOptimizer window.
.:: Even More Info
About dragging operations.
The dragging result can be either a move or a copy of the screenshot file.
The dragging behaviour is the same you are used to in Windows. For example, if
you drag the file out
of PngOptimizer to a file manager window, in the same partition than the
screenshot directory, this
will result in a move.
To force a copy, press the Control key during the dragging.
To force a move, press the Shift key during the dragging.
As usual in Windows, the mouse cursor will show a "+" symbol if the dragging
will result in a copy.
No "+" appears if the dragging will result in a move.
If the result of the dragging is a move, the link in the PngOptimizer is

5. disabled, and its
color changes.
- Support for command line filenames.
.:: More Info
It means you can select several files in the file explorer and drag them to
the PngOptimizer
executable file. You can also create a PngOptimizer shortcut into your «
SendTo » folder. Then you
select several files in the file explorer and send them to PngOptimizer.
- A new icon provided by Guillaume Schaeffer.
-----------------
2004-07-12 (1.4)
- Unicode support (for filenames and the log window).
.:: More Info
PngOptimizer uses the same font than the file explorer. To display correctly
Unicode strings in both
Windows and PngOptimizer, set the icon font to a complete unicode font, such
as "Arial Unicode MS".
Note that Windows 95/98/Me do not support Unicode filenames, so I had to add
compatibility routines
to deal with ANSI strings instead.
- A new icon :)
- Stability improvement when loading corrupted GIFs.
- Support for 32 bits BMPs.
- Better management of grayscale mode PNGs.
- New compression strategy. PngOptimizer now also checks compression with the
palette sorted
according to the number of color occurrences. It also checks the compression
result with
and without adaptive filtering. The optimization can be now a little more
slower but the
compression should be better.
.:: More Info
Adaptive filtering is a way of reordering byte values in PNGs in order to
improve
the compression. But sometimes the compression library performs better without
this reordering.
- I also created a Command Line version of PngOptimizer. It's called
PngOptimizerCL. Here are
the arguments :
For one file :
PngOptimizerCL -file:"my file cool picture.png"
You can use wildcards to specify several files at once :
PngOptimizerCL -file:"Some Folder/*.png"
The options have the same meanings than the GUI version. Here you are :
-BackupOldPngFiles
-KeepInterlacing

6. -AvoidGreyWithSimpleTransparency
Example :
PngOptimizerCL -file:"my-logo.png" -KeepInterlacing -BackupOldPngFiles
Note : the options set in the GUI version DO NOT impact on the Command Line
version. This
behaviour is by design.
Note : you will get some information if you call PngOptimizerCL without any
parameter.
-----------------
2003-12-04 (1.3.2)
- Public release with the MMX bug correction.
-----------------
2003-12-03 (1.3.1)
- Private release for F. Constantineau. Corrected a crash on CPUs without MMX
support.
-----------------
2003-11-12 (1.3)
- Added support for interlaced PNG files.
- Added an option to keep or remove interlacing for interlaced PNG files.
- New compression strategies.
.:: More Info
For palettized images, the palette is now sorted according to color
luminances.
This sometimes increases compression, like for fadings. In some cases this
could decrease
compression of some bytes in comparison with the older version.
In some cases, PngOptimizer will now perform the conversion with several
parameters
to get the best compression method. This may slow down the optimization in
somes cases
but will lead to better results.
-----------------
2003-03-21 (1.2)
- Gif transparency was not correctly detected when color 0 was used for
transparency
- Optimization for 32 bits png :
* if all alpha values are 100%, the alpha channel is discarded
* if all alpha values are 100%, but one color has an alpha of 0%, the
alpha channel is
discarded and the image is saved as RGB + simple transparency
- Optimization for 24 bits images :
* if 256 or less different colors are used in the image, and if the image
is big enough,
the image is converted to palette mode.
The image is declared big enough if (pixelcount * 3) >= (pixelcount +
colcount * 3 + 12).
Example : an image of 256 pixels with 256 different colors is kept in 24
bits.
-----------------
2002-08-27 (1.1)

7. - Improved support for black & white pictures
- The settings are now read and stored in the registry
- Added new option : "Avoid grey + simple transparency (IE Bug)"
.:: Explanation :
Internet Explorer does not support greyscaled images with simple transparency,
but it supports
palettized images with simple transparency. This option tells PngOptimizer to
avoid conversion
from palettized images into greyscale ones if simple transparency is used.
.:: More Info :
* for greyscale images, simple transparency means one grey index has an alpha
value of 0%
(completely transparent), while the other indexes have an alpha of 100%
(fully opaque).
* for palettized images, it means that for each palette entry an alpha value
is assigned.
* for true color images it means one color value has an alpha of 0%, while the
others have an
alpha of 100%.
.:: Even More Info :
Simple transparency is managed through a PNG chunk called tRNS
-----------------
2002-08-08 (1.0)
- First release