clipboardData & PNG & JPG

[Scott Rossi]

Recently, "Klaus Major"  wrote:

>> I am using the following to place a JPG onto the clipboard:
>> 
>> set the clipboardData["image"] to url ("binfile:"&tPhotoChoice)
>> 
>> When I paste the clipboard into another app it appears to paste
>> a PNG file which is much larger in k than the original JPG.
>> 
>> Is there any way to place the original JPG (and not a larger PNG)
>> onto the clipboard?
> 
> i am not a techie so my explanation my be a bit naive :-)
> 
> I think that JPG is a compressed fileformat (sic!) which means that the
> original image data (24 bit per pixel, no alpha channel in JPGs) will
> get decompressed when put into the clipboard or opened in memory
> by image editors.

It's true that JPEGs are compressed, but it's also true that the file format
is "lossy" (not lossless).  In other words, each time a JPEG is compressed,
information is lost.  With low compression, you may not notice any
artifacts, but with high compression you will see a high degree of odd color
patches and other artifacts.  So in reality, the 24 bit data is not stored
in the JPEG image.

24 bit PNG is a compressed and lossless format, and GIF can also be lossless
if the source image contains no more than 256 colors.

Regards,

Scott Rossi
Creative Director
Tactile Media, Multimedia & Design
-----
E: scott at tactilemedia.com
W: http://www.tactilemedia.com