VERSIONS: P10 and later. Not Runtime.
SUBJECT: jpeg files made with Photoshop 7
DATE: 15 July 2005
BY: JIM HARGAN
The graphic.readFromFile() displays jpegs created with Photoshop 6 and with a utility I have called FotoCanvas Lite. But it won't display
jpegs created by Photoshop 7. When I open a Photoshop 7 jpeg in FotoCanvas Lite and immediately save it, Pdox will display it.
When I use "Save As" to save a jpeg in Photoshop 7, no combination of settings will allow Paradox to display it. But when I use "Save For
Web", Pdox opens it just fine -- even if I exactly duplicate the settings used in "Save As".
- If you want to use Photoshop 7 to generate jpegs viewable in Paradox, use "Save For Web" instead of "Save" or "Save As".
- If you have a Photoshop 7 jpeg that is not viewable in Paradox, open it in Photoshop 7 and immediately save it using "Save For Web". This
should not hurt the image quality, if you use the same compression.
- If you have a jpeg that Paradox won't open, examine it in a hex viewer to see if it has an Adobe Photoshop date/time stamp at the 40th byte. If
it does, convert it as in #2.
Photoshop 7 has two different ways of saving a JPEG.
- "File/Save As" uses native Photoshop 7 algorithms (judging by the header), and produces an image that my Pdox 11 cannot read. It doesn't
matter what compression scheme is chosen.
- "File/Save For Web" uses a Hewlett-Packard algorithm (again judging by the header), and creates an image that Paradox reads just
fine.
Paradox's handling of the PS7 jpegs seem to be based on the choice of Adobe v HP engines, and independent of compression methods.