[GRASS5] r.in.png changes

[Markus Neteler]

On Thu, May 09, 2002 at 09:08:42AM +0100, Glynn Clements wrote:
> 
> Glynn Clements wrote:
> 
> > > I've made some modifications to r.in.tiff to hopefully make it a bit
> > > more useable.  I completely removed all of the color reduction
> > > code and am just forcing all RGB TIFF's into respective band files.
> > 
> > I've done something similar for r.in.png.
> > 
> > It now supports paletted, grey-scale and true-colour images, with or
> > without an alpha channel. In all cases, pixel values are imported
> > verbatim, including sBIT information (where present) and
> > 16-bit-per-component images; any translations are performed in the
> > colour table.
> 
> I've tested all of the options for which I can actually generate test
> images (8-bit grey, paletted and true-color formats, alpha channel,
> transparency, gamma setting, and interlace).
> 
> However, I haven't been able to generate test images with bit depths
> other than 8, or with sBIT information. Does anyone know of programs
> which can generate a greater variety of PNG image formats?

Maybe 'gdal_translate' generates at least 16 bit images:
http://www.remotesensing.org/gdal/frmt_various.html#PNG

"PNG files can be created with a type of PNG, using the CreateCopy() method,
requiring a prototype to read from. Writing includes support for the various
image types, and will preserve transparency/nodata values. Georeferencing
.wld files are written if option WORLFFILE setted. All pixel types other
than 16bit unsigned will be written as eight bit."

Markus