RE: Display device does not display 4-bit CMYK

Russell,

>The missing black text is related to gray_index.
>If I set gray_index to GX_CINFO_COMP_NO_INDEX then it works Ok.
>If I set gray_index to 3 if fails as you described.
>Any ideas?

This is very surprising.  (I also thought that the missing black
text was very surprising.)

Usually when there is an issue related to gray_index, it is because
one of the dither/max pairs in color_info is not set.  However for
this situation both pairs are set to the same values.

The black text in examples/alphabet.ps is visible.

I will take a look. Thanks for finding this.


Dan
 

-----Original Message-----
From: Russell Lang [mailto:[email protected]]
Sent: Thursday, September 02, 2004 4:16 AM
To: Dan Coby
Subject: RE: [gs-code-review] Display device does not display 4-bit CMYK



Dan,

Thanks for the devn fix.  I missed that one.

The missing black text is related to gray_index.
If I set gray_index to GX_CINFO_COMP_NO_INDEX then it works Ok.
If I set gray_index to 3 if fails as you described.
Any ideas?

Russell

On 1 Sep 2004 at 15:29, Dan Coby wrote:

> 
> Russell,
> 
> Things looked good until I tried the 1_2001.pdf test file.
> 
> The first problem is that the image is distorted and mostly missing.
> When I look at the color_info structure, the depth is 32 (instead of 4).
> The cause seems to be related to the changes that were made for the
> 'separation' mode'.  The routine display_put_params() calls
> devn_put_params() which is setting the depth to 32.  This based upon
> a calculation using the devn_params.bitspercomponent value.  This is
> set to 8.  So I added the following line to display_put_params().
> 
>     }
>     maxvalue = (1 << bpc) - 1;
> +   ddev->devn_params.bitspercomponent = bpc;
> 
>     switch (ddev->nFormat & DISPLAY_ALPHA_MASK) {
> 
> Now the image is much better.  However the black text is missing.
> I do not know why.  It is present in the 16#20101 mode.  It is present
> with the pkmraw device (which is also a 4 bit CMYK device.)
> 
> 
> Dan
> 
> 
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Russell Lang
> Sent: Wednesday, September 01, 2004 2:31 AM
> To: [email protected]
> Subject: [gs-code-review] Display device does not display 4-bit CMYK
> 
> 
> Dan,
> 
> Log message:
> Add support for 4-bit/pixel CMYK to the display device clients for 
> Windows and gtk+.
> 
> 
> Russell Lang                   [email protected]
> Ghostgum Software Pty Ltd      http://www.ghostgum.com.au/
> 
> 
> 
> 
> _______________________________________________
> gs-code-review mailing list
> [email protected]
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Russell Lang                   [email protected]
Ghostgum Software Pty Ltd      http://www.ghostgum.com.au/