Angband colours in Windows / Linux

[PaulBlay]

I've noticed that the colours used to display Angband are a lot easier to see when running Linux than when running Windows (same computer, same monitor). Anyone else seen the same thing?

[RogerN]

Are the fonts different? Thicker lines, perhaps?

[PaulBlay]

Are the fonts different? Thicker lines, perhaps?

I think the fonts are probably slightly different, but I'm pretty sure it's the color that is making the difference. I don't actually no how to take screen-shots in Linux or I could investigate a little more.

[PaulBlay]

OK, I (eventually) worked out how to take a screenshot in Linux.

Windows is on the left, Linux on the right. Yes, Linux was larger (I increased the Windows clip to make it easier to see the colours) but the '7' is clearly darker in the Windows version.

I think the '1' in Linux should be same colour as the 'C' in Windows as well - again Linux is lighter in colour.

[RogerN]

Unfortunately JPG screenshots are not so good for diagnosing color issues due to lossy compression. The RGB values in the screenshot may not be what's displayed on your screen since hue information is distorted by JPG.

The RGB values are hard-coded in the Angband color table. If you're seeing differences between Linux and Windows then I can only speculate that there are platform-specific differences in how the palette entries are initialized for the display. Perhaps the Linux version is using color names instead of RGB values?

[PaulBlay]

Unfortunately JPG screenshots are not so good for diagnosing color issues due to lossy compression.

Those are PNG screenshots, not JPG.

As you can see here the compression is not lossy.

[RogerN]

They may have been PNG to begin with, but whatever method you used to post the images converted them into JPGs. I can see compression artifacts clearly in both images, and my browser confirms that it is a JPG image.

Location: http://angband.oook.cz/forum/attachm...8&d=1241711556
Type: JPEG image
Dimensions: 373px x 280px
Title: win_vs_linux.jpg

[PaulBlay]

They may have been PNG to begin with, but whatever method you used to post the images converted them into JPGs.

There is only one method to post images in this forum as attachments - the "Manage Attachment" button.

However the essential point is that the difference in colours is real and not an artifact of .jpg compression as is clearly shown by the stretched image of the '7' from each respective OS snapshot.

[RogerN]

The darker 7 (the Windows version) matches the Angband color table entry for TERM_L_DARK with an RGB color value of 606060

The lighter 7 (the Linux version) does not match any entry in the Angband color table. Its RGB value appears to be 898989. Perhaps the Linux code is initializing the palette from color names rather than RGB values? I don't know what's going on here.

[Nick]

If you're using the X11 port in Linux, it does Gamma correction; I'm not sure about the others. Nor am I sure any more what Gamma correction is...

[Pete Mack]

Your trouble is either your gamma or white point is set differently on the two machines. But there's no problem. Just go into

options > Interact with colors > modify colors

and change the hue for "light dark". n/N changes which color you are editing, and R/r G/g B/b changes the corresponding hue. I have no idea what K/k does, but you probably don't need it.

[PaulBlay]

Your trouble is either your gamma or white point is set differently on the two machines.

Nuh-huh. Both are sparkly fresh new compiles so the gamma / white point is only going to be different if it's different for Windows / Linux in the code.

[Pete Mack]

gamma/whitepoint is a function of the OS, not of the programs running on it.