"Align" dialog - Various problems

[helmut]

I just found the new "Align" dialog and tried it out a bit. (Image > Adjust > Align...).

To be honest, I'm not quite clear what the dialog does and even wonder whether "Align" is the correct English word for that filter. My assumption is that it is intended for grayscale images to adjust the levels. Perhaps someone understands the dialog and can explain what it does.

When playing with the dialog, I stumbled over a variety of problems/oddities:

- Spin button jump
When opening the "Align" dialog, the values are as follows:
Black limit: 0.5 %
White limit: 0.5 %
Align: 33 %
Now, when using the spinbuttons for increasing the values, the next values shown are
Black limit: 6 %
White limit: 6 %
Align: 256 %
I doubt that this makes sense. To me it looks as if XnView does not handle the decimal point properly and interprets 0.5 as 5 and 33.0 as 330 (Align has maximum 256, so 330 becomes 256).

- GPF on values equal or larger than 100%
When increasing the white or black limit to 100% or entering a value equal or larger than 100%, XnView crashes.

- GPF on negative values
When entering negative values as black or white limit, XnView GPFs immediately

- GPF for some values
Currently the black and the white values are independant. When playing with the values a bit, XnView sometimes crashes (e.g. B: 38, W: 68, A: 33 is such a combination).

- Default value 0.5?
Does a default value of 0.5 for black and white limit make sense? When using spin buttons it is 1 % steps, so I wonder whether a default value of 0.5 makes sense.

- Number of digits not limited
You can enter values like 0.0000000001, currently the maximum number of digits is not limited. (This may apply for other dialogs, too). Not really a problem, but if you enter 0.0100 and use spin buttons, you will have a GPF - I guess due to the wrong handling of the decimal point (see above).

I have the feeling that there are more problems in this dialog. Confirmation of the above bugs and/or further bugs are welcome.

V 1.90 B6

[Olivier_G]

To be honest, I'm not quite clear what the dialog does and even wonder whether "Align" is the correct English word for that filter.

I don't know either...

To me it looks as if XnView does not handle the decimal point properly and interprets 0.5 as 5 and 33.0 as 330.

Can't confirm (I get: 1; 1; 34 which is still bad).

GPF on values equal or larger than 100%

Confirmed.

GPF on negative values

Confirmed.

GPF for some values (e.g. B: 38, W: 68, A: 33 is such a combination).

Confirmed: B and W are the Black and White points, B + W can't go over 100%.

Does a default value of 0.5 for black and white limit make sense?

Those values for B & W usually make sense (as 0.1 and others), but XnView should handle decimals correctly after spin +/-1 buttons.
I don't understand what it does actually... but the variation looks quite strange...

but if you enter 0.0100 and use spin buttons, you will have a GPF

Can't confirm.

[xnview]

To be honest, I'm not quite clear what the dialog does and even wonder whether "Align" is the correct English word for that filter.

I don't know either...

It's a function from a user, align the histogram....

To me it looks as if XnView does not handle the decimal point properly and interprets 0.5 as 5 and 33.0 as 330.

Can't confirm (I get: 1; 1; 34 which is still bad).

??? When you enter value in edit box?

GPF on values equal or larger than 100%

Confirmed.

GPF on negative values

Confirmed.

GPF for some values (e.g. B: 38, W: 68, A: 33 is such a combination).

Confirmed: B and W are the Black and White points, B + W can't go over 100%.

Ok

Does a default value of 0.5 for black and white limit make sense?

Those values for B & W usually make sense (as 0.1 and others), but XnView should handle decimals correctly after spin +/-1 buttons.
I don't understand what it does actually... but the variation looks quite strange...

Yes, it's the good default value...

[Olivier_G]

Can't confirm (I get: 1; 1; 34 which is still bad).

??? When you enter value in edit box?

No, when I use +1 spin button on default (0.5;0.5;33) values.
But that could be my mistake: I thought spin buttons were meant to add/substract a value (ex: +/-1 here) and not to reach next/previous rounded value...
I just checked with "Custom rotation' and it does the same rounding, but at 0.1. I would suggest to use that same 0.1 step for those controls here (at least B & W).