Highlight invalid pencil marks in cells

[Naomitr0n]

Currently if you fill in a square with a number, any pencil marks for that number in the same column or row are removed. An option to prevent pencil marks from being made if the number you're trying to mark already exists in the same column or row would be great.

In other words: if you have a filled 3, you can currently put a pencil mark of 3 in any unfilled square directly next to it. This option would prevent that.

For visual feedback, maybe have the number(s) that make it invalid blink or some such? I'd be weary of changing keypad coloring as that would effectively show a "per-square" pencil mark list and make it very obvious when there's only one option available, which isn't the goal of this ticket.

I say "option" because I can see some use cases where a player might not want this to be forced behavior. For example, if the player realizes they have a square filled wrong and are using pencil marks to figure out where they messed up. Probably far more obviously though is that sometimes finding out your own mistake in the pencil marks can be a challenge in and of itself and adds to the difficulty of harder levels.

[meikpiep]

Sorry for the delay without any feedback. I appreciate your ticket, thank you!

It got me thinking how much help the user should want/need, in the way "where should this game go and where not". I have no clear list of answers, but I'm sure their will be a kind of vision or so to guide the development.

Never than less, I have a idea and question your feedback: Could it solve this issue if pencil marks of number already filled in a row or column will simply colored as wrong or inconsistent, analogue to the filled cells? It could be hard to emphasize pencils marks as they do not cover much display area, e.g. to catch the eye. I would try to solve this via such a cell/pencil warning, I you feel that this solves your / the users needs. If not, feel free to tell me.

[Naomitr0n]

Oh that's actually a really good idea yeah :) And it would make an immediate visual of which cell is conflicting too just like filling two of the same numbers in the same row does now. I like that approach

[NormPlum]

I came looking through the issue queue to comment on this very thing. I find the current behaviour confusing and inconsistent, so a more consistent solution would be better.

Currently if you have a possible '3' in one cell, then fill in '3' in another cell in the same row, the possible '3' is removed.
However if you have a '3' filled in in one cell, then later add possibles '1,2,3' in another cell in the same row, the possible '3' isn't removed or highlighted in any way.

To make this more consistent between the two scenarios, I believe it should instead work like one of the following two suggestions:

• Either you're not able to enter '3' as a possible number when there's already a filled in '3' elsewhere in the same row/column, or
• Filling in a '3' doesn't remove possible '3's in the same row/column but rather highlights them as conflicting instead. In the same way, entering a possible '3' in a row/column where there's already a filled in '3' will get highlighted as a conflict.

[NormPlum]

Additionally, maybe an option could be added to the settings so users could toggle this behaviour as desired. So users who like this level of support could have it, whereas more hardcore users who are used to pencil/paper (and therefore no automatic help) could disable it.