Putting a grid on an image

[obtuse gulch]

Is there a way to put a grid on an image?

Let's imagien I have a pixel art image in 128px by 256px.

Is there a way to basiaclly draw line vertically and horizentally on it for every 1 or x pixels on it to make a grid.

Like this

[shell jasper]

tikz/pgf will do this nicely

made especially easier with foreach loops!

[obtuse gulch]

ah so I have to do it manually

[shell jasper]

oh if you want an example:

[gusty oar]

\begin{tikzpicture}
[
        scale=0.7
    ]
        \foreach \x in {0,0.25,...,10}{%
            \draw (\x, 0) --(\x, 10);
            \draw (0, \x) -- (10, \x);
        }
\end{tikzpicture}

[shell jasper]

you can also make use of axis environment but you will still need to figure out the intervals etc

arbitrary placements of shapes is not a thing in TikZ I'm afraid, this isn't Paint

[obtuse gulch]

Nah, I jsut need the lines

But I need TikZ to understand teh length and width of teh image if I'm going to do that

and some how place that on top of the image and scale it

like usually I use width=\line width for images so teh size can change

[shell jasper]

\begin{tikzpicture}
    \node[anchor=south west,inner sep=0] (image) at (0,0) {\includegraphics[width=0.9\textwidth]{Leo}};
    \begin{scope}[x={(image.south east)},y={(image.north west)}]
        \draw[help lines,xstep=.1,ystep=.1] (0,0) grid (1,1);
    \end{scope}
\end{tikzpicture}

[shell jasper]

Something like this will work

[obtuse gulch]

ey!

[shell jasper]

and yes that's me

[obtuse gulch]

Nice galsses

🤔 Also weir dquestion, not relaly related to thsi specificly

How doe slatex handel upscalling an image?

[shell jasper]

In Layman-terms or in tech jargon?

[obtuse gulch]

Liek if I throw a pixel art at it the blow it up to cover teh entire screen will it stay pixelated or will it be blury?

if it is blkury then... is tehre a way to make it not do that?

^ thsi isn't really a deal breaker, I can just upscale it in a photo editor if it can't

Aside form that, thansk for the info

[shell jasper]

I think it's just plain stretching

which will make low-res images blurry indeed

[obtuse gulch]

🤔 crab

Well what you just showed me might be able to fix that if I can ready individual pixel's RPG values which would make a very heavy proccess

[shell jasper]

might not be so bad... this is a 128 x 128

[obtuse gulch]

This doesn't look blury

the grid seems to be in the wrong place but the image doesn't seem to be blury

This is teh type of problem I'm talking baout

Which your image doesn't seem to suffer from

[shell jasper]

Yeah..

I have another suggestion

Since there's only two colours (or one) in the art, we can just map the image with 0s and 1s using python

and then render the art using the mapped grid

[obtuse gulch]

🤨 LaTeX can read Python?

Alos my question is more general, I just happen to have that image at hand

[shell jasper]

just need the numpy array (or equivalent) and then change the [] to braces and then we can just render it using for loops

more colours would just mean added layer of mapping which number corresponds to which colour

which is still quite easy to automate

[obtuse gulch]

🤔 ye I can see a 6 layer deep array do teh job.

for a full RGBA image

[shell jasper]

colour definition can be done in LaTeX though, but you could fetch the value from the array and define it on-the-fly too (which would make it really slow imo)

[obtuse gulch]

Ye would be just manually making upscalling algorithems in LaTeX

[fringe reef]

@obtuse gulch has earned the Members role!

[obtuse gulch]

Thanks for the info man

[shell jasper]

Let me make a quick demonstration of what I meant

because it genuinely sounds quite fun

[obtuse gulch]

🤣 Guess I'm not the only one with mad ideas

[shell jasper]

\def\pixels{%
    {2,1,9,9,9,4,3,2,1,0},
    {3,9,8,7,8,9,4,9,2,1},
    {9,8,5,6,7,8,9,8,9,2},
    {8,7,6,7,8,9,6,7,8,9},
    {9,8,9,9,9,6,5,6,7,8}}
\colorlet{pix 0}{black}
\colorlet{pix 1}{red}
\colorlet{pix 2}{green}
\colorlet{pix 3}{yellow}
\colorlet{pix 4}{blue}
\colorlet{pix 5}{yellow}
\colorlet{pix 6}{cyan}
\colorlet{pix 7}{brightblack}
\colorlet{pix 8}{brightgreen}
\colorlet{pix 9}{white}

\begin{tikzpicture}
  \foreach \line [count=\y] in \pixels {
    \foreach \pix [count=\x] in \line {
      \draw[fill=pix \pix] (\x,-\y) rectangle +(1,1);
    }
  }
\end{tikzpicture}

Aye

[shell jasper]

The grid is actually from AOC 2021 Day 9 challenge

[obtuse gulch]

hmmm I need to learn how to use this TikZ guy

[shell jasper]

i got carried away...

[sharp summit]

graphicx's \includegraphics accepts an interpolate option that smooths the image