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# [WSC18] ASCII?: Convert Images and GIFs into ASCII Art.

Posted 6 years ago

# ASCII?

Try it yourself at the microsite here.

## Creating an image processing function for Wolfram Mathematica

### Supports all Image files and GIF animations. Different alphabets are available. You can choose between you output image to be colored.

So, how does this work?

Buckle your seat-belts, grab your popcorn, because in twenty seven variables I'm going to teach you something that I only learned two weeks ago. So sit down, open your kernels and enjoy the experience of my 4 pm last minute pepsi fueled writing extravaganza. [[Dariia's censorship]]

The program substitutes groups of pixels with a character that

Input form for the function:

ASCIIfy[graphicchoice_, charchoice_, cbasic_, grainchoice_, coloredchoice_, fontfam_, fontsize_, blackbg_] :=


This function declares multiple variables inside of itself, so you need to use Module.

Module[{graphic, charsbasic, auto, setchars, chars, charsmean, truecharwidth, truecharheight, charwidth, charheight, pic, picwc, width, height, charpic, giftable, picmeans, graphicframe},


graphicchoice is the image or GIF. They are processed the same, so images will be converted to a list)

 If[ListQ[graphicchoice], graphic = graphicchoice, graphic = List[graphicchoice]];


charchoice specifies the charset to be used.

The default Auto uses automatic location and outputs the alphabet used in your country.

 auto = EntityValue[$GeoLocationCountry, "Languages"][[1]];  If cbasic =True the program will add numbers and symbols to the characters used. If[cbasic, charsbasic = {"$", "&", "'", ",", ".", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", ":", ";", "?"},
charsbasic = List[]];


Finally, a list of chars to be used is created.

setchars[lang_] :=  If[lang == "Auto",
Join[Alphabet[auto], Capitalize[Alphabet[auto]], charsbasic],
Join[Alphabet[lang], Capitalize[Alphabet[lang]], charsbasic]];

chars = setchars[charchoice];


The next step is finding out the average brightnesses of these characters. First their dimensions are established.

truecharwidth =
Max[Table[Length[ImageData[Rasterize[Style[chars[[c]], FontFamily -> fontfam]]][[1]]], {c, 1, Length[chars]}]];
truecharheight =
Max[Table[Length[ImageData[Rasterize[Style[chars[[c]], FontFamily -> fontfam]]]], {c, 1, Length[chars]}]];


Now to get the average brightness (or mean).

Table[ImageMeasurements[
ColorConvert[
Rasterize[
Pane[Style[chars[[a]], FontFamily -> fontfam], {truecharwidth,
truecharheight}, Alignment -> Center], ImageSize -> 50],
"Grayscale"], "Mean"], {a, 1, Length[chars]}];


grainchoice specifies how many pixels wide should the fragment replaced by one character be.

If[grainchoice == "Auto", charwidth = truecharwidth;
charheight = truecharheight, charwidth = grainchoice;
charheight = Round[grainchoice*truecharheight/truecharwidth]];


Dark images will not be well represented by chars, as they have a white background, so before applying the program the image brightness is scaled up accordingly.

bleach[im_] := im*(1 - Min[charsmean]) + Min[charsmean];


The main part is a function that creates the ASCIIfied images (when dealing with Image files, just one)

It is surrounded by a Monitor - a function used to indicate progress. This is useful when converting large images or GIFs.

Monitor[(giftable = Table[(...),{frame, 1, Length[graphic]}]),{(testy - 1)/height*1. + (frame - 1), Length[graphic]}]


If blackbg is chosen as True, the program will run in almost the same manner. Almost. It first creates a color negative of the wanted image, then creates its asciified version, and then negates it.

If[blackbg, graphicframe = ColorNegate[graphic[[frame]]], graphicframe = graphic[[frame]]];


As mentioned before, this program will compare image fragments and letters. To do that, it first partitions the image, which is first "bleached" and grayscale.

pic = ImagePartition[ImageApply[bleach,
{ColorConvert[graphicframe, "Grayscale"]}], {charwidth,
charheight}];


Checks the amount of fragments.

{height, width} = Dimensions[pic];


And calculates the average brightness of each fragment.

picmeans =
Table[ImageMeasurements[pic[[y, x]], "Mean"], {x, 1, width}, {y, 1,
height}];


It then names a function that calculates the differences between a piece of \ the image and all chars.

diffs[rownumber_, placeinrow_] :=
Table[charsmean[[a]] - picmeans[[rownumber, placeinrow]], {a, 1, Length[chars]}]^2;


And a function that picks the character whose difference is the smallest.

best[x_, y_] := chars[[Position[diffs[x, y], Min[diffs[x, y]]][[1, 1]]]];


The most important part: Creating an array (actually a column of rows) of best fitting letters. If you want to reuse this code and would prefer to output letters and not an image output charpic.

If[coloredchoice,
charpic = TableForm[Table[Style[best[testx, testy],
FontColor -> RGBColor[ImageMeasurements[picwc[[testy, testx]], "Mean"]]], {testy, 1, height}, {testx, 1, width}], TableSpacing -> {0, 0}],
charpic = TableForm[Table[Style[best[testx, testy], FontColor -> Black], {testy, 1, height}, {testx, 1, width}], TableSpacing -> {0, 0}]];


This rasterizes the array (inverts it for black background, as previously mentioned).

If[blackbg, ColorNegate[Rasterize[Style[TableForm[Map[
Pane[#, {truecharwidth, truecharheight}, Alignment -> Center] &,
charpic, {3}], TableSpacing -> {0, 1}],
FontFamily -> fontfam]]],

Rasterize[Style[TableForm[Map[
Pane[#, {truecharwidth, truecharheight}, Alignment -> Center] &,
charpic, {3}], TableSpacing -> {0, 1}], FontFamily -> fontfam]]],


Frame's ending: repetition settings and monitored value.

{frame, 1, Length[graphic]}],{(testy - 1)/height*1. + (frame - 1), Length[graphic]}];


This is the export form for cloud deployment.

If[ListQ[graphicchoice],
ExportForm[giftable, "GIF", "AnimationRepetitions" -> \[Infinity]],
ExportForm[giftable[[1]], "PNG"]]


If you're using the function locally use this instead:

If[ListQ[graphicchoice],
Export["giftable.gif", giftable,
"AnimationRepetitions" -> \[Infinity]],
Export["giftable.jpg", giftable[[1]]]];

If[ListQ[graphicchoice],
SystemOpen["giftable.gif"],
SystemOpen["giftable.jpg"]]


And of course... :)

 ]


To CloudDeploy:

CloudDeploy[
FormFunction[{
"ImageOrGIF" -> "GIF" | "Image",
"Alphabet" -> alphalist,
"FontFamily" -> CloudEvaluate[\$FontFamilies] -> "Times New Roman",
"FontSize" -> <|"Interpreter" -> Restricted["Integer", {3, 60, 3}],
"Control" -> Slider, "Default" -> 30|>,
"Grain" -> <|"Interpreter" -> Restricted["Integer", {1, 20}],
"Control" -> Slider, "Default" -> 10|>,
"BasicChars" -> "Boolean",
"Color" -> "Boolean",
"BlackBackground" -> "Boolean"},
ASCIIfy[#ImageOrGIF, #Alphabet, #BasicChars, #Grain, #Color, \
#FontFamily, #FontSize, #BlackBackground] &,
AppearanceRules -> <|"Title" -> "ascii\[CurlyPhi]",
"Description" ->
(*Your Discription - maybe Import[] an Image*)|>, PageTheme -> "Blue"], "AsciiArt",
Permissions -> "Public"]


alphalist is a list of possible alphabets

alphalist =
ToString /@ {Auto, Arabic, Belarusian, BosnianCyrillic, BosnianLatin,
Bulgarian, Croatian, Cyrillic, Danish, Devanagari, Dutch, English,
Estonian, Finnish, French, German, Greek, Hebrew, Hindi, Hiragana,
Hungarian, Italian, Katakana, Latin, MalayLatin,
MongolianCyrillic, MongolianLatin, Norwegian, Polish, Portuguese,
Romanian, Russian, Slovak, Spanish, Swedish, Turkish, Ukrainian,
Urdu}


Some Examples

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