# Word clouds

% Remco Bloemen % 2015-08-26

## Finding and weighing keywords

```
text = Import["~/text.txt"] // ToLowerCase;
text = StringReplace[text, {"educational" → "education","teachers" → "teacher","learner" → "student","technologies" → "technology","learning" → "learn","leerling" → "student","studenten" → "student","students" → "student","questions" → "question","levels" → "level"}];
tally = Tally@Cases[StringSplit[text,Except@LetterCharacter],_?(StringLength@#>4&)];
tally = Cases[tally,_?(Last@#>15&)];
tally = Reverse@SortBy[tally,Last];
range = {Min@(Last/@tally),Max@(Last/@tally)};
common = {"the","of","and","to","in","I","that","was","his","he","it","with","is","for","as","had","you","not","be","her","on","at","by","which","have","or","from","this","him","but","all","she","they","were","my","are","me","one","their","so","an","said","them","we","who","would","been","will","no","when","there","if","more","out","up","into","do","any","your","what","has","man","could","other","than","our","some","very","time","upon","about","may","its","only","now","like","little","then","can","should","made","did","us","such","a","great","before","must","two","these","see","know","over","much","down","after","first","mr","good","men","worden","around","based","where","current","because","become","means","already","possible","through","every","using","kunnen","within","wordt","first","second","binnen","while"};
tally = DeleteCases[tally, w_/; MemberQ[common,w[[1]]]];
```

## Adding color and rotation

```
words = Style[First@#, FontFamily -> "Times",
FontColor ->
Hue[RandomReal[], RandomReal[{.5, 1}], RandomReal[{.5, 1}]],
FontSize -> (Last@Rescale[#, range, {12, 150}])] & /@ tally;
wordsimg =
ImagePad[#, -3 -
BorderDimensions[#]] & /@ (Image[
Graphics[Text[Framed[#, FrameMargins -> 2]]]] & /@ words);
```

```
angles = Join[{0, 0, 0}, RandomReal[{-Pi/4, Pi/4}, 5],
RandomReal[{-Pi/2, Pi/2}, Length[wordsimg] - 3 - 5]];
wordsimgRot =
ImageRotate[##, Background -> White] & @@@
Transpose[{wordsimg, angles}];
```

## Tightly packing objects

```
iteration2[img1_, w_, fun_: (Norm[#1 - #2] &)] :=
Module[{imdil, centre, diff, dimw, padding, padded1, minpos},
dimw = ImageDimensions[w];
padded1 = ImagePad[img1, {dimw[[1]] {1, 1}, dimw[[2]] {1, 1}}, 1];
imdil =
Binarize[
ImageCorrelate[Binarize[ColorNegate[padded1], 0.05],
Dilation[Binarize[ColorNegate[w], 0.05], 5]]];
centre = ImageDimensions[padded1]/2;
minpos =
Reverse@Nearest[Position[Reverse[ImageData[imdil]], 0],
Reverse[centre], DistanceFunction -> fun][[1]];
Sow[minpos - centre];(*for creating vector plot*)
diff = ImageDimensions[imdil] - dimw;
padding[pos_] := Transpose[{#, diff - #} &@Round[pos - dimw/2]];
ImagePad[#, (-Min[#] {1, 1}) & /@ BorderDimensions[#]] &@
ImageMultiply[padded1, ImagePad[w, padding[minpos], 1]]]
poslist =
Reap[img = Fold[iteration2, wordsimgRot[[1]], Rest[wordsimgRot]];][[
2, 1]]
```

The crux of the algorithm is a call to `ImageCorrelate`

.

## Converting back to vector

We now have coordinates for the bitmap images. We re-use these
coordinates to create new `Text`

entries. This is to convert it back to
a vector image.

```
Graphics[MapThread[
Text[#1, Offset[#2, {0, 0}], {0, 0}, {Cos[#3], Sin[#3]}] &, {words,
Prepend[poslist, {0, 0}], angles}]]
```

## See also

https://mathematica.stackexchange.com/questions/2334/how-to-create-word-clouds