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# Pi visualization

edited March 2018

Hi everyone!

I was watching a video of Daniel Shiffman about visualizing the digits of Pi the other day in wich he refers to a Washington post article that shows example of some representation.

I thought I would give it a try and recreate one of them.

This is the result I got :

It is done by connecting a line between each digit and the next one. Tell me if you want to see the code, I need to refactor it a bit =)

The links I was speaking about : The Daniel Shiffman video : www.youtube.com/watch?v=WEd_UIKG-uc The Washington post article : www.washingtonpost.com/news/wonk/wp/2015/03/14/10-stunning-images-show-the-beauty-hidden-in-pi/?utm_term=.4cefc01ce593

Tagged:

• @jb4x --beautiful work.

Yes, I would love to see the code!

• Hey, thanks for the comment !

Here the code :

``````final float diameter = 700; //the diameter of the circle
color[] digitColor = new color[10]; //The color of each digit
float[] currentDigitAngle = new float[10]; //Keep track of the last angle used for each digit (each time a line goes to the digit, the line is offset)
float[] digitAngleStep = new float[10]; //Store the step to add every time the line goes to a digit
int pos; //Keep track of the current digits beeing displayed if the draw function is used
int[] digit; //All the digit of PI

void setup() {
size(1920, 1080);
background(0);
translate(width/2, height/2);
noFill();
stroke(255);
textAlign(CENTER, CENTER);
strokeWeight(5);

//Variables
String dataString; //all the PI number as string

int[] digitCount = new int[10]; //The amount of each deach from 0 to 9
float[] digitWeight = new float[10]; //The proportion of each digit from 0 to 9
final float angleGap = 0.03; //The gap between each arc
float[] digitAngleSize = new float[10]; //The size of each digit arc
float currentAngle; //Use to keep track of the last arc drawn on screen in order the draw the next one after
PFont myFont; //The font used for the text

//Initialize variables
myFont = createFont("data/Comfortaa-Regular.ttf", 40);
textFont(myFont);
textSize(diameter / 10);
text("π", -5, -10);
textSize(diameter / 30);
pos = 0;

digitColor[0] = color(236, 166, 15);
digitColor[1] = color(232, 125, 27);
digitColor[2] = color(227, 45, 42);
digitColor[3] = color(210, 0, 64);
digitColor[4] = color(168, 11, 95);
digitColor[5] = color(135, 46, 134);
digitColor[6] = color(91, 77, 163);
digitColor[7] = color(46, 116, 157);
digitColor[8] = color(30, 154, 119);
digitColor[9] = color(91, 176, 90);

//Transform data to integer and get count
digit = new int[dataString.length()];

for (int i = 0; i < dataString.length(); i++) {
digit[i] = Character.getNumericValue(dataString.charAt(i));
digitCount[digit[i]]++;
}

//Find weight and angle
for (int i = 0; i < 10; i++) {
digitWeight[i] = (float)digitCount[i] / digit.length;
digitAngleSize[i] = digitWeight[i] * (TWO_PI - (10 * angleGap));
if (digitCount[i] == 1) {
digitAngleStep[i] = 0;
} else {
digitAngleStep[i] = digitAngleSize[i] / (digitCount[i] - 1);
}
}

//Draw arcs and text
currentAngle = (3 * PI / 2) - (digitAngleSize[0] / 2);
for (int i = 0; i < 10; i++) {
//Arcs
stroke(red(digitColor[i]), green(digitColor[i]), blue(digitColor[i]));
noFill();
arc(0, 0, diameter, diameter, currentAngle, currentAngle+digitAngleSize[i]);
currentDigitAngle[i] = currentAngle;

//Text
fill(red(digitColor[i]), green(digitColor[i]), blue(digitColor[i]));
text(i, 1.1 * (diameter / 2) * cos((2*currentAngle+digitAngleSize[i])/2), 1.1 * (diameter/2) * sin((2*currentAngle+digitAngleSize[i])/2));

currentAngle = currentAngle + digitAngleSize[i] + angleGap;
}

//*******
//COMMENT THOSE LINES IF YOU USE THE DRAW FUNCTION
//*******

//Draw bezier curves
for (int i = 0; i < digit.length - 1; i++) {
drawBezier(currentDigitAngle[digit[i]], currentDigitAngle[digit[i+1]], digitColor[digit[i]]);
currentDigitAngle[digit[i]] += digitAngleStep[digit[i]];
}

//*******
}

void draw() {
//*******
//UNCOMMENT THOSE LINES TO SEE THE DRAWING PROCESS
//*******

//translate(width/2, height/2);

//for (int i = 0; i < 10; i++) {
//  if (pos < digit.length - 1) {
//    drawBezier(currentDigitAngle[digit[pos]], currentDigitAngle[digit[pos+1]], digitColor[digit[pos]]);
//    currentDigitAngle[digit[pos]] += digitAngleStep[digit[pos]];
//    pos++;
//  }
//}
}

// Function called to draw the bezier curves between two points
// angle1 is the angle of the first point
// angle2 is the angle od the second point
// Stroke color is the color used for the line
void drawBezier(float angle1, float angle2, color strokeColor) {
float x1, y1, x2, y2, r, controlAngle1, controlAngle2, controlR;

r = (diameter / 2) - 6;

x1 = r * cos(angle1);
y1 = r * sin(angle1);
x2 = r * cos(angle2);
y2 = r * sin(angle2);

noFill();
stroke(red(strokeColor), green(strokeColor), blue(strokeColor), 5);
strokeWeight(2);

//Different method is used in order to avoid line in the middle section
if (angleDiff(x1, y1, x2, y2, 0, 0) < 0.3) {
controlAngle1 = getAngle(x1, y1, 0, 0) + 0.5;
controlAngle2 = getAngle(x2, y2, 0, 0) - 0.5;
controlR = 0.9 * dist(x1, y1, 0, 0);
bezier(x1, y1, x1 + controlR * cos(controlAngle1), y1 + controlR * sin(controlAngle1), x2 + controlR * cos(controlAngle2), y2 + controlR * sin(controlAngle2), x2, y2);
} else {
bezier(x1, y1, x1/2, y1/2, x2/2, y2/2, x2, y2);
}
}

//Get angle from point 1 to point 2
float getAngle(float x1, float y1, float x2, float y2) {
float angle;

if (x2==x1) {
if (y1>y2) {
return HALF_PI;
} else {
return -HALF_PI;
}
}

angle = atan((y2-y1)/(x2-x1));
if (x1 > x2) {
return angle + PI;
} else {
return angle;
}
}

//Angle difference between pt1-2 and p1-3
float angleDiff(float x1, float y1, float x2, float y2, float x3, float y3) {
a1 = getAngle(x1, y1, x2, y2);
a2 = getAngle(x1, y1, x3, y3);

if (a1>a2) {
while (a1>a2) {
a1 = a1 - TWO_PI;
}
} else {
while (a1<a2) {
a1 = a1 + TWO_PI;
}
}
}

}
``````
• can you post the data file as well?

• Sure, just forgot about it. There you go.

• Probably something like this without the leading 8 chars?

https://www.rsok.com/~jrm/pi10000.txt

• 31415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275900994657640789512694683983525957098258226205224894077267194782684826014769909026401363944374553050682034962524517493996514314298091906592509372216964615157098583874105978859597729754989301617539284681382686838689427741559918559252459539594310499725246808459872736446958486538367362226260991246080512438843904512441365497627807977156914359977001296160894416948685558484063534220722258284886481584560285060168427394522674676788952521385225499546667278239864565961163548862305774564980355936345681743241125150760694794510965960940252288797108931456691368672287489405601015033086179286809208747609178249385890097149096759852613655497818931297848216829989487226588048575640142704775551323796414515237462343645428584447952658678210511413547357395231134271661021359695362314429524849371871101457654035902799344037420073105785390621983874478084784896833214457138687519435064302184531910484810053706146806749192781911979399520614196634287544406437451237181921799983910159195618146751426912397489409071864942319615679452080951465502252316038819301420937621378559566389377870830390697920773467221825625996615014215030680384477345492026054146659252014974428507325186660021324340881907104863317346496514539057962685610055081066587969981635747363840525714591028970641401109712062804390397595156771577004203378699360072305587631763594218731251471205329281918261861258673215791984148488291644706095752706957220917567116722910981690915280173506712748583222871835209353965725121083579151369882091444210067510334671103141267111369908658516398315019701651511685171437657618351556508849099898599823873455283316355076479185358932261854896321329330898570642046752590709154814165498594616371802709819943099244889575712828905923233260972997120844335732654893823911932597463667305836041428138830320382490375898524374417029132765618093773444030707469211201913020330380197621101100449293215160842444859637669838952286847831235526582131449576857262433441893039686426243410773226978028073189154411010446823252716201052652272111660396665573092547110557853763466820653109896526918620564769312570586356620185581007293606598764861179104533488503461136576867532494416680396265797877185560845529654126654085306143444318586769751456614068007002378776591344017127494704205622305389945613140711270004078547332699390814546646458807972708266830634328587856983052358089330657574067954571637752542021149557615814002501262285941302164715509792592309907965473761255176567513575178296664547791745011299614890304639947132962107340437518957359614589019389713111790429782856475032031986915140287080859904801094121472213179476477726224142548545403321571853061422881375850430633217518297986622371721591607716692547487389866549494501146540628433663937900397692656721463853067360965712091807638327166416274888800786925602902284721040317211860820419000422966171196377921337575114959501566049631862947265473642523081770367515906735023507283540567040386743513622224771589150495309844489333096340878076932599397805419341447377441842631298608099888687413260472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

• Looks great, thanks!

• Amazing. Thanks for sharing.