my script isn't working. It was supposed to create random circles all touching the bottom of the canvas, with their radius shrinking each circle by the number of circles.
Here is the code:
for (var i = 0; i < NUM_CIRCLES; i++){
var circle = new Circle(radius);
circle.setPosition(CENTER_X,CENTER_Y);
circle.setColor(color);
add(circle);
radius /= i;
CENTER_Y = getHeight() - radius;
color = Randomizer.nextColor();
}
Ok so here is the full code:
var NUM_CIRCLES = 30;
var BIG_RADIUS = 180;
var color = Randomizer.nextColor();
var radius = BIG_RADIUS;
var CENTER_X = getWidth() / 2;
var CENTER_Y = getHeight() - radius;
function start(){
for (var i = 0; i < NUM_CIRCLES; i++){
var circle = new Circle(radius);
circle.setPosition(CENTER_X,CENTER_Y);
circle.setColor(color);
add(circle);
radius /= i;
CENTER_Y = getHeight() - radius;
color = Randomizer.nextColor();
}
}
as far as i understand you are trying to produce circles from bigger to smaller reducing radius of them by number of circles
to achive that do eachReduce = radius / numberofcircles and use it as eachReduce constant to reduce each circle by that number to achieve bigger to smaller size till zero
take a look at below example
let numofcir = 10,
radius = 80,
reduceEachBy = radius / numofcir,
offset = radius / 2
function setup() {
createCanvas(640, 360);
noLoop()
}
function draw() {
background(0)
stroke(255)
noFill()
for(let i=0;i < numofcir;i++){
// in p5 ellipse creates circle by x and y radius
ellipse(offset + (i * offset),150,radius,radius)
radius -= reduceEachBy
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/1.4.0/p5.min.js" integrity="sha512-N4kV7GkNv7QR7RX9YF/olywyIgIwNvfEe2nZtfyj73HdjCUkAfOBDbcuJ/cTaN04JKRnw1YG1wnUyNKMsNgg3g==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
Related
Is there a way to rotate the ellipse in PlotlyJS? To draw a circle/ellipse in Plotly, you define the center and the radii in the positive and negative x and y directions. Is there a way to define an angle at which the ellipse is rotated around its center or perhaps defining the 4 outermost points of the ellipse instead perhaps rather than having plotly deducing them through the radii values?
You can "manually" construct the points of the ellipse:
var center_x = 0;
var center_y = 0;
var a = 3; // major radius
var b = 1; // minor radius
var alpha = Math.PI / 4; // angle of rotation;
var X = [];
var Y = [];
var npoints = 100;
for(var i = 0; i <= npoints; i++) {
var t = 2 * Math.PI * i / npoints;
var x = a * Math.cos(t);
var y = b * Math.sin(t);
X.push(center_x + Math.cos(alpha)*x - Math.sin(alpha)*y);
Y.push(center_y + Math.sin(alpha)*x + Math.cos(alpha)*y);
}
Then plot it with a line type.
I'm trying to fill a rectangle with diagonal lines at 30 degrees that don't get clipped by the canvas. Each line should start and end on the edges of the canvas, but do not go outside the canvas.
I've gotten somewhat of a result but is struggling to understand how I can fix the ends so the lines become evenly distributed:
Here is the code I got so far:
const myCanvas = document.getElementById("myCanvas");
const _ctx = myCanvas.getContext("2d");
const canvasWidth = 600;
const canvasHeight = 300;
// Helper function
const degToRad = (deg) => deg * (Math.PI / 180);
const angleInDeg = 30;
const spaceBetweenLines = 16;
const lineThickness = 16;
_ctx.fillStyle = `black`;
_ctx.fillRect(0, 0, canvasWidth, canvasHeight);
const step = (spaceBetweenLines + lineThickness) / Math.cos(angleInDeg * (Math.PI / 180));
for (let distance = -canvasHeight + step; distance < canvasWidth; distance += step) {
let x = 0;
let y = 0;
if(distance < 0) {
// Handle height
y = canvasHeight - (distance + canvasHeight);
} else {
// Handle height
x = distance;
}
const lineLength = canvasHeight - y;
const slant = lineLength / Math.tan(degToRad((180 - 90 - angleInDeg)));
const x2 = Math.min(x + slant, canvasWidth);
const y2 = y + lineLength;
_ctx.beginPath();
_ctx.moveTo(x, y);
_ctx.lineTo(x2, y2);
_ctx.lineWidth = lineThickness;
_ctx.strokeStyle = 'green';
_ctx.stroke();
}
and a JSFiddle for the code.
What I'm trying to achieve is drawing a pattern where I can control the angle of the lines, and that the lines are not clipped by the canvas. Reference photo (the line-ends don't have flat):
Any help?
My example is in Javascript, but it's more the logic I'm trying to wrap my head around. So I'm open to suggestions/examples in other languages.
Update 1
If the angle of the lines is 45 degree, you will see the gutter becomes correct on the left side. So I'm suspecting there is something I need to do differently on my step calculations.
My current code is based on this answer.
Maybe try something like this for drawing the lines
for(var i = 0; i < 20; i++){
_ctx.fillrect(i * spaceBetweenLines + lineThickness, -100, canvas.height + 100, lineThickness)
}
I have roulette wheel (as an image) without numbers. I want to dynamically fill the numbers of a roulette wheel at the right positions and with the right angle. I want to absolute position the numbers on that image.
My wheel image is 1000 x 1000 pixel.
I try to set the positions and angles with a loop, but the positions are not linear and (in my non-mathematical eyes) to random.
const roulette_arr = []; //contains als numbers in right order. 0..32..15..19...
for (let i = 0; i < roulette_arr.length; i++) {
let degree = 10 + (i * 10); //360 degree / 36 Numbers
let position_x=...
let position_y=...
//function do all the stuff later
setNumber(roulette_arr[i], degree, position_x, position_y);
}
I think angle works, but position is still a problem. What can I do?
It's trigonometry. Is there a bigger problem?
var can = document.getElementById("can");
var ctx = can.getContext("2d");
var numbers = "0-32-15-19-4-21-2-25-17-34-6-27-13-36-11-30-8-23-10-5-24-16-33-1-20-14-31-9-22-18-29-7-28-12-35-3-26".split("-");
var cx = can.width / 2;
var cy = can.height / 2;
var cr = Math.min(cx, cy) * 0.9;
//
for (var i = 0; i < numbers.length; i++) {
var angle = i / numbers.length * 360;
var rad = i / numbers.length * Math.PI * 2 - Math.PI / 2;
var x = cx + Math.cos(rad) * cr;
var y = cx + Math.sin(rad) * cr;
ctx.fillText(numbers[i], x, y);
}
<canvas width="400" height="400" id="can">oh no</canvas>
for a data visualization im aligning n-circels on a circle.
That just works fine - but i dont't know how to stop the circles
overlapping each other. Anybody here knows howto?
The result should work like this sketch:
Link: http://www.xup.to/dl,79345003/sketch.jpg
So i dont know how to calculate the angle for the second node
- based on the radius an position of the first node - and the
radius of the second ...
JSFIDDLE to show what i mean: http://jsfiddle.net/0z9hyvxk/
var canvas = document.getElementById("canvas");
var stage = new createjs.Stage(canvas);
canvas.width = 500;
canvas.height = 500;
var midx = 250;
var midy = 250;
var radius = 200;
var angle = 0;
var count = 30;
var step = 2 * Math.PI / count;
var xpos;
var ypos;
var nodeSize;
var node = function(size){
var dot = new createjs.Shape();
dot.graphics.beginFill("#000").drawCircle(0, 0, size);
dot.x = dot.y = -5;
dot.alpha = .25;
return dot
};
for(var i = 0; i<count; i++)
{
xpos = radius * Math.cos(angle) + midx;
ypos = radius * Math.sin(angle) + midx;
nodeSize = i;
var n = new node(nodeSize);
n.x = xpos;
n.y = ypos;
stage.addChild(n)
angle += step;
}
stage.update();
thanks in advance
simon
Your program does not make corrections based on circle sizes and angle. Smaller circles are too far from each other, bigger ones are too close.
r1 = radius of the n-th small circle
r2 = radius of the (n+1)-th small circle.
r3 = radius of the (n+2)-th small circle
r1<r2<3, so angle between 1 and 2 is smaller than between 2 and 3.
Try to tangentially increase angle correction. I can't test code at work :(
So I have this code:
var points = 6;
var width = w;
var height = h;
var angle = ((2 * Math.PI) / points);
var hexagon = [];
for (i = 0; i < points; i++) {
hexagon.push({
x: width * Math.cos(angle * i),
y: height * Math.sin(angle * i)
})
}
Which will produce 6 points/locations and if I draw a line between them I get a hexagon, but I want to rotate the points or generate the points differently so that the first point is always center-top, like so:
How would I go about doing that?
You could just swap sin and cos.