Created
January 21, 2023 12:44
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//Add this to the browser console of https://www.funnyhowtheknightmoves.com/ | |
/** | |
* Creates line element on given position, with given length and angle. | |
*/ | |
function createLineElement(x, y, length, angle) { | |
var line = document.createElement("div"); | |
var styles = 'border: 1px solid black; ' | |
+ 'width: ' + length + 'px; ' | |
+ 'height: 0px; ' | |
+ '-moz-transform: rotate(' + angle + 'rad); ' | |
+ '-webkit-transform: rotate(' + angle + 'rad); ' | |
+ '-o-transform: rotate(' + angle + 'rad); ' | |
+ '-ms-transform: rotate(' + angle + 'rad); ' | |
+ 'position: absolute; ' | |
+ 'top: ' + y + 'px; ' | |
+ 'left: ' + x + 'px; '; | |
line.setAttribute('style', styles); | |
return line; | |
} | |
function createCircleDiv(x,y,r) | |
{ | |
var dot = document.createElement("div"); | |
var styles = "height: " + 2*r +"px;" | |
+ "width: " + 2*r +"px;" | |
+ "background-color:#00ff00;" | |
+ "border-radius:50%;" | |
+ "position: absolute;" | |
+ "top: " + (y -r) + "px;" | |
+ "left: " + (x - r) + "px;"; | |
dot.setAttribute("style",styles); | |
return dot; | |
} | |
/** | |
* Creates element which represents line from point [x1, y1] to [x2, y2]. | |
* It is html div element with minimal height and width corresponding to line length. | |
* It's position and rotation is calculated below. | |
*/ | |
function createLine(x1, y1, x2, y2) { | |
var a = x1 - x2, | |
b = y1 - y2, | |
c = Math.sqrt(a * a + b * b); | |
var sx = (x1 + x2) / 2, | |
sy = (y1 + y2) / 2; | |
var x = sx - c / 2, | |
y = sy; | |
var alpha = Math.PI - Math.atan2(-b, a); | |
return createLineElement(x, y, c, alpha); | |
} | |
// Draw some lines | |
function getBoardCase(id) | |
{ | |
let board = document.querySelector('div.m-auto'); | |
return board.querySelector('[data-squareid="'+id+'"]'); | |
} | |
function getBoardCaseCenterCoord(id) | |
{ | |
let bcase = getBoardCase(id).getBoundingClientRect(); | |
return [bcase.left+bcase.width/2,bcase.top+bcase.height/2] | |
} | |
function drawLineBetweenBoardCases(id1, id2) | |
{ | |
let xy1 = getBoardCaseCenterCoord(id1); | |
let xy2 = getBoardCaseCenterCoord(id2); | |
document.body.appendChild(createLine(xy1[0], xy1[1], xy2[0], xy2[1])); | |
} | |
let forbidden = ["d8", "d7", "d6","d5","d4", "d3", "d2", "d1", "e6", "f7", "g8", "c6", "b7", "a8", "c5", "b5", "a5", "e5", "f5", "g5", "h5", "c4", "b3", "a2", "e4", "f3", "g2", "h1"]; | |
function buildAllGraph() | |
{ | |
let letters = ["a","b","c","d","e","f","g","h"]; | |
let numbers = ["1","2","3","4","5","6","7","8"]; | |
let knightoffset = [[2,1],[1,2],[-1,-2],[-2,-1],[-1,2],[2,-1],[-2,1],[1,-2]]; | |
let ids = []; | |
for( i = 0 ; i < 8 ; i++) | |
{ | |
for( j = 0 ; j < 8 ; j++) | |
{ | |
id = letters[i]+numbers[j]; | |
if( forbidden.includes(id ) ) continue; | |
for( k = 0 ; k < knightoffset.length ; k++) | |
{ | |
nx = i+knightoffset[k][0]; | |
ny = j+knightoffset[k][1]; | |
if( nx < 0 || ny < 0 || nx > 7 || ny > 7) continue; | |
nid = letters[nx]+numbers[ny]; | |
if( forbidden.includes(nid ) ) continue; | |
ids.push([id,nid]); | |
} | |
} | |
} | |
return ids; | |
} | |
//Making the forbidden cases red | |
((sq) => { let board = document.querySelector('div.m-auto'); sq.forEach(s => board.querySelector('[data-squareid="'+s+'"]').style.backgroundColor='red'); })(forbidden) | |
var lines =buildAllGraph(); | |
//Display nodes | |
for( i = 0 ; i < lines.length ; i++) | |
{ | |
coord = getBoardCaseCenterCoord( lines[i][0] ); | |
document.body.appendChild(createCircleDiv(coord[0],coord[1],10) ); | |
} | |
//Display edges | |
for( i = 0 ; i < lines.length ; i++) | |
{ | |
drawLineBetweenBoardCases(lines[i][0],lines[i][1]); | |
} |
Author
unrealwill
commented
Jan 21, 2023
Possible further improvements include fixing drag and drop when release happen on a graph div, highlighting target destination, and allowing queen movements, or other pieces...
Additional interesting visualization found in the comments :
https://news.ycombinator.com/item?id=34462822 :
https://news.ycombinator.com/item?id=34464240 :
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