hey…
i am trying to create code that will shrink the distance between x,y coordinates by 50%
it works but only when x,y coordinates move from north to south, for example…
0,0
0,10
0,20
0,30
0,40
0,50
becomes (which is right)
0,0
0,5
0,10
0,15
0,20
0,25
however when the x,y coordinates move south to north…
0,0
0,-10
0,-20
0,-30
0,-40
0,-50
it remains (and is wrong)
0,0
0,5
0,10
0,15
0,20
0,25
instead of (which would be right)
0,-0
0,-5
0,-10
0,-15
0,-20
0,-25
the problem i believe lies with this part of the function…
ang = (ang - 90);
a = degToRad(ang);
xxx = xx + Math.cos(a) * radius;
yyy = yy - Math.sin(a) * radius;
i’m nearly there, i’m just doing something fundamentally wrong with the math calculating the x,y coordinates
if anybody has any ideas, i could really use the help, i got to be missing something pretty simple…
the code is in the function testShrink, below it are the support functions
if you want to test it in flash, i’ve created a function that creates a test list of x,y coordinates, there is also a function that will automatically give you a graphical representation of the points; white line (original), red line (new, shrunk)
thanks
…
//creates a test list of x,y coordinates 0,0 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80
//“down” creates a list from 0,0 to 0,80
//“up” creates a list from 0,0 to 0,-80
create_testList(“down”);
//fires function using testList as x,y coordinates to shrink
testShrink(testList);
//the function i’ve created consists of three components…
//a) determine distance between points
//b) determine angle between points
//c) use distance and angle to create new series of points
function testShrink (arr):Void {
var distList:Array = new Array();
var angList:Array = new Array();
var shrinkList:Array = new Array();
//puts orgin x,y coordinates in shrinkList array
this[“temp” + 0] = new Array();
this[“temp” + 0][0] = arr[0][0];
this[“temp” + 0][1] = arr[0][1];
shrinkList[0] = this[“temp” + 0];
//determines distance between points and puts in distList array
for (var i=0; i<arr.length; i++) {
var n = hypot(arr*[0],arr*[1],arr[i+1][0],arr[i+1][1]);
n = Math.round(n/2);
distList.push(n);
trace(“distance…”+i+"
"+n);
}
//determines angle between points and puts in angList array
for (var k=2; k<arr.length; k++) {
var n = findDegree(arr,k);
angList.push(n);
trace(“degree…”+k+"
"+n);
}
//creates new x,y coordinates and puts in shrinkList array
for (var i=0; i<arr.length-2; i++) {
var a,xxx,yyy;
var ang = angList*;
var radius = distList*;
var xx = shrinkList*[0];
var yy = shrinkList*[1];
ang = (ang - 90);
a = degToRad(ang);
xxx = xx + Math.cos(a) * radius;
yyy = yy - Math.sin(a) * radius;
this[“temp” + i] = new Array();
this[“temp” + i][0] = Math.round(xxx);
this[“temp” + i][1] = Math.round(yyy);
shrinkList[i+1] = this[“temp” + i];
}
trace(“original…”+arr.length+"
“+arr.join(”
“));
trace(“shrinkList…”+shrinkList.length+”
“+shrinkList.join(”
"));
//create graphical representation of old and new points
drawXY(arr,shrinkList);
}
/////////////////////////////////////
//SUPPORT FUNCTIONS
function create_testList (xxx:String) {
var upDown = 1;
if (xxx==“up”) {upDown=-1;};
testList = new Array();
for (var i=0; i<9; i++) {
this[“temp” + i] = new Array();
this[“temp” + i][0] = 0;
this[“temp” + i][1] = (10 * i) * upDown;
testList* = this[“temp” + i];
}
//trace(testList.join("
"));
}
function hypot (x,y,xx,yy) {
var n = Math.pow( (diff(x,xx)),2 ) + Math.pow( (diff(y,yy)),2 );
n = Math.round(Math.sqrt(n));
return n;
}
function findDegree (list,n) {
var xxx,yyy,deltaX,deltaY,rad,ang,degree,a;
var x = list[n-1][0];
var y = list[n-1][1];
var xx = list[n][0];
var yy = list[n][1];
if (n==0) {
x = list[0][0];
y = list[0][1];
}
deltaX = xx-x;
deltaY = yy-y;
rad = Math.atan2(deltaY,deltaX);
ang = (rad/Math.PI)*180;
if (yy<y) {
degree = (Math.abs(ang) - 90);
} else {
degree = (Math.abs(ang) - 90) * -1;
}
return roundToDecimal(degree,2);
}
function degToRad (d) {
return (d/180)*Math.PI;
}
function roundToDecimal (theNumber, decPlaces) {
if (decPlaces >= 0) {
var temp = Math.pow(10, decPlaces);
return Math.round(theNumber * temp)/temp;
}
}
function diff (r,s) {
return Math.abs(r-s);
}
function drawXY (listA,listB) {
//listA
_root.createEmptyMovieClip(“path0”,0);
_root.path0.lineStyle(10,0x000000,100);
_root.path0.moveTo(listA[0][0],listA[0][1]);
for (var j=1; j<listA.length; j++) {
_root.path0.lineTo(listA[j][0],listA[j][1]);
}
//listB
_root.createEmptyMovieClip(“path1”,1);
_root.path1.lineStyle(2,0xFF0000,100);
_root.path1.moveTo(listB[0][0],listB[0][1]);
for (var j=1; j<listB.length; j++) {
_root.path1.lineTo(listB[j][0],listB[j][1]);
}
}
//////////////////////////////////////////
