Javascript 需要帮助打印分形树吗
我需要一些使用JavaScript打印分形树的帮助 我已经编写了代码,根据为树定义的规则打印树序列,但是打印树时遇到了一些麻烦。谢谢你的帮助 代码如下:Javascript 需要帮助打印分形树吗,javascript,turtle-graphics,fractals,Javascript,Turtle Graphics,Fractals,我需要一些使用JavaScript打印分形树的帮助 我已经编写了代码,根据为树定义的规则打印树序列,但是打印树时遇到了一些麻烦。谢谢你的帮助 代码如下: var sentence = "F"; var rules = []; rules[0] = { a: "F", b: "F[+F]F[-F]F" } setup(); function setup() { turtle(); for (i = 0; i < 2; i++){ genera
var sentence = "F";
var rules = [];
rules[0] = {
a: "F",
b: "F[+F]F[-F]F"
}
setup();
function setup() {
turtle();
for (i = 0; i < 2; i++){
generate();
}
}
function turtle(){
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext('2d');
for (var i = 0; i < sentence.length; i++){
context.beginPath();
var current = sentence.charAt(i);
if (current == "F"){
context.stroke();
context.lineTo(50,50);
}else if (current == "+"){
context.rotate(20*Math.PI/180);
}else if (current == "-"){
context.rotate(-20*Math.PI/180);
}else if (current == "["){
context.save();
}else if (current == "]"){
context.restore();
}
}
}
function generate(){
var nextSentence = "";
for (var i = 0; i < sentence.length; i++){
var current = sentence.charAt(i);
var found = false;
for (var j = 0; j < rules.length; j++ ){
if (current == rules[j].a){
found = true;
nextSentence += rules[j].b;
console.log(nextSentence);
break;
}
}
if (!found){
nextSentence += current;
}
}
sentence = nextSentence;
turtle();
}
我能够打印树序列,但需要一些帮助来转换树序列,以便能够在画布上打印树。
输出应如下所示:
绘图逻辑存在一些问题。您的代码似乎假设save和restore也会保存坐标并将其还原,但事实并非如此。您没有正确使用“旋转”,因为它相对于原点旋转,所以您还需要进行平移。当您应该相对于当前位置执行此操作时,您正在执行绝对行到。而且走错了方向。以及其他问题 下面是我对您的代码进行的返工,使其运行到足以生成示例树的程度:
var sentence = "F";
var rules = [];
rules[0] = {
a: "F",
b: "F[+F]F[-F]F"
}
var x = 150; // starting x
var y = 400; // starting y
var y_stack = []; // save & restore don't handle coordinates
function turtle(sentence, context) {
for (var i = 0; i < sentence.length; i++) {
var current = sentence.charAt(i);
if (current == "F") {
y -= 35;
context.lineTo(x, y);
context.stroke();
} else if (current == "+") {
context.translate(x, y);
context.rotate(20 * Math.PI / 180);
context.translate(-x, -y);
} else if (current == "-") {
context.translate(x, y);
context.rotate(-20 * Math.PI / 180);
context.translate(-x, -y);
} else if (current == "[") {
context.save();
y_stack.push(y);
} else if (current == "]") {
context.restore();
y = y_stack.pop();
context.moveTo(x, y)
}
}
}
function generate(sentence) {
var nextSentence = "";
for (var i = 0; i < sentence.length; i++) {
var current = sentence.charAt(i);
var found = false;
for (var j = 0; j < rules.length; j++ ) {
if (current == rules[j].a) {
found = true;
nextSentence += rules[j].b;
break;
}
}
if (!found) {
nextSentence += current;
}
}
return nextSentence;
}
function draw() {
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext('2d');
context.moveTo(x, y);
for (i = 0; i < 2; i++) {
sentence = generate(sentence);
}
console.log(sentence);
turtle(sentence, context);
}
我没有看到任何问题。。。发生了什么事?你的预期结果是什么?如果我运行这个,我只会在控制台中看到一些字符串。@Jorg,我已经更新了我的答案,告诉我输出应该是什么样子的?如果我想在代码中应用其他规则,比如:var rulesB=[];rulesB[0]={a:F,b:FF-[-F+F+F]+[+F-F-F]}var rulesC=[];rulesC[0]={a:F,b:FF}rulesC[1]={a:X,b:F-[[X]+X]+F[+FX]-X},那么我需要在代码中更改什么?