【发布时间】：2015-10-05 17:30:32
【问题描述】：
我有一个算法用于在 Canvas HTML 中绘制由点给出的行程。不用在我的观点上添加名称，一切都可以正常工作。
<html>
<head>
<script type="text/javascript" src="jquery-2.1.4.min.js"></script>
</head>
<body>
<canvas id="mycanvas" width="100" height="100" style="margin-top: 20px; margin-left: 50px;"></canvas>
<script type='text/javascript'>
window.onload=function(){
var jsonServicesTT = [{"NAME":"Elephant","DIRECTION":"4"},{"NAME":"Sunshine","DIRECTION":"4"},{"NAME":"Flower","DIRECTION":"4"},{"NAME":"Abricot","DIRECTION":"4"},{"NAME":"Cake","DIRECTION":"4"},{"NAME":"Mouse","DIRECTION":"4"},{"NAME":"Uther","DIRECTION":"3"},{"NAME":"Arriba","DIRECTION":"3"},{"NAME":"Hola","DIRECTION":"3"},{"NAME":"Elephant","DIRECTION":"3"}];
widthCan = 792;
heightCan = 423;
width = widthCan - 150;
height = heightCan - 130;
var perimetre = (width * 2 + height * 2);
var colors = [];
var colorTemp = '';
var table = [];
var direction = [];
var resteFaire = [];
var doubleColor = '';
var nbSegment = 0;
var percent = 0;
var up =0;
var right = 1;
var left = 0;
var bot = 0;
var tailleSegment = 0;
var decalX = 75;
var decalY = 60;
var NAME = '';
var cRot='';
var cRot2 = '';
cRot = document.getElementById("mycanvas");
ctxRot = cRot.getContext('2d');
ctxRot.canvas.width = widthCan;
ctxRot.canvas.height = heightCan;
function findColors(direction){
switch(direction)
{
case '1':
colors.push('red');
colorTemp = 'red';
break;
case '2':
colors.push('blue');
colorTemp = 'blue';
break;
case '3':
colors.push('DeepSkyBlue');
colorTemp = 'DeepSkyBlue';
break;
case '4':
colors.push('Green');
colorTemp = 'Green';
break;
default:
colors.push('Darkorange');
colorTemp = 'Darkorange';
}
}
/************** Rounded Rect *************/
function roundRect(x, y, w, h, radius) {
var r = x + w;
var b = y + h;
ctxRot.beginPath();
ctxRot.strokeStyle = "#BDBDBD";
ctxRot.lineWidth = "2";
ctxRot.moveTo(x + radius, y);
ctxRot.lineTo(r - radius, y);
ctxRot.quadraticCurveTo(r, y, r, y + radius);
ctxRot.lineTo(r, y + h - radius);
ctxRot.quadraticCurveTo(r, b, r - radius, b);
ctxRot.lineTo(x + radius, b);
ctxRot.quadraticCurveTo(x, b, x, b - radius);
ctxRot.lineTo(x, y + radius);
ctxRot.quadraticCurveTo(x, y, x + radius, y);
ctxRot.stroke();
}
function drawCircle(centerXFrom, centerYFrom, color){
var radius = 5;
ctxRot.beginPath();
ctxRot.arc(centerXFrom + decalX, centerYFrom + decalY, radius, 0, 2 * Math.PI, false);
ctxRot.fillStyle = color;
ctxRot.fill();
ctxRot.lineWidth = 1;
ctxRot.strokeStyle = '#003300';
ctxRot.stroke();
ctxRot.beginPath();
/*if(bot == 1){
ctxRot.translate(centerXFrom, centerYFrom);
ctxRot.rotate(-Math.PI / 4);
ctxRot.fillText(NAME, name.length - 50 , name.length);
ctxRot.restore();
}*/
}
function getSide(leg, taille) {
findColors(leg["DIRECTION"]);
NAME = leg["NAME"];
if(right == 1 && taille < (height - yPrec)) { //si on peut placer le point sur le même côté que précédemment
yPrec += taille;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if (right == 1 && taille > (height - yPrec)) {
var reste = height - yPrec; //calcul de combien de right il y a
if(reste > width){ //si on passe de right à left sans passer par bot
var resteY = reste - width;
yPrec = height - resteY;
xPrec = 0;
right = 0;
bot = 0;
up =0;
left = 1;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else //si on passe de right à bot
{
var resteX = taille - reste; // calcul de combien il reste de distance après avoir déduit le right
xPrec = width - resteX; // positionnement du point en Bot x
yPrec = height;
//writeBot(leg["NAME"], xPrec, yPrec);
right = 0;
bot = 1;
up =0;
left = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
else if (bot == 1 && taille < xPrec){ //si on peut placer le point sur le même côté que précédemment
xPrec = xPrec - taille;
yPrec = height;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if(bot == 1 && taille > xPrec){ // si le nouveau point ne peut pas être sur le bot
var resteY = taille - xPrec;
if(resteY > height){ //si on passe de bot à up
xPrec = resteY - height;
yPrec = 0;
right = 0;
bot = 0;
up =1;
left = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else{ //si on passe de bot à left
yPrec = height - resteY;
xPrec = 0;
bot = 0;
left = 1;
right = 0;
up =0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
else if (left == 1 && taille < yPrec){
yPrec = yPrec - taille;
xPrec = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if (left == 1 && taille > yPrec){
var resteX = taille - yPrec;
if (resteX > width){ //si on passe de left à right
yPrec = resteX - width;
xPrec = 0;
up = 0;
bot = 0;
left = 0;
right = 1;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else{ //si on passe de left à bot
xPrec = resteX;
yPrec = 0;
up = 1;
bot = 0;
left = 0;
right = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
else if(up == 1 && taille < (width - xPrec) ){
xPrec += taille;
yPrec = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if(up == 1 && taille > (width - xPrec)){
var resteX = width - xPrec;
xPrec = width;
yPrec = taille - resteX;
up = 0;
bot = 0;
left = 0;
right = 1;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
function drawCircleFirst(X, Y) {
if(jsonServicesTT[0]["NAME"] == jsonServicesTT[(jsonServicesTT.length) - 1]["NAME"])
{
table.push(jsonServicesTT[0]);
table.push(jsonServicesTT[(jsonServicesTT.length) - 1]);
for(var i = 0; i < table.length; i++){
findColors(table[i]["DIRECTION"]);
}
doubleColor = true;
}
else
{
findColors(table[0]["DIRECTION"]);
doubleColor = false;
}
var radius = 6;
var currentAngle = -0.5 * Math.PI;
for (var i = 0; i < 2; i++) {
var sliceAngle = 0.5 * 2 * Math.PI;
ctxRot.beginPath();
ctxRot.arc(X + decalX, Y + decalY, radius,currentAngle, currentAngle + sliceAngle);
ctxRot.strokeStyle = '#003300';
ctxRot.stroke();
currentAngle += sliceAngle;
ctxRot.lineTo(X + decalX, X + decalX);
ctxRot.fillStyle = colors[i];
ctxRot.fill();
}
}
function getProportion(){
if(doubleColor){
nbSegment = jsonServicesTT.slice(1).length;
}
else nbSegment = jsonServicesTT.length;
percent = 100/nbSegment;
tailleSegment = (perimetre*percent)/100;
for (var i = 1; i < nbSegment; i++){//premier et dernier points déjà placés
getSide(jsonServicesTT[i], tailleSegment);
}
}
roundRect(decalX, decalY, width, height, 20);
var firstPointX = width ;
var firstPointY = (height/2);
yPrec = firstPointY;
xPrec = firstPointX;
drawCircleFirst(firstPointX, firstPointY);
getProportion();
}
</script>
</body>
</html>但是，当您在 drawCircle 函数中取消注释用于插入文本的部分时（请不要注意名称的位置，因为我一开始只是想让它工作），您可以看到我的观点是没有画的更长。 我猜这是一个上下文问题，因为我的名字代表了重点的颜色，但我不知道如何解决。
<html>
<head>
<script type="text/javascript" src="jquery-2.1.4.min.js"></script>
</head>
<body>
<canvas id="mycanvas" width="100" height="100" style="margin-top: 20px; margin-left: 50px;"></canvas>
<script type='text/javascript'>
window.onload=function(){
var jsonServicesTT = [{"NAME":"Elephant","DIRECTION":"4"},{"NAME":"Sunshine","DIRECTION":"4"},{"NAME":"Flower","DIRECTION":"4"},{"NAME":"Abricot","DIRECTION":"4"},{"NAME":"Cake","DIRECTION":"4"},{"NAME":"Mouse","DIRECTION":"4"},{"NAME":"Uther","DIRECTION":"3"},{"NAME":"Arriba","DIRECTION":"3"},{"NAME":"Hola","DIRECTION":"3"},{"NAME":"Elephant","DIRECTION":"3"}];
widthCan = 792;
heightCan = 423;
width = widthCan - 150;
height = heightCan - 130;
var perimetre = (width * 2 + height * 2);
var colors = [];
var colorTemp = '';
var table = [];
var direction = [];
var resteFaire = [];
var doubleColor = '';
var nbSegment = 0;
var percent = 0;
var up =0;
var right = 1;
var left = 0;
var bot = 0;
var tailleSegment = 0;
var decalX = 75;
var decalY = 60;
var NAME = '';
var cRot='';
var cRot2 = '';
cRot = document.getElementById("mycanvas");
ctxRot = cRot.getContext('2d');
ctxRot.canvas.width = widthCan;
ctxRot.canvas.height = heightCan;
function findColors(direction){
switch(direction)
{
case '1':
colors.push('red');
colorTemp = 'red';
break;
case '2':
colors.push('blue');
colorTemp = 'blue';
break;
case '3':
colors.push('DeepSkyBlue');
colorTemp = 'DeepSkyBlue';
break;
case '4':
colors.push('Green');
colorTemp = 'Green';
break;
default:
colors.push('Darkorange');
colorTemp = 'Darkorange';
}
}
/************** Rounded Rect *************/
function roundRect(x, y, w, h, radius) {
var r = x + w;
var b = y + h;
ctxRot.beginPath();
ctxRot.strokeStyle = "#BDBDBD";
ctxRot.lineWidth = "2";
ctxRot.moveTo(x + radius, y);
ctxRot.lineTo(r - radius, y);
ctxRot.quadraticCurveTo(r, y, r, y + radius);
ctxRot.lineTo(r, y + h - radius);
ctxRot.quadraticCurveTo(r, b, r - radius, b);
ctxRot.lineTo(x + radius, b);
ctxRot.quadraticCurveTo(x, b, x, b - radius);
ctxRot.lineTo(x, y + radius);
ctxRot.quadraticCurveTo(x, y, x + radius, y);
ctxRot.stroke();
}
function drawCircle(centerXFrom, centerYFrom, color){
var radius = 5;
ctxRot.beginPath();
ctxRot.arc(centerXFrom + decalX, centerYFrom + decalY, radius, 0, 2 * Math.PI, false);
ctxRot.fillStyle = color;
ctxRot.fill();
ctxRot.lineWidth = 1;
ctxRot.strokeStyle = '#003300';
ctxRot.stroke();
ctxRot.beginPath();
if(bot == 1){
ctxRot.translate(centerXFrom, centerYFrom);
ctxRot.rotate(-Math.PI / 4);
ctxRot.fillText(NAME, name.length - 50 , name.length);
ctxRot.restore();
}
}
function getSide(leg, taille) {
findColors(leg["DIRECTION"]);
NAME = leg["NAME"];
if(right == 1 && taille < (height - yPrec)) { //si on peut placer le point sur le même côté que précédemment
yPrec += taille;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if (right == 1 && taille > (height - yPrec)) {
var reste = height - yPrec; //calcul de combien de right il y a
if(reste > width){ //si on passe de right à left sans passer par bot
var resteY = reste - width;
yPrec = height - resteY;
xPrec = 0;
right = 0;
bot = 0;
up =0;
left = 1;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else //si on passe de right à bot
{
var resteX = taille - reste; // calcul de combien il reste de distance après avoir déduit le right
xPrec = width - resteX; // positionnement du point en Bot x
yPrec = height;
//writeBot(leg["NAME"], xPrec, yPrec);
right = 0;
bot = 1;
up =0;
left = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
else if (bot == 1 && taille < xPrec){ //si on peut placer le point sur le même côté que précédemment
xPrec = xPrec - taille;
yPrec = height;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if(bot == 1 && taille > xPrec){ // si le nouveau point ne peut pas être sur le bot
var resteY = taille - xPrec;
if(resteY > height){ //si on passe de bot à up
xPrec = resteY - height;
yPrec = 0;
right = 0;
bot = 0;
up =1;
left = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else{ //si on passe de bot à left
yPrec = height - resteY;
xPrec = 0;
bot = 0;
left = 1;
right = 0;
up =0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
else if (left == 1 && taille < yPrec){
yPrec = yPrec - taille;
xPrec = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if (left == 1 && taille > yPrec){
var resteX = taille - yPrec;
if (resteX > width){ //si on passe de left à right
yPrec = resteX - width;
xPrec = 0;
up = 0;
bot = 0;
left = 0;
right = 1;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else{ //si on passe de left à bot
xPrec = resteX;
yPrec = 0;
up = 1;
bot = 0;
left = 0;
right = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
else if(up == 1 && taille < (width - xPrec) ){
xPrec += taille;
yPrec = 0;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
else if(up == 1 && taille > (width - xPrec)){
var resteX = width - xPrec;
xPrec = width;
yPrec = taille - resteX;
up = 0;
bot = 0;
left = 0;
right = 1;
drawCircle(xPrec, yPrec, colorTemp, NAME);
}
}
function drawCircleFirst(X, Y) {
if(jsonServicesTT[0]["NAME"] == jsonServicesTT[(jsonServicesTT.length) - 1]["NAME"])
{
table.push(jsonServicesTT[0]);
table.push(jsonServicesTT[(jsonServicesTT.length) - 1]);
for(var i = 0; i < table.length; i++){
findColors(table[i]["DIRECTION"]);
}
doubleColor = true;
}
else
{
findColors(table[0]["DIRECTION"]);
doubleColor = false;
}
var radius = 6;
var currentAngle = -0.5 * Math.PI;
for (var i = 0; i < 2; i++) {
var sliceAngle = 0.5 * 2 * Math.PI;
ctxRot.beginPath();
ctxRot.arc(X + decalX, Y + decalY, radius,currentAngle, currentAngle + sliceAngle);
ctxRot.strokeStyle = '#003300';
ctxRot.stroke();
currentAngle += sliceAngle;
ctxRot.lineTo(X + decalX, X + decalX);
ctxRot.fillStyle = colors[i];
ctxRot.fill();
}
}
function getProportion(){
if(doubleColor){
nbSegment = jsonServicesTT.slice(1).length;
}
else nbSegment = jsonServicesTT.length;
percent = 100/nbSegment;
tailleSegment = (perimetre*percent)/100;
for (var i = 1; i < nbSegment; i++){//premier et dernier points déjà placés
getSide(jsonServicesTT[i], tailleSegment);
}
}
roundRect(decalX, decalY, width, height, 20);
var firstPointX = width ;
var firstPointY = (height/2);
yPrec = firstPointY;
xPrec = firstPointX;
drawCircleFirst(firstPointX, firstPointY);
getProportion();
}
</script>
</body>
</html>【问题讨论】：
标签： javascript canvas html5-canvas