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JavaScript - Canvas And Discarding Changes Made To Canvaspixelarray?
is there any way to discard certain changes made to CanvasPixelArray?
i'm writing an bounding box detection algorithm. i scan across until i hit a specific pixel. while i'm scanning i'm also modifying the pixels (say to green) to indicate that they are bank. i am not interested in partly filling the last scanline because it does not indicate an object boundary, it merely serves to tell me that the previous full line is the boundary. if i call putImageData each time i successfully reach the end of the canvas horizontally (kind of like a DB transaction), i want to be able to not write the changed pixels out to Canvas on the line which didnt complete a full scan across. is there any way to discard this data? or do i need to run a second pass when each line is complete to modify the pixels? thanks, Leon Similar TutorialsI have been looking for someone that can make this for me. I need a program made to register accounts to this url > Register :: The Pokemon Moon RPG :: Online Pokemon RPG Game What it needs to do: Needs to use proxies Needs to use a proxy for 1 account, so say 500 accounts it needs to have 500 different proxies. Needs to be able to have a timer to make it wait ie. Wait between 1min - 3 hours between account Needs to randomize account names(that people would make their names) Needs to randomize account passwords If possible make it able to make the account, then log in to it and sit on the account for random times ie. 4 minutes or 4 hours or longer of shorter. I will donate money to whoever does this for me, I also have something else I would like to be made, so if whoever wants to be donated to twice just let me know! Reply With Quote 02-01-2015, 04:06 AM #2 Old Pedant View Profile View Forum Posts Supreme Master coder! Join Date Feb 2009 Posts 28,310 Thanks 82 Thanked 4,754 Times in 4,716 Posts Completely unethical. And probably illegal, in the sense that it violates the "Terms of Use" he Terms Of Use :: The Pokemon Moon RPG :: Online Pokemon RPG Game Users must not engage in any sort of attempts to hack this website and/or its users. (And we all know what the "something else" you want made will be. Something that gets credits in the game, somehow.) What is the point of this? Why does anybody want to cheat at an online game where there is no money reward involved. I mean I could understand trying to hack a poker site if real money is involved. But just for credits, in a game? *sigh* If I win a game, I want to know I won it the right way, not by cheating. And, if you really do get high on cheating, I'd think you'd at least want to do so with your OWN cheat, not by just buying one. I simply do not understand the attraction to this kind of stuff. So after some studying I have a pretty decent method using objects. I built it so that you hit the first number, then you would hit a plus or minus then the second number. The problem is just getting the buttons to define variables and run functions. Quote: <html> <head> <script type="text/javascript" > x=10; h=1; var numbs = new Const(x) function Const(one){ this.x=one; ADD(this.x) if(h=1){ function ADD(a){ y=5; b=y+a; alert(b); }}} </script> </head> <body> <input type="button" value="1" onclick="needs to run all that AND set x=1 and h=1"> </body> </html> Also I plan on going back and making y, which is the second number you're adding, an object. For now I'm just setting it equal to something so I don't have to mess with it. I am pretty new to javascript and descided to test my skills by making a javascript clock using the computers time it works but I know the way I am doing it isn't very good you can see the code below Code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>clock</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript">
var minutes = 0;
var seconds;
var hour = 0;
var minute = new Date().getMinutes();
minutes += minute;
var hours = new Date().getHours();
hour += hours;
var time_period = "";
if(hour > 12){
hour = hour-12;
time_period = "PM";
}else {
time_period = "AM";
}
function working_clock(){
var time = new Date;
seconds = time.getSeconds();
var clock = document.getElementById('clock');
if(seconds == 59){
minutes+=1;
}
if(minutes == 60){
minutes = 1;
hour++;
}
if(minutes < 10){
var minute_digit_two = 0;
clock.innerHTML = ("time: "+hour+":"+minute_digit_two +minutes+":"+seconds+" "+time_period);
}else {
clock.innerHTML = ("time: "+hour+":"+minutes+":"+seconds+" "+time_period);
}
setTimeout("working_clock()",1000);
}
window.onload = working_clock;
</script>
</head>
<body>
<div id="clock"></div>
</body>
</html>
heres where you can see it in action http://the-test.comoj.com/files/working-clock.html im just asking if there are any errors or if theres a better way to do this Hey guys. I made a chat client today (my first one and it's pretty sweet so far) I have a speed problem though http://xonicgames.com/hudson/chat.php Once there are ~20+ posts it starts getting slow (at least on my connection) It does an ajax request every 500 seconds (dont know if that should be slowed down or not) What can I do to speed it up? Thanks I have this code which converts Fahrenheit to Celsius. Now, I have to have a counter that displays the amount of times I have made a conversion. I have no clue how to do this. This is the initial code:
Code: <html>
<head>
<script type="text/javascript">
/* Converts given centigrade in one text box to farenheit in another */
function convert1 () {
document.getElementById("output").value =
document.getElementById("input").value*1.8+32;
}
</script>
</head>
<body>
<p>Then enter the input and view the output</p>
<input type="text" size="15" id="input">
<input type="button" value=" ==> " onclick="convert1()">
<input type="text" size="15" id="output">
</body> </html>
I don't know how to approach this so I tried different things.... Code: tml>
<head>
<script type="text/javascript">
/* Converts given centigrade in one text box to farenheit in another */
function convert1 () {
document.getElementById("output").value =
document.getElementById("input").value*1.8+32;
}
function counter()
{
if (function convert1().onclick==true)
{count++;}
}
</script>
</head>
<body>
<p>Then enter the input and view the output</p>
<input type="text" size="15" id="input">
<input type="button" value=" ==> " onclick="convert1()">
<input type="text" size="15" id="output">
</body> </html>
but then I did some research and it said I couldn't do that.... so I tried this: Code: <html>
<head>
<script type="text/javascript">
/* Converts given centigrade in one text box to farenheit in another */
var count=0;
function documentClick()
{
document.getElementById('clicked').value = ++clickCount
}
document.onclick = documentClick;
function convert1 () {
document.getElementById("output").value =
document.getElementById("input").value*1.8+32;
}
</script>
</head>
<body>
<p>Then enter the input and view the output</p>
<input type="text" size="15" id="input">
<input type="button" value=" ==> " onclick="convert1()">
<input type="text" size="15" id="output">
</body> </html>
I think this last code is correct, the problem I have now is that I don't know how to call it to just display as text under the buttons and conversions. I'm looking for some way to display it like ("you have made"+ count+ "conversions");. No boxes or buttons, just text and I don't know how to call for this after the </script>, inside the body. I am new at all this and would appreciate any help. Thanks. It should look like this. Hi, I'm not good with manipulating JavaScript for my needs and I am trying to use a JavaScript file to implement my common content in to my web page, in this case it is a news article I want to display across all of my web pages. The problem is that I want to style it and use html attributes in side of the document.write and that is apparently messing it up. Would someone be able to show me how to fix this problem or fix the code so I can get the common content to display correctly with styling from CSS. If possible I would like to keep the CSS in a separate file and put a link to it in the JavaScript file and use the class tags, but I do not know how far we can go with JavaScript. Thanks for helping. Here are links to the webpage where I would like the code to show up. Below is the JavaScript that is currently in my .js file. http://www.nasawear.com/Home.html (The news article should display in the right column.) Code: document.write("<link rel="stylesheet" type="text/css" href="css/mainpage.css" />");
document.write("<h3 class="section">");
document.write("New NASA News");
document.write("</h3>");
document.write("
<div class="picbox">
<a rel="nofollow" target="_blank" href="image/superhotplanet-full.jpg">
<img class="white" width="335" height="268" src="image/superhotplanet-full.jpg" alt="NASA Finds Super-Hot Planet with Unique Comet-Like Tail" /> Full Size</a>
<p class="imageandstuff">NASA Finds Super-Hot Planet with Unique Comet-Like Tail</p>
<p class="dis">
Astronomers using NASA's Hubble Space Telescope have confirmed the existence of a baked object that could be called a "cometary planet." The gas giant planet, named HD 209458b, is orbiting so close to its star that its heated atmosphere is escaping into space.
<br/>
<br/>
Observations taken with Hubble's Cosmic Origins Spectrograph (COS) suggest powerful stellar winds are sweeping the cast-off atmospheric material behind the scorched planet and shaping it into a comet-like tail.
<br/>
Illustration Credit: NASA, ESA, and G. Bacon (STScI)
</p>
</div> ");
Hey everyone, I have been practicing using canvas to make designs. My current code below will load the word the user inputs and makes it bounce around the canvas as well as a text spinner. However, whenever the user inputs a second word, the bounce below stops to start a new one and the text spinner messes up. I was wondering if anyone could help me so when the user inputs another word, that it either reloads a new textspinner or adds another one, as well as just add the word to the canvas without stopped the old one. Here's my current script. Thanks already, Joey Code:
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script>
var ctx;
var a=0.0;
var as=true;//true a is increasing, false decreasing
var x,y;
var xs = 1;
var ys = 1;
var userWord
var myDiv, t;
var test = 0;
var ds ="";//display string
var sli =0; //spinning letter index;
function init(){
ctx = document.getElementById("myCvs").getContext("2d");
userWord = document.getElementById("userWord").value;
x=Math.floor(Math.random()*801)
y=Math.floor(Math.random()*601);
drawText();
setInterval("onEnterFrame()", 50);
myDiv = document.getElementById("myDiv");
for (i =0; i<=userWord.length;i++){
ds += "*";
}
myDiv.innerHTML =ds;
textSpin();
}
function textSpin(){
myChar = randomChar();
var newString = userWord.slice(0, sli);
newString +=myChar;
newString += ds.slice(sli+1, ds.length-1);
myDiv.innerHTML = newString;
if (myChar == userWord.charAt(sli)){sli++;}
if (sli<userWord.length){
t = setTimeout("textSpin()", 80);
}
}
function randomChar(){
var rc = Math.random()*26 + 97; //random lowercase char code
return String.fromCharCode(rc);
}
function onEnterFrame(){
if(a>1){as = false;}
if(a<0){as = true;}
if(as){
a+=0.01;
}else{
a-=0.01;
}
if(x>800){xs = -1}
if(x<0){xs=1}
if(y>600){ys = -1}
if(y<0){ys=1}
x+=10 *xs;
y+=10 *ys;
drawText();
}
function drawText(){
ctx.font = "20px Times New Roman";
//ctx.fillStyle= "rgb(256,256,256)";
//ctx.fillText("Hello", x, y);
ctx.fillStyle = randomColor();
ctx.fillText(userWord, x,y);
}
function randomColor(){
var r = Math.floor(Math.random()*150)+55;
var g = Math.floor(Math.random()*256)+150;
var b = Math.floor(Math.random()*20)+50;
var a = Math.random();
return "rgba("+ r+ ","+g+","+b+","+ a+")";
}
//function randomFont(){
// var s = Math.floor(Math.random()*100) +100;
// return s; //+ "px Times New Roman";}
</script>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
body {
background-color:#000;
}
#myDiv {
color:#FFF;
}
</style>
</head>
<body onLoad=""><center>
<input type="text" id="userWord" value=""> </input><br>
<input type="button" id="enterWord" value="Enter Word" onClick="init()" ></input><br><br>
<div id="myDiv" > </div>
<canvas id="myCvs" width="800px" height="600px" /><br>
<br>
</center>
</body>
</html>
I've been reading a lot of tutorials on the canvas tag and seen a lot of people using JavaScript that looks something like: ctx.beginPath(); ctx.moveTo(25,25); ctx.lineTo(105,25); ctx.fill(); I understand that ctx is just the variable name and I can replace that with any variable I define, however, I'm looking for a list of all of the methods such as (moveTo, lineTo, fill etc...), as well as what they do. I hope I'm explaining this or asking this correctly. Thanks! -Mike Hi there! How should I write this - better than it's now - so that when I rotate a figure, in the next "frame" it would stay rotated? Second thing - if you run this code, and set the angle for, let's say 180 degrees the figure is being drawn in some random location. How do I fix this? Code: Code:
function GenericFigure(context) {
this.states = ["wait", "moving", "rotating", "stop"];
this.state = this.states[0];
this.ctx = context;
this.sqrW = this.sqrH = 20;
this.ctxW = 200;
this.ctxH = 350;
this.colorsO = {
red : "#ee1515",
green : "#45d137",
blue : "#17a3f3",
orange : "#ff910f",
purple : "#680077"
};
this.colorsA = ["#ee1515", "#45d137", "#17a3f3", "#ff910f", "#680077"];
this.pickColor = function() {
var num = Math.floor(Math.random() * 5);
return this.colorsA[num];
}
}
function Rectangle(context) {
this.inheritFrom = GenericFigure;
this.inheritFrom(context);
this.width = this.sqrW;
this.height = this.sqrH * 3;
this.x = this.ctxW / 2;
this.y = 0;
this.rotation = -1;
this.setRotation = function(angle) {
this.rotation = angle;
}
this.rotate = function() {
this.ctx.clearRect(0, 0, this.ctxW, this.ctxH);
this.ctx.translate(this.x + 2 * this.width, this.y - 2 * this.height + 20);
this.ctx.rotate(this.rotation * Math.PI / 180);
this.ctx.fillRect(this.ctxW / 2, 0, this.width, this.height);
this.ctx.restore();
}
this.moveDown = function() {
this.y += 20;
this.ctx.restore();
this.ctx.clearRect(0, 0, this.ctxW, this.ctxH);
this.ctx.fillRect(this.x, this.y, this.width, this.height);
this.ctx.save();
if(this.rotation > -1) {
this.rotate();
}
l("A");
}
this.draw = function() {
this.ctx.fillStyle = this.pickColor();
this.ctx.save();
this.ctx.fillRect(this.x, this.y, this.width, this.height);
}
}
//a tak można wywołać:
var ctx = document.getElementById("game").getContext("2d");
var rect = new Rectangle(ctx);
rect.draw();
var inte = setInterval(function(){if(rect.y >= rect.ctxH - rect.height){clearInterval(inte);return;}if(rect.y == 60) rect.setRotation(90);rect.moveDown();}, 500);
And the third problem: Code: this.ctx.translate(this.x, 0); I thought, that this line should set orientation point to top left corner of my figure, but it seems, that it doesn't - after rotation my figure is being drawn two heights lower. Again - how do I fix it? Any help will be much appreciated . if you take a look at this site here you can see that it no longer scrolls or even displays content, but here it does. I'll bet there's a quick fix here, but not sure what it is. Any ideas?
Hello guys! I need your help! I want to create a rectangle with a line in the middle with the canvas object. The problem is that the line in the middle gets bigger than the rest of the rectangle. How do I solve this? I believe it has something to do with shadows. If so, how do I turn them off. My code is: <html> <head> <title></title> </head> <body> <canvas id='chart' width='400' height='200'> <script type="text/javascript"> var canvas = document.getElementById('chart'); var ctx = canvas.getContext('2d'); ctx.lineWidth = 10; ctx.strokeRect(0, 0, 400, 200); ctx.moveTo(0, 100); ctx.lineTo(400, 100); ctx.stroke(); </script> </body> </html> Code: <form>
<input id="a" size=4 name="neg" placeholder="1st Screen size in inch">
<input id="b" size=4 name="hoyr" placeholder="2nd Screen size in inch">
<input type="submit" value="GO!" onclick="getValue()">
</form>
</div>
<canvas id="MyCanvas" width="1000" height="1000"></canvas>
<script type="text/javascript">
function getValue()
{
var x = document.getElementById("a").value;
var y = document.getElementById("b").value;
var aWidth;
var aHeight;
var bWidth;
var bHeight;
var c= document.getElementById("MyCanvas");
var ctx= c.getContext("2d");
ctx.fillStyle="#4AA02C";
ctx.fillRect(0,0,x,y);
}
Here, it draws canvas then disappears immediately. I just cant wrap my mind around canvas. As far as I can tell theres no logical reason as to why the code would not work. Could someone take a look at it and possibly figure out whats wrong? I'm trying to intialize and draw a canvas with a simple image. I have the functions in a custom namespace in javascript. I am also using Jquery Code: var birdr = new Image();
var birdl = new Image();
$(document).ready(function(){
if(Modernizr.canvas){
var c = document.createElement('canvas');
LK.animLoad();
document.getElementById('backg-canvas').appendChild(c);
$('canvas').attr({'width':'500','height':'500','id':'canvas'});
var context = LK.returnCanvas();
context.drawImage(birdl, 400,487,10,10);
}
});
var LK = {
birdx: 400, //unused (lets just get it to draw the image first :\)
birdy: 487, //unused
animLoad: function(){
birdl.src = "images/bird2.png";
birdr.src = "images/bird.png";
//alert(birdl);
//alert(birdr);
},
returnCanvas: function(ca){
var b_canvas = LK.getCanvas();
var b_context = b_canvas.getContext('2d');
return b_context;
},
getCanvas: function(){
var a_canvas = document.getElementById('canvas');
//alert(a_canvas);
return a_canvas;
}
}
Any help would be greatly appreciate thanks. Btw safari web inspector indicates the canvas is getting properly created and appended to the container div. So that all works fine. Anyone got any suggestions on techniques? The main one I find is to use translate to move the canvas around, which just seems odd to me. I don't even fully understand how it works. But the one I was looking at used clearRect. In examples given looked as though it had to redraw the canvas every frame. I'm just mucking around with a simple poker game, figured i'd have the table in one layer and anything that moves on a top layer? By doing that I could only clear each card as it moved around...yes? Anyone know of a better way of doing things? So I've been making a game using html canvas. Here is a link to the game. (Move around with wasd, rotate turret with left and right arrows) http://db.tt/ei3LlR The problem is that the shadow flickers when it is rotated. This does not happen in firefox. The shadow is not an image, but another canvas element, generated dynamically from the image of the tank. So the problem seems to be with webkit drawing rotated canvas elements inside another. Could this possibly be the reason behind this, or is it more likely to be a problem on my end? I have make a javascript program that uses HTML canvas and I can't get it to work in Internet Explorer. I tried using excanvas and jqcanvas but had trouble getting them to work. Does anyone know how to do this?
I made a graphing calculator using canvas in javascript. It's pretty simple as of right now. I was hoping you guys could take a look and tell me what types of things I should add. Some I'm already looking into: customizable x-min, x-max, etc., plotting more than one function on the same graph. It supports sin(), cos(), tan(), pi, e, sqrt(), ln(), abs(), acos(), asin(), atan(). Exponents can be written as b^e. Please give me some suggestions. http://jazzothegreat.com/graph.html Thanks, Julian i want to transfrom image like the picture below using canvas,it seems simple but i find no way to do , can anyone give me some ideas? ( left side is the source) Hello, I have this idea, but I wouldn't want to reinvent the wheel if it's already been done. I want to generate perspective grid on canvas depending on browser window size, something like this, but without textures: http://www.123rf.com/photo_2651286_a...rspective.html Do someone of you guys know if some similar script already exists? Or at least some tips on how not to end up writing a 1000 lines script (At this point I would just drop the idea)? All thoughts appreciated. P.S. even an obscure algorithm would probably suffice, 'cause the main problem I'm struggling with is diminishing size perspective calculations So I'm creating a game and decided to use a canvas for the map. The map is a big pictures 500kb+ (6400x6400px) and the canvas size is 320x320 so I am displaying only part of the image at a time and have the page reload on button click for database purposes. What I'd like help with is performance. Currently it's taking a few secs to reload every time and it seems that it causes some cpu strain (can't switch tabs while loading). Could I stop the canvas from reloading the image each time the page is reloaded and if so then how? Can I make the canvas only load a part of the image, if so then how? If neither is possible any tips, solutions how to solve the performance issues? |
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