I want to delete some lines on the canvas that i have created in HTML5 (with the <canvas> tag). I know one solution and that is using clearRect() (give this function the HEIGHT and WIDTH of the canvas and you clears the whole canvas.).But i don't want to clear the whole canvas, i only want to delete a few lines made by the function lineTo().
View 1 RepliesI have a menu in which is applied typeface script. Typeface 0.11 version doesn't support hover on links. There is an experimental version but doesn't work very well for me, so i tried to implement hover by myself.
Problem is: hover works pretty well changing canvas context property fillColor and then calling fill(), but the stroke on hovered voice remains on another color. Difficult to explain, so i put some test code online: TEST CODE As you can see, passing with mouse on the menu voices triggers the hover and the element change, but remains bordered in red.
[Code]...
I am trying to catch keypresses in my canvas tag, but it appears that
that is not valid.
I may try to just create a hidden input box that will allow me to catch
keypresses.
I am trying to write a very simple asteroids game for a presentation on
Ajax in July, to show that javascript can do more than it was able to a
couple of years ago.
I am working with the new canvas element. I have simplified my request.
Can I add a class to the canvas JS? Currently the fill colour is set with 'context.fillStyle="red";' I would love have this in a class as I want to change the colour of the fill with jQuery.
<!DOCTYPE html><html><head><meta charset=utf-8"><title>Canvas</title></head><body>
<canvas id="myCanvas"></canvas>
<script type="text/javascript">
var canvas=document.getElementById('myCanvas');
[Code]....
Why doesn�t the following code work in IE, I use excanvas.js as told in other articles? excanvas is in the same dir as the html-file.
Code:
<html>
<head>
<title></title>[code].....
Why won't my canvas graphics get rendered?
[Code]...
I'm writing a script that graphs data in different colors and shapes and I'm encountering two problems:(1) I can't specify different colors for the graph I'm rendering. If I use fillStyle="red"; then the entire chart becomes red. It seems to use the last color specified as the color for everything on the chart.(2) The shapes are overlapping in strange ways. The fills are not covering the lines of shapes behind them so it's unclear which shape is in front and which is behind. It's like they aren't being treated as separate shapes but instead one shape where boundaries are unclear. I don't know how else to explain it.
View 2 Replies View RelatedI 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.
View 5 Replies View RelatedBefore the canvas tag you had to write a script to make a gradient for html element backgrounds. Now you can use canvas and it's as easy as ... well messing with canvas. I have this script. At one point I had the gradient img objects resizing so the gradient would not get skewed. it was simple. just set the height% at the opposite ratio of the canvas width/height. But I went to make some changes and the next thing i knew that no longer worked. I don't remember how I did it!! I'm going to have to start over if I can't figure it out. Here's the script. Canvas only.
I haven't adapted with excanvas for IE yet, but that's coming when I can figure out how I had the thing working right. It's a css issue. I had thought I put the img objects in divs that were sized and positioned and then set the images to width 100% height= 100%*((canvas.width-canvas.height)/canvas.width) So in my example, the canvas was 100 x 30 and the factor is 7 so it would resize the image 700% and the height would grow by the relative amount to the setting I had it. I'll try to figure it out, but there's the script working somewhat. I want to figure out a way to resize the img objects when the user resizes the page, but I want the img to always maintain aspect ratio. [URL]
<script>
/*ORIGINAL SCRIPT FOUND AT [URL]*/
window.onload = function () {
var canvas = document.getElementById('c');
var ctx = canvas.getContext('2d');
var g = ctx.createLinearGradient(0, 0, 100, 50);
g.addColorStop(0, 'rgba(255, 255, 0, 0.5)');
g.addColorStop(0.5, '#0ff');
g.addColorStop(1, '#00f');
ctx.fillStyle = g;
ctx.fillRect(0, 0, 100, 50);
var data = canvas.toDataURL();
document.getElementById('i').src = data;
document.getElementById('EIMG').src = data;
var canvas2 = document.getElementById('c2');
var ctx2 = canvas2.getContext('2d');
var g2 = ctx2.createLinearGradient(0, 0, 100, 50);
g2.addColorStop(0, 'rgba(255, 0, 255, 0.5)');
g2.addColorStop(0.5, '#0ff');
g2.addColorStop(1, '#00f');
ctx2.fillStyle = g2;
ctx2.fillRect(0, 0, 100, 50);
var data2 = canvas2.toDataURL();
document.getElementById('i2').src = data2;
document.getElementById('DIMG').src = data2; .....
I'm having a problem with the <CANVAS> element in JavaScript. here's what i'm trying to do: I need 3 different canvas elements for writing a signature to. they must all 3 be visible at the same time
My problem that i'm having is that i can't seem to get the code to work which will write to more than one canvas.
[Code]...
Why doesn't the following code work:
<script type='text/javascript'>
var canvas = document.createElement('canvas');
canvas.width = 1400;
canvas.height = 700;
var context = canvas.getContext('2d');
context.strokeRect(10, 10, 50, 50);
context.stroke();
</script>
I am trying to create an Asteroids type game using JavaScript along with html5's canvas element for drawing. I have searched around and have looked at examples but I can't figure out what is wrong with my rendering that I do in the game loop that is run every frame. The problem appears to be only that the canvas is not cleared at the beginning of each frame but I feel there might be something wrong also. The code used and shown below only works in Firefox but not Google Chrome or Safari.
[Code]...
I'm new to Javascript, and having an issue with getInterval. For my programming languages class we have to create a simulation of waves breaking on a shore from above. I've decided to use a canvas object and Javascript for this animation, but am getting stuck on refreshing the frames.
Here is the code I have so far:
var shoreline = new Array();
var waves = new Array();
var canWidth = 600;
var canHeight = 400;
var waveNum = 0;
var count = 0; .....
As you can see, the idea is that each 5-pixel wide node of the shore and wave are stored in arrays so that the position of each node can differ. The wave() function initializes all the required data, and then calls setInterval on update(). The function update() draws the water, shore, and wave, and then updates the wave position node-by-node. Ideally, setInterval would cause this to happen repeatedly, so that the wave would appear to move closer to the shore every 1000ms.
However, this is not the case. It appears as though setInterval is working for one pass of update(), but fails after the first pass. You can tell that this is happening because the wave appears at its starting position, but does not continue to move. I read somewhere that setInterval can be broken by one-time functions, but I'm not sure. If you'd like to see what it's currently doing in a browser, I've hosted it here [URL]. Once I've got this animating properly I can continue my project, but I've hit a roadblock.
Here's a snippet:
canvases[i] = document.createElement('canvas');
canvases[i].style.width = '3px';
canvases[i].style.height = '100%';
canvases[i].getContext("2D");
canvases[i].fillRect(1,0,1,table_height);
I'm trying to dynamically create a canvas element. Later in the script it gets attached to the DOM, and this works fine if the last two lines are missing. I end up with a canvas element that is 3px wide and 100% of the containing div tall. However, the last two lines make it crash, with the error report 'canvases[i].fillRect is not a function'.
If I change the last two lines to:
var drawing = canvases[i].getContext("2D");
drawing.fillRect(1,0,1,table_height);
It says 'drawing is null'. Something seems to be going wrong with the getContext bit, because setting the height and width work fine. It behaves the same if I append the canvas element to the DOM before trying to do the drawing as well. This is in FF4.0.1 with a xhtml1-strict.dtd doctype and valid html.
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?
View 8 Replies View RelatedI would try to make a game/demo with legitimate script that is easy to read and properly segmented with functions instead of my previous attempts that are all one file.I'm trying to print the character (currently a circle) to screen in an external function (print_character in character.js).
View 2 Replies View RelatedI want to save my canvas-content to a single image-file. There are an approach using todataurl(), which works fine. But not if i draw an image-file (e.g. car.jpg or house.png) to the canvas additionally. It does not return the whole image? Here I have my simple example-code:
[Code]...
I want to be able to place an image on the canvas and have an onclick event for that object.
Code:
<!DOCTYPE html>
<html>
<head>
[code]....
My javascript canvas width and height are both 960. I have found that my screen horizontal and vertical resolutions are both 96 dpi. Thus, when a drawing is rendered in the full width and height of the canvas, it should be measurable by a ruler to be physically 10 inches by 10 inches. I did measure the display on the screen and found it to be actually about 11 and 3/16 inches wide. What is the proper way to scale a canvas so that the resulting physical dimensions can be calculated more precisely?
View 4 Replies View RelatedI'm playing around with full browser canvas element it seems to spill beyond the browser bounds generating horizontal and vertical scrollbars.This is the technique I'm using: [code]I've also tried to wrap the canvas element inside a div and set that div's overflow equal to hidden, but the results are unchanged.
View 2 Replies View RelatedI'm trying to figure out how to add images to a canvas element. I found a good site, but for some reason my images turn out bigger than expected.
Here's what I use (It's from different functions in different places, but essentially that is the relevant code). Assume there is a gameObject which has all the functions that I use. I tried replacing the functions with constant values but that made no difference:
PHP Code:
Somehow the image shows up much bigger than 69 pixels width and height. When I make the canvas smaller the image scales down with the canvas. So when I make the canvas twice as small, the image becomes twice as small as well. Seems like it is not using pixels as units.
How do I convert an image or datauri to canvas? I see the other way at [URL], but I also want to find out how I can create a canvas at the first place.The reason I ask this question is because I would like to create a little app that lets user create a canvas 'image', save it as something and be able to reopen it for canvas modification in the future. I figured that datauri is a good way to save a canvas, but I am not sure how I can do to reopen the datauri and use canvas to modify the drawing.
View 1 Replies View RelatedA remotely shared white board, using regular JavaScript,jQuery, the canvas element and PHP.I (or someone else) can get this thing working.The new 8:25 a.m. (US CST) version in http:[url].... should work -- though I still have not seen it work, perhaps.
View 2 Replies View RelatedI have the following code which displays a list of 6 images. Im using a reflective and magnifine plugin which seem to be working to an extent. The last three images in the list work perfectly, however the first three dont magnify, and that is becuase I have the img tags wrapped around the a tags as they are links. How to modify the magnify code so it magnifies imgs that have the a tag around it.
[Code]...
This is a question concerning the SVG plug in,Here is the code
<html>
<head>
<script language="javascript" type="text/javascript" src="jquery.js"></script>[code].....
1.SVG isn't drawing the circle
2. var svg is undefined keeps popping up.
My application is based on client-server architecture. It is a E-Learning Application. I am using ruby on rails server, javascript,canvas,SVG element. I have an idea of an interface to allow the teacher to build any type of animation for students using Cake javascript API. I wanted to save the animation build using the canvas element on the rails server either in database or as a file. Later I have to use that animation to be played to students. Any way to do it on any language except proprietary languages like flash but from that language communication can be done with rails server.
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