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  • Can you have multiple clipping regions in an HTML Canvas?

    - by emh
    I have code that loads a bunch of images into hidden img elements and then a Javascript loop which places each image onto the canvas. However, I want to clip each image so that it is a circle when placed on the canvas. My loop looks like this: $$('#avatars img').each(function(avatar) { var canvas = $('canvas'); var context = canvas.getContext('2d'); var x = Math.floor(Math.random() * canvas.width); var y = Math.floor(Math.random() * canvas.height); context.beginPath(); context.arc(x+24, y+24, 20, 0, Math.PI * 2, 1); context.clip(); context.strokeStyle = "black"; context.drawImage(document.getElementById(avatar.id), x, y); context.stroke(); }); Problem is, only the first image is drawn (or is visible). If I remove the clipping logic: $$('#avatars img').each(function(avatar) { var canvas = $('canvas'); var context = canvas.getContext('2d'); var x = Math.floor(Math.random() * canvas.width); var y = Math.floor(Math.random() * canvas.height); context.drawImage(document.getElementById(avatar.id), x, y); }); Then all my images are drawn. Is there a way to get each image individually clipped? I tried resetting the clipping area to be the entire canvas between images but that didn't work.

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  • Matlab Simulation: Point (symbol) Moving from start point to end point and back

    - by niko
    Hi, I would like to create an animation to demonstrate LDPC coding which is based on Sum-Product Algorithm So far I have created a graph which shows the connections between symbol nodes (left) and parity nodes (right) and would like to animate points travelling from symbol to parity nodes and back. The figure is drawn by executing the following method: function drawVertices(H) hold on; nodesCount = size(H); parityNodesCount = nodesCount(1); symbolNodesCount = nodesCount(2); symbolPoints = zeros(symbolNodesCount, 2); symbolPoints(:, 1) = 0; for i = 0 : symbolNodesCount - 1 ji = symbolNodesCount - i; scatter(0, ji) symbolPoints(i + 1, 2) = ji; end; parityPoints = zeros(parityNodesCount, 2); parityPoints(:, 1) = 10; for i = 0 : parityNodesCount - 1 ji = parityNodesCount - i; y0 = symbolNodesCount/2 - parityNodesCount/2; scatter(10, y0 + ji) parityPoints(i + 1, 2) = y0 + ji; end; axis([-1 11 -1 symbolNodesCount + 2]); axis off %connect vertices d = size(H); for i = 1 : d(1) for j = 1 : d(2) if(H(i, j) == 1) plot([parityPoints(i, 1) symbolPoints(j, 1)], [parityPoints(i, 2) symbolPoints(j, 2)]); end; end; end; So what I would like to do here is to add another method which takes start point (x and y) and end point as arguments and animates a travelling circle (dot) from start to end and back along the displayed lines. I would appreciate if anyone of you could show the solution or suggest any useful tutorial about matlab simulations. Thank you!

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  • Why does the following Toggle function perform four different operations instead of two?

    - by marcamillion
    You can see the implementation here: http://jsfiddle.net/BMWZd/8/ What I am trying to do, when you click on 'John Brown', you see the first element at top turn black. When you click it again, the border of the dotted circle disappears, then when you click 'John Brown' again, you see something else, then finally once again it all disappears. What I am trying to achieve is when you click it once, everything turns black (like it does now), then you click it again, everything disappears and goes back to the original state. Important distinction, what I mean is...when one of the names in the box are not clicked. So if you clicked John Brown then moved to Jack Dorsey, the #1 at top should stay black. But if you were to click Jack Dorsey again, i.e. you 'unclicked' it, then it should disappear. Also, how do I tighten it up, so that it responds quicker. Now when you click it, it feels like there is a little bit of a lag between when it was clicked and when it responds. Edit1: If anyone is interested...the UI that this will be used in is for my webapp - http://www.compversions.com

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  • Crosshairs in Java

    - by typoknig
    I am making a game that needs a crosshair. I have been playing with the java.awt.cursor class and that is easy enough, but the problem is that I do not want the crosshairs to be able to leave the window I create for my game, so I tried this instead: private void drawCrossHair(Graphics g){ Ellipse2D ellipse = new Ellipse2D.Float(); ellipse.setFrame(crossHair.x, crossHair.y, 36, 36); Color yellow = new Color (0xEDFF62); g.setColor(yellow); g.fillOval(crossHair.x, crossHair.y, 40, 40); g.setClip(ellipse); g.clip(ellipse); Basically I am trying to remove the "ellipse" from "g" leaving only a small ring behind. The problem here is that "g.clip(ellipse);" gives me an error. My objective with this code is to create a circle with a transparent center, like a donut. Once the donut is created I will add some small points on the inside of it so it looks more like crosshairs. One thing that may or may not be an issue is that I plan on moving the crosshairs with a joystick, not a mouse... I do not know if that will limit my options for what kind of object my crosshairs can be.

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  • Images in Applet not showing in web page

    - by Leanne C
    I am trying to display a JPEG image and a moving dot on a Java applet which I am using on a web based application. However, when I run the applet it works fine, but when I display the applet from the JSP page, I get the moving dot but not the JPEG image. Is there a specific folder where the JPEG needs to be? These are the 2 methods i use for drawing the picture and the moving dot on the screen. public class mapplet extends Applet implements Runnable { int x_pos = 10; int y_pos = 100; int radius = 20; Image img, img2; Graphics gr; URL base; MediaTracker m; @Override public void init() { mt = new MediaTracker(this); try { //getDocumentbase gets the applet path. base = getCodeBase(); img = getImage(base, "picture.jpg"); m.addImage(img, 1); m.waitForAll(); } catch (InterruptedException ex) { Logger.getLogger(movement.class.getName()).log(Level.SEVERE, null, ex); } public void paint (Graphics g) { g.drawImage(img, 0, 0, this); // set color g.setColor (Color.red); // paint a filled colored circle g.fillOval (x_pos - radius, y_pos - radius, 2 * radius, 2 * radius); } The code one below is the call from the jsp page <applet archive="mapplet.jar" code="myapplets/mapplet.class" width=350 height=200> </applet> The jar file and the picture are in the same folder as the jsp page, and there is also a folder containing the contents of the class and image of the applet in the web section of the application. The applet loads fine however the picture doesn't display. I think it's not the code but the location of the picture that is causing a problem. Thanks

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  • Is it possible to execute a function in Mongo that accepts any parameters?

    - by joshua.clayton
    I'm looking to write a function to do a custom query on a collection in Mongo. Problem is, I want to reuse that function. My thought was this (obviously contrived): var awesome = function(count) { return function() { return this.size == parseInt(count); }; } So then I could do something along the lines of: db.collection.find(awesome(5)); However, I get this error: error: { "$err" : "error on invocation of $where function: JS Error: ReferenceError: count is not defined nofile_b:1" } So, it looks like Mongo isn't honoring scope, but I'm really not sure why. Any insight would be appreciated. To go into more depth of what I'd like to do: A collection of documents has lat/lng values, and I want to find all documents within a concave or convex polygon. I have the function written but would ideally be able to reuse the function, so I want to pass in an array of points composing my polygon to the function I execute on Mongo's end. I've looked at Mongo's geospatial querying and it currently on supports circle and box queries - I need something more complex.

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  • remove values from an array php

    - by LiveEn
    I have a array of links and i have another array which contains certain values i would like to filter in the list eg: http://www.liquidshredder.co.uk/shop%3Fkw%3Dsurfboards%26fl%3D330343%26ci%3D3889610385%26network%3Ds http://www.bournemouth-surfing.co.uk/index.php%3FcPath%3D32 http://www.stcstores.co.uk/wetsuit-range-sizing--pricing-info-1-w.asp http://www.kingofwatersports.com/wetsuit-sale-c227.html http://www.uk.best-price.com/search/landing/query/bodyboards/s/google/altk/Surf%2Band/koid/1944273223/ http://www.surfinghardware.co.uk/Results.cfm%3Fcategory%3D20%26kw%3Dbodyboards%26fl%3D11407%26ci%3D3326979552%26network%3Ds http://www.teste.co.uk/adtrack/baod.html http://www.teste.co.uk/bodyboards/ www.sandskater.co.uk/ www.sandskater.co.uk/bodyboards/+Bodyboards&sa=X&ei=GwSWS-KaGM24rAeF-vCKDA&ved=0CBMQHzAKOAo http://www.extremesportstrader.co.uk/buy/water/bodyboarding/ www.extremesportstrader.co.uk/buy/water/bodyboarding/+Bodyboards&sa=X&ei=GwSWS-KaGM24rAeF-vCKDA&ved=0CBYQHzALOAo www.circle-one.co.uk/+Bodyboards&sa=X&ei=GwSWS-KaGM24rAeF-vCKDA&ved=0CBkQHzAMOAo http://www.teste.co.uk/bodyboards/p1 http://www.teste.co.uk/bodyboards/p2 http://www.amazon.co.uk/s/%3Fie%3DUTF8%26keywords%3Dbodyboards%26tag%3Dgooghydr-21%26index%3Daps%26hvadid%3D4764625891%26ref%3Dpd_sl_2lyzsfw1ar_e http://www.teste.co.uk/bodyboards/p3 www.extremesportstrader.co.uk/buy/water/ and i would like to remove all the instances of "http://www.teste.co.uk"? i tried the below code but it doesn't work :( $remove=array("teste.co.uk","127.0.0.1","localhost","wikipedia.org","gmail.com","answers.yahoo.com"); foreach ($list[0] as $key=>$clean) { if (in_array($clean,$remove)) { unset($list[0][$key]); } echo $clean; echo '<br>'; }

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  • Problem adding and removing a jquery tab to the existing tabs dynamically.

    - by kranthi
    hi everyone, I have a href tag, upon clicking it a new jquery tab is added to the existing tabs,using the following js. $(function() { //DECLARE FUNCTION: removetab var removetab = function(tabselector, index) { $(".removetab").click(function(){ $(tabselector).tabs('remove',index); }); }; //create tabs $("#tabs").tabs({ add: function(event, ui) { //select newely opened tab $(this).tabs('select',ui.index); //load function to close tab removetab($(this), ui.index); }, show: function(event, ui) { //load function to close selected tabs removetab($(this), ui.index); } }); //load new tab $(".addtab").click(function(){ var href=$(this).attr("href"); var title=$(this).attr("title"); $("#tabs").tabs( 'add' , href , title+' <span class="removetab ui-icon ui-icon-circle-close" style="float:right; margin: -2px -10px 0px 3px; cursor:pointer;"></span>'); return false; }); }); and <a class="addtab" title="Tab Label" href="HTMLPage.htm">Add Tab</a> If the href attribute for 'a' tag corresponds to a '.htm' page I am able to add & remove the tab successfully.Where as if it corresponds to a '.aspx' page I am able to add a new tab ,but unable to remove the tab upon clicking on the 'close' sign next to the tab title. Please help. Thanks in advance

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  • Bullets WILL NOT dissapear in firefox

    - by DunlopBurns
    Hoping you can help me with a problem. I cannot get rid of Bullets in Firefox, i don't want any anywhere, hence my list-style-type: none!important being everywhere. It only appears in Firefox as far as i can tell. the HTML.... <!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" lang="en" xml:lang="en"> <head> <title>littleprints.nl</title> <meta name="description" content="----" /> <meta name="keywords" content="----" /> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script> <script type="text/javascript" src="js/slimbox2.js"></script> <link rel="stylesheet" href="css/slimbox2.css" type="text/css" media="screen" /> <link rel="stylesheet" href="layout.css"/> <link rel="stylesheet" href="style.css"/> </head> <body> <div id="container"> <div id="inline1"> <div id="mainpic"> <img src="myimages/circle.jpg" width="100%" alt="Circle bracelet"/> </div> <div id="intro"> <p>Hi and welcome to little prints NL. we make this and that all by hand with 100% silver. my name is Donna Burns and i work by commision, ive been studying for 4 years and am currently learning to become a goldsmith.</p> </div> </div> <div id="inline2"> <p>Click for more...</p> <div id="images"> <a href="myimages/photos/dogtag.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" ><img src="myimages/work/chunky.gif" alt="chunky"/></a> <a href="myimages/photos/hearts.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" ><img src="myimages/work/hearts.gif" alt="hearts"/></a> <a href="myimages/photos/close.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" ><img src="myimages/work/close.gif" alt="close"/></a> <a href="myimages/photos/pearl.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" >&nbsp;</a> <a href="myimages/photos/flower.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" >&nbsp;</a> <a href="myimages/photos/frontcircle.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" >&nbsp;</a> <a href="myimages/photos/dogtag.jpg" rel="lightbox-gal" title="Beautiful, isn't it?" >&nbsp;</a> </div> </div> </div><!--end container--> <div id="footer"> <div id="footalign"> <div id="social"> <ul> <li> <a href="http://www.facebook.com/littleprints" title="Little Prints"> <img src="myimages/facebook.png" width="50px" height="50px" alt="FB"/> </a> </li> <li> <a href="contact.html" title="contact"> <img src="myimages/at.gif" alt="@"/> </a> </li> </ul> </div> <div id="contact"> <p><br/>To enquire about a charm either phone:<br/> 0787463289<br/> or use one of the methods to the side.</p> </div> </div> </div> </body> </html> the CSS... * {margin: 0; padding: 0; border: 0;} html, body { background-color: #000000;image; text-align: center; font: 16px/1.8 Verdana, Arial, Helvetica, sans-serif; list-style-type: none!important; text-decoration: none;} #container { position: relative; width: 900px; top: 0; min-height: 100%; margin-left: auto; margin-right: auto; padding-top: 20px; background-image: URL(myimages/back2.gif); margin-bottom: 180px; } #footer { background-color: #555555; position: relative; clear: both; bottom: 0; width: 900px; height: auto; margin-left: auto; margin-right: auto; margin-bottom: 20px; padding-bottom: 22px; margin-top: -180px; } #inline1{ display: inline-block; margin-top: 250px; margin-bottom: 20px; } #inline2 { display: inline-block; margin-top: 30px; margin-bottom: 50px; } #mainpic { float: left; width: 68%; margin-left: 20px; } #intro { float: right; width: 20%; margin-left: auto; margin-right: 50px; margin-top: 20px; } #images { margin-bottom: 20px; margin-left: auto; margin-right: auto; } #footalign { display: inline; width:900px; list-style-type: none; } #contact { text-align: center; background-color:#555555; float: middle; list-style-type: none; } #social{ background-color:#555555; float: right; list-style: none; padding:0; padding-right: 5px; text-align:center; list-style-type: none!important; } #social img{ border: none; list-style-type: none!important; margin: 3px; } #social ul{ border: none; list-style-type: none!important; } #social a{ display:inline-block; -webkit-transition:all .5s ease-out; -moz-transition:all .5s ease-out; -ms-transition:all .5s ease-out; -o-transition:all .5s ease-out; transition:all .5s ease-out; list-style-type: none!important; } #social a:hover{ display:inline-block; -webkit-transform:translate(-10px,0px); -moz-transform:translate(0px,-10px); -ms-transform:translate(-10px,0px); -o-transform:translate(-10px,0px); transform:translate(-10px,0px); list-style-type: none!important; } #form { margin-top: 250px; margin-bottom: 50px; } .nav1 {font-family: sans-serif;font-size: 22px;text-shadow: 2px 2px 5px #000000;} a:link {text-decoration:none; color:#000000; padding:3px;} a:visited {text-decoration:none; color:#000000;} a:active {text-decoration:none; color:#555555;} a:hover {text-decoration:none; color:#555555;} .nav2 {font-family: sans-serif;font-size: 22px;text-shadow: 2px 2px 5px #ffffff;} a:link {text-decoration:none; color:#ffffff; padding:3px;} a:visited {text-decoration:none; color:#ffffff;} a:active {text-decoration:none; color:#555555;} a:hover {text-decoration:none; color:#555555;} .p1 { color: #ffffff; } div#images img { max-width: 500px; height: auto; }

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  • Combination of JFreeChart with JXLayer with JHotDraw

    - by Yan Cheng CHEOK
    Recently, I had use JXLayer, to overlay two moving yellow message boxes, on the top of JFreeChart http://yccheok.blogspot.com/2010/02/investment-flow-chart.html I was wondering, had anyone experience using JXLayer + JHotdraw, to overlay all sorts of figures (Re-sizable text box, straight line, circle...), on the top of JFreeChart. I just would like to add drawing capability, without changing the JFreeChart source code. So that, JStock's user may draw trending lines, annotation text on their favorite stock charting. The code skeleton is as follow : // this.chartPanel is JFreeChartPanel final org.jdesktop.jxlayer.JXLayer<ChartPanel> layer = new org.jdesktop.jxlayer.JXLayer<ChartPanel>(this.chartPanel); this.myUI = new MyUI<ChartPanel>(this); layer.setUI(this.myUI); public class MyUI<V extends javax.swing.JComponent> extends AbstractLayerUI<V> { @Override protected void paintLayer(Graphics2D g2, JXLayer<? extends V> layer) { // Previous, I am using my own hand-coded, to draw the yellow box // // Now, How can I make use of JHotDraw at here, to draw various type of // figures? } @Override protected void processMouseEvent(MouseEvent e, JXLayer<? extends V> layer) { // How can I make use of JHotDraw at here? } @Override protected void processMouseMotionEvent(MouseEvent e, JXLayer<? extends V> layer) { // How can I make use of JHotDraw at here? } } As you see, I already got Graphics2D g2 from paintLayer method. How is it possible that I can pass the Graphics2D object to JHotDraw, and let JHotDraw handles all the drawing. My experience in using JHotDraw are with org.jhotdraw.draw.DefaultDrawingView org.jhotdraw.draw.DefaultDrawingEditor I am able to use them to draw various figures, by clicking on the toolbar and click on drawing area. How is it possible I can use DefaultDrawingView and DefaultDrawingEditor within MyUI's paintLayer? Also, shall I let MyUI handles the mouse event, or JHotDraw? Sorry, I start getting confused.

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  • Wordpress/CSS: List Style Problem.

    - by Ben
    Hi all! I am reasonably new to Wordpress custom themes but I do have some knowlege of CSS, although I am terrible at customising other peoples code which is why I have the problem I am about to explain. I have started a website that my girlfriend and I are doing together. It uses the Simplo Wordpress theme which is pretty cool but when you add a post that has a list in it. It doesn't show the bullets on each of the items. I have tried adding 'list-style:circle;' to a the.postItem class and a couple of other divs and classes that I thought were relevant but it doesn't work. You can take a look for yourself, it may be easier to understand my problem that way. If you go to: http://brokeandstarving.com/234/bennos-shepherds-pie/ there is a list of ingredients and also the steps under the method is a list as well. My question is, where do I edit the CSS to make the bullets appear next to the list items? I hope that makes sense. Thanks in advance, - Ben

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  • using a While loop to control the value of a keyframe in a timeline in Javafx

    - by dragoknight
    i want to create an animation where the ball will move in one of the 4 sectors of a circle randomly.this will happen 5 times.so,i create a while loop(i<5) and call the random function.i then create an if loop and attach some x and y values according to the random fn value.i then create an timeline object inside the while loop and in the key frame value,i use these x and y values.but when i run the program,what happens is that all the values are being created(x and y values seen through println) but only the last x and y value(for i=5)is being rendered in the screen.the animations for the previous values(1<=i<=4)are not being rendered.Please advise where have i gone wrong? public function run(args:String[]) { var i=0; while(i<5) { var z=gety(); println(z); // var relativeTime:Duration=0s; if(z==1) {xbind=120; ybind=80; } else if(z==2) {xbind=120; ybind=120; } else if(z==3) { xbind=80; ybind=120; } else if(z==4) { xbind=80; ybind=80; } var t:Timeline=Timeline{ //time: bind pos with inverse; repeatCount: Timeline.INDEFINITE autoReverse: true keyFrames: [ KeyFrame{ time: 0s values: [ x => 100.0,y => 100.0]}, KeyFrame{time: 2s values:[x => xbind tween Interpolator.LINEAR, y => ybind tween Interpolator.LINEAR,] }, ] }//end timeline i++; t.play(); Thread.sleep(2000); }//end while }

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  • Code Golf: Find the possible ways on a numpad

    - by ikar
    I was bored today at school and so I tried to amuse myself using my calculator and a "game" I've invented which isn't really a game but keeps the boringness away. Also some time has passed since the last real code-golf here, so I decided to create this one. Imagine a simplified numpad like you know it from your phone (I'll leave the 0 out for this code-golf as it kinda destroys all the fun) 1 2 3 4 5 6 7 8 9 Now the rules of the game were always: At the end every digit must have been visited exactly once You can start at any digit you want You can always move one digit up, down, left or right. You can't move diagonally! There a quite a lot of possible ways (or not; I haven't found out yet), here some trivial examples: > > v v < < > > | The output of the golf-program should look something like the above, I'll try to explain: Symbols: Go right < Go left ^ Go up v Go down | End of the way Example solutions: (Program output can either be the numbers pressed in the right order from beginning point to end, or an (ASCII) picture like above) 147852369 569874123 523698741 So if we speak out the example above it would be: Start at 1, move right to 2, move right to 3, go down to 6, go left to 5, go left to 4, go down to 7, go right to 8 then go right to 9 and we are finished! Now there are many different ways possible: You could as well start at 5 and go around it in a circle. So the task would be: Write a program that can compute (using brute-force or whatever) the possible solutions for the numpad problem described above. (Friendly rethorical question with smiley removed because it made some people think that this is homework)

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  • How to implement a simple queue properly?

    - by Stephen Hsu
    The current Go library doesn't provide the queue container. To implement a simple queue, I use circle array as the underlying data structure. It follows algorithms mentioned in TAOCP: Insert Y into queue X: X[R]<-Y; R<-(R+1)%M; if R=F then OVERFLOW. Delete Y from queue X: if F=R then UNDERFLOW; Y<-X[F]; F<-(F+1) % M. F: Front, R: Rear, M: Array length. Following is the code: package main import ( "fmt" ) type Queue struct { len int head, tail int q []int } func New(n int) *Queue { return &Queue{n, 0, 0, make([]int, n)} } func (p *Queue) Enqueue(x int) bool { p.q[p.tail] = x p.tail = (p.tail + 1) % p.len return p.head != p.tail } func (p *Queue) Dequeue() (int, bool) { if p.head == p.tail { return 0, false } x := p.q[p.head] p.head = (p.head + 1) % p.len return x, true } func main() { q := New(10) for i := 1; i < 13; i++ { fmt.Println(i, q.Enqueue(i)) } fmt.Println() for i := 1; i < 13; i++ { fmt.Println(q.Dequeue()) } } But the output is obviously wrong: 1 true 2 true 3 true 4 true 5 true 6 true 7 true 8 true 9 true 10 false 11 true 12 true 11 true 12 true 0 false 0 false 0 false 0 false 0 false 0 false 0 false 0 false 0 false 0 false I think I need one more field to make the code work properly. What do you suggest?

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  • Why is my simple python gtk+cairo program running so slowly/stutteringly?

    - by synapz
    My program draws circles moving on the window. I think I must be missing some basic gtk/cairo concept because it seems to be running too slowly/stutteringly for what I am doing. Any ideas? Thanks for any help! #!/usr/bin/python import gtk import gtk.gdk as gdk import math import random import gobject # The number of circles and the window size. num = 128 size = 512 # Initialize circle coordinates and velocities. x = [] y = [] xv = [] yv = [] for i in range(num): x.append(random.randint(0, size)) y.append(random.randint(0, size)) xv.append(random.randint(-4, 4)) yv.append(random.randint(-4, 4)) # Draw the circles and update their positions. def expose(*args): cr = darea.window.cairo_create() cr.set_line_width(4) for i in range(num): cr.set_source_rgb(1, 0, 0) cr.arc(x[i], y[i], 8, 0, 2 * math.pi) cr.stroke_preserve() cr.set_source_rgb(1, 1, 1) cr.fill() x[i] += xv[i] y[i] += yv[i] if x[i] > size or x[i] < 0: xv[i] = -xv[i] if y[i] > size or y[i] < 0: yv[i] = -yv[i] # Self-evident? def timeout(): darea.queue_draw() return True # Initialize the window. window = gtk.Window() window.resize(size, size) window.connect("destroy", gtk.main_quit) darea = gtk.DrawingArea() darea.connect("expose-event", expose) window.add(darea) window.show_all() # Self-evident? gobject.idle_add(timeout) gtk.main()

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  • Algorithm Question

    - by Ravi
    Hi, I am trying to find a O (n) algorithm for this problem but unable to do so even after spending 3 - 4 hours. The brute force method times out (O (n^2)). I am confused as to how to do it ? Does the solution requires dynamic programming solution ? http://acm.timus.ru/problem.aspx?space=1&num=1794 In short the problem is this: There are some students sitting in circle and each one of them has its own choice as to when he wants to be asked a question from a teacher. The teacher will ask the questions in clockwise order only. For example: 5 3 3 1 5 5 This means that there are 5 students and : 1st student wants to go third 2nd student wants to go third 3rd student wants to go first 4th student wants to go fifth 5th student wants to go fifth. The question is as to where should teacher start asking questions so that maximum number of students will get the turn as they want. For this particular example, the answer is 5 because 3 3 1 5 5 2 3 4 5 1 You can see that by starting at fifth student as 1st, 2 students (3 and 5) are getting the choices as they wanted. For this example the answer is 12th student : 12 5 1 2 3 6 3 8 4 10 3 12 7 because 5 1 2 3 6 3 8 4 10 3 12 7 2 3 4 5 6 7 8 9 10 11 12 1 four students get their choices fulfilled. Thanks Ravi

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  • C# / Silverlight / WPF / Fast rendering lots of circles

    - by Walt W
    I want to render a lot of circles or small graphics within either silverlight or wpf (around 1000-10000) as fast and as frequently as possible. If I have to go to DX or OGL, that's fine, but I'm wondering about doing this within either of those two frameworks first (read: it's OK if an answer is WPF-only or Silverlight-only). Also, if there is a way to access DX through WPF and render on a surface that way, I would be interested in that as well. So, what's the fastest way to draw a load of circles? They can be as plain as necessary, but they do need to have a radius. Currently I'm using DrawingVisual and a DrawingContext.DrawEllipse() command for each circle, then rendering the visual to a RenderTargetBItmap, but it becomes very slow as the number of circles rises. By the way, these circles move every frame, so caching isn't really an option unless you're going to suggest caching the individual circles . . . But their sizes are dynamic, so I'm not sure that's a great approach.

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  • How do I controll clipping with non-opaque graphics-item's in Qt?

    - by JJacobsson
    I have a bunch of QGraphicsSvgItem's in a QGraphicsScene that are drawn connected by QGraphicsLineItem's. This show's a graph of a tree-structure. What I want to do is provide a feature where everything but a selected sub-tree becomes transparent. A kind of "highlight this sub-tree" feature. That part was easy, but the results are ugly because now the lines can be seen through the semi-transparent svg's. I am looking for some way to still clip other QGraphicsItem's in the scene to the svg item's, giving the effect that the svg's are semi-transparent windows to the background. I know this code does not use svg's but I figure you can replace that yourself if you are so inclined. int main(int argc, char *argv[]) { QApplication app(argc, argv); QGraphicsScene scene; for( int i = 0; i < 10; ++i ) { QGraphicsLineItem* line = new QGraphicsLineItem; line->setLine( i * 25.0 + 1.0, 0, i * 25.0 + 23.0, 0 ); scene.addItem( line ); } for( int i = 0; i < 11; ++i ) { QGraphicsEllipseItem* ellipse = new QGraphicsEllipseItem; ellipse->setRect( (i * 25.0) - 9.0, -9.0, 18.0, 18.0f ); ellipse->setBrush( QBrush( Qt::green, Qt::SolidPattern ) ); ellipse->setOpacity( 0.5 ); scene.addItem( ellipse ); } QGraphicsView view( &scene ); view.show(); return app.exec(); } I would like the line's to not be seen behind the circle's. I have tried fiddling with the depth-buffer and the stencil buffer using opengl rendering to no avail. How do I get the QGraphicsSvgItem's (or QGraphicsEllipseItem's in the example code) to still clip the lines even though they are semi-transparent?

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  • How to move point on arc?

    - by bbZ
    I am writing an app that is simulating RobotArm movement. What I want to achieve, and where I have couple of problems is moving a Point on arc (180degree) that is arm range of movement. I am moving an arm by grabbing with mouse end of arm (Elbow, the Point I was talking about), robot can have multiple arms with diffrent arm lenghts. If u can help me with this part, I'd be grateful. This is what I have so far, drawing function: public void draw(Graphics graph) { Graphics2D g2d = (Graphics2D) graph.create(); graph.setColor(color); graph.fillOval(location.x - 4, location.y - 4, point.width, point.height); //Draws elbow if (parentLocation != null) { graph.setColor(Color.black); graph.drawLine(location.x, location.y, parentLocation.x, parentLocation.y); //Connects to parent if (arc == null) { angle = new Double(90 - getAngle(parentInitLocation)); arc = new Arc2D.Double(parentLocation.x - (parentDistance * 2 / 2), parentLocation.y - (parentDistance * 2 / 2), parentDistance * 2, parentDistance * 2, 90 - getAngle(parentInitLocation), 180, Arc2D.OPEN); //Draws an arc if not drawed yet. } else if (angle != null) //if parent is moved, angle is moved also { arc = new Arc2D.Double(parentLocation.x - (parentDistance * 2 / 2), parentLocation.y - (parentDistance * 2 / 2), parentDistance * 2, parentDistance * 2, angle, 180, Arc2D.OPEN); } g2d.draw(arc); } if (spacePanel.getElbows().size() > level + 1) {//updates all childElbows position updateChild(graph); } } I just do not know how to prevent moving Point moving outside of arc line. It can not be inside or outside arc, just on it. Here I wanted to put a screenshot, sadly I don't have enough rep. Am I allowed to put link to this? Maybe you got other ways how to achieve this kind of thing. Here is the image: Red circle is actual state, and green one is what I want to do. EDIT2: As requested, repo link: https://github.com/dspoko/RobotArm

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  • How do I toggle CSS with jQuery?

    - by marcamillion
    I have the following code: $('#bc' + $.trim($this) + ' span.dashed-circle').css({ 'border' : '5px solid #000'}); That is triggered by a click.function(). I would like that to be a toggle - so when I click the element, it changes the border to what I have above...but when it is clicked again it disappears or rather sets the border to ' '. Thoughts? Edit: I should have been explicit...but I don't want to create a CSS class. The reason being is because when I do that, it messes up the formatting of the element being styled. I am sure that it is some small quirk somewhere that would fix it, but I am not interested in wading through the entire code base to fix little positioning issues with a new class. I would much rather just edit the css attribute directly - because it doesn't interfere with the layout. Edit2: Here is the jsfiddle of the code I am trying to edit. If you notice, I have the CSS attributes last. But how do I let that be toggled ? Edit3: If anyone is interested...the UI that this will be used in is for my webapp - http://www.compversions.com

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  • Creating collaborative whiteboard drawing application

    - by Steven Sproat
    I have my own drawing program in place, with a variety of "drawing tools" such as Pen, Eraser, Rectangle, Circle, Select, Text etc. It's made with Python and wxPython. Each tool mentioned above is a class, which all have polymorphic methods, such as left_down(), mouse_motion(), hit_test() etc. The program manages a list of all drawn shapes -- when a user has drawn a shape, it's added to the list. This is used to manage undo/redo operations too. So, I have a decent codebase that I can hook collaborative drawing into. Each shape could be changed to know its owner -- the user who drew it, and to only allow delete/move/rescale operations to be performed on shapes owned by one person. I'm just wondering the best way to develop this. One person in the "session" will have to act as the server, I have no money to offer free central servers. Somehow users will need a way to connect to servers, meaning some kind of "discover servers" browser...or something. How do I broadcast changes made to the application? Drawing in realtime and broadcasting a message on each mouse motion event would be costly in terms of performance and things get worse the more users there are at a given time. Any ideas are welcome, I'm not too sure where to begin with developing this (or even how to test it)

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  • Repaint() not calling paint() in Java

    - by Joshua Auriemma
    Let me start off by saying I know I've violated some basic Java principles in this messy code, but I'm desperately trying to finish a program by Tuesday for a social science experiment, and I don't know Java, so I'm basically just fumbling through it for now. With that disclaimer out of the way, I have a separate program working where a circle is moving around the screen and the user must click on it. It works fine when its in its own separate class file, but when I add the code to my main program, it's no longer working. I don't even really understand why repaint() calls my paint() function — as far as I'm concerned, it's magic, but I've noticed that repaint() calls paint() in my test program, but not in the more complicated actual program, and I assume that's why the circle is no longer painting on my program. Entire code is below: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Rectangle; import javax.swing.*; import java.awt.event.*; import java.awt.geom.Ellipse2D; import java.io.FileReader; import java.io.IOException; import java.util.Calendar; public class Reflexology1 extends JFrame{ private static final long serialVersionUID = -1295261024563143679L; private Ellipse2D ball = new Ellipse2D.Double(0, 0, 25, 25); private Timer moveBallTimer; int _ballXpos, _ballYpos; JButton button1, button2; JButton movingButton; JTextArea textArea1; int buttonAClicked, buttonDClicked; private long _openTime = 0; private long _closeTime = 0; JPanel thePanel = new JPanel(); JPanel thePlacebo = new JPanel(); final JFrame frame = new JFrame("Reflexology"); final JFrame frame2 = new JFrame("The Test"); JLabel label1 = new JLabel("Press X and then click the moving dot as fast as you can."); public static void main(String[] args){ new Reflexology1(); } public Reflexology1(){ frame.setSize(600, 475); frame.setLocationRelativeTo(null); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setTitle("Reflexology 1.0"); frame.setResizable(false); frame2.setSize(600, 475); frame2.setLocationRelativeTo(null); frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame2.setTitle("Reflexology 1.0"); frame2.setResizable(false); button1 = new JButton("Accept"); button2 = new JButton("Decline"); //movingButton = new JButton("Click Me"); ListenForAcceptButton lForAButton = new ListenForAcceptButton(); ListenForDeclineButton lForDButton = new ListenForDeclineButton(); button1.addActionListener(lForAButton); button2.addActionListener(lForDButton); //movingButton.addActionListener(lForMButton); JTextArea textArea1 = new JTextArea(24, 50); textArea1.setText("Tracking Events\n"); textArea1.setLineWrap(true); textArea1.setWrapStyleWord(true); textArea1.setSize(15, 50); textArea1.setEditable(false); FileReader reader = null; try { reader = new FileReader("EULA.txt"); textArea1.read(reader, "EULA.txt"); } catch (IOException exception) { System.err.println("Problem loading file"); exception.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException exception) { System.err.println("Error closing reader"); exception.printStackTrace(); } } } JScrollPane scrollBar1 = new JScrollPane(textArea1, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); AdjustmentListener listener = new MyAdjustmentListener(); thePanel.add(scrollBar1); thePanel.add(button1); thePanel.add(button2); frame.add(thePanel); ListenForMouse lForMouse = new ListenForMouse(); thePlacebo.addMouseListener(lForMouse); thePlacebo.add(label1); frame2.add(thePlacebo); ListenForWindow lForWindow = new ListenForWindow(); frame.addWindowListener(lForWindow); frame2.addKeyListener(new KeyAdapter() { public void keyPressed(KeyEvent e){ if(e.getKeyChar() == 'X' || e.getKeyChar() == 'x') {moveBallTimer.start();} } }); frame.setVisible(true); moveBallTimer = new Timer(1000, new ActionListener() { public void actionPerformed(ActionEvent e) { moveBall(); System.out.println("Timer started!"); repaint(); } }); addKeyListener(new KeyAdapter() { public void keyPressed(KeyEvent e) { if(frame2.isVisible()){ moveBallTimer.start(); } } }); } private class ListenForAcceptButton implements ActionListener{ public void actionPerformed(ActionEvent e){ if (e.getSource() == button1){ Calendar ClCDateTime = Calendar.getInstance(); System.out.println(ClCDateTime.getTimeInMillis() - _openTime); _closeTime = ClCDateTime.getTimeInMillis() - _openTime; //frame.getContentPane().remove(thePanel); //thePlacebo.addKeyListener(lForKeys); //frame.getContentPane().add(thePlacebo); //frame.repaint(); //moveBallTimer.start(); frame.setVisible(false); frame2.setVisible(true); frame2.revalidate(); frame2.repaint(); } } } private class ListenForDeclineButton implements ActionListener{ public void actionPerformed(ActionEvent e){ if (e.getSource() == button2){ JOptionPane.showMessageDialog(Reflexology1.this, "You've declined the license agreement. DO NOT RESTART the program. Please go inform a researcher that you have declined the agreement.", "WARNING", JOptionPane.INFORMATION_MESSAGE); System.exit(0); } } } private class ListenForWindow implements WindowListener{ public void windowActivated(WindowEvent e) { //textArea1.append("Window is active"); } // if this.dispose() is called, this is called: public void windowClosed(WindowEvent arg0) { } // When a window is closed from a menu, this is called: public void windowClosing(WindowEvent arg0) { } // Called when the window is no longer the active window: public void windowDeactivated(WindowEvent arg0) { //textArea1.append("Window is NOT active"); } // Window gone from minimized to normal state public void windowDeiconified(WindowEvent arg0) { //textArea1.append("Window is in normal state"); } // Window has been minimized public void windowIconified(WindowEvent arg0) { //textArea1.append("Window is minimized"); } // Called when the Window is originally created public void windowOpened(WindowEvent arg0) { //textArea1.append("Let there be Window!"); Calendar OlCDateTime = Calendar.getInstance(); _openTime = OlCDateTime.getTimeInMillis(); //System.out.println(_openTime); } } private class MyAdjustmentListener implements AdjustmentListener { public void adjustmentValueChanged(AdjustmentEvent arg0) { AdjustmentEvent scrollBar1; //System.out.println(scrollBar1.getValue())); } } public void paint(Graphics g) { //super.paint(g); frame2.paint(g); Graphics2D g2d = (Graphics2D) g; g2d.setColor(Color.RED); g2d.fill(ball); System.out.println("Calling fill()"); } protected void moveBall() { //System.out.println("I'm in the moveBall() function!"); int width = getWidth(); int height = getHeight(); int min, max, randomX, randomY; min =200; max = -200; randomX = min + (int)(Math.random() * ((max - min)+1)); randomY = min + (int)(Math.random() * ((max - min)+1)); //System.out.println(randomX + ", " + randomY); Rectangle ballBounds = ball.getBounds(); //System.out.println(ballBounds.x + ", " + ballBounds.y); if (ballBounds.x + randomX < 0) { randomX = 200; } else if (ballBounds.x + ballBounds.width + randomX > width) { randomX = -200; } if (ballBounds.y + randomY < 0) { randomY = 200; } else if (ballBounds.y + ballBounds.height + randomY > height) { randomY = -200; } ballBounds.x += randomX; ballBounds.y += randomY; _ballXpos = ballBounds.x; _ballYpos = ballBounds.y; ball.setFrame(ballBounds); } public void start() { moveBallTimer.start(); } public void stop() { moveBallTimer.stop(); } private class ListenForMouse implements MouseListener{ // Called when the mouse is clicked public void mouseClicked(MouseEvent e) { //System.out.println("Mouse Panel pos: " + e.getX() + " " + e.getY() + "\n"); if (e.getX() >=_ballXpos && e.getX() <= _ballXpos + 25 && e.getY() <=_ballYpos && e.getY() >= _ballYpos - 25 ) { System.out.println("TRUE"); } System.out.println("{e.getX(): " + e.getX() + " / " + "_ballXpos: " + _ballXpos + " | " + "{e.getY(): " + e.getY() + " / " + "_ballYpos: " + _ballYpos); } public void mouseEntered(MouseEvent arg0) { // TODO Auto-generated method stub } public void mouseExited(MouseEvent arg0) { // TODO Auto-generated method stub } public void mousePressed(MouseEvent arg0) { // TODO Auto-generated method stub } public void mouseReleased(MouseEvent arg0) { // TODO Auto-generated method stub } } // System.out.println("e.getX(): " + e.getX() + " / " + "_ballXpos: " + _ballXpos); // Mouse over public void mouseEntered(MouseEvent arg0) { // TODO Auto-generated method stub } // Mouse left the mouseover area: public void mouseExited(MouseEvent arg0) { // TODO Auto-generated method stub } public void mousePressed(MouseEvent arg0) { // TODO Auto-generated method stub } public void mouseReleased(MouseEvent arg0) { // TODO Auto-generated method stub } } Could anyone tell me what I need to do to get repaint() to call the paint() method in the above program? I'm assuming the multiple frames is causing the problem, but that's just a guess. Thanks.

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  • C++ Matrix class hierachy

    - by bpw1621
    Should a matrix software library have a root class (e.g., MatrixBase) from which more specialized (or more constrained) matrix classes (e.g., SparseMatrix, UpperTriangluarMatrix, etc.) derive? If so, should the derived classes be derived publicly/protectively/privately? If not, should they be composed with a implementation class encapsulating common functionality and be otherwise unrelated? Something else? I was having a conversation about this with a software developer colleague (I am not per se) who mentioned that it is a common programming design mistake to derive a more restricted class from a more general one (e.g., he used the example of how it was not a good idea to derive a Circle class from an Ellipse class as similar to the matrix design issue) even when it is true that a SparseMatrix "IS A" MatrixBase. The interface presented by both the base and derived classes should be the same for basic operations; for specialized operations, a derived class would have additional functionality that might not be possible to implement for an arbitrary MatrixBase object. For example, we can compute the cholesky decomposition only for a PositiveDefiniteMatrix class object; however, multiplication by a scalar should work the same way for both the base and derived classes. Also, even if the underlying data storage implementation differs the operator()(int,int) should work as expected for any type of matrix class. I have started looking at a few open-source matrix libraries and it appears like this is kind of a mixed bag (or maybe I'm looking at a mixed bag of libraries). I am planning on helping out with a refactoring of a math library where this has been a point of contention and I'd like to have opinions (that is unless there really is an objective right answer to this question) as to what design philosophy would be best and what are the pros and cons to any reasonable approach.

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  • C++ design related question

    - by Kotti
    Hi! Here is the question's plot: suppose I have some abstract classes for objects, let's call it Object. It's definition would include 2D position and dimensions. Let it also have some virtual void Render(Backend& backend) const = 0 method used for rendering. Now I specialize my inheritance tree and add Rectangle and Ellipse class. Guess they won't have their own properties, but they will have their own virtual void Render method. Let's say I implemented these methods, so that Render for Rectangle actually draws some rectangle, and the same for ellipse. Now, I add some object called Plane, which is defined as class Plane : public Rectangle and has a private member of std::vector<Object*> plane_objects; Right after that I add a method to add some object to my plane. And here comes the question. If I design this method as void AddObject(Object& object) I would face trouble like I won't be able to call virtual functions, because I would have to do something like plane_objects.push_back(new Object(object)); and this should be push_back(new Rectangle(object)) for rectangles and new Circle(...) for circles. If I implement this method as void AddObject(Object* object), it looks good, but then somewhere else this means making call like plane.AddObject(new Rectangle(params)); and this is generally a mess because then it's not clear which part of my program should free the allocated memory. ["when destroying the plane? why? are we sure that calls to AddObject were only done as AddObject(new something).] I guess the problems caused by using the second approach could be solved using smart pointers, but I am sure there have to be something better. Any ideas?

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  • Largest triangle from a set of points

    - by Faken
    I have a set of random points from which i want to find the largest triangle by area who's verticies are each on one of those points. So far I have figured out that the largest triangle's verticies will only lie on the outside points of the cloud of points (or the convex hull) so i have programmed a function to do just that (using Graham scan in nlogn time). However that's where I'm stuck. The only way I can figure out how to find the largest triangle from these points is to use brute force at n^3 time which is still acceptable in an average case as the convex hull algorithm usually kicks out the vast majority of points. However in a worst case scenario where points are on a circle, this method would fail miserably. Dose anyone know an algorithm to do this more efficiently? Note: I know that CGAL has this algorithm there but they do not go into any details on how its done. I don't want to use libraries, i want to learn this and program it myself (and also allow me to tweak it to exactly the way i want it to operate, just like the graham scan in which other implementations pick up collinear points that i don't want).

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