?? display.php-n=22-8&f=22-08.js.htm
字號:
<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"><head><meta http-equiv="Keywords" name="Keywords"content="JavaScript, examples, JavaScript: The Definitive Guide"><title>Example 22-8 from JavaScript: The Definitive Guide, Fifth Edition</title><style>body { font-family: arial, sans-serif}.lefttitle { font: bold x-small arial, sans-serif; margin: 5px; letter-spacing: .15em; text-transform:uppercase;}.leftcaption { font: italic x-small sans-serif; margin-bottom: 20px;}#banner { font-family:sans-serif; color:#333; font-size:x-large; font-weight:normal; padding:15px; padding-top: 3px; border-bottom:4px double #666;}#banner h1 { font-size: x-large; margin: 0px; padding: 0px;}#banner .description { font-size:large; margin-left: 2px;}pre { border: solid black 1px; background-color: #ddd; padding: 10px; margin: 0px;} </style></script></head><body><div id="banner"><h1>davidflanagan.com/javascript5</h1><span class="description">Example 22-8 from<i>JavaScript: The Definitive Guide, Fifth Edition</i></span></div><div style="float: left; text-align: center; width:200px; margin-right:20px"><div class="lefttitle">Buy The Book</div><iframe src="../../rcm.amazon.com/e/cm-t=davidflanagancom&o=1&p=8&l=as1&asins=0596101996&fc1=000000&IS2=1<1=_blank&lc1=0000ff&bc1=000000&bg1=ffffff&f=ifr" tppabs="http://rcm.amazon.com/e/cm?t=davidflanagancom&o=1&p=8&l=as1&asins=0596101996&fc1=000000&IS2=1<1=_blank&lc1=0000ff&bc1=000000&bg1=ffffff&f=ifr" style="width:120px;height:240px;" scrolling="no" marginwidth="0" marginheight="0" frameborder="0"></iframe><div class="leftcaption">This example is posted here for the convenienceof my readers.</div><div class="lefttitle">Tip the Author</div><form action="https://www.paypal.com/cgi-bin/webscr" method="post"><input type="hidden" name="cmd" value="_s-xclick"><input type="image" src="../../www.paypal.com/en_US/i/btn/x-click-but21.gif" tppabs="https://www.paypal.com/en_US/i/btn/x-click-but21.gif" border="0" name="submit" alt="Make payments with PayPal - it's fast, free and secure!"><img alt="" border="0" src="../../www.paypal.com/en_US/i/scr/pixel.gif" tppabs="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"><input type="hidden" name="encrypted" value="-----BEGIN PKCS7-----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-----END PKCS7-----"></form><div class="leftcaption">Found a helpful example, but don't own the book?</div><div class="lefttitle">Advertising</div><script type="text/javascript"><!--google_ad_client = "pub-5162555666633441";google_alternate_color = "ffffff";google_ad_width = 160;google_ad_height = 600;google_ad_format = "160x600_as";google_ad_type = "text_image";google_ad_channel ="";//--></script><script type="text/javascript" src="../../pagead2.googlesyndication.com/pagead/show_ads.js" tppabs="http://pagead2.googlesyndication.com/pagead/show_ads.js"></script></div><div style="margin-left: 220px;"><div class="lefttitle" style="padding:0px; text-align: right"><a href="index.html" tppabs="http://www.davidflanagan.com/javascript5/index.html">Table of Examples</a></div><pre>/** * Draw a pie chart into an <svg> element. * Arguments: * canvas: the SVG element (or the id of that element) to draw into. * data: an array of numbers to chart, one for each wedge of the pie. * cx, cy, r: the center and radius of the pie * colors: an array of HTML color strings, one for each wedge * labels: an array of labels to appear in the legend, one for each wedge * lx, ly: the upper-left corner of the chart legend */function pieChart(canvas, data, cx, cy, r, colors, labels, lx, ly) { // Locate canvas if specified by id instead of element if (typeof canvas == "string") canvas = document.getElementById(canvas); // Add up the data values so we know how big the pie is var total = 0; for(var i = 0; i < data.length; i++) total += data[i]; // Now figure out how big each slice of pie is. Angles in radians. var angles = [] for(var i = 0; i < data.length; i++) angles[i] = data[i]/total*Math.PI*2; // Loop through each slice of pie. startangle = 0; for(var i = 0; i < data.length; i++) { // This is where the wedge ends var endangle = startangle + angles[i]; // Compute the two points where our wedge intersects the circle // These formulas are chosen so that an angle of 0 is at 12 o'clock // and positive angles increase clockwise. var x1 = cx + r * Math.sin(startangle); var y1 = cy - r * Math.cos(startangle); var x2 = cx + r * Math.sin(endangle); var y2 = cy - r * Math.cos(endangle); // This is a flag for angles larger than than a half circle var big = 0; if (endangle - startangle > Math.PI) big = 1; // We describe a wedge with an <svg:path> element // Notice that we create this with createElementNS() var path = document.createElementNS(SVG.ns, "path"); // This string holds the path details var d = "M " + cx + "," + cy + // Start at circle center " L " + x1 + "," + y1 + // Draw line to (x1,y1) " A " + r + "," + r + // Draw an arc of radius r " 0 " + big + " 1 " + // Arc details... x2 + "," + y2 + // Arc goes to to (x2,y2) " Z"; // Close path back to (cx,cy) // This is an XML element, so all attributes must be set // with setAttribute(). We can't just use JavaScript properties path.setAttribute("d", d); // Set this path path.setAttribute("fill", colors[i]); // Set wedge color path.setAttribute("stroke", "black"); // Outline wedge in black path.setAttribute("stroke-width", "2"); // 2 units thick canvas.appendChild(path); // Add wedge to canvas // The next wedge begins where this one ends startangle = endangle; // Now draw a little matching square for the key var icon = document.createElementNS(SVG.ns, "rect"); icon.setAttribute("x", lx); // Position the square icon.setAttribute("y", ly + 30*i); icon.setAttribute("width", 20); // Size the square icon.setAttribute("height", 20); icon.setAttribute("fill", colors[i]); // Same fill color as wedge icon.setAttribute("stroke", "black"); // Same outline, too. icon.setAttribute("stroke-width", "2"); canvas.appendChild(icon); // Add to the canvas // And add a label to the right of the rectangle var label = document.createElementNS(SVG.ns, "text"); label.setAttribute("x", lx + 30); // Position the text label.setAttribute("y", ly + 30*i + 18); // Text style attributes could also be set via CSS label.setAttribute("font-family", "sans-serif"); label.setAttribute("font-size", "16"); // Add a DOM text node to the <svg:text> element label.appendChild(document.createTextNode(labels[i])); canvas.appendChild(label); // Add text to the canvas }}</pre><div class="lefttitle" style="padding:0px; text-align: right"><a href="index.html" tppabs="http://www.davidflanagan.com/javascript5/index.html">Table of Examples</a></div><p><script type="text/javascript">amazon_ad_tag="davidflanagancom"; amazon_ad_width="300"; amazon_ad_height="250"; amazon_ad_logo="hide";</script><script type="text/javascript" src="../../www.assoc-amazon.com/s/ads.js" tppabs="http://www.assoc-amazon.com/s/ads.js"></script></div></body></html>?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -