Image Map & Canvas
I had an interesting idea a few days…. make a canvas element, put a transparent gif over it, create an image map with some shapes and then read the coords property of the area elements to draw to the canvas. I whipped it up a day or two ago and am posting it now at 2 in the morning.
click here if you don’t know what an image map is…
Here is the slightly boring result, just roll over the shapes… code is below:
This is just an interesting experiment. Having mouse events in canvas is not necessary more most of the time. This code is a bit rough, but it’s a solid proof of concept:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 | <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>Canvas Map</title> <script src="http://code.jquery.com/jquery-1.5.1.min.js"></script> <script> $(function(){ var TWO_PI = Math.PI * 2; var map = $("#map"); var areas = $("#areas"); var canvas = $("#canvas")[0]; canvas.width = 500; canvas.height = 500; var c = canvas.getContext("2d"); $.fn.render = function(){ this.data.apply(this, arguments); render(); } function clear(){ c.fillStyle = "black"; c.fillRect(0, 0, canvas.width, canvas.height); } // create a rectangle $('<area />', { shape : "rect", coords : "10, 10, 100, 100", href : "#", alt : "rect" }).data({ fillStyle: "red", strokeStyle : "white" }).mouseenter(function(){ $(this).render("fillStyle", "orange"); }).mouseleave(function(){ $(this).render("fillStyle", "red"); }).click(function(){ alert("hello"); }).appendTo(areas); // create a circle $('<area />', { shape : "circle", coords : "100, 300, 50", href : "#", alt : "circ" }).data({ fillStyle: "#a3bcd6", strokeStyle : "white", lineWidth : 5 }).mouseenter(function(){ $(this).render("strokeStyle", "red"); }).mouseleave(function(){ $(this).render("strokeStyle", "white"); }).appendTo(areas); // create a poly $('<area />', { shape : "poly", coords : "300, 200, 350,250, 250, 350, 200, 250, 260, 280", href : "#", alt : "poly" }).data({ fillStyle: "#bf9c82", strokeStyle : "#ebce59", lineWidth : 2 }).mouseenter(function(){ $(this).render({strokeStyle: "#ede1b0", fillStyle : "white"}); render(); }).mouseleave(function(){ $(this).render({strokeStyle: "#ebce59", fillStyle : "bf9c82"}); }).appendTo(areas); render(); function setStyle(fillStyle, strokeStyle, lineWidth){ if (fillStyle){ c.fillStyle = fillStyle; } if (strokeStyle){ if (lineWidth){ c.lineWidth = lineWidth; } c.strokeStyle = strokeStyle; } } function fillStroke(fillStyle, strokeStyle){ if (fillStyle) c.fill(); if (strokeStyle) c.stroke(); } function render(noClear){ if (!noClear){ clear(); } areas.children().each(function(i){ var area = $(this); var shape = area.attr("shape"); var coords = area.attr("coords").split(","); var fillStyle = area.data("fillStyle"); var strokeStyle = area.data("strokeStyle"); var lineWidth = area.data("lineWidth"); if (shape == "rect"){ if (fillStyle){ c.fillStyle = fillStyle; c.fillRect(coords[0], coords[1], coords[2] – coords[0], coords[3] – coords[1]); } if (strokeStyle){ if (lineWidth){ c.lineWidth = lineWidth; } c.strokeStyle = strokeStyle; c.strokeRect(coords[0], coords[1], coords[2] – coords[0], coords[3] – coords[1]); } }else if (shape == "circle"){ setStyle(fillStyle, strokeStyle, lineWidth); c.beginPath(); c.arc(coords[0], coords[1], coords[2], 0, TWO_PI, false); c.closePath(); fillStroke(fillStyle, strokeStyle); }else if (shape == "poly"){ if (fillStyle){ c.fillStyle = fillStyle; } if (strokeStyle){ if (lineWidth){ c.lineWidth = lineWidth; } c.strokeStyle = strokeStyle; } c.beginPath(); var leng = coords.length; c.moveTo(coords[0], coords[1]); for (var i = 2; i < leng; i+=2){ c.lineTo(coords[i], coords[i+1]); } c.closePath(); fillStroke(fillStyle, strokeStyle); } c.lineWidth = 1; }); } }); </script> <style> .canvasMap{ position : absolute; top : 0px; left : 0px; width : 500px; height : 500px; } </style> </head> <body> <div id="container"> <map name="map"> <div id="areas"> </div> </map> <canvas class="canvasMap" id="canvas"></canvas> <img id="image" class="canvasMap" src="trans.gif" usemap="#map"/> </div> </body> </html> |