<!--[if IE]><meta http-equiv="X-UA-Compatible" content="IE=5,IE=9" ><![endif]-->
<!DOCTYPE html>
<!--
Copyright (c) 2006-2013, JGraph Ltd
Grid example for mxGraph. This example demonstrates drawing
a grid dynamically using HTML 5 canvas.
-->
<html>
<head>
<title>Grid example for mxGraph</title>
<!-- Sets the basepath for the library if not in same directory -->
<script type="text/javascript">
mxBasePath = '../src';
</script>
<!-- Loads and initializes the library -->
<script type="text/javascript" src="../src/js/mxClient.js"></script>
<!-- Example code -->
<script type="text/javascript">
// Program starts here. Creates a sample graph in the
// DOM node with the specified ID. This function is invoked
// from the onLoad event handler of the document (see below).
function main(container)
{
// Checks if the browser is supported
if (!mxClient.isBrowserSupported())
{
// Displays an error message if the browser is not supported.
mxUtils.error('Browser is not supported!', 200, false);
}
else
{
mxEvent.disableContextMenu(document.body);
// Creates the graph inside the given container
var graph = new mxGraph(container);
graph.graphHandler.scaleGrid = true;
graph.setPanning(true);
// Enables rubberband selection
new mxRubberband(graph);
// Create grid dynamically (requires canvas)
(function()
{
try
{
var canvas = document.createElement('canvas');
canvas.style.position = 'absolute';
canvas.style.top = '0px';
canvas.style.left = '0px';
canvas.style.zIndex = -1;
graph.container.appendChild(canvas);
var ctx = canvas.getContext('2d');
// Modify event filtering to accept canvas as container
var mxGraphViewIsContainerEvent = mxGraphView.prototype.isContainerEvent;
mxGraphView.prototype.isContainerEvent = function(evt)
{
return mxGraphViewIsContainerEvent.apply(this, arguments) ||
mxEvent.getSource(evt) == canvas;
};
var s = 0;
var gs = 0;
var tr = new mxPoint();
var w = 0;
var h = 0;
function repaintGrid()
{
if (ctx != null)
{
var bounds = graph.getGraphBounds();
var width = Math.max(bounds.x + bounds.width, graph.container.clientWidth);
var height = Math.max(bounds.y + bounds.height, graph.container.clientHeight);
var sizeChanged = width != w || height != h;
if (graph.view.scale != s || graph.view.translate.x != tr.x || graph.view.translate.y != tr.y ||
gs != graph.gridSize || sizeChanged)
{
tr = graph.view.translate.clone();
s = graph.view.scale;
gs = graph.gridSize;
w = width;
h = height;
// Clears the background if required
if (!sizeChanged)
{
ctx.clearRect(0, 0, w, h);
}
else
{
canvas.setAttribute('width', w);
canvas.setAttribute('height', h);
}
var tx = tr.x * s;
var ty = tr.y * s;
// Sets the distance of the grid lines in pixels
var minStepping = graph.gridSize;
var stepping = minStepping * s;
if (stepping < minStepping)
{
var count = Math.round(Math.ceil(minStepping / stepping) / 2) * 2;
stepping = count * stepping;
}
var xs = Math.floor((0 - tx) / stepping) * stepping + tx;
var xe = Math.ceil(w / stepping) * stepping;
var ys = Math.floor((0 - ty) / stepping) * stepping + ty;
var ye = Math.ceil(h / stepping) * stepping;
xe += Math.ceil(stepping);
ye += Math.ceil(stepping);
var ixs = Math.round(xs);
var ixe = Math.round(xe);
var iys = Math.round(ys);
var iye = Math.round(ye);
// Draws the actual grid
ctx.strokeStyle = '#f6f6f6';
ctx.beginPath();
for (var x = xs; x <= xe; x += stepping)
{
x = Math.round((x - tx) / stepping) * stepping + tx;
var ix = Math.round(x);
ctx.moveTo(ix + 0.5, iys + 0.5);
ctx.lineTo(ix + 0.5, iye + 0.5);
}
for (var y = ys; y <= ye; y += stepping)
{
y = Math.round((y - ty) / stepping) * stepping + ty;
var iy = Math.round(y);
ctx.moveTo(ixs + 0.5, iy + 0.5);
ctx.lineTo(ixe + 0.5, iy + 0.5);
}
ctx.closePath();
ctx.stroke();
}
}
};
}
catch (e)
{
mxLog.show();
mxLog.debug('Using background image');
container.style.backgroundImage = 'url(\'editors/images/grid.gif\')';
}
var mxGraphViewValidateBackground = mxGraphView.prototype.validateBackground;
mxGraphView.prototype.validateBackground = function()
{
mxGraphViewValidateBackground.apply(this, arguments);
repaintGrid();
};
})();
// Gets the default parent for inserting new cells. This
// is normally the first child of the root (ie. layer 0).
var parent = graph.getDefaultParent();
// Adds cells to the model in a single step
graph.getModel().beginUpdate();
try
{
var v1 = graph.insertVertex(parent, null, 'Hello,', 20, 20, 80, 30);
var v2 = graph.insertVertex(parent, null, 'World!', 200, 150, 80, 30);
var e1 = graph.insertEdge(parent, null, '', v1, v2);
}
finally
{
// Updates the display
graph.getModel().endUpdate();
}
graph.centerZoom = false;
document.body.appendChild(mxUtils.button('+', function()
{
graph.zoomIn();
}));
document.body.appendChild(mxUtils.button('-', function()
{
graph.zoomOut();
}));
}
};
</script>
</head>
<!-- Page passes the container for the graph to the program -->
<body onload="main(document.getElementById('graphContainer'))">
<!-- Creates a container for the graph with a grid wallpaper -->
<div id="graphContainer"
style="overflow:hidden;width:641px;height:481px;cursor:default;">
</div>
</body>
</html>