Adding interior ring digitizing for polygons. Thanks jachym for the initial work. r=ahocevar (closes #1894)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@10828 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
This commit is contained in:
Tim Schaub
2010-10-13 22:12:52 +00:00
parent ba21865e28
commit 1397f816b5
4 changed files with 432 additions and 3 deletions

59
examples/donut.html Normal file
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@@ -0,0 +1,59 @@
<!DOCTYPE html>
<html>
<head>
<title>OpenLayers Polygon Hole Digitizing</title>
<link rel="stylesheet" href="../theme/default/style.css" type="text/css">
<link rel="stylesheet" href="style.css" type="text/css">
<style>
#controlToggle li {
list-style: none;
}
.olControlAttribution {
font-size: 9px;
bottom: 2px;
}
#output {
margin: 1em;
font-size: 0.9em;
}
</style>
</head>
<body>
<h1 id="title">Drawing Holes in Polygons</h1>
<div id="tags">
draw polygon hole
</div>
<p id="shortdesc">
The DrawFeature control can be used to digitize donut polygons.
</p>
<div id="map" class="smallmap"></div>
<ul id="controlToggle">
<li>
<input type="radio" name="type" value="none" id="noneToggle"
onclick="toggleControl(this);" checked="checked">
<label for="noneToggle">navigate</label>
</li>
<li>
<input type="radio" name="type" value="polygon" id="polygonToggle" onclick="toggleControl(this);">
<label for="polygonToggle">draw polygon</label>
</li>
</ul>
<div id="output"></div>
<div id="docs">
<p>
To digitize holes in polygons, hold down the <code>Alt</code>
key and draw over an existing polygon. By default, the
<code>Shift</code> key triggers freehand drawing. Use a
combination of the <code>Shift</code> and <code>Alt</code> keys
to digitize holes in freehand mode.
</p>
<p>
See the <a href="donut.js" target="_blank">
donut.js source</a> for details on how this is done.
</p>
</div>
<script src="../lib/OpenLayers.js"></script>
<script src="donut.js"></script>
</body>
</html>

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examples/donut.js Normal file
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var map = new OpenLayers.Map({
div: "map",
layers: [
new OpenLayers.Layer.OSM(),
new OpenLayers.Layer.Vector()
],
center: new OpenLayers.LonLat(0, 0),
zoom: 1
});
var draw = new OpenLayers.Control.DrawFeature(
map.layers[1],
OpenLayers.Handler.Polygon,
{handlerOptions: {holeModifier: "altKey"}}
);
map.addControl(draw);
// optionally listen for sketch events on the layer
var output = document.getElementById("output");
function updateOutput(event) {
window.setTimeout(function() {
output.innerHTML = event.type + " " + event.feature.id;
}, 100);
}
map.layers[1].events.on({
sketchmodified: updateOutput,
sketchcomplete: updateOutput
})
// add behavior to UI elements
function toggleControl(element) {
if (element.value === "polygon" && element.checked) {
draw.activate();
} else {
draw.deactivate();
}
}
document.getElementById("noneToggle").checked = true;

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@@ -20,6 +20,20 @@
*/ */
OpenLayers.Handler.Polygon = OpenLayers.Class(OpenLayers.Handler.Path, { OpenLayers.Handler.Polygon = OpenLayers.Class(OpenLayers.Handler.Path, {
/**
* APIProperty: holeModifier
* {String} Key modifier to trigger hole digitizing. Acceptable values are
* "altKey", "shiftKey", or "ctrlKey". If not set, no hole digitizing
* will take place. Default is null.
*/
holeModifier: null,
/**
* Property: drawingHole
* {Boolean} Currently drawing an interior ring.
*/
drawingHole: false,
/** /**
* Parameter: polygon * Parameter: polygon
* {<OpenLayers.Feature.Vector>} * {<OpenLayers.Feature.Vector>}
@@ -68,14 +82,151 @@ OpenLayers.Handler.Polygon = OpenLayers.Class(OpenLayers.Handler.Path, {
this.line = new OpenLayers.Feature.Vector( this.line = new OpenLayers.Feature.Vector(
new OpenLayers.Geometry.LinearRing([this.point.geometry]) new OpenLayers.Geometry.LinearRing([this.point.geometry])
); );
// check for hole digitizing
var polygon;
if (this.holeModifier && (this.evt[this.holeModifier])) {
var geometry = this.point.geometry;
var features = this.control.layer.features;
var candidate;
// look for intersections, last drawn gets priority
for (var i=features.length-1; i>=0; --i) {
candidate = features[i].geometry;
if ((candidate instanceof OpenLayers.Geometry.Polygon ||
candidate instanceof OpenLayers.Geometry.MultiPolygon) &&
candidate.intersects(geometry)) {
polygon = features[i];
this.control.layer.removeFeatures([polygon], {silent: true});
this.control.layer.events.registerPriority(
"sketchcomplete", this, this.finalizeInteriorRing
);
this.control.layer.events.registerPriority(
"sketchmodified", this, this.enforceTopology
);
polygon.geometry.addComponent(this.line.geometry);
this.polygon = polygon;
this.drawingHole = true;
break;
}
}
}
if (!polygon) {
this.polygon = new OpenLayers.Feature.Vector( this.polygon = new OpenLayers.Feature.Vector(
new OpenLayers.Geometry.Polygon([this.line.geometry]) new OpenLayers.Geometry.Polygon([this.line.geometry])
); );
}
this.callback("create", [this.point.geometry, this.getSketch()]); this.callback("create", [this.point.geometry, this.getSketch()]);
this.point.geometry.clearBounds(); this.point.geometry.clearBounds();
this.layer.addFeatures([this.polygon, this.point], {silent: true}); this.layer.addFeatures([this.polygon, this.point], {silent: true});
}, },
/**
* Method: enforceTopology
* Simple topology enforcement for drawing interior rings. Ensures vertices
* of interior rings are contained by exterior ring. Other topology
* rules are enforced in <finalizeInteriorRing> to allow drawing of
* rings that intersect only during the sketch (e.g. a "C" shaped ring
* that nearly encloses another ring).
*/
enforceTopology: function(event) {
var point = event.vertex;
var components = this.line.geometry.components;
// ensure that vertices of interior ring are contained by exterior ring
if (!this.polygon.geometry.intersects(point)) {
var last = components[components.length-3];
point.x = last.x;
point.y = last.y;
}
},
/**
* Method: finalizeInteriorRing
* Enforces that new ring has some area and doesn't contain vertices of any
* other rings.
*/
finalizeInteriorRing: function() {
var ring = this.line.geometry;
// ensure that ring has some area
var modified = (ring.getArea() !== 0);
if (modified) {
// ensure that new ring doesn't intersect any other rings
var rings = this.polygon.geometry.components;
for (var i=rings.length-2; i>=0; --i) {
if (ring.intersects(rings[i])) {
modified = false;
break;
}
}
if (modified) {
// ensure that new ring doesn't contain any other rings
var target;
outer: for (var i=rings.length-2; i>0; --i) {
points = rings[i].components;
for (var j=0, jj=points.length; j<jj; ++j) {
if (ring.containsPoint(points[j])) {
modified = false;
break outer;
}
}
}
}
}
if (modified) {
if (this.polygon.state !== OpenLayers.State.INSERT) {
this.polygon.state = OpenLayers.State.UPDATE;
}
} else {
this.polygon.geometry.removeComponent(ring);
}
this.restoreFeature();
return false;
},
/**
* APIMethod: cancel
* Finish the geometry and call the "cancel" callback.
*/
cancel: function() {
if (this.drawingHole) {
this.polygon.geometry.removeComponent(this.line.geometry);
this.restoreFeature(true);
}
return OpenLayers.Handler.Path.prototype.cancel.apply(this, arguments);
},
/**
* Method: restoreFeature
* Move the feature from the sketch layer to the target layer.
*
* Properties:
* cancel - {Boolean} Cancel drawing. If falsey, the "sketchcomplete" event
* will be fired.
*/
restoreFeature: function(cancel) {
this.control.layer.events.unregister(
"sketchcomplete", this, this.finalizeInteriorRing
);
this.control.layer.events.unregister(
"sketchmodified", this, this.enforceTopology
);
this.layer.removeFeatures([this.polygon], {silent: true});
this.control.layer.addFeatures([this.polygon], {silent: true});
this.drawingHole = false;
if (!cancel) {
// Re-trigger "sketchcomplete" so other listeners can do their
// business. While this is somewhat sloppy (if a listener is
// registered with registerPriority - not common - between the start
// and end of a single ring drawing - very uncommon - it will be
// called twice).
// TODO: In 3.0, collapse sketch handlers into geometry specific
// drawing controls.
this.control.layer.events.triggerEvent(
"sketchcomplete", {feature : this.polygon}
);
}
},
/** /**
* Method: destroyFeature * Method: destroyFeature
* Destroy temporary geometries * Destroy temporary geometries

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@@ -158,6 +158,187 @@
map.destroy(); map.destroy();
} }
function test_rings(t) {
t.plan(12);
var log = [];
var map = new OpenLayers.Map({
div: "map",
resolutions: [1],
maxExtent: new OpenLayers.Bounds(-10, -10, 10, 10),
layers: [
new OpenLayers.Layer.Vector(null, {
isBaseLayer: true,
eventListeners: {
featureadded: function(event) {
log.push(event);
},
sketchmodified: function(event) {
log.push(event);
},
sketchcomplete: function(event) {
log.push(event);
}
}
})
],
center: new OpenLayers.LonLat(0, 0),
zoom: 0
});
// create control for drawing polygons with holes
var draw = new OpenLayers.Control.DrawFeature(
map.layers[0],
OpenLayers.Handler.Polygon,
{handlerOptions: {holeModifier: "altKey"}}
);
map.addControl(draw);
draw.activate();
var event;
function trigger(type, event) {
map.events.triggerEvent(type, OpenLayers.Util.extend({}, event));
}
// a) draw a polygon
log = [];
// start at -9, 9
event = {xy: new OpenLayers.Pixel(-9, 9)};
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -1, 9
event = {xy: new OpenLayers.Pixel(-1, 9)};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -1, 1
event = {xy: new OpenLayers.Pixel(-1, 1)};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -9, 1
event = {xy: new OpenLayers.Pixel(-9, 1)};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// finish
event = {xy: new OpenLayers.Pixel(-9, 1)};
trigger("mousedown", event);
trigger("mouseup", event);
trigger("dblclick", event);
// make assertions
t.eq(log.length, 9, "a) correct number of events");
t.eq(log[log.length-1].type, "featureadded", "a) featureadded event last");
t.eq(log[log.length-1].feature.geometry.getArea(), 64, "a) correct polygon area");
// b) draw a hole
log = [];
// start at -6, 6
event = {xy: new OpenLayers.Pixel(-6, 6), altKey: true};
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -3, 6
event = {xy: new OpenLayers.Pixel(-3, 6), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -3, 3
event = {xy: new OpenLayers.Pixel(-3, 3), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -6, 3
event = {xy: new OpenLayers.Pixel(-6, 3), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// finish
event = {xy: new OpenLayers.Pixel(-6, 3), altKey: true};
trigger("mousedown", event);
trigger("mouseup", event);
trigger("dblclick", event);
// make assertions
t.eq(log.length, 8, "b) correct number of events");
t.eq(log[log.length-1].type, "sketchcomplete", "b) sketchcomplete event last");
t.eq(log[log.length-1].feature.geometry.getArea(), 55, "b) correct polygon area");
// c) draw a polygon that overlaps the first
log = [];
// start at -2, 2
event = {xy: new OpenLayers.Pixel(-2, 2)};
trigger("mousedown", event);
trigger("mouseup", event);
// draw to 2, 2
event = {xy: new OpenLayers.Pixel(2, 2)};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to 2, -2
event = {xy: new OpenLayers.Pixel(2, -2)};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -2, -2
event = {xy: new OpenLayers.Pixel(-2, -2)};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// finish
event = {xy: new OpenLayers.Pixel(-2, -2)};
trigger("mousedown", event);
trigger("mouseup", event);
trigger("dblclick", event);
// make assertions
t.eq(log.length, 9, "c) correct number of events");
t.eq(log[log.length-1].type, "featureadded", "c) featureadded event last");
t.eq(log[log.length-1].feature.geometry.getArea(), 16, "c) correct polygon area");
// d) draw a hole that tries to go outside the exterior ring
log = [];
// start at -1, 1
event = {xy: new OpenLayers.Pixel(-1, 1), altKey: true};
trigger("mousedown", event);
trigger("mouseup", event);
// draw to 1, 1
event = {xy: new OpenLayers.Pixel(1, 1), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// try to draw to -8, 8 (ouside active polygon)
event = {xy: new OpenLayers.Pixel(-8, 8), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to 1, -1
event = {xy: new OpenLayers.Pixel(1, -1), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// draw to -1, -1
event = {xy: new OpenLayers.Pixel(-1, -1), altKey: true};
trigger("mousemove", event);
trigger("mousedown", event);
trigger("mouseup", event);
// finish
event = {xy: new OpenLayers.Pixel(-1, 1), altKey: true};
trigger("mousedown", event);
trigger("mouseup", event);
trigger("dblclick", event);
// make assertions
t.eq(log.length, 11, "d) correct number of events");
t.eq(log[log.length-1].type, "sketchcomplete", "d) sketchcomplete event last");
t.eq(log[log.length-1].feature.geometry.getArea(), 12, "d) correct polygon area");
map.destroy();
}
function test_Handler_Polygon_destroy(t) { function test_Handler_Polygon_destroy(t) {
t.plan(8); t.plan(8);
var map = new OpenLayers.Map('map'); var map = new OpenLayers.Map('map');