diff --git a/examples/tile-extent.html b/examples/tile-origin.html
similarity index 76%
rename from examples/tile-extent.html
rename to examples/tile-origin.html
index 4f69243853..cd01f09dca 100644
--- a/examples/tile-extent.html
+++ b/examples/tile-origin.html
@@ -1,15 +1,15 @@
- OpenLayers Tile Extent Example
+ OpenLayers Tile Origin Example
Tile Extent
+ Tile Origin
- grid, tileExtent
+ grid, tileOrigin
Demonstrates the use of the tileExtent property to differentiate
@@ -23,14 +23,14 @@
Tile Extent
a particular tile lattice. In this case, the layer's
maxExtent does not align with that tile lattice.
To configure the layer with a tile extent that conforms to the
- tile extent configured on the server, use the layer's
- tileExtent property.
+ tile origin configured on the server, use the layer's
+ tileOrigin property.
- View the tile-extent.js
+ View the tile-origin.js
source to see how this is done
-
+
diff --git a/examples/tile-extent.js b/examples/tile-origin.js
similarity index 86%
rename from examples/tile-extent.js
rename to examples/tile-origin.js
index 953b2e1db4..61c5b8ea3e 100644
--- a/examples/tile-extent.js
+++ b/examples/tile-origin.js
@@ -8,7 +8,7 @@ var map = new OpenLayers.Map({
"Global Imagery",
"http://maps.opengeo.org/geowebcache/service/wms",
{layers: "bluemarble"},
- {tileExtent: new OpenLayers.Bounds(-180, -90, 180, 90)}
+ {tileOrigin: new OpenLayers.LonLat(-180, -90)}
)
],
center: new OpenLayers.LonLat(-110, 45),
diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index c31d195f0e..cc1e07372e 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -24,12 +24,26 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* {}
*/
tileSize: null,
+
+ /**
+ * Property: tileOriginCorner
+ * {String} If the property is not provided, the tile origin
+ * will be derived from the layer's . The corner of the
+ * used is determined by this property. Acceptable values
+ * are "tl" (top left), "tr" (top right), "bl" (bottom left), and "br"
+ * (bottom right). Default is "bl".
+ */
+ tileOriginCorner: "bl",
/**
- * APIProperty: tileExtent
- * {}
+ * APIProperty: tileOrigin
+ * {} Optional origin for aligning the grid of tiles.
+ * If provided, requests for tiles at all resolutions will be aligned
+ * with this location (no tiles shall overlap this location). If
+ * not provided, the grid of tiles will be aligned with the layer's
+ * . Default is ``null``.
*/
- tileExtent: null,
+ tileOrigin: null,
/** APIProperty: tileOptions
* {Object} optional configuration options for instances
@@ -315,32 +329,32 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
/**
* Method: calculateGridLayout
- * Generate parameters for the grid layout. This
+ * Generate parameters for the grid layout.
*
* Parameters:
* bounds - {}
- * extent - {}
+ * origin - {}
* resolution - {Number}
*
* Returns:
* Object containing properties tilelon, tilelat, tileoffsetlat,
* tileoffsetlat, tileoffsetx, tileoffsety
*/
- calculateGridLayout: function(bounds, extent, resolution) {
+ calculateGridLayout: function(bounds, origin, resolution) {
var tilelon = resolution * this.tileSize.w;
var tilelat = resolution * this.tileSize.h;
- var offsetlon = bounds.left - extent.left;
+ var offsetlon = bounds.left - origin.lon;
var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
var tilecolremain = offsetlon/tilelon - tilecol;
var tileoffsetx = -tilecolremain * this.tileSize.w;
- var tileoffsetlon = extent.left + tilecol * tilelon;
+ var tileoffsetlon = origin.lon + tilecol * tilelon;
- var offsetlat = bounds.top - (extent.bottom + tilelat);
+ var offsetlat = bounds.top - (origin.lat + tilelat);
var tilerow = Math.ceil(offsetlat/tilelat) + this.buffer;
var tilerowremain = tilerow - offsetlat/tilelat;
var tileoffsety = -tilerowremain * this.tileSize.h;
- var tileoffsetlat = extent.bottom + tilerow * tilelat;
+ var tileoffsetlat = origin.lat + tilerow * tilelat;
return {
tilelon: tilelon, tilelat: tilelat,
@@ -349,6 +363,32 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
};
},
+
+ /**
+ * Method: getTileOrigin
+ * Determine the origin for aligning the grid of tiles. If a
+ * property is supplied, that will be returned. Otherwise, the origin
+ * will be derived from the layer's property. In this case,
+ * the tile origin will be the corner of the given by the
+ * property.
+ *
+ * Returns:
+ * {} The tile origin.
+ */
+ getTileOrigin: function() {
+ var origin = this.tileOrigin;
+ if (!origin) {
+ var extent = this.getMaxExtent();
+ var edges = ({
+ "tl": ["left", "top"],
+ "tr": ["right", "top"],
+ "bl": ["left", "bottom"],
+ "br": ["right", "bottom"]
+ })[this.tileOriginCorner];
+ origin = new OpenLayers.LonLat(extent[edges[0]], extent[edges[1]]);
+ }
+ return origin;
+ },
/**
* Method: initGriddedTiles
@@ -367,10 +407,10 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
var minCols = Math.ceil(viewSize.w/this.tileSize.w) +
Math.max(1, 2 * this.buffer);
- var extent = this.getMaxExtent();
+ var origin = this.getTileOrigin();
var resolution = this.map.getResolution();
- var tileLayout = this.calculateGridLayout(bounds, extent, resolution);
+ var tileLayout = this.calculateGridLayout(bounds, origin, resolution);
var tileoffsetx = Math.round(tileLayout.tileoffsetx); // heaven help us
var tileoffsety = Math.round(tileLayout.tileoffsety);
@@ -452,7 +492,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
* {OpenLayers.Bounds}
*/
getMaxExtent: function() {
- return this.tileExtent || this.maxExtent;
+ return this.maxExtent;
},
/**
diff --git a/tests/Layer/WMS.html b/tests/Layer/WMS.html
index ec3e153863..f17b56a354 100644
--- a/tests/Layer/WMS.html
+++ b/tests/Layer/WMS.html
@@ -380,7 +380,7 @@
}
- function test_tileExtent(t) {
+ function test_tileOrigin(t) {
t.plan(4);
var dummy = new OpenLayers.Layer(null, {isBaseLayer: true});
@@ -392,7 +392,7 @@
var constrained = new OpenLayers.Layer.WMS(
null, "http://example.com/wms-c",
{layers: "constrained"},
- {buffer: 0, isBaseLayer: false, tileExtent: new OpenLayers.Bounds(-180, -90, 180, 90)}
+ {buffer: 0, isBaseLayer: false, tileOrigin: new OpenLayers.LonLat(-180, -90)}
);
var map = new OpenLayers.Map({
div: "map",