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adding getPixelFromLonLat() function to Map.js -- the code is lifted from OpenLayers.Layer.Marker's drawMarker() function. also test added to ensure both translation functions return valid objects and that going back and forth is consistent. Note that i only test pixel-lonlat-pixel, because going from lonlat-pixel-lonlat there is loss due to the rounding in the lonlat-pixel phase

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git-svn-id: http://svn.openlayers.org/trunk/openlayers@246 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
This commit is contained in:
euzuro
2006-05-22 09:55:20 +00:00
parent af7dc7661a
commit 78588aa8ea
2 changed files with 36 additions and 0 deletions
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17
lib/OpenLayers/Map.js
View File

@@ -271,6 +271,23 @@ OpenLayers.Map.prototype = {
center.lat - delta_y * res); center.lat - delta_y * res);
}, },
/**
* @param {OpenLayers.LonLat} lonlat
*
* @returns An OpenLayers.Pixel which is the passed-in OpenLayers.LonLat,
* translated into screen pixels given the current extent
* and resolution
* @type OpenLayers.Pixel
*/
getPixelFromLonLat: function (lonlat) {
var resolution = this.getResolution();
var extent = this.getExtent();
return new OpenLayers.Pixel(
Math.round(1/resolution * (lonlat.lon - extent.left)),
Math.round(1/resolution * (extent.top - lonlat.lat))
);
},
/** /**
* @param {OpenLayers.LonLat} lonlat * @param {OpenLayers.LonLat} lonlat
* @param {int} zoom * @param {int} zoom

19
tests/test_Map.html
View File

@@ -113,6 +113,25 @@
} }
function test_08_Map_px_lonlat_translation (t) {
t.plan( 3 );
map = new OpenLayers.Map($('map'));
map.setCenter(new OpenLayers.LonLat(0, 0), 0);
var pixel = new OpenLayers.Pixel(50,150);
var lonlat = map.getLonLatFromPixel(pixel);
t.ok( lonlat instanceof OpenLayers.LonLat, "getLonLatFromPixel returns valid OpenLayers.LonLat" );
var newPixel = map.getPixelFromLonLat(lonlat);
t.ok( newPixel instanceof OpenLayers.Pixel, "getPixelFromLonLat returns valid OpenLayers.Pixel" );
// WARNING!!! I'm faily sure that the following test's validity
// depends highly on rounding and the resolution. For now,
// in the default case, it seems to work. This may not
// always be so.
t.ok( newPixel.equals(pixel), "Translation to pixel and back to lonlat is consistent");
}
function test_99_Map_destroy (t) { function test_99_Map_destroy (t) {
t.plan( 2 ); t.plan( 2 );
map = new OpenLayers.Map($('map')); map = new OpenLayers.Map($('map'));