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Optimize ol.Extent.getForView2DAndSize

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Tom Payne
2013-03-10 15:14:50 +01:00
parent 08d3120f08
commit 3a1fcdae0f
1 changed files with 16 additions and 13 deletions
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29
src/ol/extent.js
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@@ -53,21 +53,24 @@ ol.Extent.boundingExtent = function(var_args) {
* @return {ol.Extent} Extent.
*/
ol.Extent.getForView2DAndSize = function(center, resolution, rotation, size) {
var x = resolution * size.width / 2;
var y = resolution * size.height / 2;
var corners = [
new ol.Coordinate(-x, -y),
new ol.Coordinate(-x, y),
new ol.Coordinate(x, -y),
new ol.Coordinate(x, y)
];
var corner;
var dx = resolution * size.width / 2;
var dy = resolution * size.height / 2;
var cosRotation = Math.cos(rotation);
var sinRotation = Math.sin(rotation);
var xs = [-dx, -dx, dx, dx];
var ys = [-dy, dy, -dy, dy];
var i, x, y;
for (i = 0; i < 4; ++i) {
corner = corners[i];
corner.rotate(rotation);
corner.add(center);
x = xs[i];
y = ys[i];
xs[i] = center.x + x * cosRotation - y * sinRotation;
ys[i] = center.y + x * sinRotation + y * cosRotation;
}
return ol.Extent.boundingExtent.apply(null, corners);
var minX = Math.min.apply(null, xs);
var minY = Math.min.apply(null, ys);
var maxX = Math.max.apply(null, xs);
var maxY = Math.max.apply(null, ys);
return new ol.Extent(minX, minY, maxX, maxY);
};