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Explain changes in upgrade notes

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Andreas Hocevar
2015-06-12 09:47:43 +02:00
parent 4b3aac32c3
commit 72cc824502
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changelog/upgrade-notes.md
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@@ -34,6 +34,53 @@ With the removal of `ol.FeatureOverlay`, `zIndex` symbolizer properties of overl
Note that `ol.FeatureOverlay#getFeatures()` returned an `{ol.Collection.<ol.Feature>}`, whereas `ol.source.Vector#getFeatures()` returns an `{Array.<ol.Feature>}`.
#### `ol.TileCoord` changes
Until now, the API exposed two different types of `ol.TileCoord` tile coordinates: the internal ones with bottom-left origin, and transformed ones with an origin that is determined by the tile grid configuration. With this change, the API now only exposes the transformed tile coordinates.
The first `tileCoord` argument of `ol.TileUrlFunctionType` now expects transformed tile coordinates instead of internal OpenLayers tile coordinates. Accordingly, `ol.tilegrid.TileGrid#getTileCoordForCoordAndZ` and `ol.tilegrid.TileGrid#getTileCoordForCoordAndResolution` now return transformed tile coordinates.
This change affects applications that configure a custom `tileUrlFunction` for an `ol.source.Tile`. Previously, the `tileUrlFunction` was called with bottom-left origin tile coordinates that OpenLayers uses internally. To transform these into tile coordinates supported by the tile source, a custom `tileUrlFunction` had to change the `y` value of the `ol.TileCoord`. Now the `y` value can be used unaltered.
To make it easier for application developers to perform this transform, the API provided an `ol.tilegrid.TileGrid#createTileCoordTransform()` function. This function is no longer available and no longer needed.
The code snippets below show how your application code needs to be changed:
Old application code (with `ol.tilegrid.TileGrid#createTileCoordTransform()`):
```js
var transform = source.getTileGrid().createTileCoordTransform();
var tileUrlFunction = function(tileCoord, pixelRatio, projection) {
tileCoord = transform(tileCoord, projection);
return 'http://mytiles.com/' +
tileCoord[0] + '/' + tileCoord[1] + '/' + tileCoord[2] + '.png';
};
```
Old application code (with custom `y` transform):
```js
var tileUrlFunction = function(tileCoord, pixelRatio, projection) {
var z = tileCoord[0];
var yFromBottom = tileCoord[2];
var resolution = tileGrid.getResolution(z);
var tileHeight = ol.size.toSize(tileSize)[1];
var matrixHeight =
Math.floor(ol.extent.getHeight(extent) / tileHeight / resolution);
return 'http://mytiles.com/' +
tileCoord[0] + '/' + tileCoord[1] + '/' +
(matrixHeight - yFromBottom - 1) + '.png';
};
```
New application code (no transform needed):
```js
var tileUrlFunction = function(tileCoord, pixelRatio, projection) {
return 'http://mytiles.com/' +
tileCoord[0] + '/' + tileCoord[1] + '/' + tileCoord[2] + '.png';
};
```
For easier debugging, `ol.source.DebugTile` was changed to display the transformed tile coordinates as well.
Also watch out for sections in your code where you used `ol.tilegrid.TileGrid#getTileCoordForCoordAndZ()` or `ol.tilegrid.TileGrid#getTileCoordForCoordAndResolution()`. When working with the returned tile coordinates, changes equivalent to the ones shown in the above snippets are required.
### v3.6.0
#### `ol.interaction.Draw` changes