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correct bug where the value stored for the top-left corner of the back buffer may be incorrect, thanks @ahocevar for catching the issue

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This commit is contained in:
Éric Lemoine
2011-10-30 23:20:42 +01:00
parent c0d210ef05
commit db08102fe4
1 changed files with 47 additions and 43 deletions
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90
lib/OpenLayers/Layer/Grid.js
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@@ -118,15 +118,26 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
backBuffer: null,
/**
* Property: backBufferData
* {Object} An object containing states necessary for the back buffer. It
* includes two state properties:
* - *resolution* the last resolution of the tiles. Used as the "from
* resolution" when transitioning.
* - *lonlat* the geographic coordinates of the tiles grid's top-left
* corner.
* Property: gridResolution
* {Number} The resolution of the current grid. Used for backbuffering.
* This property is updated each the grid is initialized.
*/
backBufferData: null,
gridResolution: null,
/**
* Property: backBufferResolution
* {Number} The resolution of the current back buffer. This property is
* updated each time a back buffer is created.
*/
backBufferResolution: null,
/**
* Property: backBufferLonLat
* {Object} The top-left corner of the current back buffer. Includes lon
* and lat properties. This object is updated each time a back buffer
* is created.
*/
backBufferLonLat: null,
/**
* Constructor: OpenLayers.Layer.Grid
@@ -150,7 +161,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
this.events.addEventType("tileloaded");
this.grid = [];
this.backBufferData = {};
this._moveGriddedTiles = OpenLayers.Function.bind(
this.moveGriddedTiles, this
@@ -177,9 +187,11 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
*/
destroy: function() {
this.clearGrid();
// clearGrid should remove any back buffer from the layer,
// so no need to call removeBackBuffer here
this.grid = null;
this.tileSize = null;
this.backBufferData = null;
OpenLayers.Layer.HTTPRequest.prototype.destroy.apply(this, arguments);
},
@@ -199,6 +211,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
}
}
this.grid = [];
this.gridResolution = null;
}
},
@@ -231,6 +244,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
// we do not want to copy reference to grid, so we make a new array
obj.grid = [];
obj.gridResolution = null;
return obj;
},
@@ -266,9 +280,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
// the server-supported resolution for the new map resolution
var serverResolution = this.getServerResolution(resolution);
// the last resolution of the tiles
var lastResolution = this.backBufferData.resolution;
if (this.singleTile) {
// We want to redraw whenever even the slightest part of the
@@ -289,8 +300,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
this.removeBackBuffer();
}
if(!zoomChanged || (lastResolution &&
this.transitionEffect === 'resize')) {
if(!zoomChanged || this.transitionEffect === 'resize') {
this.applyBackBuffer(serverResolution);
}
@@ -323,8 +333,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
}
if(forceReTile) {
if(zoomChanged && this.transitionEffect === 'resize' &&
lastResolution) {
if(zoomChanged && this.transitionEffect === 'resize') {
this.applyBackBuffer(serverResolution);
}
this.initGriddedTiles(bounds);
@@ -432,18 +441,28 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
}
this.div.insertBefore(backBuffer, this.div.firstChild);
this.backBuffer = backBuffer;
// set some information in the instance for subsequent
// calls to applyBackBuffer where the same back buffer
// is reused
var topLeftTileBounds = this.grid[0][0].bounds;
this.backBufferLonLat = {
lon: topLeftTileBounds.left,
lat: topLeftTileBounds.top
};
this.backBufferResolution = this.gridResolution;
}
var style = backBuffer.style;
// scale the back buffer
var ratio = this.backBufferData.resolution / resolution;
var ratio = this.backBufferResolution / resolution;
style.width = 100 * ratio + '%';
style.height = 100 * ratio + '%';
// and position it (based on the grid's top-left corner)
var position = this.getViewPortPxFromLonLat(
this.backBufferData.lonlat, resolution);
this.backBufferLonLat, resolution);
var leftOffset = parseInt(this.map.layerContainerDiv.style.left, 10);
var topOffset = parseInt(this.map.layerContainerDiv.style.top, 10);
backBuffer.style.left = (position.x - leftOffset) + '%';
@@ -452,12 +471,11 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
/**
* Method: createBackBuffer
* Create a back buffer. We apply a best effort strategy here - if for any
* reason we cannot clone a tile's markup we give up right away.
* Create a back buffer.
*
* Returns:
* {DOMElement} The DOM element for the back buffer, undefined if the
* back buffer couldn't have been created.
* grid isn't initialized yet.
*/
createBackBuffer: function() {
var backBuffer;
@@ -493,26 +511,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
if(this.backBuffer && this.backBuffer.parentNode) {
this.div.removeChild(this.backBuffer);
this.backBuffer = null;
}
},
/**
* Method: updateBackBufferData
* Upstate states in the backBufferData property
*/
updateBackBufferData: function() {
// updateBackBufferData is called asynchronously when tiles are
// received, so we need to check that the map is still there
if(this.map) {
var resolution = this.map.getResolution();
this.backBufferData.resolution = this.getServerResolution(resolution);
}
// the top left tile might have been destroyed, so its bounds
// property may be null
var topLeftTile = this.grid[0][0];
if(topLeftTile.bounds) {
this.backBufferData.lonlat = {lon: topLeftTile.bounds.left,
lat: topLeftTile.bounds.top};
this.backBufferResolution = null;
}
},
@@ -645,6 +644,9 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
//remove all but our single tile
this.removeExcessTiles(1,1);
// store the resolution of the grid
this.gridResolution = this.getServerResolution();
},
/**
@@ -805,6 +807,9 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
//shave off exceess rows and colums
this.removeExcessTiles(rowidx, colidx);
// store the resolution of the grid
this.gridResolution = this.getServerResolution();
//now actually draw the tiles
this.spiralTileLoad();
},
@@ -936,7 +941,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
if (this.numLoadingTiles == 0) {
this.events.triggerEvent("loadend");
this.removeBackBuffer();
this.updateBackBufferData();
}
};
tile.events.register("loadend", this, tile.onLoadEnd);