No deltas for tile bounds/position calculation

Now we also do not use deltas for shiftRow and shiftColumn. Some
refactoring was done so we do not need different calculateGridLayout
methods for layers with top-left and bottom-left tile origin.

TODO: With this commit, ArcGisCache and KaMap layers are broken.

lib/OpenLayers/Layer/Grid.js

@@ -270,6 +270,14 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      *     tile that could not be loaded.
      */
 
+    /**
+     * Property: gridLayout
+     * {Object} containing properties tilelon, tilelat, tileoffsetlat,
+     * tileoffsetlat, tileoffsetx, tileoffsety and optional startrow, startcol
+     * for grid layouts where absolute tile bounds calculation is possible.
+     */
+    gridLayout: null,
+
     /**
      * Constructor: OpenLayers.Layer.Grid
      * Create a new grid layer
@@ -363,6 +371,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
             }
             this.grid = [];
             this.gridResolution = null;
+            this.gridLayout = null;
         }
     },
     
@@ -866,9 +875,8 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      * resolution - {Number}
      *
      * Returns:
-     * {Object} containing properties tilelon, tilelat, tileoffsetlat,
+     * {Object} Object containing properties tilelon, tilelat, tileoffsetx,
-     * tileoffsetlat, tileoffsetx, tileoffsety and optional startrow, startcol
+     * tileoffsety, startcol, startrow
-     * for grid layouts where absolute tile bounds calculation is possible.
      */
     calculateGridLayout: function(bounds, origin, resolution) {
         var tilelon = resolution * this.tileSize.w;
@@ -884,17 +892,16 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
         var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
         var tilecolremain = offsetlon/tilelon - tilecol;
         var tileoffsetx = -tilecolremain * tileSize.w;
-        var tileoffsetlon = origin.lon + tilecol * tilelon;
         
-        var offsetlat = bounds.top - (origin.lat + tilelat);  
+        var rowSign = this.tileOriginCorner.substr(0, 1) === "t" ? 1 : -1;
-        var tilerow = Math.ceil(offsetlat/tilelat) + this.buffer;
+
+        var offsetlat = rowSign * (origin.lat - bounds.top + tilelat);  
+        var tilerow = Math[~rowSign ? 'floor' : 'ceil'](offsetlat/tilelat) - this.buffer * rowSign;
         var tilerowremain = tilerow - offsetlat/tilelat;
-        var tileoffsety = -tilerowremain * tileSize.h;
+        var tileoffsety = rowSign * tilerowremain * tileSize.h;
-        var tileoffsetlat = origin.lat + tilerow * tilelat;
         
         return { 
           tilelon: tilelon, tilelat: tilelat,
-          tileoffsetlon: tileoffsetlon, tileoffsetlat: tileoffsetlat,
           tileoffsetx: tileoffsetx, tileoffsety: tileoffsety,
           startcol: tilecol, startrow: tilerow
         };
@@ -927,6 +934,30 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
         return origin;
     },
 
+    /**
+     * Method: getTileBoundsForGridIndex
+     *
+     * Parameters:
+     * row - {Number} The row of the grid
+     * col - {Number} The column of the grid
+     *
+     * Returns:
+     * {<OpenLayers.Bounds>} The bounds for the tile at (row, col)
+     */
+    getTileBoundsForGridIndex: function(row, col) {
+        var origin = this.getTileOrigin();
+        var tileLayout = this.gridLayout;
+        var tilelon = tileLayout.tilelon;
+        var tilelat = tileLayout.tilelat;
+        var rowSign = this.tileOriginCorner.substr(0, 1) === "t" ? 1 : -1;
+        var minX = origin.lon + (tileLayout.startcol + col) * tilelon;
+        var minY = origin.lat - (tileLayout.startrow + row * rowSign) * tilelat * rowSign;
+        return new OpenLayers.Bounds(
+            minX, minY,
+            minX + tilelon, minY + tilelat
+        );
+    },
+
     /**
      * Method: initGriddedTiles
      * 
@@ -956,50 +987,34 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
                       2 * this.buffer + 1;
 
         var tileLayout = this.calculateGridLayout(bounds, origin, serverResolution);
-        var tileoffsetx = Math.round(tileLayout.tileoffsetx); // heaven help us
+        this.gridLayout = tileLayout;
-        var tileoffsety = Math.round(tileLayout.tileoffsety);
         
-        var tileoffsetlon = tileLayout.tileoffsetlon;
+        var startX = Math.round(tileLayout.tileoffsetx); // heaven help us
-        var tileoffsetlat = tileLayout.tileoffsetlat;
+        var startY = Math.round(tileLayout.tileoffsety);
         
         var tilelon = tileLayout.tilelon;
         var tilelat = tileLayout.tilelat;
         
-        var startX = tileoffsetx; 
-        var startLon = tileoffsetlon;
-
-        var rowidx = 0;
-        
         var layerContainerDivLeft = this.map.layerContainerOriginPx.x;
         var layerContainerDivTop = this.map.layerContainerOriginPx.y;
 
         var tileData = [], center = this.map.getCenter();
+
+        var rowidx = 0;
         do {
-            var row = this.grid[rowidx++];
+            var row = this.grid[rowidx];
             if (!row) {
                 row = [];
                 this.grid.push(row);
             }
             
-            tileoffsetlon = startLon;
-            tileoffsetx = startX;
             var colidx = 0;
- 
             do {
-                var tileBounds = 
+                var tileBounds = this.getTileBoundsForGridIndex(rowidx, colidx);
-                    new OpenLayers.Bounds(tileoffsetlon, 
+                var x = startX + colidx * tileSize.w - layerContainerDivLeft;
-                                          tileoffsetlat, 
+                var y = startY + rowidx * tileSize.h - layerContainerDivTop;
-                                          tileoffsetlon + tilelon,
-                                          tileoffsetlat + tilelat);
-
-                var x = tileoffsetx;
-                x -= layerContainerDivLeft;
-
-                var y = tileoffsety;
-                y -= layerContainerDivTop;
-
                 var px = new OpenLayers.Pixel(x, y);
-                var tile = row[colidx++];
+                var tile = row[colidx];
                 if (!tile) {
                     tile = this.addTile(tileBounds, px);
                     this.addTileMonitoringHooks(tile);
@@ -1014,18 +1029,12 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
                         Math.pow(tileCenter.lat - center.lat, 2)
                 });
      
-                tileoffsetlon = 'startcol' in tileLayout ?
+                colidx += 1;
-                    origin.lon + (tileLayout.startcol + colidx) * tilelon :
+            } while ((tileBounds.right <= bounds.right + tilelon * this.buffer)
-                    tileoffsetlon + tilelon;       
-                tileoffsetx += Math.round(tileSize.w);
-            } while ((tileoffsetlon <= bounds.right + tilelon * this.buffer)
                      || colidx < minCols);
              
-            tileoffsetlat = 'startrow' in tileLayout ?
+            rowidx += 1;
-                origin.lat + (tileLayout.startrow - rowidx) * tilelat :
+        } while((tileBounds.bottom >= bounds.bottom - tilelat * this.buffer)
-                tileoffsetlat - tilelat;
-            tileoffsety += Math.round(tileSize.h);
-        } while((tileoffsetlat >= bounds.bottom - tilelat * this.buffer)
                 || rowidx < minRows);
         
         //shave off exceess rows and colums
@@ -1200,31 +1209,28 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      *                          if false, then append to end
      * tileSize - {Object} rendered tile size; object with w and h properties
      */
-    shiftRow:function(prepend, tileSize) {
+    shiftRow: function(prepend, tileSize) {
-        var modelRowIndex = (prepend) ? 0 : (this.grid.length - 1);
         var grid = this.grid;
-        var modelRow = grid[modelRowIndex];
+        var rowIndex = prepend ? 0 : (grid.length - 1);
-
         var sign = prepend ? -1 : 1;
-        var deltaLat = this.getServerResolution() * -sign * this.tileSize.h;
+        var rowSign = this.tileOriginCorner.substr(0, 1) === "t" ? 1 : -1;
+        var tileLayout = this.gridLayout;
+        tileLayout.startrow += sign * rowSign;
 
-        var row = (prepend) ? grid.pop() : grid.shift();
+        var bounds = this.getTileBoundsForGridIndex(rowIndex, 0);
+        var position = this.map.getViewPortPxFromLonLat(
+            new OpenLayers.LonLat(bounds.left, bounds.top)
+        );
+        var y = Math.round(position.y - this.map.layerContainerOriginPx.y);
 
-        for (var i=0, len=modelRow.length; i<len; i++) {
+        var row = grid[prepend ? 'pop' : 'shift']();
-            var modelTile = modelRow[i];
+        for (var i=0, len=row.length; i<len; i++) {
-            var bounds = modelTile.bounds.clone();
+            var tile = row[i];
-            var position = modelTile.position.clone();
+            var position = tile.position.clone();
-            bounds.bottom = bounds.bottom + deltaLat;
+            position.y = y;
-            bounds.top = bounds.top + deltaLat;
+            tile.moveTo(this.getTileBoundsForGridIndex(rowIndex, i), position);
-            position.y = position.y + sign * tileSize.h;
-            row[i].moveTo(bounds, position);
-        }
-
-        if (prepend) {
-            grid.unshift(row);
-        } else {
-            grid.push(row);
         }
+        grid[prepend ? 'unshift' : 'push'](row);
     },
 
     /**
@@ -1237,27 +1243,25 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      * tileSize - {Object} rendered tile size; object with w and h properties
      */
     shiftColumn: function(prepend, tileSize) {
+        var grid = this.grid;
+        var colIndex = prepend ? 0 : (grid[0].length - 1);
         var sign = prepend ? -1 : 1;
-        var deltaLon = this.getServerResolution() * sign * this.tileSize.w;
+        var tileLayout = this.gridLayout;
+        tileLayout.startcol += sign;
 
-        for (var i=0, len=this.grid.length; i<len; i++) {
+        var bounds = this.getTileBoundsForGridIndex(0, colIndex);
-            var row = this.grid[i];
+        var position = this.map.getViewPortPxFromLonLat(
-            var modelTileIndex = (prepend) ? 0 : (row.length - 1);
+            new OpenLayers.LonLat(bounds.left, bounds.top)
-            var modelTile = row[modelTileIndex];
+        );
+        var x = Math.round(position.x - this.map.layerContainerOriginPx.x);
 
-            var bounds = modelTile.bounds.clone();
+        for (var i=0, len=grid.length; i<len; i++) {
-            var position = modelTile.position.clone();
+            var row = grid[i];
-            bounds.left = bounds.left + deltaLon;
+            var tile = row[prepend ? 'pop' : 'shift']();            
-            bounds.right = bounds.right + deltaLon;
+            var position = tile.position.clone();
-            position.x = position.x + sign * tileSize.w;
+            position.x = x;
-
+            tile.moveTo(this.getTileBoundsForGridIndex(i, colIndex), position);
-            var tile = prepend ? this.grid[i].pop() : this.grid[i].shift();
+            row[prepend ? 'unshift' : 'push'](tile);
-            tile.moveTo(bounds, position);
-            if (prepend) {
-                row.unshift(tile);
-            } else {
-                row.push(tile);
-            }
         }
     },
 

lib/OpenLayers/Layer/KaMap.js

@@ -114,7 +114,8 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
         return { 
           tilelon: tilelon, tilelat: tilelat,
           tileoffsetlon: tileoffsetlon, tileoffsetlat: tileoffsetlat,
-          tileoffsetx: tileoffsetx, tileoffsety: tileoffsety
+          tileoffsetx: tileoffsetx, tileoffsety: tileoffsety,
+          startcol: tilecol, startrow: tilerow
         };
     },    
 

lib/OpenLayers/Layer/MapGuide.js

@@ -439,41 +439,5 @@ OpenLayers.Layer.MapGuide = OpenLayers.Class(OpenLayers.Layer.Grid, {
         return requestString;
     },
     
-    /** 
-     * Method: calculateGridLayout
-     * Generate parameters for the grid layout. This  
-     *
-     * Parameters:
-     * bounds - {<OpenLayers.Bound>}
-     * origin - {<OpenLayers.LonLat>}
-     * resolution - {Number}
-     *
-     * Returns:
-     * {Object} Object containing properties tilelon, tilelat, tileoffsetlat,
-     * tileoffsetlat, tileoffsetx, tileoffsety
-     */
-    calculateGridLayout: function(bounds, origin, resolution) {
-        var tilelon = resolution * this.tileSize.w;
-        var tilelat = resolution * this.tileSize.h;
-        
-        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 = origin.lon + tilecol * tilelon;
-        
-        var offsetlat = origin.lat - bounds.top + tilelat; 
-        var tilerow = Math.floor(offsetlat/tilelat) - this.buffer;
-        var tilerowremain = tilerow - offsetlat/tilelat;
-        var tileoffsety = tilerowremain * this.tileSize.h;
-        var tileoffsetlat = origin.lat - tilelat*tilerow;
-        
-        return { 
-          tilelon: tilelon, tilelat: tilelat,
-          tileoffsetlon: tileoffsetlon, tileoffsetlat: tileoffsetlat,
-          tileoffsetx: tileoffsetx, tileoffsety: tileoffsety
-        };
-    },
-    
     CLASS_NAME: "OpenLayers.Layer.MapGuide"
 });

lib/OpenLayers/Layer/Zoomify.js

@@ -256,41 +256,5 @@ OpenLayers.Layer.Zoomify = OpenLayers.Class(OpenLayers.Layer.Grid, {
                                                 this.map.maxExtent.top);
     },
 
-    /**
-     * Method: calculateGridLayout
-     * Generate parameters for the grid layout. This
-     *
-     * Parameters:
-     * bounds - {<OpenLayers.Bound>}
-     * origin - {<OpenLayers.LonLat>}
-     * resolution - {Number}
-     *
-     * Returns:
-     * {Object} Object containing properties tilelon, tilelat, tileoffsetlat,
-     * tileoffsetlat, tileoffsetx, tileoffsety
-     */
-    calculateGridLayout: function(bounds, origin, resolution) {
-        var tilelon = resolution * this.tileSize.w;
-        var tilelat = resolution * this.tileSize.h;
-
-        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 = origin.lon + tilecol * tilelon;
-
-        var offsetlat = origin.lat - bounds.top + tilelat;
-        var tilerow = Math.floor(offsetlat/tilelat) - this.buffer;
-        var tilerowremain = tilerow - offsetlat/tilelat;
-        var tileoffsety = tilerowremain * this.tileSize.h;
-        var tileoffsetlat = origin.lat - tilelat*tilerow;
-
-        return {
-          tilelon: tilelon, tilelat: tilelat,
-          tileoffsetlon: tileoffsetlon, tileoffsetlat: tileoffsetlat,
-          tileoffsetx: tileoffsetx, tileoffsety: tileoffsety
-        };
-    },
-
     CLASS_NAME: "OpenLayers.Layer.Zoomify"
 });

tests/Layer/WMS.html

@@ -535,15 +535,27 @@
     }
     
     function test_tileBounds(t) {
-        t.plan(1);
+        // do not defer moveGriddedTiles
+        var isNative = OpenLayers.Animation.isNative;
+        OpenLayers.Animation.isNative = true;
+        t.plan(2);
+        
         var map = new OpenLayers.Map("map", {projection: "EPSG:3857"});
         var layer = new OpenLayers.Layer.WMS("wms", "../../img/blank.gif");
         map.addLayer(layer);
         map.setCenter([0, 0], 1);
         map.pan(2, -100);
         map.zoomIn();
-        t.eq(layer.grid[1][0].bounds, new OpenLayers.Bounds(-10018754.17, 0, 0, 10018754.17), "no floating point errors");
+        t.eq(layer.grid[1][0].bounds, new OpenLayers.Bounds(-10018754.17, 0, 0, 10018754.17), "no floating point errors after zooming");
+        map.zoomTo(14);
+        var bounds = layer.grid[0][0].bounds.clone();
+        map.pan(260, 520);
+        map.pan(-260, -520);
+        t.eq(layer.grid[0][0].bounds, bounds, "no floating point errors after dragging back and forth");
+        console.log(bounds.toString())
+        
         map.destroy();
+        OpenLayers.Animation.isNative = isNative;
     }