Correctly size Layer.Grid and Layer.KaMap in rows/cols for all values of Grid.buffer.

Closes bug #928. Thanks a mil to bartvde for identifying the solution.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@4317 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Grid.js

@@ -306,10 +306,13 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
     initGriddedTiles:function(bounds) {
         
         // work out mininum number of rows and columns; this is the number of
-        // tiles required to cover the viewport plus one for panning
+        // tiles required to cover the viewport plus at least one for panning
+
         var viewSize = this.map.getSize();
-        var minRows = Math.ceil(viewSize.h/this.tileSize.h) + 1;
+        var minRows = Math.ceil(viewSize.h/this.tileSize.h) + 
-        var minCols = Math.ceil(viewSize.w/this.tileSize.w) + 1;
+                      Math.max(1, 2 * this.buffer);
+        var minCols = Math.ceil(viewSize.w/this.tileSize.w) +
+                      Math.max(1, 2 * this.buffer);
         
         var extent = this.map.getMaxExtent();
         var resolution = this.map.getResolution();
@@ -528,7 +531,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      * bounds - {<OpenLayers.Bounds>}
      */
     moveGriddedTiles: function(bounds) {
-        var buffer = (this.buffer) ? this.buffer*1.5 : 1;
+        var buffer = this.buffer || 1;
         while (true) {
             var tlLayer = this.grid[0][0].position;
             var tlViewPort = 

lib/OpenLayers/Layer/KaMap.js

@@ -114,23 +114,25 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
     /**
      * Method: initGriddedTiles
      */    
-    initGriddedTiles:function() {
+    initGriddedTiles:function(bounds) {
 
         var viewSize = this.map.getSize();
-        var bounds = this.map.getExtent();
+        var minRows = Math.ceil(viewSize.h/this.tileSize.h) + Math.max(1, 2*this.buffer);
+        var minCols = Math.ceil(viewSize.w/this.tileSize.w) + Math.max(1, 2*this.buffer);
+        
         var extent = this.map.getMaxExtent();
         var resolution = this.map.getResolution();
         var tilelon = resolution*this.tileSize.w;
         var tilelat = resolution*this.tileSize.h;
         
         var offsetlon = bounds.left;
-        var tilecol = Math.floor(offsetlon/tilelon);
+        var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
         var tilecolremain = offsetlon/tilelon - tilecol;
         var tileoffsetx = -tilecolremain * this.tileSize.w;
         var tileoffsetlon = tilecol * tilelon;
         
         var offsetlat = bounds.top;  
-        var tilerow = Math.ceil(offsetlat/tilelat);
+        var tilerow = Math.ceil(offsetlat/tilelat) + this.buffer;
         var tilerowremain = tilerow - offsetlat/tilelat;
         var tileoffsety = -(tilerowremain+1) * this.tileSize.h;
         var tileoffsetlat = tilerow * tilelat;
@@ -146,9 +148,7 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
         var rowidx = 0;
         
         do {
-            var row;
+            var row = this.grid[rowidx++];
-            
-            row = this.grid[rowidx++];
             if (!row) {
                 row = [];
                 this.grid.push(row);
@@ -160,10 +160,11 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
             var colidx = 0;
  
             do {
-                var tileBounds = new OpenLayers.Bounds(tileoffsetlon, 
+                var tileBounds = 
-                                                      tileoffsetlat, 
+                    new OpenLayers.Bounds(tileoffsetlon, 
-                                                      tileoffsetlon + tilelon,
+                                          tileoffsetlat, 
-                                                      tileoffsetlat + tilelat);
+                                          tileoffsetlon + tilelon,
+                                          tileoffsetlat + tilelat);
 
                 var x = tileoffsetx;
                 x -= parseInt(this.map.layerContainerDiv.style.left);
@@ -172,11 +173,10 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
                 y -= parseInt(this.map.layerContainerDiv.style.top);
 
                 var px = new OpenLayers.Pixel(x, y);
-                var tile;
+                var tile = row[colidx++];
-                
-                tile = row[colidx++];
                 if (!tile) {
                     tile = this.addTile(tileBounds, px);
+                    this.addTileMonitoringHooks(tile); 
                     row.push(tile);
                 } else {
                     tile.moveTo(tileBounds, px, false);
@@ -184,12 +184,18 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
      
                 tileoffsetlon += tilelon;       
                 tileoffsetx += this.tileSize.w;
-            } while (tileoffsetlon <= bounds.right + tilelon * this.buffer)  
+            } while (tileoffsetlon <= bounds.right + tilelon * this.buffer
+                     || colidx < minCols)
             
             tileoffsetlat -= tilelat;
             tileoffsety += this.tileSize.h;
-        } while(tileoffsetlat >= bounds.bottom - tilelat * this.buffer)
+        } while(tileoffsetlat >= bounds.bottom - tilelat * this.buffer
+                || rowidx < minRows)
         
+        //shave off exceess rows and colums
+        this.removeExcessTiles(rowidx, colidx);
+        
+        //now actually draw the tiles
         this.spiralTileLoad();
 
     },

tests/Layer/test_Grid.html

@@ -547,6 +547,41 @@
         t.eq(bounds.toBBOX(), "0,-90,180,90", "get tile bounds returns correct bounds after pan"); 
     }
 
+    function test_Layer_Grid_moveTo_buffer_calculation (t) {
+        t.plan(6);
+
+        var map = new OpenLayers.Map( 'map3' ); // odd map size
+        var layer0 = new OpenLayers.Layer.WMS( "0 buffer: OpenLayers WMS", 
+                    "http://labs.metacarta.com/wms/vmap0",
+                    {layers: 'basic'}, {'buffer':0} );
+        map.addLayer(layer0);
+
+        var layer1 = new OpenLayers.Layer.WMS( "1 buffer: OpenLayers WMS", 
+                "http://labs.metacarta.com/wms/vmap0",
+                {layers: 'basic'}, {'buffer':1} );
+        map.addLayer(layer1);
+
+        var layer2 = new OpenLayers.Layer.WMS( "2 buffer: OpenLayers WMS", 
+                "http://labs.metacarta.com/wms/vmap0",
+                {layers: 'basic'}, {'buffer':2} );
+        map.addLayer(layer2);
+
+        map.setCenter(new OpenLayers.LonLat(0, 0), 4); 
+        t.eq( layer0.grid.length, 3, "Grid rows with buffer:0" );
+        map.setBaseLayer(layer1);
+        t.eq( layer1.grid.length, 4, "Grid rows with buffer:1" );
+        map.setBaseLayer(layer2);
+        t.eq( layer2.grid.length, 6, "Grid rows with buffer:2" );
+
+        // zooming in on Greenland exercises the bug from pre-r4313
+        map.setCenter(new OpenLayers.LonLat(0, 90), 4); 
+        t.eq( layer0.grid.length, 3, "Grid rows with buffer:0" );
+        map.setBaseLayer(layer1);
+        t.eq( layer1.grid.length, 4, "Grid rows with buffer:1" );
+        map.setBaseLayer(layer2);
+        t.eq( layer2.grid.length, 6, "Grid rows with buffer:2" );
+    }
+
     function test_99_Layer_Grid_destroy (t) {
 
         t.plan( 5 );
@@ -582,5 +617,6 @@
 <body>
 <div id="map" style="width:499px;height:549px;display:none"></div>
 <div id="map2" style="width:500px;height:550px;display:none"></div>
+<div id="map3" style="width:594px;height:464px;display:none"></div>
 </body>
 </html>

tests/Layer/test_KaMap.html

@@ -23,6 +23,40 @@
         t.ok( layer instanceof OpenLayers.Layer.KaMap, "returns OpenLayers.Layer.KaMap object" );
     }
 
+    function test_Layer_Grid_moveTo_buffer_calculation (t) {
+        t.plan(6);
+
+        var map = new OpenLayers.Map( 'map3' ); // odd map size
+        var layer0 = new OpenLayers.Layer.KaMap( "0 buffer: OpenLayers WMS", 
+                    "http://labs.metacarta.com/wms/vmap0",
+                    {layers: 'basic'}, {'buffer':0} );
+        map.addLayer(layer0);
+
+        var layer1 = new OpenLayers.Layer.KaMap( "1 buffer: OpenLayers WMS", 
+                "http://labs.metacarta.com/wms/vmap0",
+                {layers: 'basic'}, {'buffer':1} );
+        map.addLayer(layer1);
+
+        var layer2 = new OpenLayers.Layer.KaMap( "2 buffer: OpenLayers WMS", 
+                "http://labs.metacarta.com/wms/vmap0",
+                {layers: 'basic'}, {'buffer':2} );
+        map.addLayer(layer2);
+
+        map.setCenter(new OpenLayers.LonLat(0, 0), 4); 
+        t.eq( layer0.grid.length, 3, "Grid rows with buffer:0" );
+        map.setBaseLayer(layer1);
+        t.eq( layer1.grid.length, 4, "Grid rows with buffer:1" );
+        map.setBaseLayer(layer2);
+        t.eq( layer2.grid.length, 6, "Grid rows with buffer:2" );
+
+        // zooming in on Greenland exercises the bug from pre-r4313
+        map.setCenter(new OpenLayers.LonLat(0, 90), 4); 
+        t.eq( layer0.grid.length, 3, "Grid rows with buffer:0" );
+        map.setBaseLayer(layer1);
+        t.eq( layer1.grid.length, 4, "Grid rows with buffer:1" );
+        map.setBaseLayer(layer2);
+        t.eq( layer2.grid.length, 6, "Grid rows with buffer:2" );
+    }
 
     function test_02_Layer_KaMap_inittiles (t) {
         t.plan( 2 );
@@ -30,8 +64,8 @@
         layer = new OpenLayers.Layer.KaMap(name, url, params, units);
         map.addLayer(layer);
         map.setCenter(new OpenLayers.LonLat(0,0),5);
-        t.eq( layer.grid.length, 6, "KaMap rows is correct." );
+        t.eq( layer.grid.length, 8, "KaMap rows is correct." );
-        t.eq( layer.grid[0].length, 4, "KaMap cols is correct." );
+        t.eq( layer.grid[0].length, 6, "KaMap cols is correct." );
         
     }
 
@@ -237,5 +271,7 @@
 </head>
 <body>
 <div id="map" style="width:500px;height:550px;display:none"></div>
+<div id="map2" style="width:500px;height:550px;display:none"></div>
+<div id="map3" style="width:594px;height:464px;display:none"></div>
 </body>
 </html>