From c67ca2660dd61ac8b5dce4336961076674cc4993 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Thu, 21 Jun 2012 19:59:32 +0200
Subject: [PATCH] Partial tile layer renderer.

---
 src/ol/renderer/Composite.js         |  33 +++++++-
 src/ol/renderer/LayerRenderer.js     |  34 +++++++--
 src/ol/renderer/TileLayerRenderer.js | 108 +++++++++++++++++++--------
 3 files changed, 136 insertions(+), 39 deletions(-)

diff --git a/src/ol/renderer/Composite.js b/src/ol/renderer/Composite.js
index 59d3adc491..4bb42c6197 100644
--- a/src/ol/renderer/Composite.js
+++ b/src/ol/renderer/Composite.js
@@ -1,8 +1,10 @@
 goog.provide('ol.renderer.Composite');
 
 goog.require('ol.renderer.MapRenderer');
+goog.require('ol.renderer.LayerRenderer');
 goog.require('ol.layer.Layer');
 goog.require('ol.Loc');
+goog.require('goog.array');
 
 /**
  * @constructor
@@ -14,11 +16,20 @@ ol.renderer.Composite = function(container) {
     goog.base(this, container);
     
     /**
-     * @type Array.<ol.renderer.LayerRenderer>
+     * @type {Array.<ol.renderer.LayerRenderer>}
      * @private
      */
     this.renderers_ = [];
     
+    var target = document.createElement("div");
+    target.className = "ol-renderer-composite";
+
+    /**
+     * @type Element
+     * @private
+     */
+    this.target_ = target;
+    
 };
 
 goog.inherits(ol.renderer.Composite, ol.renderer.MapRenderer);
@@ -30,6 +41,23 @@ goog.inherits(ol.renderer.Composite, ol.renderer.MapRenderer);
  * @param {boolean} animate
  */
 ol.renderer.Composite.prototype.draw = function(layers, center, resolution, animate) {
+    // TODO: deal with layer order and removal
+    for (var i=0, ii=layers.length; i<ii; ++i) {
+        this.getOrCreateRenderer(layers[i], i).draw(center, resolution);
+    }
+};
+
+/**
+ * @param {ol.layer.Layer} layer
+ * @param {number} index
+ */
+ol.renderer.Composite.prototype.getOrCreateRenderer = function(layer, index) {
+    var renderer = this.getRenderer(layer);
+    if (goog.isNull(renderer)) {
+        renderer = this.createRenderer(layer);
+        goog.array.insertAt(this.renderers_, renderer, index);
+    }
+    return renderer;
 };
 
 /**
@@ -46,6 +74,9 @@ ol.renderer.Composite.prototype.getRenderer = function(layer) {
  * @param {ol.layer.Layer} layer
  */
 ol.renderer.Composite.prototype.createRenderer = function(layer) {
+    var Renderer = this.pickRendererType(layer);
+    goog.asserts.assert(Renderer, "No supported renderer for layer: " + layer);
+    return new Renderer(layer, this.target_);
 };
 
 /**
diff --git a/src/ol/renderer/LayerRenderer.js b/src/ol/renderer/LayerRenderer.js
index 0ed2d90382..68699cff8a 100644
--- a/src/ol/renderer/LayerRenderer.js
+++ b/src/ol/renderer/LayerRenderer.js
@@ -3,23 +3,39 @@ goog.provide('ol.renderer.LayerRenderer');
 /**
  * A single layer renderer that will be created by the composite map renderer.
  *
- * @interface
- * @param {Element} target
+ * @constructor
+ * @param {!Element} container
  * @param {!ol.layer.Layer} layer
  */
-ol.renderer.LayerRenderer = function(target, layer) {};
+ol.renderer.LayerRenderer = function(container, layer) {
+    
+    /**
+     * @type {!Element}
+     * @protected
+     */
+    this.container_ = container;
+
+    /**
+     * @type {!ol.layer.Layer}
+     * @protected
+     */
+    this.layer_ = layer;
+    
+};
 
 /**
  * Get layer being rendered.
  *
  * @returns {!ol.layer.Layer}
  */
-ol.renderer.LayerRenderer.prototype.getLayer = function() {};
+ol.renderer.LayerRenderer.prototype.getLayer = function() {
+    return this.layer_;
+};
 
 /**
  * Get an identifying string for this renderer.
  *
- * @returns {string}
+ * @returns {string|undefined}
  */
 ol.renderer.LayerRenderer.prototype.getType = function() {};
 
@@ -28,7 +44,9 @@ ol.renderer.LayerRenderer.prototype.getType = function() {};
  *
  * @returns {boolean}
  */
-ol.renderer.LayerRenderer.isSupported = function() {};
+ol.renderer.LayerRenderer.isSupported = function() {
+    return false;
+};
 
 /**
  * Determine if this renderer is capable of renderering the given layer.
@@ -36,4 +54,6 @@ ol.renderer.LayerRenderer.isSupported = function() {};
  * @param {ol.layer.Layer} layer
  * @returns {boolean}
  */
-ol.renderer.LayerRenderer.canRender = function(layer) {};
+ol.renderer.LayerRenderer.canRender = function(layer) {
+    return false;
+};
diff --git a/src/ol/renderer/TileLayerRenderer.js b/src/ol/renderer/TileLayerRenderer.js
index f55ada4b94..0ea501e38b 100644
--- a/src/ol/renderer/TileLayerRenderer.js
+++ b/src/ol/renderer/TileLayerRenderer.js
@@ -6,37 +6,61 @@ goog.require('ol.renderer.Composite');
 goog.require('ol.TileSet');
 goog.require('ol.Bounds');
 
+goog.require('goog.style');
+
 
 /**
  * A single layer renderer that will be created by the composite map renderer.
  *
  * @constructor
- * @implements {ol.renderer.LayerRenderer}
  * @param {!Element} container
  * @param {!ol.layer.Layer} layer
+ * @extends {ol.renderer.LayerRenderer}
  */
 ol.renderer.TileLayerRenderer = function(container, layer) {
     
-    /** 
-     * @type {!Element} 
-     * @private
-     */
-    this.container_ = container;
-    
-    /** 
-     * @type {!ol.layer.Layer}
-     * @private
-     */
-    this.layer_ = layer;
-    
+    goog.base(this, container, layer);
+
     /**
      * @type {ol.Bounds}
      * @private
      */
-    this.rendererdBounds = null;
+    this.rendererdBounds_ = null;
+
+    /**
+     * @type {number|undefined}
+     * @private
+     */
+    this.renderedResolution_ = undefined;
+    
+    /**
+     * @type {goog.math.Size}
+     * @private
+     */
+    this.containerSize_ = null;
 
 };
 
+goog.inherits(ol.renderer.TileLayerRenderer, ol.renderer.LayerRenderer);
+
+
+
+/**
+ * @return {goog.math.Size}
+ */
+ol.renderer.TileLayerRenderer.prototype.getContainerSize_ = function() {
+    if (goog.isNull(this.containerSize_)) {
+        this.containerSize_ = goog.style.getSize(this.container_);
+    }
+    return this.containerSize_;
+};
+
+/**
+ * Tiles rendered at the current resolution;
+ * @type {Object}
+ */
+ol.renderer.TileLayerRenderer.prototype.renderedTiles_ = {};
+
 /**
  * Render the layer.
  *
@@ -44,17 +68,19 @@ ol.renderer.TileLayerRenderer = function(container, layer) {
  * @param {number} resolution
  */
 ol.renderer.TileLayerRenderer.prototype.draw = function(center, resolution) {
-    var mapSize = goog.style.getSize(this.container_);
+    if (resolution !== this.renderedResolution_) {
+        this.renderedTiles_ = {};
+    }
+    var mapSize = this.getContainerSize_();
     var halfMapWidth = (resolution * mapSize.width) / 2;
     var halfMapHeight = (resolution * mapSize.height) / 2;
     var x = center.getX();
     var y = center.getY();
     var mapMinX = x - halfMapWidth;
     var mapMaxY = y + halfMapHeight;
+    var projection = center.getProjection();
     var bounds = new ol.Bounds(
-        mapMinX, y - halfMapHeight, x + halfMapWidth, mapMaxY,
-        center.getProjection()
-    );
+        mapMinX, y - halfMapHeight, x + halfMapWidth, mapMaxY, projection);
     var tileSet = this.layer_.getData(bounds, resolution);
     var tiles = tileSet.getTiles();
     var rows = tiles.length;
@@ -66,35 +92,55 @@ ol.renderer.TileLayerRenderer.prototype.draw = function(center, resolution) {
         // TODO: implement ol.TileSet#getBounds
         var firstBounds = first.getBounds();
         var tileMinX = firstBounds.getMinX();
+        var tileMaxX = tileMinX;
         var tileMaxY = firstBounds.getMaxY();
+        var tileMinY = tileMaxY;
         var pxOriginX = (tileMinX - mapMinX) / resolution;
         var pxOriginY = (mapMaxY - tileMaxY) / resolution;
-        var tileHeight = tileSet.getTileHeight();
-        var tileWidth = tileSet.getTileWidth();
+        var pxTileHeight = tileSet.getTileHeight();
+        var pxTileWidth = tileSet.getTileWidth();
+        var tileHeight = tileResolution * pxTileHeight;
+        var tileWidth = tileResolution * pxTileWidth;
         var fragment = document.createDocumentFragment();
         var tile, img;
-        for (var j=0, tileTop=pxOriginY; j<rows; ++j, tileTop+=tileHeight) {
-            for (var i=0, tileLeft=pxOriginX; i<cols; ++i, tileLeft+=tileWidth) {
+        for (var j=0, pxTileTop=pxOriginY; j<rows; ++j, pxTileTop+=pxTileHeight) {
+            tileMinY -= tileHeight;
+            for (var i=0, pxTileLeft=pxOriginX; i<cols; ++i, pxTileLeft+=pxTileWidth) {
+                tileMaxX += tileWidth;
                 tile = tiles[j][i];
                 img = tile.getImg();
                 // TODO: scale is almost always 1, set size on the archetype img
-                img.style.height = Math.round(tileHeight * scale) + "px";
-                img.style.width = Math.round(tileWidth * scale) + "px";
-                img.style.top = tileTop + "px";
-                img.style.left = tileLeft + "px";
+                img.style.height = Math.round(pxTileHeight * scale) + "px";
+                img.style.width = Math.round(pxTileWidth * scale) + "px";
+                img.style.top = pxTileTop + "px";
+                img.style.left = pxTileLeft + "px";
                 tile.load();
+                this.renderedTiles_[tile.getUrl()] = tile;
                 fragment.appendChild(img);
             }
         }
+        var renderedBounds =  new ol.Bounds(
+            tileMinX, tileMinY, tileMaxX, tileMaxY, projection);
+        this.pruneUnrenderedTiles_(renderedBounds);
+        this.renderedBounds_ = renderedBounds;
+        this.renderedResolution_ = resolution;
         this.container_.appendChild(fragment);
     }
 };
 
-/** @inheritDoc */
-ol.renderer.TileLayerRenderer.prototype.getLayer = function() {
-    return this.layer_;
+/**
+ * Get rid of tiles outside the newly rendered extent.
+ *
+ * @param {ol.Bounds} newBounds Newly rendered bounds.
+ * @private
+ */
+ol.renderer.TileLayerRenderer.prototype.pruneUnrenderedTiles_ = function(newBounds) {
+    for (var url in this.renderedTiles_) {
+        var tile = this.renderedTiles_[url];
+    }
 };
 
+
 /** @inheritDoc */
 ol.renderer.TileLayerRenderer.prototype.getType = function() {
     // TODO: revisit
@@ -104,7 +150,7 @@ ol.renderer.TileLayerRenderer.prototype.getType = function() {
 /** 
  * Determine if this renderer type is supported in this environment.
  *
- * @returns {boolean} This renderer is supported.
+ * @return {boolean} This renderer is supported.
  */
 ol.renderer.TileLayerRenderer.isSupported = function() {
     return true;
@@ -114,7 +160,7 @@ ol.renderer.TileLayerRenderer.isSupported = function() {
  * Determine if this renderer can render the given layer.
  *
  * @param {ol.layer.Layer} layer The candidate layer.
- * @returns {boolean} This renderer is capable of rendering the layer.
+ * @return {boolean} This renderer is capable of rendering the layer.
  */
 ol.renderer.TileLayerRenderer.canRender = function(layer) {
     return layer instanceof ol.layer.TileLayer;