From 3c305db4a44bca70d19ed465fc2895353a79278c Mon Sep 17 00:00:00 2001
From: ahocevar <andreas.hocevar@gmail.com>
Date: Fri, 4 Jan 2013 18:47:33 +0100
Subject: [PATCH] Canvas tile renderer - first cut

Untested and no styling
---
 src/ol/renderer/canvas/canvastilerenderer.js | 174 +++++++++++++++++++
 1 file changed, 174 insertions(+)
 create mode 100644 src/ol/renderer/canvas/canvastilerenderer.js

diff --git a/src/ol/renderer/canvas/canvastilerenderer.js b/src/ol/renderer/canvas/canvastilerenderer.js
new file mode 100644
index 0000000000..7055d122be
--- /dev/null
+++ b/src/ol/renderer/canvas/canvastilerenderer.js
@@ -0,0 +1,174 @@
+goog.provide('ol.renderer.tile.Canvas');
+
+goog.require('goog.style');
+goog.require('ol.Coordinate');
+goog.require('ol.Pixel');
+goog.require('ol.Projection');
+
+
+
+ol.renderer.tile.Canvas = function(layerRenderer) {
+  
+  this.layerRenderer_ = layerRenderer;
+
+  /**
+   * @type {ol.Projection}
+   * @private
+   */
+  this.projection_;
+  
+  /**
+   * @type {number}
+   * @private
+   */
+  this.resolution_;
+
+  /**
+   * @type {ol.Coordinate}
+   * @private
+   */
+  this.origin_ = new ol.Coordinate(0, 0);
+  
+  /**
+   * @type {ol.Pixel}
+   * @private
+   */
+  this.originPixel_;
+
+  /**
+   * @type {Object|ol.Size}
+   * @private
+   */
+  this.size_;
+  
+  /**
+   * @type {CanvasContext}
+   * @private
+   */
+  this.context_;
+  
+  /**
+   * @type {CanvasImageData}
+   * @private
+   */
+  this.pixelData_;
+
+};
+
+/**
+ * @param size {Object|ol.Size}
+ */
+ol.renderer.tile.Canvas.prototype.setSize = function(size) {
+  if (!(size instanceof ol.Size)) {
+    size = new ol.Size(size.width, size.height);
+  }
+  this.size_ = size;
+  if (!this.context_) {
+    this.context_ = document.createElement('canvas').getContext('2d');
+    this.pixelData_ = this.context_.createImageData(1,1).data;
+    this.pixelData[3] = 1; // opacity
+  }
+  goog.style.setSize(this.canvas_, size);
+};
+
+/**
+ * @param size {Object|ol.Coordinate}
+ */
+ol.renderer.tile.Canvas.prototype.setOrigin = function(origin) {
+  if (!(origin instanceof ol.Coordinate)) {
+    origin = new ol.Coordinate(origin.x, origin.y);
+  }
+  this.origin_ = origin;
+  this.originPixel_ = this.layerRenderer_.getPixelFromCoordinate(origin);
+};
+
+/**
+ * @param resolution {number}
+ */
+ol.renderer.tile.Canvas.prototype.setResolution = function(resolution) {
+  this.resolution_ = resolution;
+};
+
+/*
+ * @param geoJson {Object|Array} GeoJSON or an array of GeoJSON features 
+ * @param projection {ol.Projection=}
+ */
+ol.renderer.tile.Canvas.prototype.render = function(geoJson, projection) {
+  var map = this.map;
+  this.projection_ = map.getProjection();
+  this.resolution_ = map.getResolution();
+  
+  var features;
+  if (goog.isArray(geoJson)) {
+    features = geoJson;
+  } else if (geoJson.type === 'FeatureCollection') {
+    features = geoJson.features;
+  } else if (geoJson.type === 'Feature') {
+    features = [geoJson];
+  }
+  
+  if (features) {
+    //FIXME Support geometry level projections
+    projection = projection || new ol.Projection('EPSG:4326');
+    if (!(projection instanceof ol.Projection)) {
+      projection = new ol.Projection(projection);
+    }
+    for (var i=0, ii=features.length; i<ii; ++i) {
+      this.renderGeometry(features[i].geometry, projection);
+    }
+  }
+};
+
+ol.renderer.tile.Canvas.prototype.renderGeometry =
+    function(geometry, projection) {
+  var i, coordinates, hole = false;
+  if (geometry.type === 'Point') {
+    this.renderPosList([geometry.coordinates], projection, false, false, hole);
+  } else if (geometry.type === 'MultiPoint') {
+    this.renderPosList(geometry.coordinates, projection, false, false, hole);
+  } else if (geometry.type === 'LineString') {
+    this.renderPosList(geometry.coordinates, projection, true, false, hole);
+  } else if (geometry.type === 'MultiLineString') {
+    coordinates = geometry.coordinates;
+    for (i=0, ii=coordinates.length; i<ii; ++i) {
+      this.renderPosList(coordinates[i], projection, true, false, hole);
+    }
+  } else if (geometry.type === 'Polygon') {
+    coordinates = geometry.coordinates;
+    for (i=0, ii=coordinates.length; i<ii; ++i) {
+      this.renderPosList(coordinates[i], projection, true, true, hole);
+      hole = true;
+    }
+  }
+};
+
+ol.renderer.tileCanvas.prototype.renderPosList =
+    function(posList, projection, connect, fill, hole) {
+  var position, coordinate, pixel, localX, localY;
+  if (connect === true) {
+    this.context_.beginPath();
+  }
+  for (i=0, ii=posList.length; i<ii; ++i) {
+    position = posList[i];
+    coordinate = ol.Projection.transform(new ol.Coordinate(
+        position[0], position[1]), projection, this.projection);
+    pixel = this.layerRenderer_.getPixelFromCoordinate(coordinate);
+    localX = pixel.x - this.originPixel_.x;
+    localY = pixel.y - this.originPixel_.y + this.size_.height;
+    if (connect === false && fill === false) {
+      //FIXME Draw more than just a black pixel for points
+      this.context_.putImageData(this.pixelData_, localX, localY);
+    } else {
+      this.context_[i === 0 ? 'moveTo' : 'pathTo'](localX, localY);
+    }
+  }
+  if (connect === true) {
+    this.context_.closePath();
+    this.context_.stroke();
+  }
+  if (fill === true) {
+    //FIXME deal with holes
+    this.context_.fill();
+  }
+  
+};