diff --git a/src/ol/renderer/canvas/canvastilelayerrenderer.js b/src/ol/renderer/canvas/canvastilelayerrenderer.js
index 4848715c9c..ce334386a7 100644
--- a/src/ol/renderer/canvas/canvastilelayerrenderer.js
+++ b/src/ol/renderer/canvas/canvastilelayerrenderer.js
@@ -168,9 +168,6 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
this.renderedCanvasTileRange_ = null;
}
}
- if (goog.isNull(this.renderedCanvasTileRange_)) {
- context.clearRect(0, 0, canvasWidth, canvasHeight);
- }
}
var canvasTileRange, canvasTileRangeWidth, minX, minY;
@@ -200,6 +197,8 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
*/
var tilesToDrawByZ = {};
tilesToDrawByZ[z] = {};
+ /** @type {Array.
} */
+ var tilesToClear = [];
var getTileIfLoaded = this.createGetTileIfLoadedFunction(function(tile) {
return !goog.isNull(tile) && tile.getState() == ol.TileState.LOADED;
@@ -227,6 +226,9 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
fullyLoaded = tileGrid.forEachTileCoordParentTileRange(
tile.tileCoord, findLoadedTiles, null, tmpTileRange, tmpExtent);
if (!fullyLoaded) {
+ // FIXME we do not need to clear the tile if it is fully covered by its
+ // children
+ tilesToClear.push(tile);
childTileRange = tileGrid.getTileCoordChildTileRange(
tile.tileCoord, tmpTileRange, tmpExtent);
if (!goog.isNull(childTileRange)) {
@@ -237,13 +239,21 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
}
}
+ var i;
+ for (i = 0; i < tilesToClear.length; ++i) {
+ tile = tilesToClear[i];
+ x = tileSize.width * (tile.tileCoord.x - canvasTileRange.minX);
+ y = tileSize.height * (canvasTileRange.maxY - tile.tileCoord.y);
+ context.clearRect(x, y, tileSize.width, tileSize.height);
+ }
+
/** @type {Array.} */
var zs = goog.array.map(goog.object.getKeys(tilesToDrawByZ), Number);
goog.array.sort(zs);
var opaque = tileSource.getOpaque();
var origin = tileGrid.getTileCoordExtent(new ol.TileCoord(
z, canvasTileRange.minX, canvasTileRange.maxY), tmpExtent).getTopLeft();
- var currentZ, i, index, scale, tileCoordKey, tileExtent, tilesToDraw;
+ var currentZ, index, scale, tileCoordKey, tileExtent, tilesToDraw;
var ix, iy, interimTileExtent, interimTileRange, maxX, maxY;
var height, width;
for (i = 0; i < zs.length; ++i) {