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Skip coordinates that don't affect the rendered extent

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Segments that intersect the replay group's extent are drawn.  Any segment that represents a change in coordinate-extent relationship is drawn.  This maintains the left/right relationship (or cross product) between points in the rendered extent and every rendered segment.

Still left undone: clip the replay group's rendering to the max extent.
This commit is contained in:
Tim Schaub
2014-02-24 16:58:55 -07:00
parent 6b018bbaf9
commit 50822a4d58
1 changed files with 31 additions and 4 deletions
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35
src/ol/render/canvas/canvasreplay.js
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@@ -14,6 +14,7 @@ goog.require('ol.BrowserFeature');
goog.require('ol.array');
goog.require('ol.color');
goog.require('ol.extent');
goog.require('ol.extent.Relationship');
goog.require('ol.geom.flat');
goog.require('ol.geom.simplify');
goog.require('ol.render.IReplayGroup');
@@ -133,12 +134,38 @@ ol.render.canvas.Replay = function(tolerance, maxExtent) {
*/
ol.render.canvas.Replay.prototype.appendFlatCoordinates =
function(flatCoordinates, offset, end, stride, close) {
var myEnd = this.coordinates.length;
var i;
for (i = offset; i < end; i += stride) {
this.coordinates[myEnd++] = flatCoordinates[i];
this.coordinates[myEnd++] = flatCoordinates[i + 1];
var extent = this.maxExtent;
var lastCoord = [flatCoordinates[offset], flatCoordinates[offset + 1]];
var nextCoord = [NaN, NaN];
var skipped = true;
var i, lastRel, nextRel;
for (i = offset + stride; i < end; i += stride) {
nextCoord[0] = flatCoordinates[i];
nextCoord[1] = flatCoordinates[i + 1];
nextRel = ol.extent.coordinateRelationship(extent, nextCoord);
if (nextRel !== lastRel) {
if (skipped) {
this.coordinates[myEnd++] = lastCoord[0];
this.coordinates[myEnd++] = lastCoord[1];
}
this.coordinates[myEnd++] = nextCoord[0];
this.coordinates[myEnd++] = nextCoord[1];
skipped = false;
} else if (nextRel === ol.extent.Relationship.INTERSECTING) {
this.coordinates[myEnd++] = nextCoord[0];
this.coordinates[myEnd++] = nextCoord[1];
skipped = false;
} else {
skipped = true;
}
lastCoord[0] = nextCoord[0];
lastCoord[1] = nextCoord[1];
lastRel = nextRel;
}
if (close) {
this.coordinates[myEnd++] = flatCoordinates[offset];
this.coordinates[myEnd++] = flatCoordinates[offset + 1];