/**
* This method draws the line. Note - highly optimized to handle long paths, proceed with care.
* Should be fine up to 10K points.
*/
@Override
protected void draw(final Canvas canvas, final MapView mapView, final boolean shadow) {
if (shadow) {
return;
}
if (this.mPoints.size() < 2) {
// nothing to paint
return;
}
final Projection pj = mapView.getProjection();
// precompute new points to the intermediate projection.
final int size = this.mPoints.size();
while (this.mPointsPrecomputed < size) {
final Point pt = this.mPoints.get(this.mPointsPrecomputed);
pj.toMapPixelsProjected(pt.x, pt.y, pt);
this.mPointsPrecomputed++;
}
Point screenPoint0 = null; // points on screen
Point screenPoint1 = null;
Point projectedPoint0; // points from the points list
Point projectedPoint1;
// clipping rectangle in the intermediate projection, to avoid performing projection.
final Rect clipBounds = pj.fromPixelsToProjected(pj.getScreenRect());
mPath.rewind();
projectedPoint0 = this.mPoints.get(size - 1);
mLineBounds.set(projectedPoint0.x, projectedPoint0.y, projectedPoint0.x, projectedPoint0.y);
for (int i = size - 2; i >= 0; i--) {
// compute next points
projectedPoint1 = this.mPoints.get(i);
mLineBounds.union(projectedPoint1.x, projectedPoint1.y);
if (!Rect.intersects(clipBounds, mLineBounds)) {
// skip this line, move to next point
projectedPoint0 = projectedPoint1;
screenPoint0 = null;
continue;
}
// the starting point may be not calculated, because previous segment was out of clip
// bounds
if (screenPoint0 == null) {
screenPoint0 = pj.toMapPixelsTranslated(projectedPoint0, this.mTempPoint1);
mPath.moveTo(screenPoint0.x, screenPoint0.y);
}
screenPoint1 = pj.toMapPixelsTranslated(projectedPoint1, this.mTempPoint2);
// skip this point, too close to previous point
if (Math.abs(screenPoint1.x - screenPoint0.x) + Math.abs(screenPoint1.y - screenPoint0.y)
<= 1) {
continue;
}
mPath.lineTo(screenPoint1.x, screenPoint1.y);
// update starting point to next position
projectedPoint0 = projectedPoint1;
screenPoint0.x = screenPoint1.x;
screenPoint0.y = screenPoint1.y;
mLineBounds.set(projectedPoint0.x, projectedPoint0.y, projectedPoint0.x, projectedPoint0.y);
}
canvas.drawPath(mPath, this.mPaint);
}
