ios 百度地图根据路径规划自动缩放，显示完整路线

//根据polyline设置地图范围

- (void)mapViewFitPolyLine:(BMKPolyline *) polyLine {

CGFloat ltX, ltY, rbX, rbY;

if (polyLine.pointCount <1) {

return;

}

BMKMapPoint pt = polyLine.points[0];

ltX = pt.x, ltY = pt.y;

rbX = pt.x, rbY = pt.y;

for (int i =1; i < polyLine.pointCount; i++) {

BMKMapPoint pt = polyLine.points[i];

if (pt.x < ltX) {

ltX = pt.x;

}

if (pt.x > rbX) {

rbX = pt.x;

}

if (pt.y > ltY) {

ltY = pt.y;

}

if (pt.y < rbY) {

rbY = pt.y;

}

}

// BMKMapRect rect;

//

// rect.origin = BMKMapPointMake(ltX , ltY);

// rect.size = BMKMapSizeMake(rbX - ltX, rbY - ltY);

// [_mapView setVisibleMapRect:rect];

_mapView.zoomLevel =_mapView.zoomLevel;

}