Question

查看此url

有“浮动图像”，带有箭头的图像在点击时将地图置于某个位置的中心。我一直在拼命想要找到这样做的方法，而且我已经编写了我的谷歌地图应用程序，只缺少一件事。任何想法？

修改：尝试远离地图中心（这将是红色标记）导航。如果在地图中看不到中心，会出现带箭头的红色标记。这就是我要找的东西：）

Answer 1

它列在Map Basics，“Info Windows”

下

http://code.google.com/apis/maps/documentation/introduction.html#Info_Windows

Answer 2

这是创建“跟踪器”标记的代码。逻辑完全驻留在Pointer对象中。

您可以简单地实例化一个新的Pointer并传递标记和地图。 Pointer会自动显示和隐藏，您无需做任何必要的工作。

我看不到许可信息，但如果我没有弄错，这是基于我过去看过的gmap示例。你用它做什么取决于你。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Marker Tracker Code</title>

    <script src="http://maps.google.com/maps?file=api&amp;v=3"
        type="text/javascript"></script>

    <style type="text/css">
        .map
        {
            height: 450px;
            width: 500px;
        }
    </style>

    <script type="text/javascript">

        var map;

        function load() {
            if (GBrowserIsCompatible()) {

                var latlng = new GLatLng(37.4419, -122.1419);

                map = new GMap2(document.getElementById("map"));
                map.setCenter(latlng, 13);


                // create a marker
                var marker = new GMarker(latlng);
                map.addOverlay(marker);

                // create a tracker for marker
                var tracker = new Pointer(marker, map);
            }
        }


        /*
        Pointer creates an intelligent 'minimarker' that shows with a compass arrow pointing to 
        the marker passed in to the constructor when the parent marker is off screen
        */

        // Creates a Pointer for the given marker and displays it on the map as needed.     
        function Pointer(marker, map) {
            this.map_ = map;
            this.marker_ = marker;
            this.enabled_ = true;
            this.arrowDisplayed_ = false;
            this.arrow_ = null;
            this.oldArrow_ = null;
            this.control_ = null;

            this.iconScale_ = 0.6;
            this.padding_ = 65;
            this.color_ = '#0000ff';
            this.weight_ = 10;
            this.length_ = 10
            this.opacity_ = 0.6
            this.updateEvent_ = 'move';
            this.panEvent_ = 'click';
            this.quickPanEnabled_ = true;

            //replicate a different sized icon 
            var babyIcon = new GIcon(marker.getIcon());
            babyIcon.iconSize = new GSize(
            marker.getIcon().iconSize.width * this.iconScale_,
            marker.getIcon().iconSize.height * this.iconScale_);
            babyIcon.iconAnchor = new GPoint(
            marker.getIcon().iconAnchor.x * this.iconScale_,
            marker.getIcon().iconAnchor.y * this.iconScale_ / 2);
            // kill the shadow
            babyIcon.shadow = null;
            this.babyMarker_ = new GMarker(new GPoint(0, 0), babyIcon);

            //bind the update task to the event trigger
            GEvent.bind(this.map_, this.updateEvent_, this, this.updateArrow_);
            //update the arrow if the marker moves
            GEvent.bind(this.marker_, 'changed', this, this.updateArrow_);
            if (this.quickPanEnabled_) {
                GEvent.bind(this.babyMarker_, this.panEvent_, this, this.panToMarker_);
            }

            //do an inital check
            this.updateArrow_();
        };

        // Disables the pointer.
        Pointer.prototype.disable = function() {
            this.enabled_ = false;
            this.updateArrow_();
        };

        //Enables the pointer.
        Pointer.prototype.enable = function() {
            this.enabled_ = true;
            this.updateArrow_();
        };

        // Called on on the trigger event to update the arrow. Primary function is to
        // check if the parent marker is in view, if not draw the tracking arrow.
        Pointer.prototype.updateArrow_ = function() {
            if (!this.map_.getBounds().containsLatLng(this.marker_.getLatLng()) && this.enabled_) {
                this.drawArrow_();
            } else if (this.arrowDisplayed_) {
                this.hideArrow_();
            }
        };

        //Draws or redraws the arrow as needed, called when the parent marker is
        //not with in the map view.
        Pointer.prototype.drawArrow_ = function() {
            //convert to pixels
            var bounds = this.map_.getBounds();
            var SE = this.map_.fromLatLngToDivPixel(bounds.getSouthWest());
            var NE = this.map_.fromLatLngToDivPixel(bounds.getNorthEast());
            //include the padding while deciding on the arrow location
            var minX = SE.x + this.padding_;
            var minY = NE.y + this.padding_;
            var maxX = NE.x - this.padding_;
            var maxY = SE.y - this.padding_;

            // find the geometric info for the marker realative to the center of the map
            var center = this.map_.fromLatLngToDivPixel(this.map_.getCenter());
            var loc = this.map_.fromLatLngToDivPixel(this.marker_.getLatLng());

            //get the slope of the line
            var m = (center.y - loc.y) / (center.x - loc.x);
            var b = (center.y - m * center.x);

            // end the line within the bounds
            if (loc.x < maxX && loc.x > minX) {
                var x = loc.x;
            } else if (center.x > loc.x) {
                var x = minX;
            } else {
                var x = maxX;
            }

            //calculate y and check boundaries again  
            var y = m * x + b;
            if (y > maxY) {
                y = maxY;
                x = (y - b) / m;
            } else if (y < minY) {
                y = minY;
                x = (y - b) / m;
            }

            // get the proper angle of the arrow
            var ang = Math.atan(-m);
            if (x > center.x) {
                ang = ang + Math.PI;
            }

            // define the point of the arrow
            var arrowLoc = this.map_.fromDivPixelToLatLng(new GPoint(x, y));

            // left side of marker is at -1,1
            var arrowLeft = this.map_.fromDivPixelToLatLng(
            this.getRotatedPoint_(((-1) * this.length_), this.length_, ang, x, y));

            // right side of marker is at -1,-1
            var arrowRight = this.map_.fromDivPixelToLatLng(
            this.getRotatedPoint_(((-1) * this.length_), ((-1) * this.length_), ang, x, y));


            var center = this.map_.getCenter();
            var loc = this.marker_.getLatLng();

            this.oldArrow_ = this.arrow_;
            this.arrow_ = new GPolyline([arrowLeft, arrowLoc, arrowRight],
        this.color_, this.weight_, this.opacity_);
            this.map_.addOverlay(this.arrow_);

            // move the babyMarker to -1,0
            this.babyMarker_.setLatLng(this.map_.fromDivPixelToLatLng(
            this.getRotatedPoint_(((-2) * this.length_), 0, ang, x, y)));

            if (!this.arrowDisplayed_) {
                this.map_.addOverlay(this.babyMarker_);
                this.arrowDisplayed_ = true;
            }
            if (this.oldArrow_) {
                this.map_.removeOverlay(this.oldArrow_);
            }
        };

        //Hides the arrows.
        Pointer.prototype.hideArrow_ = function() {
            this.map_.removeOverlay(this.babyMarker_);
            if (this.arrow_) {
                this.map_.removeOverlay(this.arrow_);
            }
            if (this.oldArrow_) {
                this.map_.removeOverlay(this.oldArrow_);
            }
            this.arrowDisplayed_ = false;
        };

        //Pans the map to the parent marker.
        Pointer.prototype.panToMarker_ = function() {
            this.map_.panTo(this.marker_.getLatLng());
        };

        //This applies a counter-clockwise rotation to any point.
        Pointer.prototype.getRotatedPoint_ = function(x, y, ang, xoffset, yoffset) {
            var newx = y * Math.sin(ang) - x * Math.cos(ang) + xoffset;
            var newy = x * Math.sin(ang) + y * Math.cos(ang) + yoffset;
            var rotatedPoint = new GPoint(newx, newy);
            return (rotatedPoint);
        };        

    </script>

</head>
<body onload="load()" onunload="GUnload()">
    <div>
        <div id="map" class="map">
        </div>
    </div>
</body>
</html>

如何编码：“浮动图像”谷歌地图控制

2 个答案: