Google Maps Advanced Drawing

<!DOCTYPE html>
<html>
    <head>
        <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
        <meta charset="UTF-8">
        <title>Drawing Tools</title>
        <script type="text/javascript"
        src="https://maps.google.com/maps/api/js?sensor=false&libraries=drawing"></script>
        <style type="text/css">
            #map, html, body {
                padding: 0;
                margin: 0;
                width: 960px;
                height: 700px;
            }

#panel {
                width: 200px;
                font-family: Arial, sans-serif;
                font-size: 13px;
                float: right;
                margin: 10px;
            }

#color-palette {
                clear: both;
            }

.color-button {
                width: 14px;
                height: 14px;
                font-size: 0;
                margin: 2px;
                float: left;
                cursor: pointer;
            }

#delete-button {
                margin-top: 5px;
            }
        </style>
        <script type="text/javascript">
            var drawingManager;
            var selectedShape;
            var colors = ['#1E90FF', '#FF1493', '#32CD32', '#FF8C00', '#4B0082'];
            var selectedColor;
            var colorButtons = {};

function clearSelection () {
                if (selectedShape) {
                    if (selectedShape.type !== 'marker') {
                        selectedShape.setEditable(false);
                    }
                    
                    selectedShape = null;
                }
            }

function setSelection (shape) {
                if (shape.type !== 'marker') {
                    clearSelection();
                    shape.setEditable(true);
                    selectColor(shape.get('fillColor') || shape.get('strokeColor'));
                }
                
                selectedShape = shape;
            }

function deleteSelectedShape () {
                if (selectedShape) {
                    selectedShape.setMap(null);
                }
            }

function selectColor (color) {
                selectedColor = color;
                for (var i = 0; i < colors.length; ++i) {
                    var currColor = colors[i];
                    colorButtons[currColor].style.border = currColor == color ? '2px solid #789' : '2px solid #fff';
                }

// Retrieves the current options from the drawing manager and replaces the
                // stroke or fill color as appropriate.
                var polylineOptions = drawingManager.get('polylineOptions');
                polylineOptions.strokeColor = color;
                drawingManager.set('polylineOptions', polylineOptions);

var rectangleOptions = drawingManager.get('rectangleOptions');
                rectangleOptions.fillColor = color;
                drawingManager.set('rectangleOptions', rectangleOptions);

var circleOptions = drawingManager.get('circleOptions');
                circleOptions.fillColor = color;
                drawingManager.set('circleOptions', circleOptions);

var polygonOptions = drawingManager.get('polygonOptions');
                polygonOptions.fillColor = color;
                drawingManager.set('polygonOptions', polygonOptions);
            }

function setSelectedShapeColor (color) {
                if (selectedShape) {
                    if (selectedShape.type == google.maps.drawing.OverlayType.POLYLINE) {
                        selectedShape.set('strokeColor', color);
                    } else {
                        selectedShape.set('fillColor', color);
                    }
                }
            }

function makeColorButton (color) {
                var button = document.createElement('span');
                button.className = 'color-button';
                button.style.backgroundColor = color;
                google.maps.event.addDomListener(button, 'click', function () {
                    selectColor(color);
                    setSelectedShapeColor(color);
                });

return button;
            }

function buildColorPalette () {
                var colorPalette = document.getElementById('color-palette');
                for (var i = 0; i < colors.length; ++i) {
                    var currColor = colors[i];
                    var colorButton = makeColorButton(currColor);
                    colorPalette.appendChild(colorButton);
                    colorButtons[currColor] = colorButton;
                }
                selectColor(colors[0]);
            }

function initialize () {
                var map = new google.maps.Map(document.getElementById('map'), {
                    zoom: 16,
                    center: new google.maps.LatLng(52.25097, 20.97114),
                    mapTypeId: google.maps.MapTypeId.SATELLITE,
                    disableDefaultUI: true,
                    zoomControl: true
                });

var polyOptions = {
                    strokeWeight: 0,
                    fillOpacity: 0.45,
                    editable: true,
                    draggable: true
                };
                // Creates a drawing manager attached to the map that allows the user to draw
                // markers, lines, and shapes.
                drawingManager = new google.maps.drawing.DrawingManager({
                    drawingMode: google.maps.drawing.OverlayType.POLYGON,
                    markerOptions: {
                        draggable: true
                    },
                    polylineOptions: {
                        editable: true,
                        draggable: true
                    },
                    rectangleOptions: polyOptions,
                    circleOptions: polyOptions,
                    polygonOptions: polyOptions,
                    map: map
                });

google.maps.event.addListener(drawingManager, 'overlaycomplete', function (e) {
                    var newShape = e.overlay;
                    
                    newShape.type = e.type;
                    
                    if (e.type !== google.maps.drawing.OverlayType.MARKER) {
                        // Switch back to non-drawing mode after drawing a shape.
                        drawingManager.setDrawingMode(null);

// Add an event listener that selects the newly-drawn shape when the user
                        // mouses down on it.
                        google.maps.event.addListener(newShape, 'click', function (e) {
                            if (e.vertex !== undefined) {
                                if (newShape.type === google.maps.drawing.OverlayType.POLYGON) {
                                    var path = newShape.getPaths().getAt(e.path);
                                    path.removeAt(e.vertex);
                                    if (path.length < 3) {
                                        newShape.setMap(null);
                                    }
                                }
                                if (newShape.type === google.maps.drawing.OverlayType.POLYLINE) {
                                    var path = newShape.getPath();
                                    path.removeAt(e.vertex);
                                    if (path.length < 2) {
                                        newShape.setMap(null);
                                    }
                                }
                            }
                            setSelection(newShape);
                        });
                        setSelection(newShape);
                    }
                    else {
                        google.maps.event.addListener(newShape, 'click', function (e) {
                            setSelection(newShape);
                        });
                        setSelection(newShape);
                    }
                });

// Clear the current selection when the drawing mode is changed, or when the
                // map is clicked.
                google.maps.event.addListener(drawingManager, 'drawingmode_changed', clearSelection);
                google.maps.event.addListener(map, 'click', clearSelection);
                google.maps.event.addDomListener(document.getElementById('delete-button'), 'click', deleteSelectedShape);

buildColorPalette();
            }
            google.maps.event.addDomListener(window, 'load', initialize);
        </script>
    </head>
    <body>
        <div id="panel">
            <div id="color-palette"></div>
            <div>
                <button id="delete-button">Delete Selected Shape</button>
            </div>
        </div>
        <div id="map"></div>
    </body>
</html>