Question

我有一张图片，我有图像上各点的坐标值。现在，当在网页上呈现图像时，我必须显示一个大点或任何用户可以在谷歌地图上看到像标记一样的点。

示例 - 假设谷歌地图作为我的图像（但它不是地图，它将是一个家的天花板图像）和地图上的标记作为点。我必须在我的图像上显示标记类型的东西。

如何使用jquery，javascript，css等实现这一目标。

任何帮助表示赞赏。谢谢：）

Answer 1

I got the answer.. :)
check out the fiddle here

HTML

<p>Click on the map to place a marker</p>
<canvas id="Canvas" width="700" height="700"></canvas>

Javascript

var canvas = document.getElementById('Canvas');
var context = canvas.getContext("2d");

// Map sprite
var mapSprite = new Image();
mapSprite.src = "http://www.retrogameguide.com/images/screenshots/snes-legend-of-zelda-link-to-the-past-8.jpg";

var Marker = function () {
    this.Sprite = new Image();
    this.Sprite.src = "http://www.clker.com/cliparts/w/O/e/P/x/i/map-marker-hi.png"
    this.Width = 12;
    this.Height = 20;
    this.XPos = 0;
    this.YPos = 0;
}

var Markers = new Array();

var mouseClicked = function (mouse) {
    // Get corrent mouse coords
    var rect = canvas.getBoundingClientRect();
    var mouseXPos = (mouse.x - rect.left);
    var mouseYPos = (mouse.y - rect.top);

    console.log("Marker added");

    // Move the marker when placed to a better location
    var marker = new Marker();
    marker.XPos = mouseXPos - (marker.Width / 2);
    marker.YPos = mouseYPos - marker.Height;

    Markers.push(marker);
}

// Add mouse click event listener to canvas
canvas.addEventListener("mousedown", mouseClicked, false);

var firstLoad = function () {
    context.font = "15px Georgia";
    context.textAlign = "center";
}

firstLoad();

var main = function () {
    draw();
};

var draw = function () {
    // Clear Canvas
    context.fillStyle = "#000";
    context.fillRect(0, 0, canvas.width, canvas.height);

    // Draw map
    // Sprite, X location, Y location, Image width, Image height
    // You can leave the image height and width off, if you do it will draw the image at default size
    context.drawImage(mapSprite, 0, 0, 700, 700);

    // Draw markers
    for (var i = 0; i < Markers.length; i++) {
        var tempMarker = Markers[i];
        // Draw marker
        context.drawImage(tempMarker.Sprite, tempMarker.XPos, tempMarker.YPos, tempMarker.Width, tempMarker.Height);

        // Calculate postion text
        var markerText = "Postion (X:" + tempMarker.XPos + ", Y:" + tempMarker.YPos;

        // Draw a simple box so you can see the position
        var textMeasurements = context.measureText(markerText);
        context.fillStyle = "#666";
        context.globalAlpha = 0.7;
        context.fillRect(tempMarker.XPos - (textMeasurements.width / 2), tempMarker.YPos - 15, textMeasurements.width, 20);
        context.globalAlpha = 1;

        // Draw position above
        context.fillStyle = "#000";
        context.fillText(markerText, tempMarker.XPos, tempMarker.YPos);
    }
};

setInterval(main, (1000 / 60)); // Refresh 60 times a second

如何根据图像上各点的坐标值在图像上绘制一个点

1 个答案: