Echars保存图片

1.用ECharts配置项手册中的toolbox.feature.saveAsImage

toolbox: {

　　show: true,

　　feature: {

　　　　saveAsImage: {

　　　　show:true,

　　　　excludeComponents :['toolbox'],

　　　　pixelRatio: 2

　　　　}
　　}
}

这一段一定要写在option中，这样会在图形右上角产生一个保存为图片的标识，点击即可下载图片。

2.用ECharts实例方法getDataURL

myChart.setOption(option);
var picInfo = myChart.getDataURL();

 图片处理类：

public class ImageClass
    {
        public Image ResourceImage;
        private int ImageWidth;
        private int ImageHeight;
        public string ErrMessage;
        /// <summary>     
        /// 类的构造函数     
        /// </summary>     
        /// <param name="ImageFileName">图片文件的全路径名称</param>     
        public ImageClass(string ImageFileName)
        {
            ResourceImage = Image.FromFile(ImageFileName);
            ErrMessage = "";
        }
        public bool ThumbnailCallback()
        {
            return false;
        }
        /// <summary>     
        /// 生成缩略图重载方法1，返回缩略图的Image对象     
        /// </summary>     
        /// <param name="Width">缩略图的宽度</param>     
        /// <param name="Height">缩略图的高度</param>     
        /// <returns>缩略图的Image对象</returns>     
        public Image GetReducedImage(int Width, int Height)
        {
            try
            {
                Image ReducedImage;

                Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

                ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);

                return ReducedImage;
            }
            catch (Exception e)
            {
                ErrMessage = e.Message;
                return null;
            }
        }
        /// <summary>     
        /// 生成缩略图重载方法2，将缩略图文件保存到指定的路径     
        /// </summary>     
        /// <param name="Width">缩略图的宽度</param>     
        /// <param name="Height">缩略图的高度</param>     
        /// <param name="targetFilePath">缩略图保存的全文件名，(带路径)，参数格式：D:Images ilename.jpg</param>     
        /// <returns>成功返回true，否则返回false</returns>     
        public bool GetReducedImage(int Width, int Height, string targetFilePath)
        {
            try
            {
                Image ReducedImage;

                Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

                ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);
                ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);

                ReducedImage.Dispose();

                return true;
            }
            catch (Exception e)
            {
                ErrMessage = e.Message;
                return false;
            }
        }
        /// <summary>     
        /// 生成缩略图重载方法3，返回缩略图的Image对象     
        /// </summary>     
        /// <param name="Percent">缩略图的宽度百分比 如：需要百分之80，就填0.8</param>       
        /// <returns>缩略图的Image对象</returns>     
        public Image GetReducedImage(double Percent)
        {
            try
            {
                Image ReducedImage;

                Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

                ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
                ImageHeight = Convert.ToInt32(ResourceImage.Height * Percent);

                ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

                return ReducedImage;
            }
            catch (Exception e)
            {
                ErrMessage = e.Message;
                return null;
            }
        }
        /// <summary>     
        /// 生成缩略图重载方法4，返回缩略图的Image对象     
        /// </summary>     
        /// <param name="Percent">缩略图的宽度百分比 如：需要百分之80，就填0.8</param>       
        /// <param name="targetFilePath">缩略图保存的全文件名，(带路径)，参数格式：D:Images ilename.jpg</param>     
        /// <returns>成功返回true,否则返回false</returns>     
        public bool GetReducedImage(double Percent, string targetFilePath)
        {
            try
            {
                Image ReducedImage;

                Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

                ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
                ImageHeight = Convert.ToInt32(ResourceImage.Height * Percent);

                ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

                ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);

                ReducedImage.Dispose();

                return true;
            }
            catch (Exception e)
            {
                ErrMessage = e.Message;
                return false;
            }
        }
        public bool GetReducedImage(double Percent, string targetFilePath, ImageFormat imgF)
        {
            try
            {
                Image ReducedImage;

                Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

                ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
                ImageHeight = Convert.ToInt32(ResourceImage.Height * Percent);

                ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

                ReducedImage.Save(@targetFilePath, imgF);

                ReducedImage.Dispose();

                return true;
            }
            catch (Exception e)
            {
                ErrMessage = e.Message;
                return false;
            }
        }
    }

后台服务端：

private string strAction = "";
        protected void Page_Load(object sender, EventArgs e)
        {
            strAction = Request["method"];
            string FolderName = Request["FolderName"];
            if (strAction != null && strAction.Trim() != "")
            {
                switch (strAction)
                {
                    case "SaveImage":
                        SaveImage(FolderName);
                        break;
                }
            }
        }
        protected void SaveImage(string FolderName)
        {
            int returnid = 0;
            string ImageSend = Request["ImageSend"];
            ImageSend = Server.UrlDecode(ImageSend);
            ImageSend = ImageSend.Replace(" ", "+");
            try
            {
                string[] url = ImageSend.Split(',');
                string u = url[1];
                // Base64解码
                byte[] b = Convert.FromBase64String(u);
                string saveUrl = Server.MapPath("~/images/")+ DateTime.Now.ToString("yyyyMMddmmhhss")+ ".png";
                System.IO.File.WriteAllBytes(saveUrl, b);
                ImageClass ic = new ImageClass(saveUrl);
                ic.GetReducedImage(0.7, saveUrl.Replace(".png", "sl.png"), System.Drawing.Imaging.ImageFormat.Png);
            }
            catch (Exception e)
            {
            }
            System.Web.HttpContext.Current.Response.Write(returnid.ToString());
            System.Web.HttpContext.Current.Response.End();
        }　　

前端源码：

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>echars保存图片</title>
    <script src="/Jquery/jquery.min.js"></script>
    <script src="/Jquery/echarts/echarts.min.js"></script>
</head>
<body>
    <div id="main" style="width: 600px;height:400px;"></div>
    <script type="text/javascript">
        // 基于准备好的dom，初始化echarts实例
        var myChart = echarts.init(document.getElementById('main'));
        // 指定图表的配置项和数据
        var option = {
            title: {
                text: 'ECharts保存图片'
            },
            tooltip: {},
            legend: {
                data: ['销量']
            },
            xAxis: {
                data: ["衬衫", "羊毛衫", "雪纺衫", "裤子", "高跟鞋", "袜子"]
            },
            yAxis: {},
            series: [{
                name: '销量',
                type: 'bar',
                data: [5, 20, 36, 10, 10, 20]
            }]
        };
        // 使用刚指定的配置项和数据显示图表。
        myChart.setOption(option);
        var data =myChart.getDataURL();
        $.ajax({
            type: "post",
            url: "SaveImg.aspx",
            data: "method=SaveImage&ImageSend=" + data,
            cache: false,
            success: function (msg) { }
        });
    </script>
</body>
</html>

　　

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