Question

我想绘制一条线宽可变的曲线。如果我想使用点而不是线，通常会执行以下操作：

    public static void WriteWorkBookToResponse(this IWorkbook book, HttpContext httpContext, string fileName)
    {
        var response = httpContext.Response;

        using (var exportData = new MemoryStream())
        {
            response.Clear();
            book.Write(exportData);
            response.ContentType = "application/vnd.ms-excel";
            response.Headers.Add("Content-Disposition", $"attachment;filename={fileName}.xls");
            response.Body.Write(exportData.GetBuffer());
        }
    }

其中 curve.dat 充满：

    public static async void WriteToResponse2(this IWorkbook book, HttpContext httpContext, string templateName)
    {
        var response = httpContext.Response;

        using (var exportData = new MemoryStream())
        {
            book.Write(exportData);
            // response.ContentLength = exportData.GetBuffer().Length;
            response.ContentType = "application/vnd.ms-excel";
            SetContentDispositionHeader(httpContext, templateName);
            await StreamCopyOperation.CopyToAsync(exportData, response.Body, count: null, bufferSize: 64 * 1024, cancel: httpContext.RequestAborted);
        }
    }

    private static void SetContentDispositionHeader(HttpContext httpContext, string fileName)
    {
        if (!string.IsNullOrEmpty(fileName))
        {
            var contentDisposition = new Microsoft.Net.Http.Headers.ContentDispositionHeaderValue("attachment");
            contentDisposition.SetHttpFileName(fileName);
            httpContext.Response.Headers[HeaderNames.ContentDisposition] = contentDisposition.ToString();
        }
    }

，依此类推。现在，如果我尝试对线宽进行类似操作：

gnuplot> plot 'curve.dat' u ($1):($2):($1) ps var

我收到错误消息：

或者这是gnuplot无法完成的吗？

Answer 1

这解决了加文答案的问题：他的方法会创建特定的线高（而不是线宽）。我发现了另一种方式，which works with widths。

我的解决方案中的缺陷：一个人需要事先知道“坐标空间宽高比”，并且在连接处会出现工件。

绘图时如何设置可变的线宽？

1 个答案: