告诉 abcPdf 缩放 html 以适应单个 pdf 页面

Question

我正在使用 abcPdf 将 HTML 报告转换为 pdf 文件。 pdf 必须是单个横向 A4 页面。

您知道是否有任何方法可以告诉 abcPdf 缩放 HTML 页面以适应 pdf 中的单个页面？我尝试使用Magnify() method，它会缩放内容，但仍会将其分成页面，即使它适合一页。我已经为此苦苦思索了一段时间，想知道是否有人这样做过。

这是我目前正在使用的代码：

public byte[] UrlToPdf(string url, PageOrientation po)
{
    using (Doc theDoc = new Doc())
    {
        // When in landscape mode:
        // We use two transforms to apply a generic 90 degree rotation around
        // the center of the document and rotate the drawing rectangle by the same amount.
        if (po == PageOrientation.Landscape)
        {
            // apply a rotation transform
            double w = theDoc.MediaBox.Width;
            double h = theDoc.MediaBox.Height;
            double l = theDoc.MediaBox.Left;
            double b = theDoc.MediaBox.Bottom;
            theDoc.Transform.Rotate(90, l, b);
            theDoc.Transform.Translate(w, 0);

            // rotate our rectangle
            theDoc.Rect.Width = h;
            theDoc.Rect.Height = w;

            // To change the default orientation of the document we need to apply a rotation to the root page object.
            //By doing this we ensure that every page in the document is viewed rotated.
            int theDocID = Convert.ToInt32(theDoc.GetInfo(theDoc.Root, "Pages"));
            theDoc.SetInfo(theDocID, "/Rotate", "90");
        }

        theDoc.HtmlOptions.PageCacheEnabled = false;
        theDoc.HtmlOptions.AddForms = false;
        theDoc.HtmlOptions.AddLinks = false;
        theDoc.HtmlOptions.AddMovies = false;
        theDoc.HtmlOptions.FontEmbed = false;
        theDoc.HtmlOptions.UseResync = false;
        theDoc.HtmlOptions.UseVideo = false;
        theDoc.HtmlOptions.UseScript = false;
        theDoc.HtmlOptions.HideBackground = false;
        theDoc.HtmlOptions.Timeout = 60000;
        theDoc.HtmlOptions.BrowserWidth = 0;
        theDoc.HtmlOptions.ImageQuality = 101;

        // Add url to document.
        int theID = theDoc.AddImageUrl(url, true, 0, true);
        while (true)
        {
            if (!theDoc.Chainable(theID))
                break;
            theDoc.Page = theDoc.AddPage();
            theID = theDoc.AddImageToChain(theID);
        }
        //Flattening the pages (Whatever that means)
        for (int i = 1; i <= theDoc.PageCount; i++)
        {
            theDoc.PageNumber = i;
            theDoc.Flatten();
        }

        return theDoc.GetData();
    }
}

Answer 1

这就是我解决这个问题的方法。

首先，我需要将HTML页面的高度传递给pdf生成方法，所以我在要pdf-ed的页面上添加了这个：

<asp:HiddenField ID="hfHeight" runat="server" />

在后面的代码中：

protected void Page_Init(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        string scriptKey = "WidhtHeightForPdf";
        if (!Page.ClientScript.IsClientScriptBlockRegistered(scriptKey))
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendLine("<script>")
                .AppendLine("document.getElementById('" + hfHeight.ClientID + "').value = document.body.clientHeight;")
                .AppendLine("</script>");

            Page.ClientScript.RegisterStartupScript(typeof(Page), scriptKey, sb.ToString());
        }
    }
}

现在，当我调用 pdf 生成方法时，我可以将 HTML 的高度传递给它。一旦我有了高度，只需计算 pdf“视口”的宽度，以使高度适合 pdf 页面：

int intHTMLWidth = height.Value * Convert.ToInt32(theDoc.Rect.Width / theDoc.Rect.Height);

然后通过HtmlOptions或theDoc指定BrowserWidth参数：

theDoc.HtmlOptions.BrowserWidth = intHTMLWidth;

或将网址添加到theDoc时：

int theID = theDoc.AddImageUrl(url, true, intHTMLWidth, true);

编辑：这解决了问题，所以我将其标记为答案。现在接下来要做的就是根据 HTML 的宽度和高度以 protrait 或横向模式创建 pdf，以便在 pdf 页面上使用最大空间。

Answer 2

这可能会简单一些

    /// <summary>
    /// Calculate the height of given html
    /// </summary>
    /// <param name="html"></param>
    /// <returns></returns>
    public int CalculateHeight(string html)
    {
        int id = _Document.AddImageHtml(html);
        int height = (int)(_Document.GetInfoInt(id, "ScrollHeight") * PixelToPointScale);
        _Document.Delete( id );
        return height;
    }

[编辑] 好吧，scrollHeight 使用 ver8 失败了，不过这可以工作

    private int AddImageHtml(string html)
    {
        try
        {
            return _Document.AddImageHtml("<div id='pdfx-div-pdf-frame' class='abcpdf-tag-visible' style='abcpdf-tag-visible: true; border: 1px solid red'>" + html + "</div>");
        }
        catch (Exception ex)
        {
            throw new Exception(html, ex);
        }
    }

    private double GetElementHeight(int id)
    {
        abcpdf.XRect[] tagRects = _Document.HtmlOptions.GetTagRects(id);
        string[] tagIds = _Document.HtmlOptions.GetTagIDs(id);

        for (int i=0;i<tagRects.Length;i++)
        {
            abcpdf.XRect rect = tagRects[i];
            string tagId = tagIds[i];
            if (string.Equals(tagId, "pdfx-div-pdf-frame", StringComparison.CurrentCultureIgnoreCase))
            {
                return rect.Height;
            }
        }
        return -1;
    }

Answer 3

如果您使用“Gecko”引擎，该引擎不支持“GetInfoInt”，因此我们需要编写一些 javascript 来获取高度。首先进行虚拟渲染以确定高度，然后将此高度设置为原始 AbcDoc。

using (var tempDoc = new Doc())
                {
                    tempDoc.HtmlOptions.Engine = EngineType.Gecko;
                    tempDoc.HtmlOptions.Media = MediaType.Print;
                    tempDoc.HtmlOptions.UseScript = true;
                    if (width.HasValue)
                        tempDoc.HtmlOptions.BrowserWidth = width.Value;

                    tempDoc.HtmlOptions.OnLoadScript = " window.onbeforeprint = function () { document.documentElement.abcpdf = Math.max( document.body.scrollHeight, document.body.offsetHeight, document.documentElement.clientHeight, document.documentElement.scrollHeight, document.documentElement.offsetHeight );}";
                    int theTempID = tempDoc.AddImageHtml(htmlData);

                    int height = Convert.ToInt32(tempDoc.HtmlOptions.GetScriptReturn(theTempID));

                    tempDoc.Clear();
                    tempDoc.Dispose();

                    theDoc.MediaBox.Height = height;
                    theDoc.Rect.String = theDoc.MediaBox.String;
                    theDoc.AddImageHtml(htmlData);
                }