Itextsharp:在一页上调整2个元素

Question

所以,我在使用C#(.NET 4.0 + WinForms)和iTextSharp 5.1.2时遇到了这个问题.

我有一些扫描图像存储在数据库中,需要与这些图像一起构建.有些文件只有一页,其他有几百页.这工作正常使用:

    foreach (var page in pages)
    {
        Image pageImage = Image.GetInstance(page.Image);
        pageImage.ScaleToFit(document.PageSize.Width,document.PageSize.Height);
        pageImage.Alignment = Image.ALIGN_TOP | Image.ALIGN_CENTER;
        document.Add(pageImage);
        document.NewPage();
        //...
    }

问题是:

我需要在最后一页的底部添加一个小表.

我尝试:

    foreach (var page in pages)
    {
        Image pageImage = Image.GetInstance(page.Image);
        pageImage.ScaleToFit(document.PageSize.Width,document.PageSize.Height);
        pageImage.Alignment = Image.ALIGN_TOP | Image.ALIGN_CENTER;
        document.Add(pageImage);
        document.NewPage();
        //...
    }
    Table t = new table....
    document.Add(t);

表已成功添加,但如果图像的大小符合文档的页面大小,则表格将添加到下一页.

我需要调整文档的最后一个图像(如果它有多个,或第一个if只有1),以便将表直接放在该页面上(带有图像),并且两个都只是一页.

我尝试按百分比缩放图像,但是假设最后一页上的图像的图像大小是未知的,并且它必须填充页面的最大部分,我需要做到这一点.

任何的想法？

Answer 1

让我给你一些可能对你有帮助的事情,然后我会给你一个你应该能够自定义的完整工作示例.

第一件事就是PdfPTable有一个特殊的方法WriteSelectedRows(),允许你在一个精确的x,y坐标上绘制一个表.它有六个重载,但最常用的一个可能是:

PdfPTable.WriteSelectedRows(int rowStart,int rowEnd, float xPos, float yPos, PdfContentByte canvas)

要将左上角放置在400,400您的桌子上,请拨打:

t.WriteSelectedRows(0, t.Rows.Count, 400, 400, writer.DirectContent);

在调用此方法之前,您需要先使用以下方法设置表的宽度SetTotalWidth():

//Set these to your absolute column width(s), whatever they are.
t.SetTotalWidth(new float[] { 200, 300 });

第二件事是在呈现整个表之前,表的高度是未知的.这意味着您无法准确知道放置表的位置,以便它真正位于底部.解决方案是首先将表格渲染为临时文档,然后计算高度.以下是我用来执行此操作的方法:

    public static float CalculatePdfPTableHeight(PdfPTable table)
    {
        using (MemoryStream ms = new MemoryStream())
        {
            using (Document doc = new Document(PageSize.TABLOID))
            {
                using (PdfWriter w = PdfWriter.GetInstance(doc, ms))
                {
                    doc.Open();

                    table.WriteSelectedRows(0, table.Rows.Count, 0, 0, w.DirectContent);

                    doc.Close();
                    return table.TotalHeight;
                }
            }
        }
    }

这可以像这样调用:

        PdfPTable t = new PdfPTable(2);
        //In order to use WriteSelectedRows you need to set the width of the table
        t.SetTotalWidth(new float[] { 200, 300 });
        t.AddCell("Hello");
        t.AddCell("World");
        t.AddCell("Test");
        t.AddCell("Test");

        float tableHeight = CalculatePdfPTableHeight(t);

所以这里有一个完整的WinForms示例,目标是iTextSharp 5.1.1.0(我知道你说5.1.2,但这应该是一样的).此示例查找桌面上名为"Test"的文件夹中的所有JPEG.然后将它们添加到8.5"x11"PDF中.然后在PDF的最后一页上,或者如果在唯一页面上只有1个JPEG开头,它会扩展PDF的高度,但是我们正在添加的表是高,然后将表放在左下角角.有关详细说明,请参阅代码中的注释.

using System;
using System.Text;
using System.Windows.Forms;
using iTextSharp.text;
using iTextSharp.text.pdf;
using System.IO;

namespace Full_Profile1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public static float CalculatePdfPTableHeight(PdfPTable table)
        {
            //Create a temporary PDF to calculate the height
            using (MemoryStream ms = new MemoryStream())
            {
                using (Document doc = new Document(PageSize.TABLOID))
                {
                    using (PdfWriter w = PdfWriter.GetInstance(doc, ms))
                    {
                        doc.Open();

                        table.WriteSelectedRows(0, table.Rows.Count, 0, 0, w.DirectContent);

                        doc.Close();
                        return table.TotalHeight;
                    }
                }
            }
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            //Create our table
            PdfPTable t = new PdfPTable(2);
            //In order to use WriteSelectedRows you need to set the width of the table
            t.SetTotalWidth(new float[] { 200, 300 });
            t.AddCell("Hello");
            t.AddCell("World");
            t.AddCell("Test");
            t.AddCell("Test");

            //Calculate true height of the table so we can position it at the document's bottom
            float tableHeight = CalculatePdfPTableHeight(t);

            //Folder that we are working in
            string workingFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Test");

            //PDF that we are creating
            string outputFile = Path.Combine(workingFolder, "Output.pdf");

            //Get an array of all JPEGs in the folder
            String[] AllImages = Directory.GetFiles(workingFolder, "*.jpg", SearchOption.TopDirectoryOnly);

            //Standard iTextSharp PDF init
            using (FileStream fs = new FileStream(outputFile, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                using (Document document = new Document(PageSize.LETTER))
                {
                    using (PdfWriter writer = PdfWriter.GetInstance(document, fs))
                    {
                        //Open our document for writing
                        document.Open();

                        //We do not want any margins in the document probably
                        document.SetMargins(0, 0, 0, 0);

                        //Declare here, init in loop below
                        iTextSharp.text.Image pageImage;

                        //Loop through each image
                        for (int i = 0; i < AllImages.Length; i++)
                        {
                            //If we only have one image or we are on the second to last one
                            if ((AllImages.Length == 1) | (i == (AllImages.Length - 1)))
                            {
                                //Increase the size of the page by the height of the table
                                document.SetPageSize(new iTextSharp.text.Rectangle(0, 0, document.PageSize.Width, document.PageSize.Height + tableHeight));
                            }

                            //Add a new page to the PDF
                            document.NewPage();

                            //Create our image instance
                            pageImage = iTextSharp.text.Image.GetInstance(AllImages[i]);
                            pageImage.ScaleToFit(document.PageSize.Width, document.PageSize.Height);
                            pageImage.Alignment = iTextSharp.text.Image.ALIGN_TOP | iTextSharp.text.Image.ALIGN_CENTER;
                            document.Add(pageImage);

                            //If we only have one image or we are on the second to last one
                            if ((AllImages.Length == 1) | (i == (AllImages.Length - 1)))
                            {
                                //Draw the table to the bottom left corner of the document
                                t.WriteSelectedRows(0, t.Rows.Count, 0, tableHeight, writer.DirectContent);
                            }

                        }

                        //Close document for writing
                        document.Close();
                    }
                }
            }

            this.Close();
        }
    }
}

编辑

以下是基于您的评论的编辑.我只发布for循环的内容,这是唯一改变的部分.打电话给ScaleToFit你时只需要考虑tableHeight到.

                    //Loop through each image
                    for (int i = 0; i < AllImages.Length; i++)
                    {
                        //Add a new page to the PDF
                        document.NewPage();

                        //Create our image instance
                        pageImage = iTextSharp.text.Image.GetInstance(AllImages[i]);

                        //If we only have one image or we are on the second to last one
                        if ((AllImages.Length == 1) | (i == (AllImages.Length - 1)))
                        {
                            //Scale based on the height of document minus the table height
                            pageImage.ScaleToFit(document.PageSize.Width, document.PageSize.Height - tableHeight);
                        }
                        else
                        {
                            //Scale normally
                            pageImage.ScaleToFit(document.PageSize.Width, document.PageSize.Height);
                        }

                        pageImage.Alignment = iTextSharp.text.Image.ALIGN_TOP | iTextSharp.text.Image.ALIGN_CENTER;
                        document.Add(pageImage);

                        //If we only have one image or we are on the second to last one
                        if ((AllImages.Length == 1) | (i == (AllImages.Length - 1)))
                        {
                            //Draw the table to the bottom left corner of the document
                            t.WriteSelectedRows(0, t.Rows.Count, 0, tableHeight, writer.DirectContent);
                        }

                    }