[C#] Chuyển đổi nhiều file hình ảnh thành một file PDF - sử dụng PdfSharp library

Xin chào các bạn, bài viết hôm nay mình sẽ hướng dẫn các bạn cách sử dụng thư viện PDFSharp để convert nhiều hình ảnh (image) thành một file PDF trong lập trình C# winform.

Trong ứng dụng demo này, mình có tích hợp thêm chức năng tạo Watermask khi mình chuyển đổi danh sách hình ảnh sang file PDF.

Ứng dụng này các bạn có thể sử dụng để chuyển đổi nhiều hình ảnh của truyện tranh thành một file PDF.

Giao diện demo ứng dụng Nối nhiều hình ảnh thành một file PDF C# Winform:

và dưới đây là file PDF kết quả khi các bạn chuyển đổi convert xong:

Source code Convert Image to PDF C#:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Windows.Forms;
using PdfSharp;
using PdfSharp.Drawing;
using PdfSharp.Pdf;

namespace ImageToPdf
{
    public partial class MainForm : Form
    {

        bool success = false;

        public MainForm()
        {
            InitializeComponent();        
            initCtrls();
        }

        #region form events
        private void btnSelectSrc_Click(object sender, EventArgs e)
        {
            if (ofdSrcFile.ShowDialog() != DialogResult.OK)
                return;

            toolStripStatusLabel1.Text = "";

            initCtrls();

            listBox1.Items.Clear();
            foreach (string fName in ofdSrcFile.FileNames) listBox1.Items.Add(fName);
            listBox1.SelectedIndex = 0;
            txbxDestFile.Text =
                Path.GetDirectoryName((string)listBox1.Items[0]) + "\\" +
                getCommonPart(listBox1.Items) + ".pdf";
        }

        private void btnSelectDest_Click(object sender, EventArgs e)
        {
            if (sfdDestFile.ShowDialog() != DialogResult.OK)
                return;
            toolStripStatusLabel1.Text = "";

            txbxDestFile.Text = sfdDestFile.FileName;
        }

        private void buttonPreviewSource_Click(object sender, EventArgs e)
        {
            errProv.Clear();

            if (listBox1.Items.Count == 0)
            {
                errProv.SetError(btnSelectSrc, toolStripStatusLabel1.Text = "Please point source file(s).");
                return;
            }
            else if (listBox1.SelectedIndex < 0)
            {
                errProv.SetError(listBox1, toolStripStatusLabel1.Text = "Please select source file to preview.");
                return;
            }

            try
            {
                foreach (string s in listBox1.SelectedItems)
                    Process.Start(s);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void buttonPreviewDest_Click(object sender, EventArgs e)
        {
            errProv.Clear();

            if (txbxDestFile.Text.Length == 0)
            {
                errProv.SetError(btnSelectDest, "Please point destination file.");
                return;
            }

            try
            {
                Process.Start(txbxDestFile.Text);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }

        }

        private void buttonUp_Click(object sender, EventArgs e)
        {
            MoveItem(-1);
            checkDestination();
        }

        private void buttonDown_Click(object sender, EventArgs e)
        {
            MoveItem(1);
            checkDestination();
        }

        private void btnConvert_Click(object sender, EventArgs e)
        {
            errProv.Clear();


            if (listBox1.Items.Count == 0)
            {
                errProv.SetError(listBox1, toolStripStatusLabel1.Text = "Please point source file(s).");
                return;
            }

            if (!checkBoxSeparate.Checked)
            {
                if (txbxDestFile.Text.Length == 0)
                {
                    errProv.SetError(txbxDestFile, toolStripStatusLabel1.Text = "Please point destination file.");
                    return;
                }
                else if (File.Exists(txbxDestFile.Text))
                {
                    if (MessageBox.Show("Overwrite file " + txbxDestFile.Text,
                        toolStripStatusLabel1.Text = "Destination file exists",
                        MessageBoxButtons.OKCancel,
                        MessageBoxIcon.Warning) != System.Windows.Forms.DialogResult.OK)
                    {
                        return;
                    }
                }
            }

            success = false;
            List<string> l = new List<string>();
            //      1st argument = destination file

            l.Add(txbxDestFile.Text);

            //      Rest arguments = source files in required order
            foreach (string f in listBox1.Items)
                l.Add(f);

            bw.RunWorkerAsync(l.ToArray());
            toolStripProgressBar1.Style = ProgressBarStyle.Marquee;

        }

        private void button1Clr_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            checkDestination();
        }

        private void checkBoxSeparate_CheckedChanged(object sender, EventArgs e)
        {
            checkDestination();
            checkBoxAutoPreviewDest.Checked = false;
        }

        private void txbxDestFile_TextChanged(object sender, EventArgs e)
        {
            btnConvert.Enabled = checkBoxDeleteSource.Enabled = true;
            buttonPreviewDest.Enabled = File.Exists(txbxDestFile.Text);
        }
        #endregion

        #region ListBox
        private void listBox1_DoubleClick(object sender, EventArgs e)
        {
            if ((listBox1.Items.Count > 0) & (listBox1.SelectedIndex >= 0))
                Process.Start((string)listBox1.SelectedItems[0]);
        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            buttonDown.Enabled = buttonUp.Enabled = buttonPreviewSource.Enabled = true;
        }

        private void listBox1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Delete && listBox1.Items.Count > 0 && listBox1.SelectedItem != null)
            {
                listBox1.Items.Remove(listBox1.SelectedItem);
                checkDestination();
            }
        }

        private void listBox1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
                e.Effect = DragDropEffects.Copy;
            else
                e.Effect = DragDropEffects.None;
        }

        private void listBox1_DragDrop(object sender, DragEventArgs e)
        {
            string[] s = (string[])e.Data.GetData(DataFormats.FileDrop, false);
            for (int i = 0; i < s.Length; i++)
            {
                try
                {
                    // accept only files specified in the filer
                    FileInfo fi = new FileInfo(s[i]);
                    if (ofdSrcFile.Filter.Contains(fi.Extension.ToUpper()))
                        listBox1.Items.Add(s[i]);
                }
                catch { }
            }
            checkDestination();
        }
        #endregion

        #region work
        private void bw_DoWork(object sender, DoWorkEventArgs e)
        {
            try
            {
                string[] fNames = (e.Argument as string[]);

                if (checkBoxSeparate.Checked)
                {
                    XSize size = new XSize(0, 0);
                    for (int i = 1; i < fNames.Length; i++)
                    {
                        // each source file saeparate
                        PdfDocument doc = new PdfDocument();
                        toolStripStatusLabel1.Text = "Processing " + fNames[i];
                        var page = new PdfPage();
                        page.Size = PageSize.A4;




                        XPdfForm form = XPdfForm.FromFile(fNames[i]);



                        if (form.Width > form.Height)
                            page.Orientation = PageOrientation.Landscape;
                        else
                            page.Orientation = PageOrientation.Portrait;

                        doc.Pages.Add(page);



                        XGraphics xgr = XGraphics.FromPdfPage(doc.Pages[0]);
                        XImage img = XImage.FromFile(fNames[i]);


                        if (true)
                        {
                            size = new XSize(img.Width, img.Height);
                            page.Height = size.Height;
                            page.Width = size.Width;
                        }


                        xgr.DrawImage(img, 0, 0);
                        img.Dispose();
                        xgr.Dispose();
                        //  save to destination file
                        FileInfo fi = new FileInfo(fNames[i]);

                        doc.Save(fi.FullName.Replace(fi.Extension, ".PDF"));
                        doc.Close();
                    }

                }
                else
                {
                    // single document
                    PdfDocument doc = new PdfDocument();
                    XSize size = new XSize(0, 0);

                    for (int i = 1; i < fNames.Length; i++)
                    {
                        toolStripStatusLabel1.Text = "Processing " + fNames[i];
                        // each source on separate page
                        var page = new PdfPage();
                        page.Size = PageSize.Letter;
                        doc.Pages.Add(page);
                        XGraphics xgr = XGraphics.FromPdfPage(doc.Pages[i - 1]);
                        XImage img = XImage.FromFile(fNames[i]);

                        if (true)
                        {
                            size = new XSize(img.Width, img.Height);
                            page.Height = size.Height - 320;
                            page.Width = size.Width - 230;
                        }



                        xgr.DrawImage(img, 0, 0);

                        if (chk_waterMask.Checked)
                        {
                            var font = new XFont("Tahoma", 120.0f);
                            var sizes = xgr.MeasureString(txt_waterMask.Text, font);
                            xgr.TranslateTransform(page.Width / 2, page.Height / 2);
                            xgr.RotateTransform(-Math.Atan(page.Height / page.Width) * 180 / Math.PI);
                            xgr.TranslateTransform(-page.Width / 2, -page.Height / 2);
                            var format = new XStringFormat();
                            format.Alignment = XStringAlignment.Near;
                            format.LineAlignment = XLineAlignment.Near;
                            XBrush brush = new XSolidBrush(XColor.FromArgb(128, 255, 0, 0));
                            xgr.DrawString(txt_waterMask.Text, font, brush,
                                new XPoint((page.Width - sizes.Width) / 2, (page.Height - sizes.Height) / 2),
                                format);

                        }

                        img.Dispose();
                        xgr.Dispose();

                    }

                    //  save to destination file
                    doc.Save(fNames[0]);
                    doc.Close();
                }
                success = true;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            toolStripProgressBar1.Style = ProgressBarStyle.Blocks;
            toolStripProgressBar1.Value = 0;

            Boolean anyErr = false;
            if (checkBoxDeleteSource.Checked)
            {
                foreach (string fName in listBox1.Items)
                {
                    try
                    {
                        toolStripStatusLabel1.Text = "Deleting " + fName;
                        File.Delete(fName);
                    }
                    catch
                    {
                        anyErr = true;
                    }
                }
                listBox1.Items.Clear();
            }

            if (checkBoxAutoPreviewDest.Checked && File.Exists(txbxDestFile.Text))
            {
                Process.Start(txbxDestFile.Text);
            }

            if (success && !anyErr)
            {
                initCtrls();
                toolStripStatusLabel1.Text = "The converion ended successfully.";
            }
            else
            {
                toolStripStatusLabel1.Text = "WARNING! Some errors during converion !";
            }
        }
        #endregion

        #region utils
        public void MoveItem(int direction)
        {
            // Checking selected item
            if (listBox1.SelectedItem == null || listBox1.SelectedIndex < 0)
                return; // No selected item - nothing to do

            // Calculate new index using move direction
            int newIndex = listBox1.SelectedIndex + direction;

            // Checking bounds of the range
            if (newIndex < 0 || newIndex >= listBox1.Items.Count)
                return; // Index out of range - nothing to do

            object selected = listBox1.SelectedItem;

            // Removing removable element
            listBox1.Items.Remove(selected);
            // Insert it in new position
            listBox1.Items.Insert(newIndex, selected);
            // Restore selection
            listBox1.SetSelected(newIndex, true);
        }

        private void initCtrls()
        {
            errProv.Clear();
            toolStripStatusLabel1.Text = "";
            buttonPreviewSource.Enabled = false;
            buttonUp.Enabled =
            buttonDown.Enabled = (listBox1.Items.Count > 0);
            checkDestination();
        }

        private string getCommonPart(ListBox.ObjectCollection fnames)
        {
            string res = "";
            try
            {
                res = Path.GetFileNameWithoutExtension(fnames[0].ToString());
                if (fnames.Count > 1)
                {
                    int posOfCommonPart = -1;
                    string f1 = Path.GetFileNameWithoutExtension(fnames[0].ToString());
                    for (int j = 1; j < fnames.Count; j++)
                    {
                        string f2 = Path.GetFileNameWithoutExtension(fnames[j].ToString());
                        for (int i = Math.Min(f1.Length, f2.Length); i > 0; i--)
                        {
                            if (f1.Substring(0, i) == f2.Substring(0, i))
                            {
                                if (posOfCommonPart > 0)
                                    posOfCommonPart = Math.Min(posOfCommonPart, i);
                                else
                                    posOfCommonPart = i;

                                break;
                            }
                        }
                    }
                    if (posOfCommonPart > 0)
                    {
                        res = f1.Substring(0, posOfCommonPart);
                    }
                }
            }
            catch { }
            return res;
        }

        private void checkDestination()
        {
            txbxDestFile.Enabled = btnSelectDest.Enabled = buttonPreviewDest.Enabled = !checkBoxSeparate.Checked;


            if (!checkBoxSeparate.Checked && listBox1.Items.Count > 0)
            {
                txbxDestFile.Text = Path.GetDirectoryName((string)listBox1.Items[0]) + "\\" + getCommonPart(listBox1.Items) + ".pdf";
            }
            else
            {
                txbxDestFile.Text = "";
            }

        }


        #endregion

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {

        }
    }
}

Thanks for watching!

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