Convert Excel Sheet to a High-Resolution Image in C#, VB.NET

Sometimes, you may want to convert Excel sheet to a high-resolution image, especially when the Excel report contains graphs or pictures. This article will show you how to set image resolution when saving Excel sheet to JPG using Spire.XLS.

Step 1: Create a custom function that you can use to reset the image resolution.

private static Bitmap ResetResolution(Metafile mf, float resolution)
{
    int width = (int)(mf.Width * resolution / mf.HorizontalResolution);
    int height = (int)(mf.Height * resolution / mf.VerticalResolution);
    Bitmap bmp = new Bitmap(width, height);
    bmp.SetResolution(resolution, resolution);
    Graphics g = Graphics.FromImage(bmp);
    g.DrawImage(mf, 0, 0);
    g.Dispose();
    return bmp;
}

Step 2: Create a workbook instance and load the sample Excel file.

Workbook workbook = new Workbook();
workbook.LoadFromFile("Chart.xlsx",ExcelVersion.Version2013);

Step 3: Get the worksheet you want to convert.

Worksheet worksheet = workbook.Worksheets[0];

Step 4: Convert the worksheet to EMF stream.

MemoryStream ms = new MemoryStream();
worksheet.ToEMFStream(ms, 1, 1, worksheet.LastRow, worksheet.LastColumn);

Step 5: Create an image from the EMF stream, and call ResetResolution to reset the resolution for the image.

Image image = Image.FromStream(ms);
Bitmap images = ResetResolution(image as Metafile, 300);

Step 6: Save the image in JPG file format.

images.Save("Result.jpg", ImageFormat.Jpeg);

Output:

Convert Excel Sheet to a High-Resolution Image in C#, VB.NET

Full Code:

[C#]

using Spire.Xls;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
namespace Convert
{
    class Program
    {
        static void Main(string[] args)
        {
            Workbook workbook = new Workbook();
            workbook.LoadFromFile("Chart.xlsx", ExcelVersion.Version2013);
            Worksheet worksheet = workbook.Worksheets[0];

            using (MemoryStream ms = new MemoryStream())
            {

                worksheet.ToEMFStream(ms, 1, 1, worksheet.LastRow, worksheet.LastColumn);
                Image image = Image.FromStream(ms);
                Bitmap images = ResetResolution(image as Metafile, 300);
                images.Save("Result.jpg", ImageFormat.Jpeg);
            }
        }
        private static Bitmap ResetResolution(Metafile mf, float resolution)
        {
            int width = (int)(mf.Width * resolution / mf.HorizontalResolution);
            int height = (int)(mf.Height * resolution / mf.VerticalResolution);
            Bitmap bmp = new Bitmap(width, height);
            bmp.SetResolution(resolution, resolution);
            Graphics g = Graphics.FromImage(bmp);
            g.DrawImage(mf, 0, 0);
            g.Dispose();
            return bmp;
        }
    }
}

[VB.NET]

Imports Spire.Xls
Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.IO
Namespace Convert
	Class Program
		Private Shared Sub Main(args As String())
			Dim workbook As New Workbook()
			workbook.LoadFromFile("Chart.xlsx", ExcelVersion.Version2013)
			Dim worksheet As Worksheet = workbook.Worksheets(0)

			Using ms As New MemoryStream()

				worksheet.ToEMFStream(ms, 1, 1, worksheet.LastRow, worksheet.LastColumn)
				Dim image__1 As Image = Image.FromStream(ms)
				Dim images As Bitmap = ResetResolution(TryCast(image__1, Metafile), 300)
				images.Save("Result.jpg", ImageFormat.Jpeg)
			End Using
		End Sub
		Private Shared Function ResetResolution(mf As Metafile, resolution As Single) As Bitmap
			Dim width As Integer = CInt(mf.Width * resolution / mf.HorizontalResolution)
			Dim height As Integer = CInt(mf.Height * resolution / mf.VerticalResolution)
			Dim bmp As New Bitmap(width, height)
			bmp.SetResolution(resolution, resolution)
			Dim g As Graphics = Graphics.FromImage(bmp)
			g.DrawImage(mf, 0, 0)
			g.Dispose()
			Return bmp
		End Function
	End Class
End Namespace

Convert Excel Sheet to a High-Resolution Image in C#, VB.NET

See Also