EPPlus实现Excel工作簿中插入图片

插入图片主方法代码:

/// <summary>
/// 插入图片
/// </summary>
/// <param name="worksheet"></param>
/// <param name="imageBytes"></param>
/// <param name="rowNum"></param>
/// <param name="columnNum"></param>
/// <param name="autofit"></param>
public static void InsertImage(ExcelWorksheet worksheet, byte[] imageBytes, int rowNum, int columnNum, bool autofit)
{
    using (var image = Image.FromStream(new MemoryStream(imageBytes)))
    {
        var picture = worksheet.Drawings.AddPicture($"image_{DateTime.Now.Ticks}", image);
        var cell = worksheet.Cells[rowNum, columnNum];
        int cellColumnWidthInPix = GetWidthInPixels(cell);
        int cellRowHeightInPix = GetHeightInPixels(cell);
        int adjustImageWidthInPix = cellColumnWidthInPix;
        int adjustImageHeightInPix = cellRowHeightInPix;
        if (autofit)
        {
            //图片尺寸适应单元格
            var adjustImageSize = GetAdjustImageSize(image, cellColumnWidthInPix, cellRowHeightInPix);
            adjustImageWidthInPix = adjustImageSize.Item1;
            adjustImageHeightInPix = adjustImageSize.Item2;
        }
        //设置为居中显示
        int columnOffsetPixels = (int)((cellColumnWidthInPix - adjustImageWidthInPix) / 2.0);
        int rowOffsetPixels = (int)((cellRowHeightInPix - adjustImageHeightInPix) / 2.0);
        picture.SetSize(adjustImageWidthInPix, adjustImageHeightInPix);
        picture.SetPosition(rowNum - 1, rowOffsetPixels, columnNum - 1, columnOffsetPixels);
    }
}

GetAdjustImageSize方法:

/// <summary>
/// 获取自适应调整后的图片尺寸
/// </summary>
/// <param name="image"></param>
/// <param name="cellColumnWidthInPix"></param>
/// <param name="cellRowHeightInPix"></param>
/// <returns>item1:调整后的图片宽度; item2:调整后的图片高度</returns>
private static Tuple<int, int> GetAdjustImageSize(Image image, int cellColumnWidthInPix, int cellRowHeightInPix)
{
    int imageWidthInPix = image.Width;
    int imageHeightInPix = image.Height;
    //调整图片尺寸,适应单元格
    int adjustImageWidthInPix;
    int adjustImageHeightInPix;
    if (imageHeightInPix * cellColumnWidthInPix > imageWidthInPix * cellRowHeightInPix)
    {
        //图片高度固定,宽度自适应
        adjustImageHeightInPix = cellRowHeightInPix;
        double ratio = (1.0) * adjustImageHeightInPix / imageHeightInPix;
        adjustImageWidthInPix = (int)(imageWidthInPix * ratio);
    }
    else
    {
        //图片宽度固定,高度自适应
        adjustImageWidthInPix = cellColumnWidthInPix;
        double ratio = (1.0) * adjustImageWidthInPix / imageWidthInPix;
        adjustImageHeightInPix = (int)(imageHeightInPix * ratio);
    }
    return new Tuple<int, int>(adjustImageWidthInPix, adjustImageHeightInPix);
}

GetWidthInPixels方法:

/// <summary>
/// 获取单元格的宽度(像素)
/// </summary>
/// <param name="cell"></param>
/// <returns></returns>
private static int GetWidthInPixels(ExcelRange cell)
{
    double columnWidth = cell.Worksheet.Column(cell.Start.Column).Width;
    Font font = new Font(cell.Style.Font.Name, cell.Style.Font.Size, FontStyle.Regular);
    double pxBaseline = Math.Round(MeasureString("1234567890", font) / 10);
    return (int)(columnWidth * pxBaseline);
}

GetHeightInPixels方法:

/// <summary>
/// 获取单元格的高度(像素)
/// </summary>
/// <param name="cell"></param>
/// <returns></returns>
private static int GetHeightInPixels(ExcelRange cell)
{
    double rowHeight = cell.Worksheet.Row(cell.Start.Row).Height;
    using (Graphics graphics = Graphics.FromHwnd(IntPtr.Zero))
    {
        float dpiY = graphics.DpiY;
        return (int)(rowHeight * (1.0 / DEFAULT_DPI) * dpiY);
    }
}

MeasureString方法:

/// <summary>
/// MeasureString
/// </summary>
/// <param name="s"></param>
/// <param name="font"></param>
/// <returns></returns>
private static float MeasureString(string s, Font font)
{
    using (var g = Graphics.FromHwnd(IntPtr.Zero))
    {
        g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
        return g.MeasureString(s, font, int.MaxValue, StringFormat.GenericTypographic).Width;
    }
}