使用NPOI从Excel中提取图片及图片位置信息

问题背景：

话说，在ExcelReport的开发过程中，有一个比较棘手的问题：怎么复制图片呢？

当然，解决这个问题的第一步是：能使用NPOI提取到图片及图片的位置信息。到这里，一切想法都很顺利。但NPOI到底怎么提取图片及图片的位置信息呢？NPOI能不能提取到图片的位置信息呢？

这是两个问题。是两个让BaiGoogleDu几近沉默的问题。但官方教程的评论中还是流露出了答案的蛛丝马迹。

哇咔咔，这是我去看源码寻答案的的动力。

此处省去（N多字）… …，这里宕掉了我三个晚上的时间。

不再累述，代码你懂的… ….

PicturesInfo.cs

public class PicturesInfo
{
    public int MinRow { get;set; }
    public int MaxRow { get;set; }
    public int MinCol { get;set; }
    public int MaxCol { get;set; }
    public Byte[] PictureData { get; private set; }

    public PicturesInfo(int minRow, int maxRow, int minCol, int maxCol,Byte[] pictureData)
    {
        this.MinRow = minRow;
        this.MaxRow = maxRow;
        this.MinCol = minCol;
        this.MaxCol = maxCol;
        this.PictureData = pictureData;
    }
}

NpoiExtend.cs

public static class NpoiExtend
{
    public static List<PicturesInfo> GetAllPictureInfos(this ISheet sheet)
    {
        return sheet.GetAllPictureInfos(null,null,null,null);
    }

    public static List<PicturesInfo> GetAllPictureInfos(this ISheet sheet,int? minRow,int? maxRow,int? minCol,int? maxCol,bool onlyInternal = true)
    {
        if (sheet is HSSFSheet)
        {
            return GetAllPictureInfos((HSSFSheet)sheet,minRow,maxRow,minCol,maxCol,onlyInternal);
        }
        else if (sheet is XSSFSheet)
        {
            return GetAllPictureInfos((XSSFSheet)sheet, minRow, maxRow, minCol, maxCol, onlyInternal);
        }
        else
        {
            throw new Exception("未处理类型，没有为该类型添加：GetAllPicturesInfos()扩展方法！");
        }
    }

    private static List<PicturesInfo> GetAllPictureInfos(HSSFSheet sheet,int? minRow, int? maxRow, int? minCol, int? maxCol, bool onlyInternal)
    {
        List<PicturesInfo> picturesInfoList = new List<PicturesInfo>();

        var shapeContainer = sheet.DrawingPatriarch as HSSFShapeContainer;
        if (null != shapeContainer)
        {
            var shapeList = shapeContainer.Children;
            foreach (var shape in shapeList)
            {
                if (shape is HSSFPicture && shape.Anchor is HSSFClientAnchor)
                {
                    var picture = (HSSFPicture)shape;
                    var anchor = (HSSFClientAnchor)shape.Anchor;

                    if (IsInternalOrIntersect(minRow, maxRow, minCol, maxCol, anchor.Row1, anchor.Row2, anchor.Col1, anchor.Col2, onlyInternal))
                    {
                        picturesInfoList.Add(new PicturesInfo(anchor.Row1, anchor.Row2, anchor.Col1, anchor.Col2, picture.PictureData.Data));
                    }
                }
            }
        }

        return picturesInfoList;
    }

    private static List<PicturesInfo> GetAllPictureInfos(XSSFSheet sheet, int? minRow, int? maxRow, int? minCol, int? maxCol, bool onlyInternal)
    {
        List<PicturesInfo> picturesInfoList = new List<PicturesInfo>();

        var documentPartList = sheet.GetRelations();
        foreach (var documentPart in documentPartList)
        {
            if (documentPart is XSSFDrawing)
            {
                var drawing = (XSSFDrawing)documentPart;
                var shapeList = drawing.GetShapes();
                foreach (var shape in shapeList)
                {
                    if (shape is XSSFPicture)
                    {
                        var picture = (XSSFPicture)shape;
                        var anchor = picture.GetPreferredSize();

                        if (IsInternalOrIntersect(minRow, maxRow, minCol, maxCol, anchor.Row1, anchor.Row2, anchor.Col1, anchor.Col2, onlyInternal))
                        {
                            picturesInfoList.Add(new PicturesInfo(anchor.Row1, anchor.Row2, anchor.Col1, anchor.Col2, picture.PictureData.Data));
                        }
                    }
                }
            }
        }

        return picturesInfoList;
    }

    private static bool IsInternalOrIntersect(int? rangeMinRow, int? rangeMaxRow, int? rangeMinCol, int? rangeMaxCol,
        int pictureMinRow, int pictureMaxRow, int pictureMinCol, int pictureMaxCol, bool onlyInternal)
    {
        int _rangeMinRow = rangeMinRow ?? pictureMinRow;
        int _rangeMaxRow = rangeMaxRow ?? pictureMaxRow;
        int _rangeMinCol = rangeMinCol ?? pictureMinCol;
        int _rangeMaxCol = rangeMaxCol ?? pictureMaxCol;

        if (onlyInternal)
        {
            return (_rangeMinRow <= pictureMinRow && _rangeMaxRow >= pictureMaxRow &&
                    _rangeMinCol <= pictureMinCol && _rangeMaxCol >= pictureMaxCol);
        }
        else
        {
            return ((Math.Abs(_rangeMaxRow - _rangeMinRow) + Math.Abs(pictureMaxRow - pictureMinRow) >= Math.Abs(_rangeMaxRow + _rangeMinRow - pictureMaxRow - pictureMinRow)) &&
            (Math.Abs(_rangeMaxCol - _rangeMinCol) + Math.Abs(pictureMaxCol - pictureMinCol) >= Math.Abs(_rangeMaxCol + _rangeMinCol - pictureMaxCol - pictureMinCol)));
        }
    }
}