OpenXmlPictureImplement.cs

using System.Drawing;
using MiniExcelLib.Core.Enums;

namespace MiniExcelLib.OpenXml.Picture;

internal static partial class MiniExcelPictureImplement
{
    private static XmlNamespaceManager GetRNamespaceManager(XmlDocument doc)
    {
        var nsmgr = new XmlNamespaceManager(doc.NameTable);
        nsmgr.AddNamespace("x", "http://schemas.openxmlformats.org/spreadsheetml/2006/main");
        nsmgr.AddNamespace("r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships");
        return nsmgr;
    }

    [CreateSyncVersion]
    public static async Task AddPictureAsync(Stream excelStream, CancellationToken cancellationToken = default, params MiniExcelPicture[] images)
    {
        // get sheets
        var excelArchive = await OpenXmlZip.CreateAsync(excelStream, cancellationToken: cancellationToken).ConfigureAwait(false);
        await using var disposableExcelArchive = excelArchive.ConfigureAwait(false);

        using var reader = await OpenXmlReader.CreateAsync(excelStream, null, cancellationToken).ConfigureAwait(false);

#if NET10_0_OR_GREATER
        var archive = await ZipArchive.CreateAsync(excelStream, ZipArchiveMode.Update, true, null, cancellationToken).ConfigureAwait(false);
        await using var disposableArchive = archive.ConfigureAwait(false);
#else
        using var archive = new ZipArchive(excelStream, ZipArchiveMode.Update, true);
#endif
		var rels = await reader.GetWorkbookRelsAsync(excelArchive.EntryCollection, cancellationToken).ConfigureAwait(false);
        var sheetEntries = rels?.ToList() ?? [];

        // Group images by sheet
        var imagesBySheet = images.GroupBy(img => img.SheetName ?? sheetEntries[0].Name);
        foreach (var sheetGroup in imagesBySheet)
        {
            var sheetName = sheetGroup.Key;
            var sheetEnt = sheetEntries.Find(x => x.Name == sheetName) ?? sheetEntries[0];
            var sheetXmlName = !string.IsNullOrEmpty(sheetEnt.Path) ? sheetEnt.Path.Split('/')[^1].Split('.')[0] : null;
            var sheetPath = $"xl/worksheets/{sheetXmlName}.xml";

            var sheetEntry = archive.GetEntry(sheetPath);
            var sheetDoc = LoadXml(sheetEntry);

            // Check for existing <drawing> node
            string drawingRelId;
            string drawingId;
            var nsmgr = GetRNamespaceManager(sheetDoc);
            if (sheetDoc.SelectSingleNode("/x:worksheet/x:drawing", nsmgr) is XmlElement drawingNode)
            {
                // Drawing exists, get r:id
                drawingRelId = drawingNode.GetAttribute("id", nsmgr.LookupNamespace("r"));
                    
                // Find the drawing target from .rels
                var relsPath = $"xl/worksheets/_rels/{sheetXmlName}.xml.rels";
                var relsEntry = archive.GetEntry(relsPath);
                var relsDoc = LoadXml(relsEntry);
                    
                var namespaceManager = new XmlNamespaceManager(relsDoc.NameTable);
                namespaceManager.AddNamespace("x", "http://schemas.openxmlformats.org/package/2006/relationships");
                    
                var xpath = $"/x:Relationships/x:Relationship[@Id='{drawingRelId}']";
                var relNode = relsDoc.SelectSingleNode(xpath, namespaceManager);
                var drawingTarget = relNode?.Attributes["Target"]?.Value;
                drawingId = drawingTarget is not null
                    ? drawingTarget.Split('/').Last().Replace("drawing", "").Replace(".xml", "")
                    : Guid.NewGuid().ToString("N");
            }
            else
            {
                // No drawing, create new
                drawingRelId = $"rId{Guid.NewGuid():N}";
                drawingId = Guid.NewGuid().ToString("N");
                    
                // Add <drawing> node
                var newDrawingNode = sheetDoc.CreateElement("drawing", sheetDoc.DocumentElement.NamespaceURI);
                newDrawingNode.SetAttribute("id", nsmgr.LookupNamespace("r"), drawingRelId);
                sheetDoc.DocumentElement.AppendChild(newDrawingNode);
                SaveXml(sheetDoc, sheetEntry);
                    
                // Add relationship
                var relsPath = $"xl/worksheets/_rels/{sheetXmlName}.xml.rels";
                var relsEntry = archive.GetEntry(relsPath) ?? archive.CreateEntry(relsPath);
                var relsDoc = LoadXml(relsEntry);
                var relNode = relsDoc.CreateElement("Relationship", relsDoc.DocumentElement.NamespaceURI);
                relNode.SetAttribute("Id", drawingRelId);
                relNode.SetAttribute("Type", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/drawing");
                relNode.SetAttribute("Target", $"../drawings/drawing{drawingId}.xml");
                relsDoc.DocumentElement.AppendChild(relNode);
                SaveXml(relsDoc, relsEntry);
                    
                // Update [Content_Types].xml for drawing
                var contentTypesEntry = archive.GetEntry("[Content_Types].xml");
                var contentTypesDoc = LoadXml(contentTypesEntry);
                var overrideDrawingFileExists = contentTypesDoc.DocumentElement
                    .ChildNodes
                    .Cast<XmlNode>()
                    .Any(node => node.Name == "Override" && 
                                 node.Attributes["PartName"].Value == $"/xl/drawings/drawing{drawingId}.xml");

                if (!overrideDrawingFileExists)
                {
                    var overrideNode = contentTypesDoc.CreateElement("Override", contentTypesDoc.DocumentElement.NamespaceURI);
                    overrideNode.SetAttribute("PartName", $"/xl/drawings/drawing{drawingId}.xml");
                    overrideNode.SetAttribute("ContentType", "application/vnd.openxmlformats-officedocument.drawing+xml");
                    contentTypesDoc.DocumentElement.AppendChild(overrideNode);
                }

                SaveXml(contentTypesDoc, contentTypesEntry);
            }

            // Load or create drawing XML
            var drawingPath = $"xl/drawings/drawing{drawingId}.xml";
            var drawingEntry = archive.GetEntry(drawingPath) ?? archive.CreateEntry(drawingPath);
            var drawingDoc = LoadXml(drawingEntry);

            // Load or create drawing rels
            var drawingRelsPath = $"xl/drawings/_rels/drawing{drawingId}.xml.rels";
            var drawingRelsEntry = archive.GetEntry(drawingRelsPath) ?? archive.CreateEntry(drawingRelsPath);
            var drawingRelsDoc = LoadXml(drawingRelsEntry);

            // Add each image to drawing and rels
            foreach (var image in sheetGroup)
            {
                var imageBytes = image.ImageBytes;
                var col = image.ColumnNumber;
                var row = image.RowNumber;
                var widthPx = image.WidthPx;
                var heightPx = image.HeightPx;
                var imgtype = image.ImgType;
                var location = image.Location;
                
                // Step 1: Add image to /xl/media/
                var imageName = $"image{Guid.NewGuid():N}.png";
                var imagePath = $"xl/media/{imageName}";
                var imageEntry = archive.CreateEntry(imagePath);

#if NET10_0_OR_GREATER
                var entryStream = await imageEntry.OpenAsync(cancellationToken).ConfigureAwait(false);
                await using var disposableStream = entryStream.ConfigureAwait(false);
#else
                using var entryStream = imageEntry.Open();
#endif
#if NET5_0_OR_GREATER
                await entryStream.WriteAsync(imageBytes.AsMemory(), cancellationToken).ConfigureAwait(false);
#else
                await entryStream.WriteAsync(imageBytes, 0, imageBytes.Length, cancellationToken).ConfigureAwait(false);
#endif

                // Step 2: Update [Content_Types].xml for image
                var contentTypesEntry = archive.GetEntry("[Content_Types].xml");
                var contentTypesDoc = LoadXml(contentTypesEntry);
                if (!contentTypesDoc.DocumentElement.InnerXml.Contains("image/png"))
                {
                    var defaultNode = contentTypesDoc.CreateElement("Default", contentTypesDoc.DocumentElement.NamespaceURI);
                    defaultNode.SetAttribute("Extension", "png");
                    defaultNode.SetAttribute("ContentType", "image/png");
                    contentTypesDoc.DocumentElement.AppendChild(defaultNode);
                    SaveXml(contentTypesDoc, contentTypesEntry);
                }

                // Step 3: Add anchor to drawing XML
                var relId = $"rId{Guid.NewGuid():N}";
                drawingDoc = CreateDrawingXml(drawingDoc, col, row, widthPx, heightPx, relId, imgtype, location);
                    
                // Step 4: Add image relationship to drawing rels
                var relNode = drawingRelsDoc.CreateElement("Relationship", drawingRelsDoc.DocumentElement.NamespaceURI);
                relNode.SetAttribute("Id", relId);
                relNode.SetAttribute("Type", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/image");
                relNode.SetAttribute("Target", $"../media/{imageName}");
                drawingRelsDoc.DocumentElement.AppendChild(relNode);
            }

            SaveXml(drawingDoc, drawingEntry);
            SaveXml(drawingRelsDoc, drawingRelsEntry);
        }
    }
    
    private static XmlDocument LoadXml(ZipArchiveEntry? entry)
    {
        var doc = new XmlDocument();
        if (entry is null)
        {
            doc.LoadXml("""<?xml version="1.0" encoding="UTF-8" standalone="yes"?><Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"/>""");
            return doc;
        }

        using var stream = entry.Open();
        using var reader = new StreamReader(stream);
        var streamString = reader.ReadToEnd();
        if (string.IsNullOrEmpty(streamString))
        {
            doc.LoadXml("""<?xml version="1.0" encoding="UTF-8" standalone="yes"?><Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"/>""");
            return doc;
        }

        stream.Position = 0;
        doc.Load(stream);

        return doc;
    }

    private static void SaveXml(XmlDocument doc, ZipArchiveEntry entry)
    {
        using var stream = entry.Open();
        stream.SetLength(0);
        doc.Save(stream);
    }

    private static XmlNamespaceManager GetNamespaceManager(XmlDocument doc)
    {
        var nsmgr = new XmlNamespaceManager(doc.NameTable);
        nsmgr.AddNamespace("x", "http://schemas.openxmlformats.org/spreadsheetml/2006/main");
        return nsmgr;
    }

	private static XmlDocument CreateDrawingXml(XmlDocument existingDoc, int col, int row, int widthPx, int heightPx, string relId, XlsxImgType imgtype, Point location)
	{
		return DrawingXmlHelper.CreateOrUpdateDrawingXml(existingDoc, col, row, widthPx, heightPx, relId,imgtype, location);
	}

	private static class DrawingXmlHelper
    {
        private const string XdrNamespace = "http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing";
        private const string ANamespace = "http://schemas.openxmlformats.org/drawingml/2006/main";

        private static long PixelsToEmu(int pixels) => pixels * 9525;

        private static string GetColumnName(int colIndex)
        {
            string columnName = "";
            int dividend = colIndex + 1;
            while (dividend > 0)
            {
                int modulo = (dividend - 1) % 26;
                columnName = Convert.ToChar('A' + modulo) + columnName;
                dividend = (dividend - modulo) / 26;
            }

            return columnName;
        }
        
		public static XmlDocument CreateOrUpdateDrawingXml(
			XmlDocument? existingDoc,
			int col, int row,
			int widthPx, int heightPx,
			string relId,
			XlsxImgType imgType,
		    Point location
		)
		{
			var doc = existingDoc ?? new XmlDocument();
			var ns = new XmlNamespaceManager(doc.NameTable);
			ns.AddNamespace("xdr", XdrNamespace);
			ns.AddNamespace("a", ANamespace);
			ns.AddNamespace("r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships");

			// Root
			XmlElement wsDr;
			if (existingDoc is null)
			{
				wsDr = doc.CreateElement("xdr", "wsDr", XdrNamespace);
				wsDr.SetAttribute("xmlns:xdr", XdrNamespace);
				wsDr.SetAttribute("xmlns:a", ANamespace);
				doc.AppendChild(wsDr);
			}
			else
			{
				wsDr = doc.DocumentElement!;
			}

			XmlNodeList anchors = wsDr.SelectNodes("//xdr:oneCellAnchor | //xdr:twoCellAnchor | //xdr:absoluteAnchor", ns);
			int imageCount = anchors?.Count ?? 0;
			int nextId = imageCount + 2;

			string anchorType = imgType switch
			{
				XlsxImgType.AbsoluteAnchor => "absoluteAnchor",
				XlsxImgType.TwoCellAnchor => "twoCellAnchor",
				XlsxImgType.OneCellAnchor => "oneCellAnchor",
				_ => "oneCellAnchor"
			};

			var anchor = doc.CreateElement("xdr", anchorType, XdrNamespace);
			if (imgType == XlsxImgType.TwoCellAnchor)
				anchor.SetAttribute("editAs", "twoCell");

			if (imgType == XlsxImgType.AbsoluteAnchor)
			{
				var pos = doc.CreateElement("xdr", "pos", XdrNamespace);
				pos.SetAttribute("x", PixelsToEmu(location.X).ToString()); // 使用实际列宽
				pos.SetAttribute("y", PixelsToEmu(location.Y).ToString()); // 使用实际行高

				var ext = doc.CreateElement("xdr", "ext", XdrNamespace);
				ext.SetAttribute("cx", PixelsToEmu(widthPx).ToString());
				ext.SetAttribute("cy", PixelsToEmu(heightPx).ToString());

				anchor.AppendChild(pos);
				anchor.AppendChild(ext);
			}
			else if (imgType == XlsxImgType.TwoCellAnchor)
			{
                var from = doc.CreateElement("xdr", "from", XdrNamespace);
                AppendXmlElement(doc, from, "xdr", "col", col.ToString());
                AppendXmlElement(doc, from, "xdr", "colOff", "0");
                AppendXmlElement(doc, from, "xdr", "row", row.ToString());
                AppendXmlElement(doc, from, "xdr", "rowOff", "0");
                
              var to = doc.CreateElement("xdr", "to", XdrNamespace);
				AppendXmlElement(doc, to, "xdr", "col", (col + 1).ToString());
				AppendXmlElement(doc, to, "xdr", "colOff", "0");
				AppendXmlElement(doc, to, "xdr", "row", (row + 1).ToString());
				AppendXmlElement(doc, to, "xdr", "rowOff", "0");

				anchor.AppendChild(from);
				anchor.AppendChild(to);
			}
			else // OneCellAnchor
			{
                var from = doc.CreateElement("xdr", "from", XdrNamespace);
                AppendXmlElement(doc, from, "xdr", "col", col.ToString());
                AppendXmlElement(doc, from, "xdr", "colOff", "0");
                AppendXmlElement(doc, from, "xdr", "row", row.ToString());
                AppendXmlElement(doc, from, "xdr", "rowOff", "0");
				
				var to = doc.CreateElement("xdr", "to", XdrNamespace);
				AppendXmlElement(doc, to, "xdr", "col", (col ).ToString()); // Adjust the column and row for size
				AppendXmlElement(doc, to, "xdr", "colOff", "0");
				AppendXmlElement(doc, to, "xdr", "row", (row ).ToString());
				AppendXmlElement(doc, to, "xdr", "rowOff", "0");

				var ext = doc.CreateElement("xdr", "ext", XdrNamespace);
				ext.SetAttribute("cx", PixelsToEmu(widthPx).ToString());
				ext.SetAttribute("cy", PixelsToEmu(heightPx).ToString());

				anchor.AppendChild(from);
				anchor.AppendChild(ext);
			}

			// -------- Image Content --------
			// <xdr:pic>
			var pic = doc.CreateElement("xdr", "pic", XdrNamespace);

			// <xdr:nvPicPr>
			var nvPicPr = doc.CreateElement("xdr", "nvPicPr", XdrNamespace);
			var cNvPr = doc.CreateElement("xdr", "cNvPr", XdrNamespace);
			cNvPr.SetAttribute("id", nextId.ToString());
			cNvPr.SetAttribute("name", $"ImageAt{GetColumnName(col)}{row + 1}");

			// <a:extLst>...<a16:creationId ... />
			var extLst = doc.CreateElement("a", "extLst", ANamespace);
			var extNode = doc.CreateElement("a", "ext", ANamespace);
			extNode.SetAttribute("uri", "{FF2B5EF4-FFF2-40B4-BE49-F238E27FC236}");

			var creationId = doc.CreateElement("a16", "creationId", "http://schemas.microsoft.com/office/drawing/2014/main");
			creationId.SetAttribute("id", "http://schemas.microsoft.com/office/drawing/2014/main", $"{{00000000-0008-0000-0000-0000{nextId:D6}000000}}");

			extNode.AppendChild(creationId);
			extLst.AppendChild(extNode);
			cNvPr.AppendChild(extLst);

			// <xdr:cNvPicPr><a:picLocks noChangeAspect="1" /></xdr:cNvPicPr>
			var cNvPicPr = doc.CreateElement("xdr", "cNvPicPr", XdrNamespace);
			var picLocks = doc.CreateElement("a", "picLocks", ANamespace);
			picLocks.SetAttribute("noChangeAspect", "1");
			cNvPicPr.AppendChild(picLocks);

			nvPicPr.AppendChild(cNvPr);
			nvPicPr.AppendChild(cNvPicPr);
			pic.AppendChild(nvPicPr);

			// <xdr:blipFill>
			var blipFill = doc.CreateElement("xdr", "blipFill", XdrNamespace);
			var blip = doc.CreateElement("a", "blip", ANamespace);

			blip.SetAttribute("xmlns:r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships");
			blip.SetAttribute("embed", ns.LookupNamespace("r"), relId);
			blip.SetAttribute("cstate", "print");

			var stretch = doc.CreateElement("a", "stretch", ANamespace);
			var fillRect = doc.CreateElement("a", "fillRect", ANamespace);
			stretch.AppendChild(fillRect);

			blipFill.AppendChild(blip);
			blipFill.AppendChild(stretch);
			pic.AppendChild(blipFill);

			// <xdr:spPr>
			var spPr = doc.CreateElement("xdr", "spPr", XdrNamespace);
			var xfrm = doc.CreateElement("a", "xfrm", ANamespace);

			var off = doc.CreateElement("a", "off", ANamespace);
			off.SetAttribute("x", "0");
			off.SetAttribute("y", "0");

			//var spExt = doc.CreateElement("a", "ext", ANamespace);
			//spExt.SetAttribute("cx", "0");
			//spExt.SetAttribute("cy", "0");

			xfrm.AppendChild(off);
			//xfrm.AppendChild(spExt);

			var prstGeom = doc.CreateElement("a", "prstGeom", ANamespace);
			prstGeom.SetAttribute("prst", "rect");

			var avLst = doc.CreateElement("a", "avLst", ANamespace);
			prstGeom.AppendChild(avLst);

			spPr.AppendChild(xfrm);
			spPr.AppendChild(prstGeom);

			pic.AppendChild(spPr);

			// <xdr:clientData />
			var clientData = doc.CreateElement("xdr", "clientData", XdrNamespace);

			//oneCellAnchor.AppendChild(from);
			//oneCellAnchor.AppendChild(ext);
			//oneCellAnchor.AppendChild(pic);
			//oneCellAnchor.AppendChild(clientData);

			//wsDr.AppendChild(oneCellAnchor);
			//var pic = CreatePictureNode(doc, col, row, widthPx, heightPx, relId, nextId);
			//var clientData = doc.CreateElement("xdr", "clientData", XdrNamespace);

			anchor.AppendChild(pic);
			anchor.AppendChild(clientData);
			wsDr.AppendChild(anchor);

			return doc;
		}

		private static void AppendXmlElement(XmlDocument doc, XmlElement parent, string prefix, string localName, string value)
        {
            var el = doc.CreateElement(prefix, localName, prefix == "xdr" ? XdrNamespace : ANamespace);
            el.InnerText = value;
            parent.AppendChild(el);
        }
    }
}