Implement support for Excel EMBED function and object file embedding

- Add AddEmbeddedObject function to embed files as objects in cells
- Add SetCellEmbedFormula convenience function for EMBED formulas
- Add content types and relationship support for OLE objects
- Include comprehensive tests for both functions
- Support Package and other object types for embedding

Co-authored-by: xuri <[email protected]>

Author: Copilot

cell.go

@@ -1745,3 +1745,18 @@ func shiftCell(val string, dCol, dRow int) string {
 	}
 	return strings.Join(parts, ":")
 }
+
+// SetCellEmbedFormula provides a function to set EMBED formula on the cell.
+// This is a convenience function for setting object embedding formulas in Excel cells.
+// For example:
+//
+//	err := f.SetCellEmbedFormula("Sheet1", "A1", "Package")
+//
+// This will set the formula =EMBED("Package","") in cell A1.
+func (f *File) SetCellEmbedFormula(sheet, cell, objectType string) error {
+	if objectType == "" {
+		objectType = "Package"
+	}
+	formula := fmt.Sprintf("EMBED(\"%s\",\"\")", objectType)
+	return f.SetCellFormula(sheet, cell, formula)
+}

picture.go

@@ -14,6 +14,7 @@ package excelize
 import (
 	"bytes"
 	"encoding/xml"
+	"fmt"
 	"image"
 	"io"
 	"os"
@@ -1018,3 +1019,155 @@ func (f *File) getDispImages(sheet, cell string) ([]Picture, error) {
 	}
 	return pics, err
 }
+
+// EmbeddedObjectOptions defines the format set of embedded object.
+type EmbeddedObjectOptions struct {
+	AltText     string
+	PrintObject *bool
+	Locked      *bool
+	ObjectType  string // Default is "Package"
+}
+
+// AddEmbeddedObject provides a method to embed a file as an object in a cell.
+// The embedded object will be accessible through Excel's EMBED formula.
+// Supported object types include "Package" for general files. For example:
+//
+//	package main
+//
+//	import (
+//	    "fmt"
+//	    "os"
+//
+//	    "github.com/xuri/excelize/v2"
+//	)
+//
+//	func main() {
+//	    f := excelize.NewFile()
+//	    defer func() {
+//	        if err := f.Close(); err != nil {
+//	            fmt.Println(err)
+//	        }
+//	    }()
+//
+//	    // Read file to embed
+//	    file, err := os.ReadFile("document.pdf")
+//	    if err != nil {
+//	        fmt.Println(err)
+//	        return
+//	    }
+//
+//	    // Add embedded object
+//	    if err := f.AddEmbeddedObject("Sheet1", "A1", "document.pdf", file, 
+//	        &excelize.EmbeddedObjectOptions{
+//	            ObjectType: "Package",
+//	            AltText:    "Embedded PDF Document",
+//	        }); err != nil {
+//	        fmt.Println(err)
+//	        return
+//	    }
+//
+//	    if err := f.SaveAs("Book1.xlsx"); err != nil {
+//	        fmt.Println(err)
+//	    }
+//	}
+func (f *File) AddEmbeddedObject(sheet, cell, filename string, file []byte, opts *EmbeddedObjectOptions) error {
+	if opts == nil {
+		opts = &EmbeddedObjectOptions{
+			ObjectType:  "Package",
+			PrintObject: boolPtr(true),
+			Locked:      boolPtr(true),
+		}
+	}
+	if opts.ObjectType == "" {
+		opts.ObjectType = "Package"
+	}
+	if opts.PrintObject == nil {
+		opts.PrintObject = boolPtr(true)
+	}
+	if opts.Locked == nil {
+		opts.Locked = boolPtr(true)
+	}
+
+	// Add embedded object to package
+	objPath := f.addEmbeddedObject(file, filename)
+	
+	// Add relationships
+	sheetXMLPath, _ := f.getSheetXMLPath(sheet)
+	sheetRels := "xl/worksheets/_rels/" + strings.TrimPrefix(sheetXMLPath, "xl/worksheets/") + ".rels"
+	rID := f.addRels(sheetRels, SourceRelationshipOLEObject, "../"+objPath, "")
+	
+	// Set EMBED formula in cell
+	formula := fmt.Sprintf("EMBED(\"%s\",\"\")", opts.ObjectType)
+	if err := f.SetCellFormula(sheet, cell, formula); err != nil {
+		return err
+	}
+
+	// Add OLE object to worksheet
+	ws, err := f.workSheetReader(sheet)
+	if err != nil {
+		return err
+	}
+
+	if ws.OleObjects == nil {
+		ws.OleObjects = &xlsxInnerXML{}
+	}
+
+	// Create OLE object XML content
+	oleObjectXML := fmt.Sprintf(`<oleObject progId="Package" dvAspect="DVASPECT_ICON" link="false" oleUpdate="OLEUPDATE_ONCALL" autoLoad="false" shapeId="1025" r:id="rId%d"/>`, rID)
+	if ws.OleObjects.Content == "" {
+		ws.OleObjects.Content = oleObjectXML
+	} else {
+		ws.OleObjects.Content += oleObjectXML
+	}
+
+	// Add content type for embedded object
+	return f.addContentTypePartEmbeddedObject()
+}
+
+// addEmbeddedObject adds embedded object file to the package and returns the path.
+func (f *File) addEmbeddedObject(file []byte, filename string) string {
+	count := f.countEmbeddedObjects()
+	objPath := "embeddings/oleObject" + strconv.Itoa(count+1) + ".bin"
+	f.Pkg.Store("xl/"+objPath, file)
+	return objPath
+}
+
+// countEmbeddedObjects counts the number of embedded objects in the package.
+func (f *File) countEmbeddedObjects() int {
+	count := 0
+	f.Pkg.Range(func(k, v interface{}) bool {
+		if strings.Contains(k.(string), "xl/embeddings/oleObject") {
+			count++
+		}
+		return true
+	})
+	return count
+}
+
+// addContentTypePartEmbeddedObject adds content type for embedded objects.
+func (f *File) addContentTypePartEmbeddedObject() error {
+	content, err := f.contentTypesReader()
+	if err != nil {
+		return err
+	}
+	content.mu.Lock()
+	defer content.mu.Unlock()
+
+	// Check if bin extension already exists
+	var binExists bool
+	for _, v := range content.Defaults {
+		if v.Extension == "bin" {
+			binExists = true
+			break
+		}
+	}
+
+	if !binExists {
+		content.Defaults = append(content.Defaults, xlsxDefault{
+			Extension:   "bin",
+			ContentType: ContentTypeOLEObject,
+		})
+	}
+
+	return nil
+}

picture_test.go

@@ -615,3 +615,70 @@ func TestGetImageCells(t *testing.T) {
 	assert.EqualError(t, err, "XML syntax error on line 1: invalid UTF-8")
 	assert.NoError(t, f.Close())
 }
+
+func TestAddEmbeddedObject(t *testing.T) {
+	f := NewFile()
+	defer func() {
+		assert.NoError(t, f.Close())
+	}()
+
+	// Test data for embedding
+	testData := []byte("This is a test document content")
+
+	// Test adding embedded object with default options
+	err := f.AddEmbeddedObject("Sheet1", "A1", "test.txt", testData, nil)
+	assert.NoError(t, err)
+
+	// Verify the EMBED formula was set
+	formula, err := f.GetCellFormula("Sheet1", "A1")
+	assert.NoError(t, err)
+	assert.Equal(t, `EMBED("Package","")`, formula)
+
+	// Test adding embedded object with custom options
+	err = f.AddEmbeddedObject("Sheet1", "B1", "document.pdf", testData, 
+		&EmbeddedObjectOptions{
+			ObjectType: "Package",
+			AltText:    "Embedded PDF Document",
+		})
+	assert.NoError(t, err)
+
+	// Verify the second EMBED formula
+	formula, err = f.GetCellFormula("Sheet1", "B1")
+	assert.NoError(t, err)
+	assert.Equal(t, `EMBED("Package","")`, formula)
+
+	// Test with invalid sheet name
+	err = f.AddEmbeddedObject("", "A1", "test.txt", testData, nil)
+	assert.EqualError(t, err, ErrSheetNameBlank.Error())
+
+	// Test with invalid cell reference
+	err = f.AddEmbeddedObject("Sheet1", "", "test.txt", testData, nil)
+	assert.EqualError(t, err, `cannot convert cell "" to coordinates: invalid cell name ""`)
+}
+
+func TestSetCellEmbedFormula(t *testing.T) {
+	f := NewFile()
+	defer func() {
+		assert.NoError(t, f.Close())
+	}()
+
+	// Test setting EMBED formula with default Package type
+	err := f.SetCellEmbedFormula("Sheet1", "A1", "")
+	assert.NoError(t, err)
+
+	formula, err := f.GetCellFormula("Sheet1", "A1")
+	assert.NoError(t, err)
+	assert.Equal(t, `EMBED("Package","")`, formula)
+
+	// Test setting EMBED formula with custom object type
+	err = f.SetCellEmbedFormula("Sheet1", "B1", "Document")
+	assert.NoError(t, err)
+
+	formula, err = f.GetCellFormula("Sheet1", "B1")
+	assert.NoError(t, err)
+	assert.Equal(t, `EMBED("Document","")`, formula)
+
+	// Test with invalid sheet name
+	err = f.SetCellEmbedFormula("", "A1", "Package")
+	assert.EqualError(t, err, ErrSheetNameBlank.Error())
+}

templates.go

@@ -62,6 +62,7 @@ const (
 	ContentTypeTemplateMacro                      = "application/vnd.ms-excel.template.macroEnabled.main+xml"
 	ContentTypeVBA                                = "application/vnd.ms-office.vbaProject"
 	ContentTypeVML                                = "application/vnd.openxmlformats-officedocument.vmlDrawing"
+	ContentTypeOLEObject                          = "application/vnd.openxmlformats-officedocument.oleObject"
 	NameSpaceDrawingMLMain                        = "http://schemas.openxmlformats.org/drawingml/2006/main"
 	NameSpaceDublinCore                           = "http://purl.org/dc/elements/1.1/"
 	NameSpaceDublinCoreMetadataInitiative         = "http://purl.org/dc/dcmitype/"
@@ -88,6 +89,8 @@ const (
 	SourceRelationshipTable                       = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/table"
 	SourceRelationshipVBAProject                  = "http://schemas.microsoft.com/office/2006/relationships/vbaProject"
 	SourceRelationshipWorkSheet                   = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet"
+	SourceRelationshipOLEObject                   = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/oleObject"
+	SourceRelationshipPackage                     = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/package"
 	StrictNameSpaceDocumentPropertiesVariantTypes = "http://purl.oclc.org/ooxml/officeDocument/docPropsVTypes"
 	StrictNameSpaceDrawingMLMain                  = "http://purl.oclc.org/ooxml/drawingml/main"
 	StrictNameSpaceExtendedProperties             = "http://purl.oclc.org/ooxml/officeDocument/extendedProperties"