I needed to extract two diagrams from a worksheet in a Microsoft Excel workbook. The diagrams appeared to have been put in the worksheet as an image through a copy and paste operation. I could right-click on an image in the sheet and choose "Copy" or "Save as Picture" and for the latter option I could choose PNG, JPEG, PDF, GIF, or BMP for the "Save as Type" value, but I wondered what type of file Excel was using for the embedded image. The file was a .xlsm file, which like a .xlsx file is an Office Open XML (OpenXML) file format that can be "unzipped" to reveal the constituent files within it by renaming the file to have a .zip filename extension or copying the file to a new file with a .zip extension - see Zipping and unzipping Excel xlsx files. So I copied the file giving the new file a .zip extension and then extracted the contents of that file by unzipping it. I then had a file named "[Content_Types].xml" and the following directories in the directory where I had extracted files from the zip file:
_rels
customXml
docProps
xl
Beneath the "xl" directory was a "media" directory which contained one
.jpeg file, two
.png files, and a bunch of
.emf files. An Enhanced Metafile (EMF) file is
an
image file format created by
Microsoft
Corporation. I was using an Apple
Macbook Pro
laptop and OS
X doesn't provide a default viewing application for that type of file.
But I have the
free and open-source software (FOSS) application
LibreOffice, which comes with a program, soffice, which can convert EMF
files to PNG files, so I converted the files using that utility by using
command substitution to feed
the output of an ls -l *.emf command into that program.
$ /Applications/LibreOffice.app/Contents/MacOS/soffice --headless --convert-to png `ls *.emf` convert /Users/jasmith1/DocumentsCRQ/xl/media/image3.emf -> /Users/jasmith1/Docu ments/www/CRQ/CRQ000000906773/CRQ-906773 SDP/xl/media/image3.png using filter : draw_png_Export convert /Users/jasmith1/DocumentsCRQ/xl/media/image4.emf -> /Users/jasmith1/Docu ments/www/CRQ/CRQ000000906773/CRQ-906773 SDP/xl/media/image4.png using filter : draw_png_Export convert /Users/jasmith1/DocumentsCRQ/xl/media/image5.emf -> /Users/jasmith1/Docu ments/www/CRQ/CRQ000000906773/CRQ-906773 SDP/xl/media/image5.png using filter : draw_png_Export convert /Users/jasmith1/DocumentsCRQ/xl/media/image6.emf -> /Users/jasmith1/Docu ments/www/CRQ/CRQ000000906773/CRQ-906773 SDP/xl/media/image6.png using filter : draw_png_Export convert /Users/jasmith1/DocumentsCRQ/xl/media/image7.emf -> /Users/jasmith1/Docu ments/www/CRQ/CRQ000000906773/CRQ-906773 SDP/xl/media/image7.png using filter : draw_png_Export convert /Users/jasmith1/DocumentsCRQ/xl/media/image9.emf -> /Users/jasmith1/Docu ments/www/CRQ/CRQ000000906773/CRQ-906773 SDP/xl/media/image9.png using filter : draw_png_Export $
Checking the resultant .png files, I found that I had the diagrams I needed, though I found they didn't look exactly the same as they appeared in the Excel workbook, e.g., some background colors were missing from sections of the images, so I resorted to clicking on the images inside the worksheet and choosing "Save as Picture" to save them as PNG files that looked exactly the same as how they appeared in the worksheet.
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