It seems Japanese excel file cannot convert to image nor pdf correctly. I guess some encoding configuration have to be done before saving, but I could not find any document related to it. It occurred in Mac, Linux. But it was successful in Windows. I would like to consider buying if these could be overcome.
Thank you for contacting Aspose support.
The most important factor while converting spreadsheets (Excel files) to PDF format is the availability of the required True Type Fonts on the machine where conversion has to take place. In case Aspose.Cells API does not find the required fonts, it will try to substitute the fonts with any other closely resembling available fonts. In this scenario, you may receive unwanted results. It is advised that you should first place the TTFs in your Linux/MAC environment, and direct the API to use these fonts with the help of CellsHelper.setFontDir method. Please note, aforesaid statement should be at the start of your application. Moreover, you do not need to install the fonts on both Linux & MAC environments, you can simply copy the fonts from your Windows machine in some folder on Linux & MAC. Then use the CellsHelper.setFontDir method to point the API to the correct folder containing TTFs.
Please feel free to write back in case you have further questions or concerns.