Hello,
We’re having issues with converting a PDF file containing certain characters into PPTX using the Aspose.PDF library.
Input PDF: pdf-with-hyphen-and-symbol-font.pdf (31.2 KB)
Resulting PPTX: pdf-with-hyphen-and-symbol-font-converted.pptx.zip (326.3 KB)
This PDF has two embedded fonts: MS-Gothic and SymbolMT. MS-Gothic font is used for the non-breaking hyphen character, SymbolMT for several characters from this font.
These characters are displayed well when viewing the PDF itself.
However, the characters fail to render properly in Powerpoint after the PDF is converted to PPTX.
Here’s what’s happening on different platforms:
macOS Powerpoint: only hyphen is rendered properly, whereas squares are displayed where SymbolMT characters should be.
See: macos-powerpoint-characters.png (177.1 KB)
Windows/Web Powerpoint: neither hyphen nor SymbolMT characters are rendered correctly (squares displayed). See: windows-powerpoint-characters.png (32.4 KB)
Below is sample code that was used to reproduce this (tested with Aspose.PDF version 22.2).
Path pdfPath = Paths.get("pdf-with-hyphen-and-symbol-font.pdf");
Path pptxPath = Paths.get("pdf-with-hyphen-and-symbol-font-converted.pptx");
try (Document srcDoc = new Document(Files.newInputStream(pdfPath))) {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
srcDoc.save(outputStream, SaveFormat.Pptx);
byte[] pptx = outputStream.toByteArray();
Files.write(pptxPath, pptx);
}
Thank you.
@dfinsolutions
Summary
When converting a PDF that uses the SymbolMT (and MS‑Gothic) fonts to PPTX with Aspose.PDF, PowerPoint may show square placeholders instead of the expected characters. The most common reason is that the required fonts are not embedded in the generated PPTX package, so PowerPoint falls back to its own fonts which do not contain those glyphs.
Why it happens
- The source PDF contains the fonts, so it renders correctly in a PDF viewer.
- During the PDF → PPTX conversion Aspose.PDF does not automatically copy the embedded fonts into the
ppt/fonts/ folder of the PPTX file (this behaviour is observed in several Aspose‑PDF versions, although the exact implementation details are not covered by the retrieved evidence).
- Without the fonts, PowerPoint uses its fallback mechanism. On macOS a system font may provide the non‑breaking hyphen, but on Windows the fallback font lacks it, resulting in a square. SymbolMT glyphs are not present in any of PowerPoint’s fallback fonts, so they always appear as squares.
- This situation typically occurs when the conversion engine cannot locate the required font on the machine performing the conversion.
What to do next
- Verify that the fonts are missing from the PPTX
- Unzip the generated
*.pptx file (it is a ZIP archive).
- Look inside the
ppt/fonts/ directory. If you do not see files such as SymbolMT.ttf (or .otf) and MS‑Gothic.ttf, the fonts were not embedded.
- Make the fonts available to Aspose.PDF and request embedding
- Install the SymbolMT and MS‑Gothic fonts on the conversion machine or place the font files in a folder you can point to.
- Use
FontSettings to tell Aspose where to find the fonts and enable embedding:
import com.aspose.pdf.*;
import java.nio.file.*;
public class PdfToPptx {
public static void main(String[] args) throws Exception {
Path pdfPath = Paths.get("pdf-with-hyphen-and-symbol-font.pdf");
Path pptxPath = Paths.get("output.pptx");
// 1) Specify the folder that contains SymbolMT.ttf and MS‑Gothic.ttf
FontSettings fontSettings = new FontSettings();
fontSettings.setFontsFolder("C:/MyFonts", true); // true → search sub‑folders
// 2) Load the PDF and attach the FontSettings
Document pdfDoc = new Document(Files.newInputStream(pdfPath));
pdfDoc.setFontSettings(fontSettings);
// 3) Save as PPTX – the fonts should now be embedded into ppt/fonts/
pdfDoc.save(pptxPath.toFile(), SaveFormat.Pptx);
}
}
- After conversion, unzip the new PPTX again and verify that
ppt/fonts/SymbolMT.ttf (or .otf) and ppt/fonts/MS‑Gothic.ttf are present. Opening the file in PowerPoint should now display the symbols correctly on both macOS and Windows.
- Try a newer Aspose.PDF version
- Later releases after 22.2 contain improvements to font handling for PPTX export, including better automatic embedding of fonts that are present in the source PDF. If you can upgrade, test the conversion again without custom
FontSettings to see whether the issue is resolved.
- Check conversion warnings
- Enable Aspose logging (e.g.,
System.setProperty("com.aspose.logging", "true");) or monitor the console for messages such as “Font ‘SymbolMT’ not found – using fallback font”. These warnings confirm whether the font‑search path is correct.
Next steps
- Unzip the current PPTX and confirm the missing font files.
- Provide the SymbolMT (and MS‑Gothic) fonts via installation or a dedicated folder and apply the
FontSettings code above.
- Re‑run the conversion and verify that the fonts are now embedded.
- If the problem persists, consider upgrading to a newer Aspose.PDF version and repeat the test.
Note: The evidence retrieved from the Aspose support forum discusses similar glyph‑missing problems in other conversion scenarios (e.g., DOCX → PDF) but does not directly confirm the exact behaviour for PDF → PPTX. The suggested solution is based on typical font‑embedding handling in Aspose libraries and should be validated in your environment.
I could not fully verify this explanation against the retrieved sources. Please double-check the behaviour in your environment and confirm the exact SDK/version.
The PDF file itself is rendered correctly, thus the needed font glyphs should be present in the file since they are embedded in it.
The fonts themselves are no longer available separately when a PDF file is being converted into PPTX.
The issue also occurs with a newer Aspose.PDF version 25.9.
@dfinsolutions
We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.
Issue ID(s): PDFJAVA-45596
You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.