Requirement to render two different font styles within a single PDF template.

[Ramu-kandimalla]

Hi Team,

For the On Courts platform, we have received a requirement to render two different font styles within a single PDF template.

Currently, we are using the DIGIT PDF service for PDF generation on our platform. Could you please confirm whether supporting multiple font styles in the same PDF template is feasible with the existing PDF service?

Additionally, please let us know if any configuration or service-level changes would be required to support this.

[atulgupta2024]

Specifically we are working with English and Malayalam for now. Some sections of the PDF like header, footer, signatures etc. will be english and text in between would be Malayalam

[talele08]

@vinothrallapalli-eGov Could you please take a look

[atulgupta2024]

here's more context. We have been using Roboto font for the document and this was working fine even with Malayalam, until we hit a snag where there is some specific text of Malayalam ( “പ്രകാരമുള്ള”) was not shown properly in the PDF and it changed the meaning slightly and it is due to indic script shaping failure. We are supposed to use a font that supports the complex text shaping as required by malayalam. After trying various fonts we found that Manjari seems to work best (Noto Sans/Serif Malayalam is supposed to be the best, but we are having some issues with the GSUB/GPOS table in the TTF font).

However using Manjari for the document now is making the English text appear differently i.e. it is not looking that good. So for the PDF Generation, we want to use Roboto for the part where the text is English and Manjari where the text is malayalam. But we don't really know how to make this work with the DIGIT PDF Service.

[mithunhegde-egov]

@atulgupta2024 @Ramu-kandimalla few changes are needed in the pdf service. You will have to add new font descriptors for Manjari. Below is what I tried you can make those changes and test it. Adding a sample config file also just for reference. The Manjari fonts are not supported currently.

Add Malayalam-capable glyphs (Manjari regular/bold) under src/fonts and wired them into pdfmake’s descriptors in src/index.js (line 97). The entry looks something like:

var fontDescriptors = {
Roboto: {
normal: "src/fonts/Roboto-Regular.ttf",
bold: "src/fonts/Roboto-Bold.ttf",
italics: "src/fonts/Roboto-Italic.ttf",
bolditalics: "src/fonts/Roboto-BoldItalic.ttf"
},
Malayalam: {
normal: "src/fonts/Manjari-Regular.ttf",
bold: "src/fonts/Manjari-Bold.ttf",
italics: "src/fonts/Manjari-Regular.ttf",
bolditalics: "src/fonts/Manjari-Bold.ttf"
},
…
};

var defaultFontMapping = { en_IN: "default", hi_IN: "default", ml_IN: "Malayalam" };

Sample Configs – English + Malayalam Split

mixed font data.json
{
  "key": "mixed-font",
  "DataConfigs": {
    "moduleName": "on-courts",
    "serviceName": "on-courts",
    "version": "1.0.0",
    "baseKeyPath": "$.documents[*]",
    "entityIdPath": "$.docNumber",
    "mappings": [
      {
        "topic": "mixed-font",
        "mappings": [
          {
            "direct": [
              { "variable": "headerTitle",    "value": { "path": "$.headerTitle" } },
              { "variable": "malayalamTitle", "value": { "path": "$.malayalamTitle" } },
              { "variable": "malayalamBody",  "value": { "path": "$.malayalamBody" } },
              { "variable": "englishBody",    "value": { "path": "$.englishBody" } },
              { "variable": "malayalamSuffix","value": { "path": "$.malayalamSuffix" } },
              { "variable": "footerText",     "value": { "path": "$.footerText" } },
              { "variable": "docNumber",      "value": { "path": "$.docNumber" } }
            ]
          }
        ]
      }
    ]
  }
}

mixed-font-format.json

{
  "key": "mixed-font",
  "config": {
    "pageMargins": [40, 60, 40, 60],
    "defaultStyle": { "font": "Roboto", "fontSize": 11 },
    "content": [
      { "text": "{{headerTitle}}", "style": "englishHeader" },
      { "text": "{{malayalamTitle}}", "style": "malayalamSectionTitle", "margin": [0,16,0,4] },
      { "text": "{{malayalamBody}}", "style": "malayalamBody", "margin": [0,8,0,8] },
      {
        "text": [
          { "text": "{{englishBody}}", "style": "englishBody" },
          { "text": "{{malayalamSuffix}}", "style": "malayalamBody" }
        ],
        "margin": [0,16,0,0]
      },
      { "text": "{{footerText}}", "style": "footer", "margin": [0,40,0,0] },
      { "text": "Reference: {{docNumber}}", "style": "englishBody", "margin": [0,12,0,0] }
    ],
    "styles": {
      "englishHeader": { "font": "Roboto", "bold": true, "fontSize": 18, "alignment": "center" },
      "malayalamSectionTitle": { "font": "Malayalam", "fontSize": 16, "bold": true },
      "malayalamBody": { "font": "Malayalam", "fontSize": 14, "lineHeight": 1.3 },
      "englishBody": { "font": "Roboto", "fontSize": 12, "lineHeight": 1.4 },
      "footer": { "font": "Roboto", "bold": true, "alignment": "right" }
    }
  }
}

Mixed paragraph is rendered as two inline spans so Malayalam and English sit side by side but with different fonts.
Steps to Run and test the above changes

• Copy Manjari-Regular.ttf and Manjari-Bold.ttf into src/fonts
• Ensure src/index.js contains the Malayalam descriptor shown above
• run the below command with the format and data env set

DATA_CONFIG_URLS=file:///path/to/local-config/mixed-font-data.json
FORMAT_CONFIG_URLS=file:///path/to/local-config/mixed-font-format.json
npm run dev

generate the pdf using below sample curl

curl --location 'http://localhost:8080/pdf-service/v1/_createnosave?tenantId=kl.test&key=mixed-font' \
  --header 'Content-Type: application/json' \
  --data '{
        "RequestInfo": {
          "apiId": "on-courts",
          "ver": "1.0",
          "msgId": "sample|ml_IN",
          "userInfo": { "id": 1 }
        },
        "documents": [{
          "docNumber": "DOC-002",
          "headerTitle": "ON COURTS PLATFORM",
          "malayalamTitle": "മഞ്ജരി ഉപയോഗിച്ചുള്ള മലയാളം",
          "malayalamBody": "ഇത് ഒരു മൾട്ടി ഫോണ്ട് പി.ഡി.എഫ് സാംപി്ളാണ്, ഇവിടെ പ്രഖ്യാപനത്തിന്റെ വകുപ്പുകൾ പ്രകാരമുള്ള രേഖാമൂലമുള്ള വിവരങ്ങൾ മനസ്സിലാകുന്ന വിധത്തിൽ മഞ്ജരി ഫോണ്ട് ഉപയോഗിക്കുന്നു.",
          "englishBody": "The English paragraph continues to be rendered in Roboto so that headers, footers, and signatures remain crisp while Malayalam sections use Manjari for complex shaping like ",
          "malayalamSuffix": "പ്രകാരമുള്ള.",
          "footerText": "Signature / സഹി"
        }]
      }'

you should see both together as shown in the screenshot.

[atulgupta2024]

Thanks @mithunhegde-egov. There is one issue we have is

we have a rich text box on the UI, where a person can enter a mix of English and Malayalam sentences. it will be at a sentence level and we do not expect it to go be a word level.

the current approach will work when I know the specific sections. But for text entered by user in the edit box, this will be a challenge, unless we do some check to identify the language for each sentence

[santhosh-7777]

We can extend the current multi-font support by introducing a preprocessing layer before PDF generation.
For dynamic user input (rich text), we can:

1. Split the content into sentences.
2. Detect language using Unicode range (Malayalam: \u0D00–\u0D7F).
3. Map each sentence to corresponding font style (Roboto / Manjari).
4. Convert into pdfmake inline text spans.
   This allows rendering mixed-language content without predefined sections.
   Optionally, we can enhance this further using language detection libraries like franc for better accuracy.
   This approach avoids major changes in PDF service and keeps logic modular at the backend layer.