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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/arverma/Bihar-Police-Notebook/llms.txt

Use this file to discover all available pages before exploring further.

Bihar Police Notebook ships two print-ready A4 templates that share the same editor shell. Letter is a plain multi-page text document; Diary is a structured FIR case diary with a fixed header block and two-column pages. Switching between them starts a fresh document of the chosen type after flushing any pending autosave.
TemplateModuleContent shape
Lettereditor/js/paged-sheet.jsPlain text that spills across page cards automatically
Diaryeditor/js/diary-sheet.jsFIR header + pages each with a 20 % left column and 80 % right column

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A4 Geometry Constants

Both templates derive all measurements from a shared set of constants so that screen preview and print output remain pixel-perfect:
ConstantValueMeaning
PAGE_W_MM210A4 page width in millimetres
PAGE_H_MM297A4 page height in millimetres
MARGIN_MM12.7Page margin — half of Google Docs’ default 1 inch margin
FONT_PX15Base body font size in CSS pixels
LINE_HEIGHT_PX24Line height in CSS pixels
LEFT_COL_PCT20Diary left column width as a percentage of the page content area
HEADER_BLOCK_H_PX140FIR header block height in CSS pixels
TITLES_ROW_H_PX72Column-titles row height in CSS pixels
TABLE_BORDER_H_PX4Combined table border height consumed from the page content area
All box heights in the Diary template snap to whole multiples of LINE_HEIGHT_PX (24 px). This guarantees that no line of Devanagari text is ever split across a page boundary.

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Letter Template

The Letter template (paged-sheet.js) renders a sequence of .letter-page card elements, each containing a <textarea class="letter-page-input">. When a textarea overflows its fixed-height page card, content spills automatically to the next page card.
1

User types in a page card

Each keystroke fires an input event that paged-sheet.js listens to via the onChange callback passed from main.js.
2

Overflow detection

paged-sheet.js measures scrollHeight vs the page card’s fixed height. If the text overflows, a new page card is created and excess content is moved there.
3

Autosave debounce

main.js receives the onChange callback and calls scheduleSave(), which debounces the IndexedDB write by 600 ms.
4

Page indicator update

The onPageFocus callback updates #pageIndicator with the current and total page count.

​
Diary Template

The Diary template (diary-sheet.js) manages a richer data model: a top-level header object plus an array of pages, each page holding left-column and right-column content.

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Structural Layout

┌─────────────────────────────────────────────┐
│  FIR Header block (140 px)                  │
│  Titles row      (72 px)                    │
├──────────┬──────────────────────────────────┤
│ Left col │ Right col                        │
│  (20 %)  │  (80 %)                          │
│          │                                  │
└──────────┴──────────────────────────────────┘
The header block is exactly 140 px tall (HEADER_BLOCK_H_PX); the titles row is 72 px (TITLES_ROW_H_PX). Both values are multiples of LINE_HEIGHT_PX so the first body line of the diary aligns cleanly to the 24 px grid. A 4 px table border (TABLE_BORDER_H_PX) is also deducted when computing the usable text area height.

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Diary-Specific Controls

Add Page

Appends a new blank page object to the model and re-renders the diary pages container.

Delete Page

Removes the selected page from the model (minimum one page is always retained).

Hide / Show Header

Toggles the FIR header visibility per page. Useful when printing continuation pages that do not need the header repeated.

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Content Model

The diary content is stored as JSON in IndexedDB: 
{
  "header": {
    "fir_number": "123/2024",
    "case_diary_no": "456",
    "police_station": "Patna Sadar",
    "district": "Patna"
  },
  "pages": [
    {
      "left": "पृष्ठ सं. 1",
      "right": "विवरण...",
      "hideHeader": false
    }
  ]
}

​
Screen vs Print

The same A4 geometry drives both the on-screen preview and the printed output, but the two rendering paths are independent:
Pages are rendered into the DOM as styled <div> elements and then scaled visually to fit the viewport using a CSS transform applied by page-scale.js. The scale is purely cosmetic — it does not affect layout dimensions, so paginating logic always operates on full A4 pixels.See Page Preview for scaling details.
PDF button click  ──►  runPdfExport()
                           │
                ┌──────────▼──────────┐
                │ getActiveTemplate() │
                └──────────┬──────────┘
              letter ◄─────┴─────► diary
                 │                    │
    letterPagesHtml(pages)   diaryPagesHtml(model)
                 │                    │
                 └─────────┬──────────┘
                           ▼
                  Build print HTML + CSS
                           │
                  window.open('', '_blank')
                           │
                  document.fonts.ready.then(print)
                           │
                   window.print() → PDF
1

Collect content

runPdfExport() reads letterSheet.getPages() or diarySheet.getModel() depending on getActiveTemplate().
2

Generate HTML

letterPagesHtml(pages) or diaryPagesHtml(model) returns a string of <div class="page"> elements with inline content at real A4 pixel dimensions.
3

Apply print CSS

letterPrintCss() / diaryPrintCss() returns a <style> block that sets @page { size: A4; margin: 12.7mm; }, loads Noto Sans Devanagari from Google Fonts, and disables any transforms.
4

Open print window

window.open('', '_blank') creates the print target. If pop-ups are blocked an alert prompts the user to allow them.
5

Wait for fonts, then print

The export waits for document.fonts.ready before calling window.print(). If the Fonts API is unavailable it falls back to a 500 ms setTimeout.
Pop-up blockers will prevent the print window from opening. Users must allow pop-ups from the app’s origin. The export button does not silently fail — it shows an alert() when the window cannot be created.
Ctrl/Cmd+P is intercepted by main.js and calls runPdfExport() instead of the browser’s native print dialog. This ensures the correct print CSS and font preloading are always applied.

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