pptx-glimpse

A Node.js library to render PPTX as SVG / PNG.

Demo | npm

Motivation

pptx-glimpse is designed for two primary use cases:

• Frontend PPTX preview — Render slide thumbnails without depending on Microsoft Office or LibreOffice. The SVG output can be embedded directly in web pages.
• AI image recognition — Convert slides to PNG so that vision-capable LLMs can understand slide content and layout.

The library focuses on accurately reproducing text, shapes, and spatial layout rather than pixel-perfect rendering of every PowerPoint feature.

Requirements

• Node.js >= 20

Installation

npm install pptx-glimpse

Usage

import { readFileSync, writeFileSync } from "fs";
import { convertPptxToSvg, convertPptxToPng } from "pptx-glimpse";

const pptx = readFileSync("presentation.pptx");

// Convert to SVG
const svgResults = await convertPptxToSvg(pptx);
// [{ slideNumber: 1, svg: "<svg>...</svg>" }, ...]

// Convert to PNG
const pngResults = await convertPptxToPng(pptx);
// [{ slideNumber: 1, png: Buffer, width: 960, height: 540 }, ...]

writeFileSync("slide1.png", pngResults[0].png);

Options

Both convertPptxToSvg and convertPptxToPng accept an optional ConvertOptions object.

const results = await convertPptxToPng(pptx, {
  slides: [1, 3], // Convert only slides 1 and 3
  width: 1920, // Output width in pixels (default: 960)
  logLevel: "warn", // Warning log level: "off" | "warn" | "error"
  fontDirs: ["/custom/fonts"], // Additional font directories to search
  fontMapping: {
    "Custom Corp Font": "Noto Sans", // Custom font name mapping
  },
});

Fonts

Automatic Font Loading

pptx-glimpse automatically scans system font directories and loads fonts using opentype.js. Text in SVG output is converted to <path> elements, ensuring consistent rendering regardless of the environment.

Default system font directories:

| OS | Directories | | ------- | ------------------------------------------------------------ | | Linux | /usr/share/fonts, /usr/local/share/fonts | | macOS | /System/Library/Fonts, /Library/Fonts, ~/Library/Fonts | | Windows | C:\Windows\Fonts |

Use the fontDirs option to add custom font directories.

Font Mapping

PPTX files often reference proprietary fonts (e.g., Calibri, Meiryo). pptx-glimpse maps these to open-source alternatives available on Google Fonts.

Default mapping:

| PPTX Font | Mapped to | | ----------------------------------- | ------------- | | Calibri | Carlito | | Arial | Arimo | | Times New Roman | Tinos | | Courier New | Cousine | | Cambria | Caladea | | Meiryo / Yu Gothic / MS Gothic etc. | Noto Sans JP | | MS Mincho / Yu Mincho etc. | Noto Serif JP |

You can customize the mapping via the fontMapping option:

const results = await convertPptxToSvg(pptx, {
  fontMapping: {
    "Custom Corp Font": "Noto Sans", // Add a new mapping
    Arial: "Inter", // Override the default
  },
});

Feature Support

Supports conversion of static visual content in PowerPoint. Dynamic elements such as animations and transitions are not supported.

Supported Features

Shapes

| Feature | Details | | ------------- | ------------------------------------------------------------------------------------------------------------------------------ | | Preset shapes | 136 types (rectangles, ellipses, arrows, flowcharts, callouts, stars, math symbols, etc.) | | Custom shapes | Arbitrary shape drawing using custom paths (moveTo, lnTo, cubicBezTo, quadBezTo, arcTo, close), adjust values / guide formulas | | Connectors | Straight / bent / curved connectors, arrow endpoints (headEnd/tailEnd), line style / color / width | | Groups | Shape grouping, nested groups, group rotation / flip | | Transforms | Position, size, rotation, flip (flipH/flipV), adjustment values |

Text

| Feature | Details | | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------- | | Character formatting | Font size, font family (East Asian font support), bold, italic, underline, strikethrough, font color, superscript / subscript, hyperlinks | | Paragraph formatting | Horizontal alignment (left/center/right/justify), vertical anchor (top/center/bottom), line spacing, before/after paragraph spacing, indent | | Bullet points | Character bullets (buChar), auto-numbering (buAutoNum, 9 types), bullet font / color / size | | Text boxes | Word wrap (square/none), auto-fit (noAutofit/normAutofit/spAutofit), font scaling, margins | | Word wrapping | Word wrapping for English, Japanese, and CJK text, wrapping with mixed font sizes | | Style inheritance | Full text style inheritance chain (run → paragraph default → body lstStyle → layout → master → txStyles → defaultTextStyle → theme fonts) | | Tab stops / fields | Tab stop positions, field codes (slide number, date, etc.) |

Fill

| Feature | Details | | ------------ | ---------------------------------------------------------------- | | Solid color | RGB color specification, transparency | | Gradient | Linear gradient, radial gradient, multiple gradient stops, angle | | Image fill | PNG/JPEG/GIF, stretch mode, cropping (srcRect) | | Pattern fill | Hatching patterns (horizontal, vertical, diagonal, cross, etc.) | | Group fill | Inherit fill from parent group | | No fill | noFill specification |

Lines & Borders

| Feature | Details | | ---------- | ----------------------------------------------------------------- | | Line style | Line width, solid color, transparency, lineCap, lineJoin | | Dash style | solid, dash, dot, dashDot, lgDash, lgDashDot, sysDash, sysDot | | Arrows | Head / tail arrow endpoints with type, width, and length settings |

Colors

| Feature | Details | | ---------------- | ------------------------------------------------------------------------ | | Color types | RGB (srgbClr), theme color (schemeClr), system color (sysClr) | | Theme colors | Color scheme (dk1, lt1, dk2, lt2, accent1-6, hlink, folHlink), color map | | Color transforms | Luminance adjustment (lumMod/lumOff), tint, shade, transparency (alpha) |

Effects

| Feature | Details | | ------------ | ------------------------------------------------------ | | Outer shadow | Blur radius, distance, direction, color / transparency | | Inner shadow | Blur radius, distance, direction, color / transparency | | Glow | Radius, color / transparency | | Soft edge | Radius |

Images

| Feature | Details | | -------------- | ---------------------------------------------------------------------------- | | Image elements | PNG/JPEG/GIF, position / size / rotation / flip, cropping (srcRect), effects | | Image fill | Image fill for shapes and backgrounds |

Tables

| Feature | Details | | --------------- | ------------------------------------------------------------------------------- | | Table structure | Row and column grid, cell merging (gridSpan/rowSpan), row height / column width | | Cell formatting | Text, fill (solid/gradient/image), borders (top/bottom/left/right, styles) |

Charts

| Feature | Details | | ---------------- | ------------------------------------------------------------------------------------------------------------ | | Supported charts | Bar chart (vertical/horizontal), line chart, pie chart, scatter plot, area chart, doughnut, bubble, radar | | Chart elements | Title, legend (position), series (name/values/categories/color), category axis, value axis |

SmartArt

| Feature | Details | | ------------------- | ------------------------------------------------------------------------------ | | Pre-rendered shapes | Renders SmartArt using PowerPoint's pre-rendered drawing shapes (drawingN.xml) | | mc:AlternateContent | Handles AlternateContent fallback mechanism used by SmartArt |

Background & Slide Settings

| Feature | Details | | ------------ | ---------------------------------------------------------------------- | | Background | Solid, gradient, image. Fallback order: slide → layout → master | | Slide size | 16:9, 4:3, custom sizes | | Theme | Theme color scheme, theme fonts (majorFont/minorFont), theme font refs | | showMasterSp | Control visibility of master shapes per slide / layout |

Unsupported Features

| Category | Unsupported features | | -------------- | ---------------------------------------------------------------------------------------------- | | Fill | Path gradient (rect/shape type) | | Effects | Reflection, 3D rotation / extrusion, artistic effects | | Charts | Stock, combo, histogram, box plot, waterfall, treemap, sunburst | | Chart details | Data labels, axis titles / tick marks / grid lines, error bars, trendlines | | Text | Individual text effects (shadow/glow), text columns | | Tables | Table style template application, diagonal borders | | Shapes | Shape operations (Union/Subtract/Intersect/Fragment) | | Multimedia | Embedded video / audio | | Animations | Object animations, slide transitions | | Slide elements | Slide notes, comments, headers / footers, slide numbers / dates | | Image formats | EMF/WMF (parsed but not rendered) | | Other | Macros / VBA, sections, zoom slides |

Test Rendering

You can specify a PPTX file to preview SVG and PNG conversion results.

npm run render -- <pptx-file> [output-dir]

• If output-dir is omitted, output is saved to ./output

# Examples
npm run render -- presentation.pptx
npm run render -- presentation.pptx ./my-output

License

MIT