Add isPalette and bitsPerSample metadata, deprecate paletteBitDepth

docs/api-input.md

@@ -22,9 +22,10 @@ A `Promise` is returned when `callback` is not provided.
 - `density`: Number of pixels per inch (DPI), if present
 - `chromaSubsampling`: String containing JPEG chroma subsampling, `4:2:0` or `4:4:4` for RGB, `4:2:0:4` or `4:4:4:4` for CMYK
 - `isProgressive`: Boolean indicating whether the image is interlaced using a progressive scan
+- `isPalette`: Boolean indicating whether the image is palette-based (GIF, PNG).
+- `bitsPerSample`: Number of bits per sample for each channel (GIF, PNG, HEIF).
 - `pages`: Number of pages/frames contained within the image, with support for TIFF, HEIF, PDF, animated GIF and animated WebP
 - `pageHeight`: Number of pixels high each page in a multi-page image will be.
-- `paletteBitDepth`: Bit depth of palette-based image (GIF, PNG).
 - `loop`: Number of times to loop an animated image, zero refers to a continuous loop.
 - `delay`: Delay in ms between each page in an animated image, provided as an array of integers.
 - `pagePrimary`: Number of the primary page in a HEIF image

docs/changelog.md

@@ -6,6 +6,8 @@ Requires libvips v8.16.0-rc2
 
 ### v0.33.6 - TBD
 
+* Add `isPalette` and `bitsPerSample` to metadata, deprecate `paletteBitDepth`.
+
 * TypeScript: Ensure channel counts use the correct range.
   [#4197](https://github.com/lovell/sharp/pull/4197)
   [@DavidVaness](https://github.com/DavidVaness)