Mathis/sharp
1
0
Fork 0
mirror of https://github.com/lovell/sharp.git synced 2025-12-19 07:15:08 +01:00
Code Issues Packages Projects Releases Wiki Activity

Add method for fast access to image metadata #32

Browse Source
This commit is contained in:
Lovell Fuller
2014-08-22 14:17:43 +01:00
parent 5fe945fca8
commit f2f3eb76e1
4 changed files with 387 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
README.md
View File

@@ -169,6 +169,21 @@ JPEG, PNG or WebP format image data can be streamed into the object when `input`
JPEG, PNG or WebP format image data can be streamed out from this object.
#### metadata([callback])
Fast access to image metadata without decoding any compressed image data.
`callback`, if present, gets the arguments `(err, metadata)` where `metadata` has the attributes:
* `format`: Name of decoder to be used to decompress image data e.g. `jpeg`, `png`, `webp` (for file-based input additionally `tiff` and `magick`)
* `width`: Number of pixels wide
* `height`: Number of pixels high
* `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `scrgb`, `cmyk`, `lab`, `xyz`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L502)
* `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
* `orientation`: Number value of the EXIF Orientation header, if present
A Promises/A+ promise is returned when `callback` is not provided.
#### sequentialRead()
An advanced setting that switches the libvips access method to `VIPS_ACCESS_SEQUENTIAL`. This will reduce memory usage and can improve performance on some systems.