# image_size_getter 2.4.1 Get image width and height, the library does not completely decode the image file, just read the metadata to get the image width and height. ## Installing ``` export PUB_HOSTED_URL=https://pub.mirror.p-hatan.com flutter pub add image_size_getter ``` Published: 2025-08-06T06:23:07.530585Z Expected archive SHA-256: 7c26937e0ae341ca558b7556591fd0cc456fcc454583b7cb665d2f03e93e590f Available in cache; verification: upstream_checksum ## Direct dependencies - collection: ^1.15.0 - hashcodes: ^2.0.0 - meta: ^1.9.0 ## Package README (untrusted upstream documentation) # image_size_getter [![pub package](https://img.shields.io/pub/v/image_size_getter.svg)](https://pub.dev/packages/image_size_getter) [![likes](https://img.shields.io/pub/likes/image_size_getter)](https://pub.dev/packages/image_size_getter/score) [![popularity](https://img.shields.io/pub/popularity/image_size_getter)](https://pub.dev/packages/image_size_getter/score) [![pub points](https://img.shields.io/pub/points/image_size_getter)](https://pub.dev/packages/image_size_getter/score) [![GitHub stars](https://img.shields.io/github/stars/CaiJingLong/dart_image_size_getter.svg)](https://github.com/CaiJingLong/dart_image_size_getter) [![GitHub forks](https://img.shields.io/github/forks/CaiJingLong/dart_image_size_getter.svg)](https://github.com/CaiJingLong/dart_image_size_getter) [![GitHub license](https://img.shields.io/github/license/CaiJingLong/dart_image_size_getter.svg)](https://github.com/CaiJingLong/dart_image_size_getter/blob/master/LICENSE) Do not completely decode the image file, just read the metadata to get the image width and height. Just support jpeg, gif, png, webp, bmp. ## Install ```yaml dependencies: image_size_getter: ^2.3.0 ``` ## Usage ### Image of File ```dart import 'dart:io'; import 'package:image_size_getter/image_size_getter.dart'; import 'package:image_size_getter/file_input.dart'; void main(List arguments) async { final file = File('asset/IMG_20180908_080245.jpg'); final jpgResult = ImageSizeGetter.getSizeResult(FileInput(file)); print( 'jpg = ${jpgResult.size} (decoded by ${jpgResult.decoder.decoderName})'); final pngFile = File('asset/ic_launcher.png'); final pngResult = ImageSizeGetter.getSizeResult(FileInput(pngFile)); print( 'png = ${pngResult.size} (decoded by ${pngResult.decoder.decoderName})'); final webpFile = File('asset/demo.webp'); final webpResult = ImageSizeGetter.getSizeResult(FileInput(webpFile)); print( 'webp = ${webpResult.size} (decoded by ${webpResult.decoder.decoderName})'); final gifFile = File('asset/dialog.gif'); final gifResult = ImageSizeGetter.getSizeResult(FileInput(gifFile)); print( 'gif = ${gifResult.size} (decoded by ${gifResult.decoder.decoderName})'); // errorExample(); } ``` ### Image of Memory ```dart import 'package:image_size_getter/image_size_getter.dart'; void foo(Uint8List image){ final memoryImageSizeResult = ImageSizeGetter.getSizeResult(MemoryInput(image)); final size = memoryImageSizeResult.size; final decoder = memoryImageSizeResult.decoder; print('size = $size, decoder = ${decoder.decoderName}'); } ``` ### Image of Http See [HttpInput][]. ## About Size The size contains width and height. But some image have orientation. Such as jpeg, when the orientation of exif is 5, 6, 7 or 8, the width and height will be swapped. We can use next code to get width and height. ```dart void foo(File file) { final sizeResult = ImageSizeGetter.getSizeResult(FileInput(file)); final size = sizeResult.size; if (size.needRotate) { final width = size.height; final height = size.width; print('width = $width, height = $height'); } else { print('width = ${size.width}, height = ${size.height}'); } print('decoder = ${sizeResult.decoder.decoderName}'); } ``` ## AsyncImageInput If your data source is read asynchronously, consider using `AsyncImageInput`. A typical use case is [http_input][HttpInput]. ## Check the extension for decoder > Since 2.4.0 ```dart void checkExtension(String ext, BaseDecoder decoder) { final isSupport = decoder.isExtensionSupported(ext); print('The decoder ${decoder.decoderName} support $ext: $isSupport'); } ``` ## Custom We can implement our own input or decoder. In addition to several built-in implementations, subsequent implementations will also be added to the project through plugin. ### Custom Input Such as: [http_input](https://github.com/CaiJingLong/dart_image_size_getter/tree/master/image_size_getter_http_input). In addition, if your picture has verification, for example, you need to use the request header to access it, or you need a post request to get it, you need to customize input. ### Custom Decoder Such as bmp decoder Check the file type: ![VPMMfA](https://cdn.jsdelivr.net/gh/kikt-blog/image@branch-2/uPic/VPMMfA.png) The width and height: ![AZnx9I](https://cdn.jsdelivr.net/gh/kikt-blog/image@branch-2/uPic/AZnx9I.png) So, we can write code with: ```dart import 'package:image_size_getter/image_size_getter.dart'; class BmpDecoder extends BaseDecoder { const BmpDecoder(); @override String get decoderName => 'bmp'; @override Size getSize(ImageInput input) { final widthList = input.getRange(0x12, 0x16); final heightList = input.getRange(0x16, 0x1a); final width = convertRadix16ToInt(widthList, reverse: true); final height = convertRadix16ToInt(heightList, reverse: true); return Size(width, height); } @override Future getSizeAsync(AsyncImageInput input) async { final widthList = await input.getRange(0x12, 0x16); final heightList = await input.getRange(0x16, 0x1a); final width = convertRadix16ToInt(widthList, reverse: true); final height = convertRadix16ToInt(heightList, reverse: true); return Size(width, height); } @override bool isValid(ImageInput input) { final list = input.getRange(0, 2); return _isBmp(list); } @override Future isValidAsync(AsyncImageInput input) async { final list = await input.getRange(0, 2); return _isBmp(list); } bool _isBmp(List startList) { return startList[0] == 66 && startList[1] == 77; } } ``` Use it: ```dart final bmp = File('../../example/asset/demo.bmp'); const BmpDecoder decoder = BmpDecoder(); final input = FileInput(bmp); assert(decoder.isValid(input)); expect(decoder.getSizeResult(input).size, Size(256, 256)); ``` #### Register custom decoder to image size getter ```dart ImageSizeGetter.registerDecoder(const BmpDecoder()); ``` The method can also be used to replace the default decoder. For example, you think the existing JPEG format is not rigorous enough. ```dart ImageSizeGetter.registerDecoder(const MyJpegDecoder()); ``` #### Use decoder alone Each decoder can be used alone. ```dart void decodeWithImageInput(ImageInput input) { BaseDecoder decoder = const GifDecoder(); final isGif = decoder.isValid(input); print('isGif: $isGif'); if (isGif) { final sizeResult = decoder.getSizeResult(input); final size = sizeResult.size; print('size: $size'); } } void decodeWithAsyncImageInput(AsyncImageInput input) async { BaseDecoder decoder = const PngDecoder(); final isPng = await decoder.isValidAsync(input); print('isPng: $isPng'); if (isPng) { final sizeResult = await decoder.getSizeResultAsync(input); final size = sizeResult.size; print('size: $size'); } } ``` ## migrate See [migrate](https://github.com/CaiJingLong/dart_image_size_getter/blob/master/library/migrate.md) ## Other question The package is dart package, no just flutter package. So, if you want to get flutter asset image size, you must convert it to memory(Uint8List). ```dart final buffer = await rootBundle.load('assets/logo.png'); // get the byte buffer final memoryImageSizeResult = ImageSizeGetter.getSizeResult(MemoryInput.byteBuffer(buffer)); final size = memoryImageSizeResult.size; print('size = $size'); ``` ## LICENSE Apache 2.0 [HttpInput]: https://pub.dev/packages/image_size_getter_http_input ## Changelog # CHANGELOG - [CHANGELOG](#changelog) - [2.4.1](#241) - [2.4.0](#240) - [2.3.0+1](#2301) - [2.3.0](#230) - [2.2.0](#220) - [2.1.3](#213) - [2.1.2](#212) - [2.1.1](#211) - [2.1.0](#210) - [2.0.0](#200) - [1.1.0](#110) - [1.0.0](#100) - [0.3.0](#030) - [0.2.1](#021) - [0.2.0](#020) - [0.1.1](#011) - [0.1.0](#010) ## 2.4.1 - Fix: Corrected orientation retrieval in JPEG images. ## 2.4.0 - Add `isExtensionSupported` to `BaseDecoder` ## 2.3.0+1 - Docs: Add docs for dartdoc. ## 2.3.0 Feature: - Add `getSizeResult` for `SizeResult` ## 2.2.0 Feature: - Add non-standard jpeg decoder ## 2.1.3 Fix: - Support lossless WebP ([#38](https://github.com/CaiJingLong/dart_image_size_getter/issues/38)) ## 2.1.2 Fix： - Support gif 87a type [#23] [#24]. ## 2.1.1 - fix: remove debug value print calls from `jpeg_decoder` by @ZaLiTHkA in - @ZaLiTHkA made their first contribution in **Full Changelog**: ## 2.1.0 Feature: - Add `needRotate` for `Size` **What's Changed:** - Add needRotate for Size by @CaiJingLong in **Full Changelog**: ## 2.0.0 New feature: - Refactored the code and removed the `AsyncImageSizeGetter` class. - We can customize the decoder. ## 1.1.0 - Support webp extended format by @nkming2 in - Http input by @CaiJingLong in **New Contributors:** - @nkming2 made their first contribution in **Full Changelog:** ## 1.0.0 Null safety version. ## 0.3.0 Support get size of async input of image. ## 0.2.1 Update dependency. Fix readme. ## 0.2.0 Support memory type. Breaking change: Fix: type of `ImageSizeGetter` ## 0.1.1 FIx jpeg format. ## 0.1.0 Initial version.