extended_image

Official extension image, support placeholder(loading)/ failed state, cache network, zoom/pan, photo view, slide out page, editor(crop,rotate,flip), painting etc.


Keywords
cache, crop, flip, flutter, image, rotate, zoom
License
MIT

Documentation

extended_image

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A powerful official extension library of images, which supports placeholder(loading)/ failed state, cache network, zoom pan image, photo view, slide-out page, editor (crop, rotate, flip), paint custom etc.

Web demo for ExtendedImage

ExtendedImage is an third-party library that extends the functionality of Flutter's Image component. The main extended features are as follows:

Feature ExtendedImage Image
Cache network images locally and load from cache Supported Not supported
Compression display Supported, with additional options (compressionRatio and maxBytes) Supported, with cacheHeight, cacheWidth
Automatic release of image resources Supported Requires manual management
Scaling mode Supported Not supported
Editing mode Supported Not supported
Drag-to-dismiss effect for images in a page transition Supported Not supported

Table of contents

Import

  • null-safety
environment:
  sdk: '>=2.12.0 <3.0.0'
  flutter: '>=2.0'
dependencies:
  extended_image: ^4.0.0
  • non-null-safety

1.22.6 to 2.0, Flutter Api has breaking change,please use non-null-safety if you under 1.22.6.

environment:
  sdk: '>=2.6.0 <2.12.0'
  flutter: '>1.17.0 <=1.22.6'
dependencies:
  extended_image: ^3.0.0-non-null-safety

Cache Network

Simple use

You can use ExtendedImage.network as Image Widget

ExtendedImage.network(
  url,
  width: ScreenUtil.instance.setWidth(400),
  height: ScreenUtil.instance.setWidth(400),
  fit: BoxFit.fill,
  cache: true,
  border: Border.all(color: Colors.red, width: 1.0),
  shape: boxShape,
  borderRadius: BorderRadius.all(Radius.circular(30.0)),
  //cancelToken: cancellationToken,
)

Use ExtendedNetworkImageProvider

ExtendedNetworkImageProvider

   ExtendedNetworkImageProvider(
      this.url, {
      this.scale = 1.0,
      this.headers,
      this.cache: false,
      this.retries = 3,
      this.timeLimit,
      this.timeRetry = const Duration(milliseconds: 100),
      CancellationToken cancelToken,
    })  : assert(url != null),
          assert(scale != null),
          cancelToken = cancelToken ?? CancellationToken();
parameter description default
url The URL from which the image will be fetched. required
scale The scale to place in the [ImageInfo] object of the image. 1.0
headers The HTTP headers that will be used with [HttpClient.get] to fetch image from network. -
cache whether cache image to local false
retries the time to retry to request 3
timeLimit time limit to request image -
timeRetry the time duration to retry to request milliseconds: 100
cancelToken token to cancel network request CancellationToken()

you can create new provider and extends it with ExtendedProvider, and override instantiateImageCodec method. so that you can handle image raw data here (compress image).

Load State

Extended Image provide 3 states(loading,completed,failed), you can define your state widget with loadStateChanged call back.

loadStateChanged is not only for network, if your image need long time to load, you can set enableLoadState(default value is true for network and others are false) to true

img

Notice:

  • if you don't want to override any state, please return null in this case

  • if you want to override size or sourceRect, you can override it with ExtendedRawImage at completed state

  • if you want to add something (like animation) at completed state, you can override it with ExtendedImageState.completedWidget

  • ExtendedImageState.completedWidget is include gesture or editor, so that you would't miss them

/// custom load state widget if you want
    final LoadStateChanged loadStateChanged;

enum LoadState {
  //loading
  loading,
  //completed
  completed,
  //failed
  failed
}

  ///whether has loading or failed state
  ///default is false
  ///but network image is true
  ///better to set it's true when your image is big and take some time to ready
  final bool enableLoadState;

ExtendedImageState(LoadStateChanged call back)

parameter/method description default
extendedImageInfo image info -
extendedImageLoadState LoadState(loading,completed,failed) -
returnLoadStateChangedWidget if this is true, return widget which from LoadStateChanged function immediately(width/height/gesture/border/shape etc, will not effect on it) -
imageProvider ImageProvider -
invertColors invertColors -
imageStreamKey key of image -
reLoadImage() if image load failed,you can reload image by call it -
completedWidget return completed widget include gesture or editor -
loadingProgress return the loading progress for network image (ImageChunkEvent ) -
abstract class ExtendedImageState {
  void reLoadImage();
  ImageInfo get extendedImageInfo;
  LoadState get extendedImageLoadState;

  ///return widget which from LoadStateChanged function immediately
  bool returnLoadStateChangedWidget;

  ImageProvider get imageProvider;

  bool get invertColors;

  Object get imageStreamKey;

  Widget get completedWidget;
}

demo code

ExtendedImage.network(
  url,
  width: ScreenUtil.instance.setWidth(600),
  height: ScreenUtil.instance.setWidth(400),
  fit: BoxFit.fill,
  cache: true,
  loadStateChanged: (ExtendedImageState state) {
    switch (state.extendedImageLoadState) {
      case LoadState.loading:
        _controller.reset();
        return Image.asset(
          "assets/loading.gif",
          fit: BoxFit.fill,
        );
        break;

      ///if you don't want override completed widget
      ///please return null or state.completedWidget
      //return null;
      //return state.completedWidget;
      case LoadState.completed:
        _controller.forward();
        return FadeTransition(
          opacity: _controller,
          child: ExtendedRawImage(
            image: state.extendedImageInfo?.image,
            width: ScreenUtil.instance.setWidth(600),
            height: ScreenUtil.instance.setWidth(400),
          ),
        );
        break;
      case LoadState.failed:
        _controller.reset();
        return GestureDetector(
          child: Stack(
            fit: StackFit.expand,
            children: <Widget>[
              Image.asset(
                "assets/failed.jpg",
                fit: BoxFit.fill,
              ),
              Positioned(
                bottom: 0.0,
                left: 0.0,
                right: 0.0,
                child: Text(
                  "load image failed, click to reload",
                  textAlign: TextAlign.center,
                ),
              )
            ],
          ),
          onTap: () {
            state.reLoadImage();
          },
        );
        break;
    }
  },
)

Zoom Pan

img

ExtendedImage

parameter description default
mode image mode (none, gesture, editor) none
initGestureConfigHandler init GestureConfig when image is ready,for example, base on image width/height -
onDoubleTap call back of double tap under ExtendedImageMode.gesture -
extendedImageGestureKey you can handle zoom/pan by using this key manually -

GestureConfig

parameter description default
minScale min scale 0.8
animationMinScale the min scale for zooming then animation back to minScale when scale end minScale _ 0.8
maxScale max scale 5.0
animationMaxScale the max scale for zooming then animation back to maxScale when scale end maxScale _ 1.2
speed speed for zoom/pan 1.0
inertialSpeed inertial speed for zoom/pan 100
cacheGesture save Gesture state (for example in ExtendedImageGesturePageView, gesture state will not change when scroll back),remember clearGestureDetailsCache at right time false
inPageView whether in ExtendedImageGesturePageView false
initialAlignment init image rect with alignment when initialScale > 1.0 InitialAlignment.center
hitTestBehavior How to behave during hit tests HitTestBehavior.deferToChild
ExtendedImage.network(
  imageTestUrl,
  fit: BoxFit.contain,
  //enableLoadState: false,
  mode: ExtendedImageMode.gesture,
  initGestureConfigHandler: (state) {
    return GestureConfig(
        minScale: 0.9,
        animationMinScale: 0.7,
        maxScale: 3.0,
        animationMaxScale: 3.5,
        speed: 1.0,
        inertialSpeed: 100.0,
        initialScale: 1.0,
        inPageView: false,
        initialAlignment: InitialAlignment.center,
        );
  },
)

double tap animation

onDoubleTap: (ExtendedImageGestureState state) {
  ///you can use define pointerDownPosition as you can,
  ///default value is double tap pointer down postion.
  var pointerDownPosition = state.pointerDownPosition;
  double begin = state.gestureDetails.totalScale;
  double end;

  //remove old
  _animation?.removeListener(animationListener);

  //stop pre
  _animationController.stop();

  //reset to use
  _animationController.reset();

  if (begin == doubleTapScales[0]) {
    end = doubleTapScales[1];
  } else {
    end = doubleTapScales[0];
  }

  animationListener = () {
    //print(_animation.value);
    state.handleDoubleTap(
        scale: _animation.value,
        doubleTapPosition: pointerDownPosition);
  };
  _animation = _animationController
      .drive(Tween<double>(begin: begin, end: end));

  _animation.addListener(animationListener);

  _animationController.forward();
},

Editor

img

    ExtendedImage.network(
      imageTestUrl,
      fit: BoxFit.contain,
      mode: ExtendedImageMode.editor,
      extendedImageEditorKey: editorKey,
      initEditorConfigHandler: (state) {
        return EditorConfig(
            maxScale: 8.0,
            cropRectPadding: EdgeInsets.all(20.0),
            hitTestSize: 20.0,
            cropAspectRatio: _aspectRatio.aspectRatio);
      },
    );

ExtendedImage

parameter description default
mode image mode (none,gestrue,editor) none
initEditorConfigHandler init EditorConfig when image is ready. -
extendedImageEditorKey key of ExtendedImageEditorState to flip/rotate/get crop rect -

EditorConfig

parameter description default
maxScale max scale of zoom 5.0
cropRectPadding the padding between crop rect and image layout rect. EdgeInsets.all(20.0)
cornerSize size of corner shape (DEPRECATED! Use cornerPainter) Size(30.0, 5.0)
cornerColor color of corner shape (DEPRECATED! Use cornerPainter) primaryColor
lineColor color of crop line scaffoldBackgroundColor.withOpacity(0.7)
lineHeight height of crop line 0.6
editorMaskColorHandler call back of editor mask color base on pointerDown scaffoldBackgroundColor.withOpacity(pointerDown ? 0.4 : 0.8)
hitTestSize hit test region of corner and line 20.0
animationDuration auto center animation duration Duration(milliseconds: 200)
tickerDuration duration to begin auto center animation after crop rect is changed Duration(milliseconds: 400)
cropAspectRatio aspect ratio of crop rect null(custom)
initialCropAspectRatio initial aspect ratio of crop rect null(custom: initial crop rect will fill the entire image)
initCropRectType init crop rect base on initial image rect or image layout rect imageRect
cornerPainter corner shape ExtendedImageCropLayerPainterNinetyDegreesCorner()
hitTestBehavior How to behave during hit tests HitTestBehavior.deferToChild

crop aspect ratio

it's a double value, so it's easy for you to define by yourself. following are official values

class CropAspectRatios {
  /// no aspect ratio for crop
  static const double custom = null;

  /// the same as aspect ratio of image
  /// [cropAspectRatio] is not more than 0.0, it's original
  static const double original = 0.0;

  /// ratio of width and height is 1 : 1
  static const double ratio1_1 = 1.0;

  /// ratio of width and height is 3 : 4
  static const double ratio3_4 = 3.0 / 4.0;

  /// ratio of width and height is 4 : 3
  static const double ratio4_3 = 4.0 / 3.0;

  /// ratio of width and height is 9 : 16
  static const double ratio9_16 = 9.0 / 16.0;

  /// ratio of width and height is 16 : 9
  static const double ratio16_9 = 16.0 / 9.0;
}

crop layer painter

you can define your crop layer by override [EditorConfig.editorCropLayerPainter].

class EditorCropLayerPainter {
  const EditorCropLayerPainter();
  void paint(Canvas canvas, Size size, ExtendedImageCropLayerPainter painter) {
    paintMask(canvas, size, painter);
    paintLines(canvas, size, painter);
    paintCorners(canvas, size, painter);
  }

  /// draw crop layer corners
  void paintCorners(
      Canvas canvas, Size size, ExtendedImageCropLayerPainter painter) {
  }

  /// draw crop layer lines
  void paintMask(
      Canvas canvas, Size size, ExtendedImageCropLayerPainter painter) {
  }
  

  /// draw crop layer lines
  void paintLines(
      Canvas canvas, Size size, ExtendedImageCropLayerPainter painter) {
  } 
}

crop,flip,reset

  • add key for ExtendedImageEditorState

    final GlobalKey<ExtendedImageEditorState> editorKey =GlobalKey<ExtendedImageEditorState>();

  • rotate right

    editorKey.currentState.rotate(right: true);

  • rotate left

    editorKey.currentState.rotate(right: false);

  • flip

    editorKey.currentState.flip();

  • reset

    editorKey.currentState.reset();

crop data

dart library(stable)

  • add Image library into your pubspec.yaml, it's used to crop/rotate/flip image data
dependencies:
  image: any
  • get crop rect and raw image data from ExtendedImageEditorState
  ///crop rect base on raw image
  final Rect cropRect = state.getCropRect();

  var data = state.rawImageData;
  • convert raw image data to image library data.
  /// it costs much time and blocks ui.
  //Image src = decodeImage(data);

  /// it will not block ui with using isolate.
  //Image src = await compute(decodeImage, data);
  //Image src = await isolateDecodeImage(data);
  final lb = await loadBalancer;
  Image src = await lb.run<Image, List<int>>(decodeImage, data);
  • crop,flip,rotate data
  //clear orientation
  src = bakeOrientation(src);

  if (editAction.needCrop)
    src = copyCrop(src, cropRect.left.toInt(), cropRect.top.toInt(),
        cropRect.width.toInt(), cropRect.height.toInt());

  if (editAction.needFlip) {
    Flip mode;
    if (editAction.flipY && editAction.flipX) {
      mode = Flip.both;
    } else if (editAction.flipY) {
      mode = Flip.horizontal;
    } else if (editAction.flipX) {
      mode = Flip.vertical;
    }
    src = flip(src, mode);
  }

  if (editAction.hasRotateAngle) src = copyRotate(src, editAction.rotateAngle);
  • convert to original image data

output is raw image data, you can use it to save or any other thing.

  /// you can encode your image
  ///
  /// it costs much time and blocks ui.
  //var fileData = encodeJpg(src);

  /// it will not block ui with using isolate.
  //var fileData = await compute(encodeJpg, src);
  //var fileData = await isolateEncodeImage(src);
  var fileData = await lb.run<List<int>, Image>(encodeJpg, src);

native library(faster)

  • add ImageEditor library into your pubspec.yaml, it's used to crop/rotate/flip image data
dependencies:
  image_editor: any
  • get crop rect and raw image data from ExtendedImageEditorState
  ///crop rect base on raw image
  final Rect cropRect = state.getCropRect();

  var data = state.rawImageData;
  • prepare crop option
  final rotateAngle = action.rotateAngle.toInt();
  final flipHorizontal = action.flipY;
  final flipVertical = action.flipX;
  final img = state.rawImageData;

  ImageEditorOption option = ImageEditorOption();

  if (action.needCrop) option.addOption(ClipOption.fromRect(rect));

  if (action.needFlip)
    option.addOption(
        FlipOption(horizontal: flipHorizontal, vertical: flipVertical));

  if (action.hasRotateAngle) option.addOption(RotateOption(rotateAngle));
  • crop with editImage

output is raw image data, you can use it to save or any other thing.

  final result = await ImageEditor.editImage(
    image: img,
    imageEditorOption: option,
  );

more detail

Photo View

ExtendedImageGesturePageView is the same as PageView and it's made for show zoom/pan image.

if you have cache the gesture, remember call clearGestureDetailsCache() method at the right time.(for example,page view page is disposed)

img

ExtendedImageGesturePageView

parameter description default
cacheGesture whether should move page true

GestureConfig

parameter description default
cacheGesture save Gesture state (for example in ExtendedImageGesturePageView, gesture state will not change when scroll back),remember clearGestureDetailsCache at right time false
inPageView whether in ExtendedImageGesturePageView false
ExtendedImageGesturePageView.builder(
  itemBuilder: (BuildContext context, int index) {
    var item = widget.pics[index].picUrl;
    Widget image = ExtendedImage.network(
      item,
      fit: BoxFit.contain,
      mode: ExtendedImageMode.gesture,
      gestureConfig: GestureConfig(
        inPageView: true, initialScale: 1.0,
        //you can cache gesture state even though page view page change.
        //remember call clearGestureDetailsCache() method at the right time.(for example,this page dispose)
        cacheGesture: false
      ),
    );
    image = Container(
      child: image,
      padding: EdgeInsets.all(5.0),
    );
    if (index == currentIndex) {
      return Hero(
        tag: item + index.toString(),
        child: image,
      );
    } else {
      return image;
    }
  },
  itemCount: widget.pics.length,
  onPageChanged: (int index) {
    currentIndex = index;
    rebuild.add(index);
  },
  controller: PageController(
    initialPage: currentIndex,
  ),
  scrollDirection: Axis.horizontal,
),

Slide Out Page

Extended Image support to slide out page as WeChat.

img

enable slide out page

ExtendedImage

parameter description default
enableSlideOutPage whether enable slide out page false
heroBuilderForSlidingPage build Hero only for sliding page, the transform of sliding page must be working on Hero,so that Hero animation wouldn't be strange when pop page null

include your page in ExtendedImageSlidePage

take care of onSlidingPage call back, you can update other widgets' state as you want. but, do not setState directly here, image state will changed, you should only notify the widgets which are needed to change

    return ExtendedImageSlidePage(
      child: result,
      slideAxis: SlideAxis.both,
      slideType: SlideType.onlyImage,
      onSlidingPage: (state) {
        ///you can change other widgets' state on page as you want
        ///base on offset/isSliding etc
        //var offset= state.offset;
        var showSwiper = !state.isSliding;
        if (showSwiper != _showSwiper) {
          // do not setState directly here, the image state will change,
          // you should only notify the widgets which are needed to change
          // setState(() {
          // _showSwiper = showSwiper;
          // });

          _showSwiper = showSwiper;
          rebuildSwiper.add(_showSwiper);
        }
      },
    );

ExtendedImageGesturePage

parameter description default
child The [child] contained by the ExtendedImageGesturePage. -
slidePageBackgroundHandler build background when slide page defaultSlidePageBackgroundHandler
slideScaleHandler customize scale of page when slide page defaultSlideScaleHandler
slideEndHandler call back of slide end,decide whether pop page defaultSlideEndHandler
slideAxis axis of slide(both,horizontal,vertical) SlideAxis.both
resetPageDuration reset page position when slide end(not pop page) milliseconds: 500
slideType slide whole page or only image SlideType.onlyImage
onSlidingPage call back when it's sliding page, change other widgets state on page as you want -
slideOffsetHandler customize offset when slide page -
Color defaultSlidePageBackgroundHandler(
    {Offset offset, Size pageSize, Color color, SlideAxis pageGestureAxis}) {
  double opacity = 0.0;
  if (pageGestureAxis == SlideAxis.both) {
    opacity = offset.distance /
        (Offset(pageSize.width, pageSize.height).distance / 2.0);
  } else if (pageGestureAxis == SlideAxis.horizontal) {
    opacity = offset.dx.abs() / (pageSize.width / 2.0);
  } else if (pageGestureAxis == SlideAxis.vertical) {
    opacity = offset.dy.abs() / (pageSize.height / 2.0);
  }
  return color.withOpacity(min(1.0, max(1.0 - opacity, 0.0)));
}

bool defaultSlideEndHandler(
    {Offset offset, Size pageSize, SlideAxis pageGestureAxis}) {
  if (pageGestureAxis == SlideAxis.both) {
    return offset.distance >
        Offset(pageSize.width, pageSize.height).distance / 3.5;
  } else if (pageGestureAxis == SlideAxis.horizontal) {
    return offset.dx.abs() > pageSize.width / 3.5;
  } else if (pageGestureAxis == SlideAxis.vertical) {
    return offset.dy.abs() > pageSize.height / 3.5;
  }
  return true;
}

double defaultSlideScaleHandler(
    {Offset offset, Size pageSize, SlideAxis pageGestureAxis}) {
  double scale = 0.0;
  if (pageGestureAxis == SlideAxis.both) {
    scale = offset.distance / Offset(pageSize.width, pageSize.height).distance;
  } else if (pageGestureAxis == SlideAxis.horizontal) {
    scale = offset.dx.abs() / (pageSize.width / 2.0);
  } else if (pageGestureAxis == SlideAxis.vertical) {
    scale = offset.dy.abs() / (pageSize.height / 2.0);
  }
  return max(1.0 - scale, 0.8);
}

make sure your page background is transparent

if you use ExtendedImageSlidePage and slideType =SlideType.onlyImage, make sure your page background is transparent

push with transparent page route

you should push page with TransparentMaterialPageRoute/TransparentCupertinoPageRoute

  Navigator.push(
    context,
    Platform.isAndroid
        ? TransparentMaterialPageRoute(builder: (_) => page)
        : TransparentCupertinoPageRoute(builder: (_) => page),
  );

Slide Out Page Demo Code 1

Slide Out Page Demo Code 2

Border BorderRadius Shape

ExtendedImage

parameter description default
border BoxShape.circle and BoxShape.rectangle,If this is [BoxShape.circle] then [borderRadius] is ignored. -
borderRadius If non-null, the corners of this box are rounded by this [BorderRadius].,Applies only to boxes with rectangular shapes; ignored if [shape] is not [BoxShape.rectangle]. -
shape BoxShape.circle and BoxShape.rectangle,If this is [BoxShape.circle] then [borderRadius] is ignored. -
ExtendedImage.network(
  url,
  width: ScreenUtil.instance.setWidth(400),
  height: ScreenUtil.instance.setWidth(400),
  fit: BoxFit.fill,
  cache: true,
  border: Border.all(color: Colors.red, width: 1.0),
  shape: boxShape,
  borderRadius: BorderRadius.all(Radius.circular(30.0)),
),

img

Clear Save

clear

to clear disk cached , call clearDiskCachedImages method.

// Clear the disk cache directory then return if it succeed.
///  <param name="duration">timespan to compute whether file has expired or not</param>
Future<bool> clearDiskCachedImages({Duration duration})

to clear disk cached with specific url, call clearDiskCachedImage method.

/// clear the disk cache image then return if it succeed.
///  <param name="url">clear specific one</param>
Future<bool> clearDiskCachedImage(String url) async {

get the local cached image file

Future<File> getCachedImageFile(String url) async {

to clear memory cache , call clearMemoryImageCache method.

///clear all of image in memory
 clearMemoryImageCache();

/// get ImageCache
 getMemoryImageCache() ;

save network

call saveNetworkImageToPhoto and save image with image_picker_saver

///save network image to photo
Future<bool> saveNetworkImageToPhoto(String url, {bool useCache: true}) async {
  var data = await getNetworkImageData(url, useCache: useCache);
  var filePath = await ImagePickerSaver.saveFile(fileData: data);
  return filePath != null && filePath != "";
}

Show Crop Image

get your raw image by [Load State](#Load State), and crop image by sourceRect.

ExtendedRawImage sourceRect is which you want to show image rect.

img

ExtendedRawImage(
  image: image,
  width: num400,
  height: num300,
  fit: BoxFit.fill,
  sourceRect: Rect.fromLTWH(
      (image.width - width) / 2.0, 0.0, width, image.height.toDouble()),
)

Paint

provide BeforePaintImage and AfterPaintImage callback, you will have the chance to paint things you want.

img

ExtendedImage

parameter description default
beforePaintImage you can paint anything if you want before paint image. -
afterPaintImage you can paint anything if you want after paint image. -
  ExtendedImage.network(
    url,
    width: ScreenUtil.instance.setWidth(400),
    height: ScreenUtil.instance.setWidth(400),
    fit: BoxFit.fill,
    cache: true,
    beforePaintImage: (Canvas canvas, Rect rect, ui.Image image) {
      if (paintType == PaintType.ClipHeart) {
        if (!rect.isEmpty) {
          canvas.save();
          canvas.clipPath(clipheart(rect, canvas));
        }
      }
      return false;
    },
    afterPaintImage: (Canvas canvas, Rect rect, ui.Image image) {
      if (paintType == PaintType.ClipHeart) {
        if (!rect.isEmpty) canvas.restore();
      } else if (paintType == PaintType.PaintHeart) {
        canvas.drawPath(
            clipheart(rect, canvas),
            Paint()
              ..colorFilter =
                  ColorFilter.mode(Color(0x55ea5504), BlendMode.srcIn)
              ..isAntiAlias = false
              ..filterQuality = FilterQuality.low);
      }
    },
  );

see paint image demo and push to refresh header which is used in crop image demo

Notch

By setting layoutInsets, you can ensure the image is positioned outside of obstructing elements such as the phone notch or home indicator if displayed in full screen. This will still allow the image margin to show underneath the notch if zoomed in.

ExtendedImage

parameter description default
layoutInsets Amount to inset from the edge during image layout EdgeInsets.zero
  ExtendedImage.network(
    url,
    fit: BoxFit.contain,
    layoutInsets: MediaQuery.of(context).padding
  );

MemoryUsage

You can reduce memory usage with following settings now.

  • ExtendedResizeImage
parameter description default
[ExtendedResizeImage.compressionRatio] The images size will resize to original * [compressionRatio].It's ExtendedResizeImages first pick.The compressionRatio`s range is from 0.0 (exclusive), to 1.0 (exclusive). null
[ExtendedResizeImage.maxBytes] [ExtendedResizeImage] will compress the image to a size that is smaller than [maxBytes]. The default size is 50KB. It's actual bytes of Image, not decode bytes 50 << 10
[ExtendedResizeImage.width]/[ExtendedResizeImage.height] The width/height the image should decode to and cache. It's same as [ResizeImage], null
    ExtendedImage.network(
      'imageUrl',  
      compressionRatio: 0.1,
      maxBytes: null,
      cacheWidth: null,
      cacheHeight: null,  
    )

    ExtendedImage(
      image: ExtendedResizeImage(
        ExtendedNetworkImageProvider(
          'imageUrl',  
        ),
        compressionRatio: 0.1,
        maxBytes: null,
        width: null,
        height: null,
      ),
    )
  • clearMemoryCacheWhenDispose
parameter description default
clearMemoryCacheWhenDispose It's not good enough after Flutter 2.0, it seems that we can't release memory usage if this image is not completed(#317). It will release memory usage only for completed image now. false
   ExtendedImage.network(
     'imageUrl',     
     clearMemoryCacheWhenDispose: true,
   )
  • imageCacheName
parameter description default
imageCacheName The name of [ImageCache], you can define custom [ImageCache] to store this image. In this way you can work with them without affecting other [ImageCache] null
   ExtendedImage.network(
     'imageUrl',  
     imageCacheName: 'MemoryUsage',
   )
     
  /// clear when this page is disposed   
  @override
  void dispose() {
    // clear ImageCache which named 'MemoryUsage'
    clearMemoryImageCache(imageCacheName);
    super.dispose();
  }   

Other APIs

ExtendedImage

parameter description default
enableMemoryCache whether cache in PaintingBinding.instance.imageCache) true
clearMemoryCacheIfFailed when failed to load image, whether clear memory cache.if true, image will reload in next time. true
clearMemoryCacheWhenDispose when image is removed from the tree permanently, whether clear memory cache. false