Draw SVG (and some Android VectorDrawable (XML)) files on a Flutter Widget.
Getting Started #
This is a Dart-native rendering library. Issues/PRs will be raised in Flutter and flutter/engine as necessary for features that are not good candidates for Dart implementations (especially if they're impossible to implement without engine support). However, not everything that Skia can easily do needs to be done by Skia; for example, the Path parsing logic here isn't much slower than doing it in native, and Skia isn't always doing low level GPU accelerated work where you might think it is (e.g. Dash Paths).
All of the SVGs in the
assets/ folder (except the text related one(s)) now
have corresponding PNGs in the
golden/ folder that were rendered using
flutter test tool/gen_golden.dart and compared against their rendering output
in Chrome. Automated tests will continue to compare these to ensure code changes
do not break known-good renderings.
Basic usage (to create an SVG rendering widget from an asset):
final String assetName = 'assets/image.svg'; final Widget svg = SvgPicture.asset( assetName, semanticsLabel: 'Acme Logo' );
You can color/tint the image like so:
final String assetName = 'assets/up_arrow.svg'; final Widget svgIcon = SvgPicture.asset( assetName, color: Colors.red, semanticsLabel: 'A red up arrow' );
The default placeholder is an empty box (
LimitedBox) - although if a
width is specified on the
SizedBox will be used instead
(which ensures better layout experience). There is currently no way to show an
Error visually, however errors will get properly logged to the console in debug
You can also specify a placeholder widget. The placeholder will display during parsing/loading (normally only relevant for network access).
// Will print error messages to the console. final String assetName = 'assets/image_that_does_not_exist.svg'; final Widget svg = SvgPicture.asset( assetName, ); final Widget networkSvg = SvgPicture.network( 'https://site-that-takes-a-while.com/image.svg', semanticsLabel: 'A shark?!', placeholderBuilder: (BuildContext context) => Container( padding: const EdgeInsets.all(30.0), child: const CircularProgressIndicator()), );
If you'd like to render the SVG to some other canvas, you can do something like:
import 'package:flutter_svg/flutter_svg.dart'; final String rawSvg = '''<svg viewBox="...">...</svg>'''; final DrawableRoot svgRoot = await svg.fromSvgString(rawSvg, rawSvg); // If you only want the final Picture output, just use final Picture picture = svgRoot.toPicture(); // Otherwise, if you want to draw it to a canvas: // Optional, but probably normally desirable: scale the canvas dimensions to // the SVG's viewbox svgRoot.scaleCanvasToViewBox(canvas); // Optional, but probably normally desireable: ensure the SVG isn't rendered // outside of the viewbox bounds svgRoot.clipCanvasToViewBox(canvas); svgRoot.draw(canvas, size);
SvgPicture helps to automate this logic, and it provides some convenience
wrappers for getting assets from multiple sources and caching the resultant
Picture. It does not render the data to an
Image at any point; you
certainly can do that in Flutter, but you then lose some of the benefit of
having a vector format to begin with.
While I'm making every effort to avoid needlessly changing the API, it's not
guarnateed to be stable yet (hence the pre-1.0.0 version). To date, the biggest
change is deprecating the
SvgImage widgets in favor of
SvgPicture - it
became very confusing to maintain that name, as
Pictures are the underlying
mechanism for rendering rather than
See main.dart for a complete sample.
Use Cases #
- Your designer creates a vector asset that you want to include without converting to 5 different raster format resolutions.
- Your vector drawing is meant to be static and non (or maybe minimally) interactive.
- You want to load SVGs dynamically from network sources at runtime.
- You want to paint SVG data and render it to an image.
This list is not very well ordered. I'm mainly picking up things that seem interesting or useful, or where I've gotten a request to fix something/example of something that's broken.
- Text support (partially implemented).
- Support Radial gradients that use percentages in the offsets.
- Dash path with percentage dasharray values (need good examples).
- Display/visibility support. My hunch is that this is usually used more for SVG specific interactivity, which isn't supported or planned.
- Inheritance of inheritable properties (
necessary? preprocess?significant progress, still some rough edges, particularly for definitions).
- Support for minimal CSS/styles? See also usvg (partial style attribute mostly supported).
- Filters/effects (will require upstream engine changes, but doable).
- Android Vector Drawable support beyond PoC - I'm willing to put more time into this if there's actually demand, but it doesn't come up often.
Probably out of scope/non-goals #
- SMIL animations. That just seems crazy. I think it'll be possible to animate the SVG but probably in a more Flutter driven way.
- Interactivity/events in SVG.
- Full (any?) CSS support - preprocess your SVGs (perhaps with usvg or scour to get rid of all CSS?).
- Scripting in SVGs
- Foreign elements
- Rendering properties/hints
Recommended Adobe Illustrator SVG Configuration #
- In Styling: choose Presentation Attributes instead of Inline CSS because CSS is not fully supported.
- In Images: choose Embded not Linked to other file to get a single svg with no dependency to other files.
- In Objects IDs: choose layer names to add every layer name to svg tags or you can use minimal,it is optional.
SVG sample attribution #
/assets/w3samples pulled from W3 sample files
/assets/deborah_ufw provided by @deborah-ufw
/assets/simple are pulled from trivial examples or generated to test
basic functionality - some of them come directly from the SVG 1.1 spec. Some
have also come or been adapted from issues raised in this repository.
/assets/wikimedia are pulled from Wikimedia Commons
Android Drawables in
/assets/android_vd are pulled from Android Documentation
The Flutter Logo created based on the Flutter Logo Widget © Google.
The Dart logo is from dartlang.org © Google
/assets/noto-emoji are from Google i18n noto-emoji,
licensed under the Apache license.
Please submit SVGs this can't render properly (e.g. that don't render here the way they do in chrome), as long as they're not using anything "probably out of scope" (above).
- Respect transformations on
- Be more tolerant of malformed base64 data, similar to browsers (specifically, having spaces present in the data). ## 0.14.4
- Apply masks in the correct order when blend modes are involved in shapes.
- Support for masks on groups.
- Update example project to Android X.
- Support for the
- Format, open up obtainKey for testing.
- Support for HSL colors (thanks to @christianalfoni)
- Added support for masks (thanks to @krispypen)
- Allow for clearing of the picture cache
- Fix case where color filters were incorrectly getting created.
- Same fix for group opacity/saveLayer as in 0.12.4+2
- Bump path_drawing dependency, which includes bug fixes in parsing.
- Updated SDK constraint to support new error message formats
- Updated error message formats
- Misc. updates for new SDK features
- Changed version constraint to prevent pulling down from wrong flutter version.
- Fixed group opacity/saveLayer bug.
- Bump dep on path_drawing which contains bugfixes for parsing.
opacityhandling, particularly for groups. Previously, opacities were averaged together, which resulted in incorrect compositing (particularly if overlapping shapes were drawn within a group). Now, a new layer is created with the opacity applied to the whole. This may cause some performance degredation, but is more correct.
- Allow font-size to be specified in
px(with an explicit postfix).
excludeFromSemanticsproperty for purely decorative SVGs. The default value is false.
- Fixed bug with stream completer unregistration.
- Fixed bug with text transforms in new parsing.
- Fixed bug with RGBA parsing for opacity
- Fixed bug with AVD parsing from strings.
- Support for
- BREAKING Avoid scaling based on devicePixelRatio. This turned out to be a mistake, and caused rendering inconsistencies across devices. It was particularly harmful on devices where the ratio was less than 1.0.
precachePicturemethod to allow for pre-caching of SVG assets. Similar in functionality to
precacheImagein the Flutter framework. Also added improvements to error handling in the various related routines.
- Format source code
- Remove unintentionally committed pubspec.lock
- Rewrote parsing logic to unpin dart-xml dependency, and bumped Dart XML dependency.
- Fix bug where unsupported elements could impact drawing. Unhandled elements that have children will now be completely ignored. This is technically a breaking change, as previously a child of an unsupported element could have been drawn if it was supported. Fixes #126.
- Fix bug in transform logic #122
- Avoid defaulting to the rootBundle, using th DefaultAssetBundle instead when resolving pictures #118
- Pin dart-xml to 3.2.5, as 3.3.0 is a breaking change (next release will address this).
pxpostfixes on many double literals.
- Added a
- Updated tests to support async changes in Flutter's
- This is breaking for tests - tests will now require a more recent version of Flutter to run. It should not break consumers though.
This is technically a breaking release, but it also includes important fixes for v0.10.0. Rather than splitting the breaking parts out in to v0.11.0 so soon after the release of v0.10.0, I'm including some more breaking changes here. This will not normally be done.
- Fix bug that caused
<stop>elements that weren't self-closing to parse improperly.
- Many documentation updates/improvements.
- Added support for gradients that use
- BREAKING: Changed some of the methods on
DrawableDefinitionServerto support gradients better.
- BREAKING: Removed the
PaintServertypedef, since this was only serving gradients and we need to have more control there for
- Fix bug that caused an empty
<defs/>element prevent rendering.
- Rewrite parsing to be more space efficient.
- Refactor parsing to enable more output possibilities.
- Create a dedicated SVG parsing class (SvgParser).
- Updates to text - better support for nested text/tspans.
- Miscellaneous bug fixes.
- Testing improvements.
- Fix inheritance issues with
- Fix a few inconsistencies in text anchor processing/positioning.
- BREAKING Improvements to text positioning. Thanks to @krispypen!
- Implement support for
- Implement support for
svgcleanerper author's recommendation.
DrawableStyleableto avoid crashing with certain unhandled elements.
- Improve error reporting for certain
- Revert changes made on 0.7.0 to attempt to utilize
height. These changes did not quite fix what they were intended to fix and caused problems they weren't intended to case.
- Made parsing
asyncto support image loading.
- Added support for
- By default,
SvgPicture.assetwill now cache the asset. We already cached the final picture, but the caching included any color filtering provided on the image. This is problematic if the color is animated. See dnfield/flutter_svg#33
- BREAKING Correct erroneous
heightprocessing on the root element.
heightwere treated as synonyms for the width and height of the
viewBox. This is not correct, and resulted in meaningful rendering errors in some scenarios compared to Chrome. Fixing this makes the parser more conformant to the spec, but may make your SVGs look significantly different if they specify
height. If you want the old behavior, you'll have to update your SVGs to not specify
MediaQuery.of(context).devicePixelRatioif available before defaulting to
window.devicePixelRatioin places that need awareness of devicePixelRatios.
- Support for
<symbol>, and shape/group elements in
<defs>. There are some limitations to this currently,
- Consume updated version of path_drawing.
- Fix bug with fill-rule inheritance + example to test.
- Consume updated version of path_drawing, which fixes dnfield/flutter_svg#73
- Fixed an issue with stroke and fill inheritance (and added test)
- General formatting/analyzer cleanup
- BREAKING Update Flutter version dependencies/package dependencies
- Print unhandled errors only once, and only in debug mode (000e17f)
- Add ability to specify a
Alignmentfor SvgPictures (Thanks @sroddy!).
- Miscellaneous bug fixes
- Restructure project to match expectations of Flutter tooling
- Create a new class to encapsulate
Paintand assist with inheriting all painting properties.
- Fixes regression introduced in v0.5.2 where some previously working inheritance stopped working.
- Support more complex stroke/fill property inheritance.
- Consume latest path_drawing (and path_parsing) packages to fix issue(s) with smooth curve handling.
HttpStatus.OKchange - not ready yet for Flutter beta channel
- Fix bug(s) in processing stroke and fill opacity when stroke/fill are inherited.
- Fix HTTP network headers for network pictures
- Consume latest change from path_drawing (fixes exponent validation)
- Minimum Flutter version is now 0.5.1 (latest beta as of release)
- Merge in support for Focal Pointed Radial Gradients
- Use asset directory references in pubspec.yaml
- Better support for nested
- Support for
<ellipse>parsing bug (ellipses were drawn at half the expected size)
<polyline>parsing bug (polylines were incorrectly forced to be closed)
- Fix bug where widget caused exception in a
- Remove deprecated code related to
- Improved reporting of error conditions
- Unsupported style elements will report an error
- Unresolvable definitions will report an error
- Support for
- Fix centering/scaling of canvas when viewBox is not square
- Improved color parsing
- Bug fix around caching for tinting/coloring (color was not being properly included in cache keys)
- Support for tinting/coloring the output
- Documentation updates
- This version represents a major rewrite of the widget(s) involved in rendering SVG drawings. This is primarily to support caching and better performance in rendering.
- New method on DrawableRoot toPicture to create a ui.Picture object from the SVG.
- Support for caching of Pictures, similar to how framework caches images. This will eventually be configurable, but is not as of this release.
BREAKING CHANGES #
- BREAKING CHANGE:
VectorDrawableImagehave been deprecated. They relied on methods that are less efficient than those now surfaced in
- BREAKING CHANGE: Size is no longer passed to
SvgPicture- its size is determined by parent size.
- BREAKING CHANGE:
clipToViewBoxis now called
allowDrawingOutsideViewBox. It defaults to false. It should not ordinarily be set to true, as it can allow unexpected memory usage if your vector graphic tries to draw far outside of the viewBox bounds.
- BREAKING CHANGE:
SvgPicturedoes not support custom
ErrorWidgetBuilders at this point in time. However, errors will be properly logged to the console. This is a result of improvements in the loading/caching of drawings.
- Fix bug(s) in inheritance (better rendering of Ghostscript_Tiger.svg)
- Support for
- Refactoring of how gradients are handled to enable clipPaths
- Refactor of SVG shape -> path logic
- Fix bugs in
- Add error widget on error.
- Add ability to specify error/placeholder widgets.
- Minor improvement on flutter logo SVG (add missing gradient).
- Improve docs, unit tests.
- Add more unit tests and rendering tests (!).
- Add top level flutter_svg.dart.
- Fix bugs found in transform matrix logic for skewX and skewY.
- Minor improvements in handling inheritance for PathFillType.
- Support gradient spread types (TileModes in Flutter).
- Bump to path_drawing 0.2.3 (fix arc defect).
- Handle 'none' in dasharray without throwing exception.
- Better handling of inheritance and 'none' in fill/stroke/dasharray
- Handle opacity on groups and inherited/blended opacity.
- Fixes elements that have both opacity and stroke-opacity or fill-opacity.
- Improvements for inheritance.
- Fixes related to unspecified fills on shapes.
Bumping minor version due to internal breaking changes and new support. Works on dev channel as of release (Flutter >= 0.3.6).
DrawableRootto support top level style definition.
- Support for dash paths.
- Support for more inherited attributes.
- Initial support for
- Support for
- Change painting order from stroke first, then fill to fill first, then stroke
(matches Chrome rendering of
Initial text support. Relies on flutter 0.3.6.
Initial release. Relies on pre-released master.
A new Flutter project.
Getting Started #
For help getting started with Flutter, view our online documentation.
Use this package as a library
1. Depend on it
Add this to your package's pubspec.yaml file:
dependencies: flutter_svg: ^0.15.0
2. Install it
You can install packages from the command line:
$ flutter pub get
Alternatively, your editor might support
flutter pub get.
Check the docs for your editor to learn more.
3. Import it
Now in your Dart code, you can use:
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We analyzed this package on Dec 10, 2019, and provided a score, details, and suggestions below. Analysis was completed with status completed using:
- Dart: 2.7.0
- pana: 0.13.1+4
- Flutter: 1.12.13+hotfix.4
|Dart SDK||>=2.2.0 <3.0.0|