sketchify 1.0.0

Turn any image into a "draw itself" animation. Traces PNG, JPEG, WebP, SVG and more into smooth outlines that sketch in, then ends on the exact original.

1.0.0

First stable release, published on pub.dev. The public API is now stable.

• Everything from the 0.x development versions below, tested on Android, iOS, web (JavaScript and WebAssembly), macOS, Windows and Linux.
• New showcase app in example/. It includes sample illustrations, five looks (Pencil, Neon, Ink, Blueprint and Vector), playback controls, a timeline scrubber, every style option, the palette that was found, and your own images through a file picker.
• Complete README covering installation, recipes, every option, caching, formats, accuracy, performance tips, troubleshooting and limitations.
• API documentation for every public class and member.
• Test and example images are original artwork, released under the package's MIT licence.
• Minimum versions: Dart 3.9 and Flutter 3.35 (the same as flutter_svg 2.3).
• The internal traceImageInBackground helper is no longer public.

0.6.0

Trace caching: an image is traced only once.

• Tracing the same image with the same options again comes from a cache and is almost instant (for example 511 ms → 55 ms), also after the app restarts. It works with no setup.
• Results are kept in memory (Sketchify.cache, up to 32 MB) and in SketchCacheStore.platformDefault() (up to 100 MB): the app's cache directory on Android, iOS, macOS, Windows and Linux, or IndexedDB on the web. They stay until the app's cache or data is cleared, or until Sketchify.cache.clear() is called.
• SketchCacheStore.directory(path) keeps results in a directory you choose. You can also implement SketchCacheStore for your own storage.
• Images are recognised by their contents and the options used, so an edited image is never served stale. Pass cacheKey to name an image yourself instead.
• useCache: false skips the cache for one call. Sketch.fromCache tells you whether the cache was used. SketchCache.flush() waits for results still being saved.
• The cache stores outlines and a compressed final image, never decoded images, so Sketch.dispose() still frees memory.
• A failing cache (a full disk, a corrupted file, private browsing) never breaks tracing.
• New dependencies: path_provider and web.
• onProgress is no longer called in the middle of a build. Replacing the sketch restarted the drawing during the rebuild. If onProgress updated other widgets, Flutter threw "setState() or markNeedsBuild() called during build".
• Pending delay and repeatPause waits are now cancelled on pause, replay and dispose, so they never leave a timer running.

0.5.0

Stability: fixes found while testing on every platform.

• SketchAnimation no longer crashes on web (JavaScript builds). The playback duration was clamped with 1 << 52, which is 0 on the web.
• Tracing an image that is only semi-transparent (no fully opaque pixels) no longer throws a RangeError.
• Line art in one or two inks with few flat areas (for example thin strokes on white) no longer breaks into dozens of fragments.
• seek() no longer calls onCompleted. It also no longer starts the next loop or ping-pong run while paused.
• Changing playMode while paused no longer starts playback.
• Switching autoPlay on, or replacing the sketch, now starts after delay.
• Out-of-range SketchOptions now fail clearly: an assert in debug, and an ArgumentError in release. Added SketchOptions.validate(), ==, hashCode and toString.
• Decoded images are now freed if tracing fails partway through.
• Format detection: files that merely start with two zero bytes (such as MP4 videos) are no longer reported as WBMP. AVIF is now identified as SketchImageFormat.avif, so its error message is accurate. Added SketchImageFormat.isSupported.
• Pen dots on a lineGradient now take the gradient's colour at the pen tip.
• The pen glow now uses a radial gradient instead of a blur filter, which is much cheaper with many pens.
• New SketchOptions.removeEnclosedBackground. Set it to false to remove only the background that touches the image border, so enclosed areas of that colour (such as white eyes on a white background) stay in the artwork.
• New SketchAnimationState.isPaused.

0.4.0

Any image format.

• Added WebP, GIF, BMP, WBMP and ICO support, plus HEIC/HEIF where the platform can decode it. Animated GIF and WebP use their first frame.
• Added SVG support through flutter_svg. SVGs are rendered at SketchOptions.svgRenderSize, then traced. Added Sketchify.traceSvgString.
• The format is detected from the file's contents, not its name (SketchImageFormat.detect).
• SketchImageFormat.allExtensions and allMimeTypes provide ready-made lists for file pickers.
• Unreadable files throw UnsupportedImageException, with a clear message.

0.3.0

Playback control.

• SketchAnimation gained speed, curve, playMode (once, loop, pingPong), delay, repeatPause, autoPlay and width.
• Control from code through a GlobalKey<SketchAnimationState>: replay, pause, resume, seek, progress and isPlaying.
• New onCompleted and onProgress callbacks.

0.2.0

Styles.

• New SketchStyle:
  • Lines: a line colour or a gradient across the artwork, each shape's own colour, width, caps and joins, and keeping lines on top of the fill.
  • A pen dot with an optional glow.
  • Drawing order: together, staggered or sequential.
  • The fill: the original image, the traced vector layers, or none.
  • Six reveal styles: fade, four wipes and a growing circle.
• New SketchPainter, for drawing a sketch at any progress in your own CustomPaint.

0.1.0

Cleaner traces.

• A solid background is detected from the image border and cut out with soft, fringe-free edges. Real transparency is kept.
• Colours are found from flat areas first, so anti-aliased edges don't become fake colours. Colours that only appear in thin lines are found too.
• Edges are placed to a fraction of a pixel. Circles and ellipses come out exactly round, and real corners stay sharp.
• Specks are merged into their neighbours, and shapes inside other shapes are layered correctly.
• Tracing runs in a background isolate.

0.0.1

First working version.

• Sketchify.trace and Sketchify.traceAsset turn PNG and JPEG images into coloured vector layers with smooth Bézier outlines.
• SketchAnimation draws the outlines in, then fades in the original image, so the last frame matches it exactly.