paper_canvas 0.2.3

A multi-page handwriting and drawing canvas with configurable paper sizes, vector paper templates, an unbounded mode, and true vector PDF export and printing.

Changelog

0.2.3

Fixed

• An infinite canvas can now be panned horizontally. The horizontal bound was measured against the page width while the vertical one used the document height, so the surface was pinned to a single sheet sideways no matter how large infiniteCanvasMinSize was set: only the vertical extent responded to it. Both axes now measure the document. Paged mode is unchanged, since there the document is exactly one page wide.
• An infinite canvas no longer opens with the viewport parked left of its own origin. resetView centred the sheet horizontally, which on a mode that has no sheet left a band of host background showing down the side of the screen where there was no canvas to paint. It now opens at the document origin.

Changed

• infiniteCanvasMinSize defaults to 60000x80000 (was 10000x15000) and infiniteCanvasMargin to 8000 (was 2000). With the panning bug above fixed, the old default was reachable in a few swipes on a tablet.

0.2.2

Packaging only -- no functional change.

Fixed

• The LICENSE file is once again recognised as MIT. An explanatory paragraph about the derivation had been inserted into the license body, which stopped pub.dev's license detector matching it against the canonical MIT text. The file is now verbatim MIT, retaining both copyright holders; the derivation is documented in NOTICE.md and the README, where it belongs.
• Shortened the pubspec description to 158 characters. It was 207, over the 180-character limit pub.dev checks, which meant search engines truncated it.

0.2.1

Added

• PaperCanvas.canvasColor sets the paper colour directly, without having to construct a whole PaperTemplateTheme just to change the sheet. It composes with the theme rather than replacing it, so the ruling colours and metrics are preserved, and it applies everywhere paper is drawn -- the canvas, the exported PDF and thumbnails. Defaults to null, meaning the theme's own pageColor (white for PaperTemplateTheme.light), so existing behaviour and the PaperTemplateTheme.dark preset are unchanged.

The default pen colour was already a parameter: PaperCanvas.color, which defaults to black. Its seeding from initialColor no longer compares against an inline colour literal.

0.2.0

Fixed

• The CanvasMode.infinite surface was far too small. Its size was derived from the page format (two pages plus a margin), giving roughly 3191x3684 points on A4 -- only a few screens in each direction, which does not feel unbounded. It now defaults to a 10000x15000 minimum and still grows beyond that to keep a margin past the drawn content.

Added

• PaperCanvas.infiniteCanvasMinSize (default Size(10000, 15000)) and PaperCanvas.infiniteCanvasMargin (default 2000) make the unbounded surface configurable instead of implied by the page size.

Changed

• The render cache no longer opens a document-sized saveLayer unless an eraser stroke is actually present. Erasers remove whole strokes and are never persisted, so the layer was only ever needed for imported legacy data -- and its cost scales with the canvas, which now matters.

0.1.0

First release.

Published as 0.x while the API settles: under semver, breaking changes before 1.0.0 land as a minor bump (0.2.0) rather than a major one.

paper_canvas is a derivative work of scribe_canvas v0.6.3 by SKS-0212, used under the MIT License — see NOTICE.md for what was inherited. Upstream's own history is preserved in doc/upstream_scribe_canvas_changelog.md.

Added

• Configurable paper sizes. PageFormat with PaperSize (A3, A4, A5, Letter, Legal) and PageOrientation, replacing hard-coded A4 constants. Dimensions are in PostScript points so screen and PDF geometry match. PageFormat.fromDimensions() recovers a format from stored dimensions, and toJson/fromJson let page setup travel with a document.
• Vector paper templates. PaperTemplate.lined, .grid, .dots and .cornell, drawn through a TemplateSink shared by the Flutter canvas and PdfGraphics, so the printed page cannot drift from the screen. Colours and metrics are configurable via PaperTemplateTheme, with light and dark presets. Templates can also be rendered standalone via PaperTemplateRenderer and renderTemplateImage().
• Unbounded canvas mode. CanvasMode.infinite removes page bands and x-clamping and grows the surface in both axes as you draw. Export crops to the drawn region and fits it to one sheet, never scaling above 1:1.
• Shape tools. PaperTool.line, .rectangle and .circle. Shapes store two anchors and derive their outline on demand, so rendering, eraser hit-testing and PDF export all work from one representation and a shape stays a shape across save and reload.
• Distinct pen and brush. PaperTool.pen draws at a constant width; PaperTool.brush varies width with drawing speed.
• Printing. printPdf() opens the platform print dialog (AirPrint on iOS, the print framework on Android). buildPdf() returns raw bytes with no UI, for upload or preview.
• Structured JSON persistence. getStrokesJson() / loadStrokesJson() store one JSON object per stroke, alongside the existing compact string codec. Malformed entries are skipped rather than failing the whole load.
• Thumbnails. renderThumbnail() rasterises the content bounding box with its template, rather than the whole surface.
• Introspection. hasStrokes, pageCount and contentBounds on the controller.

Changed

• Public API renamed from the Scribe* prefix to Paper*. There is no source compatibility with upstream.
• PDF export rewritten for configurable page formats, vector templates and shape strokes.
• Changing pageFormat or canvasMode at runtime now re-derives page count, cached geometry and the render cache, so page setup can be a live setting.
• Minimum SDK corrected to Flutter 3.27 / Dart 3.6, which is what the code actually requires (Color.toARGB32(), Color.withValues()). Upstream declared flutter: ">=1.17.0", which would resolve on toolchains it could not compile against.

Fixed

• The documented color property was inert: the pen colour was seeded from initialColor once in initState and color was never read again, so a host toolbar could not change it and every stroke came out black. Now adopted in didUpdateWidget.

Removed

• loadPdfBackground(), and with it the pdfx dependency — vector templates cover the same need without a second PDF engine. Use setBackgroundImage() for image backgrounds.
• The unused file_picker dependency, which upstream declared but never referenced.