v0 source pure

Package svg is a minimalist and extensible SVG generation library for Gno.

`gno.land/p/moul/svg/v0`

Minimalist, extensible SVG generation library for Gno.

The canvas style map is backed by gno.land/p/nt/bptree/v0: a B+ tree packs many entries per persisted node, so styles cost less storage and inserts spend less gas than an AVL backing would.

Compatibility caveats (from the in-place-mutating B+ tree backing):

do not call AddStyle from inside a Canvas.String/Render iteration;
do not copy a non-zero Canvas by value once styles have been added — the copies would share live tree nodes.

Part of moul/gno-contracts — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

Dependency graph:

gno.land/p/moul/svg/v0 dependency graph

⚠️ Disclaimer: provided as-is, without warranty; not security-audited. Full disclaimer: DISCLAIMER.

Package svg is a minimalist and extensible SVG generation library for Gno.

It is the B+ tree successor to gno.land/p/moul/svg/v0 (whose canvas styles are backed by an AVL tree): a bump to v2 because the backing data structure used for the canvas style map — and thus the on-chain storage layout — changed from gno.land/p/nt/avl/v0 to gno.land/p/nt/bptree/v0. The exported API is otherwise identical to v1.

A B+ tree packs many entries per persisted node, so a stored style entry costs less storage than the AVL backing (and inserts spend materially less gas). Prefer v2 when the canvas is part of persisted realm state.

Two behavioral caveats inherited from the in-place-mutating B+ tree backing:

do NOT call AddStyle from inside a Canvas.String/Render iteration — the AVL backing tolerated mutation during iteration, the B+ tree one does not;
do NOT copy a non-zero Canvas by value once styles have been added — the copies would share live B+ tree nodes (v1's AVL copies were independent).

It provides a structured way to create and compose SVG elements such as rectangles, circles, text, paths, and more. The package is designed to be modular and developer-friendly, enabling optional attributes and method chaining for ease of use.

Each SVG element embeds a BaseAttrs struct, which supports common SVG attributes like `id`, `class`, `style`, `fill`, `stroke`, and `transform`.

Canvas objects represent the root SVG container and support global dimensions, viewBox configuration, embedded styles, and element composition.

Example:

Example

 1import "gno.land/p/moul/svg/v0"
 2
 3func Foo() string {
 4	canvas := svg.NewCanvas(200, 200).WithViewBox(0, 0, 200, 200)
 5	canvas.AddStyle(".my-rect", "stroke:black;stroke-width:2")
 6	canvas.Append(
 7		svg.NewRectangle(60, 40, 100, 50, "red").WithClass("my-rect"),
 8		svg.NewCircle(50, 80, 40, "blue"),
 9		&svg.Path{D: `M 10,30
10		A 20,20 0,0,1 50,30
11			A 20,20 0,0,1  90,30
12			Q 90,60 50,90
13			Q 10,60 10,30 z`, Fill: "magenta"},
14		svg.NewText(20, 50, "Hello SVG", "black"),
15	)
16	mysvg := canvas.Base64()
17}

1func NewCanvas(width, height int) *Canvas

source

1func NewCircle(cx, cy, r int, fill string) *Circle

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1func NewEllipse(cx, cy int, fill string) *Ellipse

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1func NewGroup(fill string) *Group

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1func NewPath(d, fill string) *Path

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1func NewPolygon(points, fill string) *Polygon

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1func NewPolyline(points, fill string) *Polyline

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1func NewRectangle(x, y, width, height int, fill string) *Rectangle

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1func NewText(x, y int, text, fill string) *Text

source

 1type BaseAttrs struct {
 2	ID          string
 3	Class       string
 4	Style       string
 5	Stroke      string
 6	StrokeWidth string
 7	Opacity     string
 8	Transform   string
 9	Visibility  string
10}

source

1func (b BaseAttrs) String() string

source

1type Canvas struct {
2	Width, Height int
3	ViewBox       string
4	Elems         []Elem
5	Style         *bptree.BPTree
6}

source

1func (c *Canvas) AddStyle(key, value string) *Canvas

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1func (c *Canvas) Append(elem ...Elem)

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1func (c Canvas) Base64() string

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1func (c Canvas) Render(alt string) string

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Render renders your canvas

1func (c Canvas) String() string

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1func (c *Canvas) WithViewBox(x, y, width, height int) *Canvas

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1type Circle struct {
2	CX   int // center X
3	CY   int // center Y
4	R    int // radius
5	Fill string
6	Attr BaseAttrs
7}

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1func (c Circle) String() string

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1func (c *Circle) WithClass(class string) *Circle

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1type Elem interface{ String() string }

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1type Ellipse struct {
2	CX   int // center X
3	CY   int // center Y
4	RX   int // radius X
5	RY   int // radius Y
6	Fill string
7	Attr BaseAttrs
8}

source

1func (e Ellipse) String() string

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1func (e *Ellipse) WithClass(class string) *Ellipse

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1type Group struct {
2	Elems []Elem
3	Fill  string
4	Attr  BaseAttrs
5}

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1func (g *Group) Append(elem ...Elem)

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1func (g Group) String() string

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1func (g *Group) WithClass(class string) *Group

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1type Path struct {
2	D    string
3	Fill string
4	Attr BaseAttrs
5}

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1func (p Path) String() string

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1func (p *Path) WithClass(class string) *Path

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1type Polygon struct {
2	Points string
3	Fill   string
4	Attr   BaseAttrs
5}

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1func (p Polygon) String() string

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1func (p *Polygon) WithClass(class string) *Polygon

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1type Polyline struct {
2	Points string
3	Fill   string
4	Attr   BaseAttrs
5}

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1func (p Polyline) String() string

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1func (p *Polyline) WithClass(class string) *Polyline

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1type Rectangle struct {
2	X, Y, Width, Height int
3	RX, RY              int // corner radiuses
4	Fill                string
5	Attr                BaseAttrs
6}

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1func (r Rectangle) String() string

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1func (r *Rectangle) WithClass(class string) *Rectangle

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1type Text struct {
2	X, Y       int
3	DX, DY     int // shift text pos horizontally/ vertically
4	Rotate     string
5	Text, Fill string
6	Attr       BaseAttrs
7}

source

1func (c Text) String() string

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1func (c *Text) WithClass(class string) *Text

source

encoding/base64 stdlib
gno.land/p/nt/bptree/v0 package
gno.land/p/nt/ufmt/v0 package
strings stdlib

Readme View source

gno.land/p/moul/svg/v0

Overview

Functions 9

Types 11

Methods on BaseAttrs

Methods on Canvas

Methods on Circle

Methods on Ellipse

Methods on Group

Methods on Path

Methods on Polygon

Methods on Polyline

Methods on Rectangle

Methods on Text

Imports 4

Source Files 4

`gno.land/p/moul/svg/v0`