Icon

The Icon type, its three constructors, all fluent transform methods, and the output methods that produce HTML.

Overview

The Icon type represents a parsed SVG icon with inner content and attributes. Every fluent method returns a new *Icon; the original is never modified.

For a usage guide covering chaining, transforms, and sizing, see Icon Manipulation.

Types

Icon

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type Icon struct {
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    // unexported fields
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}

Fields (unexported):

• content string: SVG inner markup (without the <svg> wrapper).
• attributes map[string]string: SVG element attributes.

Constructors

New

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func New(content string, attrs map[string]string) *Icon

Creates an Icon from raw SVG inner content and an attribute map. The attribute map is deep-copied; the caller's map is not retained. Passing nil for attrs produces an icon with an empty attribute map.

FromFile

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func FromFile(path string) (*Icon, error)

Reads the SVG file at path, parses and sanitizes it, and returns the resulting Icon. Returns an error wrapping ErrProviderError on I/O failure or ErrInvalidSVG if the content has no <svg> element.

FromString

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func FromString(svg string) (*Icon, error)

Parses an SVG string and returns the resulting Icon. Returns ErrInvalidSVG if the input is empty or contains no <svg> element. The inner content is sanitized automatically. When the input contains multiple <svg> elements, only the first is parsed.

Fluent methods

All methods return a new *Icon with deep-copied attributes.

Attr

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func (ic *Icon) Attr(attrs map[string]string) *Icon

Merges the given attributes into the existing set. Empty-string values are ignored. For CSS classes, prefer Class (which appends) over Attr with a "class" key (which overwrites).

Class

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func (ic *Icon) Class(classes ...string) *Icon

Appends the given CSS classes to any existing class attribute, space-separated. Does not replace existing classes.

Size

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func (ic *Icon) Size(size int) *Icon

Sets both width and height to size.

Width

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func (ic *Icon) Width(w string) *Icon

Sets width to w and derives height from the viewBox aspect ratio. Supports CSS units ("24", "1.5em", "2rem"). Special values: "auto" resolves to the viewBox width/height; "unset", "none", or "undefined" remove both width and height attributes.

Height

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func (ic *Icon) Height(h string) *Icon

Sets height to h and derives width from the viewBox aspect ratio. Same CSS unit support and special values as Width.

Fill

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func (ic *Icon) Fill(fill string) *Icon

Sets the fill attribute.

Stroke

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func (ic *Icon) Stroke(stroke string) *Icon

Sets the stroke attribute.

StrokeWidth

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func (ic *Icon) StrokeWidth(w string) *Icon

Sets the stroke-width attribute.

Opacity

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func (ic *Icon) Opacity(o float64) *Icon

Sets the opacity attribute. Formatted with %g (e.g., 0.5 becomes "0.5", 1.0 becomes "1").

Rotate

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func (ic *Icon) Rotate(degrees float64) *Icon

Appends a CSS rotate(Xdeg) function to the style attribute's transform declaration. If a transform already exists in the style, the function is appended to it. Otherwise a new transform declaration is added.

Flip

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func (ic *Icon) Flip(direction string) *Icon

Appends a CSS scale transform to the style attribute. Accepted values:

Chaining Rotate and Flip produces a single transform declaration.

Title

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func (ic *Icon) Title(title string) *Icon

Prepends a <title> element to the SVG content. The title text is HTML-escaped via html.EscapeString.

Output methods

ToHTML

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func (ic *Icon) ToHTML() string

Renders the icon as a complete <svg> element string. Attributes are sorted alphabetically for deterministic output. Attribute names are validated against ^[a-zA-Z_:][\w:.\-]*$; invalid names are silently dropped. Attribute values are HTML-escaped.

String

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func (ic *Icon) String() string

Implements fmt.Stringer. Returns the same value as ToHTML.

Content

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func (ic *Icon) Content() string

Returns the SVG inner content without the <svg> wrapper.

Attributes

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func (ic *Icon) Attributes() map[string]string

Returns a deep copy of the icon's attribute map. Modifying the returned map does not affect the icon.

IsEmpty

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func (ic *Icon) IsEmpty() bool

Reports whether the icon has no inner content (empty string).

ViewBox

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func (ic *Icon) ViewBox() (minX, minY, w, h int)

Parses the viewBox attribute and returns its four components. Falls back to width/height attributes (with minX=0, minY=0) if viewBox is absent. Returns 0, 0, 0, 0 when neither is available.

ViewBoxSize

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func (ic *Icon) ViewBoxSize() (w, h int)

Returns the width and height from the viewBox. Convenience wrapper around ViewBox().

See also

• Icon Manipulation: practical guide to the fluent API with chaining examples
• Attribute Management: how attributes merge across five layers when the manager resolves an icon