SVG API — SVGParser & SVGRenderer in Prowl.Quill

Prowl.Quill includes a self-contained SVG pipeline composed of two static classes — SVGParser and SVGRenderer — and a hierarchy of typed element classes rooted at SvgElement. SVGParser converts an SVG XML file on disk into an in-memory tree of SvgElement objects, each already pre-parsed for colours, stroke widths, and path commands. SVGRenderer walks that tree and issues the equivalent Canvas draw calls, applying strokes and fills with anti-aliasing. The pipeline supports the most common SVG primitives and is designed for embedding icons, illustrations, and other vector assets in Quill-rendered UIs.

SVGParser

SVGParser is a static class. It parses SVG XML files and returns the root SvgElement of the document tree. Internally it uses System.Xml.XmlDocument and maps each recognised XML element to a typed subclass.

Methods

ParseSVGDocument

public static SvgElement ParseSVGDocument(string filePath)

Reads an SVG file from disk, validates that the root element is <svg>, and recursively parses all child elements into a typed SvgElement tree.

filePath

string

Absolute or relative path to the .svg file.

Returns: The root SvgElement (always of TagType.svg). Use SvgElement.Flatten() to enumerate all descendants, or pass the root directly to SVGRenderer.DrawToCanvas. Exceptions:

FileNotFoundException — file does not exist at the given path.
InvalidOperationException — document root is not an <svg> element.

SvgElement icon = SVGParser.ParseSVGDocument("assets/icons/star.svg");

Supported Element Types

The parser maps XML tag names to typed subclasses. Unsupported tags are silently skipped during tree construction.

SVG tag	C# class	Parsed fields
`<svg>`	`SvgElement`	Container root
`<path>`	`SvgPathElement`	`d` attribute → `DrawCommand[]`
`<circle>`	`SvgCircleElement`	`cx`, `cy`, `r`
`<rect>`	`SvgRectElement`	`x`, `y`, `width`, `height`, `rx`, `ry`
`<line>`	`SvgLineElement`	`x1`, `y1`, `x2`, `y2`
`<ellipse>`	`SvgEllipseElement`	`cx`, `cy`, `rx`, `ry`
`<polyline>`	`SvgPolylineElement`	`points`
`<polygon>`	`SvgPolygonElement`	`points`
`<g>`	`SvgElement`	Group container (children parsed recursively)

SVGRenderer

SVGRenderer is a static class that translates a parsed SvgElement tree into canvas draw calls. It calls SvgElement.Flatten() internally and dispatches each element to the appropriate drawing function.

Static Fields

currentColor

Color32

The colour substituted when an SVG element declares stroke="currentColor" or fill="currentColor". Defaults to Color.White. Set this before calling DrawToCanvas to match the ambient UI colour:

SVGRenderer.currentColor = Color32.FromArgb(255, 30, 144, 255);
SVGRenderer.DrawToCanvas(canvas, new Float2(10, 10), icon);

debug

bool

When true, the renderer prints each processed draw command to Console.WriteLine. Automatically reset to false at the end of each DrawToCanvas call. Useful for diagnosing incorrect path rendering:

SVGRenderer.debug = true;
SVGRenderer.DrawToCanvas(canvas, Float2.Zero, element);
// debug is false again after the call returns

Methods

DrawToCanvas

public static void DrawToCanvas(Canvas canvas, Float2 position, SvgElement svgElement)

Renders a parsed SVG element (and all its descendants) to the canvas, offset by position. The method:

Calls svgElement.Flatten() to produce a depth-first ordered list of all descendants.
For each element, configures the canvas stroke colour, fill colour, and stroke width from the element’s parsed style properties.
Dispatches to the element-type-specific draw function.
Resets debug to false before returning.

canvas

Canvas

The target canvas. The canvas’s current transform, scissor, and global alpha are respected. The SVG elements are drawn on top of any geometry already accumulated in the frame.

position

Float2

A pixel-space offset added to all coordinates in the SVG. Use this to position the SVG within the canvas without modifying the SVG’s internal coordinate system.

svgElement

SvgElement

The root element returned by SVGParser.ParseSVGDocument. You can also pass any subtree node to render only a portion of the document.

SvgElement

SvgElement is the base class for all parsed SVG nodes. It stores common presentation attributes (stroke, fill, stroke-width) and the hierarchical structure (parent–child relationships). Specialised subclasses add geometry-specific fields.

Fields

tag

SvgElement.TagType

The element type, corresponding to the XML tag name. Possible values: svg, path, circle, rect, line, polyline, polygon, ellipse, g.

depth

int

Zero-based nesting depth in the original document. The root <svg> element has depth 0; direct children have depth 1, etc.

Attributes

Dictionary<string, string>

All XML attributes defined on this element, keyed case-insensitively. Access raw attribute values for properties not explicitly surfaced on subclasses.

Children

List<SvgElement>

Direct child elements. Recursively populated during parsing. Use Flatten() to iterate the entire subtree in depth-first order.

drawCommands

DrawCommand[]

Path draw commands for SvgPathElement instances. null on non-path elements. Each DrawCommand stores the command type (DrawType), whether coordinates are relative, and a float[] of parameters.

stroke

Color32

The parsed stroke colour. Only valid when strokeType == ColorType.specific.

fill

Color32

The parsed fill colour. Only valid when fillType == ColorType.specific.

strokeType

SvgElement.ColorType

Determines how the stroke colour is sourced: none (no stroke), currentColor (use SVGRenderer.currentColor), or specific (use stroke).

fillType

SvgElement.ColorType

Determines how the fill colour is sourced: none (no fill), currentColor (use SVGRenderer.currentColor), or specific (use fill).

strokeWidth

float

The stroke width in SVG user units. Defaults to 1.0 if the stroke-width attribute is absent.

Methods

Flatten

public List<SvgElement> Flatten()

Returns a flat, depth-first list containing this element and all of its descendants. Useful for custom rendering logic or debugging.

var all = icon.Flatten();
Console.WriteLine($"Total elements: {all.Count}");
foreach (var el in all)
    Console.WriteLine($"  {"  ".PadLeft(el.depth * 2)}{el}");

ToString

public override string ToString()

Returns a short summary string in the format:

<tagName Depth=N Attributes='A' Children='C'>

(SvgPathElement overrides this to also list each DrawCommand.)

ColorType Enum

SvgElement.ColorType describes how a colour value is sourced for stroke or fill.

Value	Meaning
`none`	No colour — the property is disabled (no stroke or no fill).
`currentColor`	Inherit the colour from `SVGRenderer.currentColor`.
`specific`	A concrete colour is defined in the SVG attribute.

DrawCommand and DrawType

DrawCommand is a struct holding one parsed SVG path command. DrawType is the corresponding enum.

DrawType	SVG letter	Parameters
`MoveTo`	M / m	x, y
`LineTo`	L / l	x, y
`HorizontalLineTo`	H / h	x
`VerticalLineTo`	V / v	y
`CubicCurveTo`	C / c	x1 y1 x2 y2 x y
`SmoothCubicCurveTo`	S / s	x2 y2 x y
`QuadraticCurveTo`	Q / q	x1 y1 x y
`SmoothQuadraticCurveTo`	T / t	x y
`ArcTo`	A / a	rx ry x-rot large-arc sweep x y
`ClosePath`	Z / z	(none)

Lowercase SVG letters set DrawCommand.relative = true; uppercase set false.

Full Usage Example

// 1. Parse an SVG file once (e.g. at startup)
SvgElement icon = SVGParser.ParseSVGDocument("assets/ui/close-icon.svg");

// 2. Each frame, render it at a specific canvas position
canvas.BeginFrame(windowWidth, windowHeight, dpiScale);

SVGRenderer.currentColor = Color32.FromArgb(255, 220, 220, 220); // icon tint
SVGRenderer.DrawToCanvas(canvas, new Float2(buttonX, buttonY), icon);

canvas.Render();

Inspecting the element tree

var elements = icon.Flatten();
foreach (var el in elements)
{
    Console.Write($"{new string(' ', el.depth * 2)}{el.tag}");
    Console.Write($"  fill={el.fillType}");
    if (el.fillType == SvgElement.ColorType.specific)
        Console.Write($"({el.fill})");
    Console.Write($"  stroke={el.strokeType}");
    if (el.strokeType == SvgElement.ColorType.specific)
        Console.Write($"({el.stroke}) w={el.strokeWidth}");
    Console.WriteLine();
}

Canvas

Types

Renderer Interface

SVG API — SVGParser & SVGRenderer in Prowl.Quill

SVGParser

Methods

ParseSVGDocument

Supported Element Types

SVGRenderer

Static Fields

Methods

DrawToCanvas

SvgElement

Fields

Methods

Flatten

ToString

ColorType Enum

DrawCommand and DrawType

Full Usage Example

Inspecting the element tree

Build docs developers (and LLMs) love

Canvas

Types

Renderer Interface

Documentation Index

​SVGParser

​Methods

​ParseSVGDocument

​Supported Element Types

​SVGRenderer

​Static Fields

​Methods

​DrawToCanvas

​SvgElement

​Fields

​Methods

​Flatten

​ToString

​ColorType Enum

​DrawCommand and DrawType

​Full Usage Example

​Inspecting the element tree

Build docs developers (and LLMs) love

SVGParser

Methods

ParseSVGDocument

Supported Element Types

SVGRenderer

Static Fields

Methods

DrawToCanvas

SvgElement

Fields

Methods

Flatten

ToString

ColorType Enum

DrawCommand and DrawType

Full Usage Example

Inspecting the element tree