PeachPDF

Supported SVG Features

PeachPDF renders SVG — inline <svg> elements in HTML, standalone SVG (<img src="x.svg"> / data:image/svg+xml), and SVG used as a CSS background-image/list-style-image url() source — as real vector PDF content. Shapes become native PDF path-construction operators, gradients become native PDF shadings, and clips/masks/patterns become native PDF constructs. SVG is never rasterized to a bitmap: this preserves scalability and keeps the PDF’s file size small regardless of the output resolution. This page documents exactly what is and is not supported. Where a feature is only partially supported, the specific gaps are noted.

SVG Root & Document Structure

Element MDN Reference Notes
svg svg Inline (<svg> inside HTML), standalone (<img src="x.svg">, data:image/svg+xml), and as a CSS background-image/list-style-image url() source are all supported — see HTML & CSS Support for the CSS-side details. viewBox, width, height, and preserveAspectRatio are all honored. A nested <svg> establishes its own viewport, coordinate system, and clip
g g Full support, including presentation-attribute inheritance
defs defs Content is never painted directly, only through a reference (<use>, fill="url(#id)", clip-path, mask, marker properties)
symbol symbol Never painted directly; establishes its own viewport (viewBox/preserveAspectRatio) only when referenced via <use>, sized by the <use> element’s width/height (defaulting to the current viewport’s size, per spec)
use use Resolves href/xlink:href references, including to symbol, nested svg, and ordinary shapes. x/y offset and (for symbol/nested-svg targets) width/height overrides are supported. The <use> element’s own resolved paint becomes the inherited default for an otherwise-unstyled target. A reference cycle is guarded against (max depth 8)
switch switch Renders only the first buildable child. PeachPDF has no requiredFeatures/requiredExtensions/systemLanguage conditional-support axis to evaluate, so this is equivalent to every other candidate always failing its (nonexistent) test — a deliberate v1 simplification
a a Groups children like <g>, and additionally becomes a real PDF link annotation (same-page #id fragments become /GoTo links, other href values become /URI links) covering the transformed content’s bounding box. A rotated/skewed anchor’s link region is approximated by its axis-aligned bounding box, since PDF link annotations are themselves always axis-aligned rectangles

Shapes

Element MDN Reference Notes
path path Full support for the d attribute grammar: move/line/cubic-bezier/quadratic-bezier/elliptical-arc, absolute and relative, including all shorthand/smooth variants
rect rect Full support, including independently-rounded corners via rx/ry (each defaults to the other when only one is specified, per spec)
circle circle Full support
ellipse ellipse Full support
line line Full support. Per spec, fill never applies to a <line> (it has no interior) — no fill operator is emitted regardless of the element’s fill paint
polyline polyline Stroke never closes back to the first point, matching spec. A filled (rather than the far more common fill="none") polyline is a known simplification: fill uses the same unclosed geometry as the stroke rather than spec’s implicit closing segment for fill purposes only
polygon polygon Full support

Painting: Fill, Stroke, Color

Feature MDN Reference Notes
fill fill Solid colors (named, hex, rgb()), gradient references (url(#id)), pattern references (url(#id)), none, and currentColor
fill-rule fill-rule nonzero and evenodd, inherited
fill-opacity fill-opacity Full support, inherited, independent of opacity and stroke-opacity
stroke stroke Solid colors and gradient references paint a real stroke (including a real gradient-filled stroke, not an approximation). Pattern-filled strokes are not supported — see Unsupported SVG Features
stroke-width stroke-width Full support, inherited
stroke-opacity stroke-opacity Full support, inherited
stroke-linecap stroke-linecap butt, round, square, inherited
stroke-linejoin stroke-linejoin miter, round, bevel, inherited
stroke-miterlimit stroke-miterlimit Full support, inherited
stroke-dasharray stroke-dasharray Full support, inherited
stroke-dashoffset stroke-dashoffset Full support, inherited
opacity opacity Not inherited as a property — it composites instead, per spec. On a leaf shape (no children), applied as a simple alpha multiply on the shape’s own fill/stroke/text color. On a container (<g>, <a>, nested <svg>) it’s rendered as a genuine, isolated PDF transparency group — the container’s children are painted into an offscreen Form XObject and flattened, then that single flattened result is composited once at the container’s own opacity, so overlapping children no longer double-blend where they overlap. (A <use> referencing a container indirectly still uses the simpler per-shape multiply for that target’s children — a narrower residual v1 gap.)
currentColor currentColor Resolves to the CSS color property of the inline <svg>’s HTML ancestor; for standalone SVG (no CSS context), resolves to black
color-interpolation / color-interpolation-filters — Not supported — see Unsupported SVG Features

Gradients

Element MDN Reference Notes
linearGradient linearGradient x1/y1/x2/y2, gradientUnits (objectBoundingBox — the spec default — and userSpaceOnUse, both fully resolved against the referencing shape’s bounding box or the user-space coordinate system respectively), gradientTransform (translate/scale; a rotated/skewed gradientTransform on a radial gradient can’t turn the circle into a rotated ellipse — see below), spreadMethod
radialGradient radialGradient cx/cy/r, plus focal point fx/fy (independent of the center, per spec), same gradientUnits/gradientTransform/spreadMethod support as linearGradient. A rotated gradientTransform renders as an axis-aligned ellipse (the closest 2D approximation) rather than a true rotated ellipse
stop stop offset, stop-color, stop-opacity (as both presentation attributes and via style=)
spreadMethod spreadMethod pad, reflect, repeat. reflect/repeat are implemented by tiling the gradient’s own stop list across an axis (or radius) extended to cover the filled shape’s bounding box — mirroring alternate cycles for reflect so adjacent cycles share a color with no seam — capped at 500 tiled cycles as a safety guard against pathological short-axis/large-shape combinations

Gradients render as native PDF shadings (/ShadingType), not rasterized bitmaps.

Clipping, Masking, Patterns

Element MDN Reference Notes
clipPath clipPath Full support; clip-rule (nonzero/evenodd) controls the clip region’s fill rule. Renders as a real PDF clipping path (W n), not a mask
mask mask Renders as a real PDF luminosity soft mask (/SMask via /ExtGState) — mask content is painted (not just used for geometry, unlike clipPath) into an offscreen form, and its luminance becomes the mask’s alpha. maskUnits/maskContentUnits (objectBoundingBox/userSpaceOnUse) are both supported, including the spec’s -10%/-10%/120%/120% default region
pattern pattern patternUnits/patternContentUnits (objectBoundingBox/userSpaceOnUse), patternTransform, viewBox/preserveAspectRatio. Implemented by rendering the pattern’s content once into a PDF Form XObject “tile,” then drawing that same tile repeatedly (clipped to the filled shape’s geometry) across the fill region — every repeat is a reference to the same underlying vector content, never a rasterized bitmap, but this is not a native PDF /PatternType 1 tiling pattern object. Capped at 10,000 tile placements per fill as a safety guard against pathological pattern/shape size ratios

Markers

Element MDN Reference Notes
marker marker refX/refY, markerWidth/markerHeight, viewBox/preserveAspectRatio, markerUnits (strokeWidth/userSpaceOnUse), orient (auto, auto-start-reverse, and a fixed angle)
marker-start / marker-mid / marker-end marker-start Full support, plus the marker shorthand (sets all three; an individually-specified property overrides just that one). Inherited. Per spec, markers only attach to path/line/polyline/polygon — not basic shapes like rect/circle/ellipse, which have no defined vertex sequence
Tangent/orientation math — Exact for straight-line and cubic-bezier path segments (computed from the segment’s own control-point vectors); chord-approximated for elliptical arc segments (a documented v1 simplification — the tangent is estimated from the arc’s endpoints rather than its true derivative)

See a in SVG Root & Document Structure above.

Raster & Nested Content

Element MDN Reference Notes
image image Only a data: URI href is resolved. A raster payload (data:image/png, data:image/jpeg, etc.) embeds as a real PDF image XObject; a data:image/svg+xml payload renders as its own real vector scene graph (never rasterized), with its own url(#id) references resolving against its own definitions. x/y/width/height/preserveAspectRatio are all honored — including for raster images, which are fit into their box per preserveAspectRatio’s alignment/meet/slice rules, the same math used for viewports elsewhere in this renderer. A network URL or local file path href is a documented v1 gap (see below) — the element still builds but renders nothing
Nested svg see svg above Establishes its own viewport, coordinate system, and clip

Why <image> only supports data: URIs: SVG document parsing (SvgTreeBuilder.Build) is synchronous, while resolving a network or file-path image reference needs this library’s general asynchronous resource-loading pipeline. data: URI resolution needs no actual I/O (it’s pure in-memory base64 decoding), so it’s resolved synchronously inline without that pipeline. This matches PeachPDF’s own general guidance that “all images and assets must be local to the file system or in data: URIs” for predictable, self-contained rendering.

Text

Element MDN Reference Notes
text text x/y/dx/dy, a single leading rotate value, text-anchor (start/middle/end), font-family/font-size/font-weight/font-style (as both presentation attributes and style=). Bridges directly into PeachPDF’s existing font/text-measurement pipeline — the same font resolution ordinary HTML text uses
tspan tspan A tspan without its own x/y flows immediately after its previous sibling’s rendered width (ordinary SVG text flow), at whole-run granularity. A tspan with its own x and/or y starts a new absolute position. Font properties and paint (fill/stroke/etc.) are inherited from the enclosing text/tspan when not overridden
tref tref (deprecated in SVG2, still supported here) href/xlink:href resolves to another element’s own text content, reused as this run’s text
textPath textPath Not supported — see Unsupported SVG Features

Known text simplifications (all documented in code as deliberate v1 scope reductions, the same category as <switch>’s first-child-only behavior above):

Coordinate Systems & Units

Feature Notes
viewBox Full support, including all 9 preserveAspectRatio alignment keywords (xMinYMin, xMidYMid, xMaxYMax, etc.) and both meet and slice, plus none (independent-axis stretch)
Length units Unitless numbers, % (resolved against the viewport width/height/diagonal per the axis, per spec), px, pt, pc, in, cm, mm, em, rem (the latter two approximate CSS’s 16px initial font-size, since no live font-size cascade context reaches arbitrary SVG geometry attributes)
transform matrix(), translate(), scale(), rotate() (including the 3-argument rotate(angle, cx, cy) form), skewX(), skewY(). Multiple functions may be chained; they compose per spec

CSS Integration

Feature Notes
Presentation attributes Every property above is readable as a plain XML attribute (e.g. fill="red")
style="..." Inline style= is supported on every element, taking precedence over presentation attributes, per CSS cascade rules
<style> element Supported, with a deliberately minimal selector matcher scoped to type (rect), class (.foo), ID (#foo), and compound selectors (rect.foo), plus comma-separated selector lists. Specificity follows standard CSS rules. Descendant/child/sibling combinators, attribute selectors, and pseudo-classes are not supported in an SVG <style> block — a rule using one of those is silently skipped, and does not apply. Known gap: for an inline <svg> inside HTML (not standalone <img>/data: SVG), a <style> element nested inside the <svg> is not reliably associated with it by PeachPDF’s underlying HTML tokenizer, and may fail to apply — this is a pre-existing HTML-parsing limitation, not specific to SVG <style> handling itself. Standalone SVG is not affected
class / id Read for <style> selector matching, same as HTML

Unsupported SVG Features

The following SVG 1.0/1.1 features are not supported, each for the reason given: