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Scalable Vector Graphics (SVG) 1.1 (Second Edition) 1 Introduction 1.1 About SVG 1.2 SVG MIME type 1.3 SVG Namespace 1.4 Compatibility with Other Standards Efforts 1.5 Terminology 1.6 Definitions 2 Concepts 2.1 Explaining the name: SVG 2.2 Important SVG concepts 2.3 Options for using SVG in Web pages 3 Rendering Model 3.1 Introduction 3.2 The painters model 3.3 Rendering Order 3.4 How groups are rendered 3.5 How elements are rendered 3.6 Types of graphics elements 3.6.1 Painting shapes and text 3.6.2 Painting raster images 3.7 Filtering painted regions 3.8 Clipping 3.9 Parent Compositing 4 Basic Data Types and Interfaces 4.1 Syntax 4.2 Basic data types 4.3 Real number precision 4.4 Recognized color keyword names 4.5 Basic DOM interfaces 4.5.1 Interface SVGElement 4.5.2 Interface SVGAnimatedBoolean 4.5.3 Interface SVGAnimatedString 4.5.4 Interface SVGStringList 4.5.5 Interface SVGAnimatedEnumeration 4.5.6 Interface SVGAnimatedInteger 4.5.7 Interface SVGNumber 4.5.8 Interface SVGAnimatedNumber 4.5.9 Interface SVGNumberList 4.5.10 Interface SVGAnimatedNumberList 4.5.11 Interface SVGLength 4.5.12 Interface SVGAnimatedLength 4.5.13 Interface SVGLengthList 4.5.14 Interface SVGAnimatedLengthList 4.5.15 Interface SVGAngle 4.5.16 Interface SVGAnimatedAngle 4.5.17 Interface SVGColor 4.5.18 Interface SVGICCColor 4.5.19 Interface SVGRect 4.5.20 Interface SVGAnimatedRect 4.5.21 Interface SVGUnitTypes 4.5.22 Interface SVGStylable 4.5.23 Interface SVGLocatable 4.5.24 Interface SVGTransformable 4.5.25 Interface SVGTests 4.5.26 Interface SVGLangSpace 4.5.27 Interface SVGExternalResourcesRequired 4.5.28 Interface SVGFitToViewBox 4.5.29 Interface SVGZoomAndPan 4.5.30 Interface SVGViewSpec 4.5.31 Interface SVGURIReference 4.5.32 Interface SVGCSSRule 4.5.33 Interface SVGRenderingIntent 5 Document Structure 5.1 Defining an SVG document fragment: the 憇vg?element 5.1.1 Overview 5.1.2 The 憇vg?element 5.2 Grouping: the 慻?element 5.2.1 Overview 5.2.2 The 慻?element 5.3 Defining content for reuse 5.3.1 Overview 5.3.2 The 慸efs?element 5.4 The 慸esc?and 憈itle?elements 5.5 The 憇ymbol?element 5.6 The 憉se?element 5.7 The 慽mage?element 5.8 Conditional processing 5.8.1 Conditional processing overview 5.8.2 The 憇witch?element 5.8.3 The 憆equiredFeatures?attribute 5.8.4 The 憆equiredExtensions?attribute 5.8.5 The 憇ystemLanguage?attribute 5.8.6 Applicability of test attributes 5.9 Specifying whether external resources are required for proper rendering 5.10 Common attributes 5.10.1 Attributes common to all elements: 慽d?and 憍ml:base? 5.10.2 The 憍ml:lang?and 憍ml:space?attributes 5.11 DOM interfaces 5.11.1 Interface SVGDocument 5.11.2 Interface SVGSVGElement 5.11.3 Interface SVGGElement 5.11.4 Interface SVGDefsElement 5.11.5 Interface SVGDescElement 5.11.6 Interface SVGTitleElement 5.11.7 Interface SVGSymbolElement 5.11.8 Interface SVGUseElement 5.11.9 Interface SVGElementInstance 5.11.10 Interface SVGElementInstanceList 5.11.11 Interface SVGImageElement 5.11.12 Interface SVGSwitchElement 5.11.13 Interface GetSVGDocument 6 Styling 6.1 SVG's styling properties 6.2 Usage scenarios for styling 6.3 Alternative ways to specify styling properties 6.4 Specifying properties using the presentation attributes 6.5 Styling with XSL 6.6 Styling with CSS 6.7 Case sensitivity of property names and values 6.8 Facilities from CSS and XSL used by SVG 6.9 Referencing external style sheets 6.10 The 憇tyle?element 6.11 The 慶lass?attribute 6.12 The 憇tyle?attribute 6.13 Specifying the default style sheet language 6.14 Property inheritance 6.15 The scope/range of styles 6.16 User agent style sheet 6.17 Aural style sheets 6.18 DOM interfaces 6.18.1 Interface SVGStyleElement 7 Coordinate Systems 7.1 Introduction 7.2 The initial viewport 7.3 The initial coordinate system 7.4 Coordinate system transformations 7.5 Nested transformations 7.6 The 憈ransform?attribute 7.7 The 憊iewBox?attribute 7.8 The 憄reserveAspectRatio?attribute 7.9 Establishing a new viewport 7.10 Units 7.11 Object bounding box units 7.12 Intrinsic sizing properties of the viewport of SVG content 7.13 Geographic coordinate systems 7.14 The 憇vg:transform?attribute 7.15 DOM interfaces 7.15.1 Interface SVGPoint 7.15.2 Interface SVGPointList 7.15.3 Interface SVGMatrix 7.15.4 Interface SVGTransform 7.15.5 Interface SVGTransformList 7.15.6 Interface SVGAnimatedTransformList 7.15.7 Interface SVGPreserveAspectRatio 7.15.8 Interface SVGAnimatedPreserveAspectRatio 8 Paths 8.1 Introduction 8.2 The 憄ath?element 8.3 Path data 8.3.1 General information about path data 8.3.2 The "moveto" commands 8.3.3 The "closepath" command 8.3.4 The "lineto" commands 8.3.5 The curve commands 8.3.6 The cubic B閦ier curve commands 8.3.7 The quadratic B閦ier curve commands 8.3.8 The elliptical arc curve commands 8.3.9 The grammar for path data 8.4 Distance along a path 8.5 DOM interfaces 8.5.1 Interface SVGPathSeg 8.5.2 Interface SVGPathSegClosePath 8.5.3 Interface SVGPathSegMovetoAbs 8.5.4 Interface SVGPathSegMovetoRel 8.5.5 Interface SVGPathSegLinetoAbs 8.5.6 Interface SVGPathSegLinetoRel 8.5.7 Interface SVGPathSegCurvetoCubicAbs 8.5.8 Interface SVGPathSegCurvetoCubicRel 8.5.9 Interface SVGPathSegCurvetoQuadraticAbs 8.5.10 Interface SVGPathSegCurvetoQuadraticRel 8.5.11 Interface SVGPathSegArcAbs 8.5.12 Interface SVGPathSegArcRel 8.5.13 Interface SVGPathSegLinetoHorizontalAbs 8.5.14 Interface SVGPathSegLinetoHorizontalRel 8.5.15 Interface SVGPathSegLinetoVerticalAbs 8.5.16 Interface SVGPathSegLinetoVerticalRel 8.5.17 Interface SVGPathSegCurvetoCubicSmoothAbs 8.5.18 Interface SVGPathSegCurvetoCubicSmoothRel 8.5.19 Interface SVGPathSegCurvetoQuadraticSmoothAbs 8.5.20 Interface SVGPathSegCurvetoQuadraticSmoothRel 8.5.21 Interface SVGPathSegList 8.5.22 Interface SVGAnimatedPathData 8.5.23 Interface SVGPathElement 9 Basic Shapes 9.1 Introduction 9.2 The 憆ect?element 9.3 The 慶ircle?element 9.4 The 慹llipse?element 9.5 The 憀ine?element 9.6 The 憄olyline?element 9.7 The 憄olygon?element 9.7.1 The grammar for points specifications in 憄olyline?and 憄olygon?elements 9.8 DOM interfaces 9.8.1 Interface SVGRectElement 9.8.2 Interface SVGCircleElement 9.8.3 Interface SVGEllipseElement 9.8.4 Interface SVGLineElement 9.8.5 Interface SVGAnimatedPoints 9.8.6 Interface SVGPolylineElement 9.8.7 Interface SVGPolygonElement 10 Text 10.1 Introduction 10.2 Characters and their corresponding glyphs 10.3 Fonts 10.4 The 憈ext?element 10.5 The 憈span?element 10.6 The 憈ref?element 10.7 Text layout 10.7.1 Text layout introduction 10.7.2 Setting the inline-progression-direction 10.7.3 Glyph orientation within a text run 10.7.4 Relationship with bidirectionality 10.8 Text rendering order 10.9 Alignment properties 10.9.1 Text alignment properties 10.9.2 Baseline alignment properties 10.10 Font selection properties 10.11 Spacing properties 10.12 Text decoration 10.13 Text on a path 10.13.1 Introduction to text on a path 10.13.2 The 憈extPath?element 10.13.3 Text on a path layout rules 10.14 Alternate glyphs 10.14.1 The 慳ltGlyph?element 10.14.2 The 慳ltGlyphDef? 慳ltGlyphItem?and 慻lyphRef?elements 10.15 White space handling 10.16 Text selection and clipboard operations 10.17 DOM interfaces 10.17.1 Interface SVGTextContentElement 10.17.2 Interface SVGTextPositioningElement 10.17.3 Interface SVGTextElement 10.17.4 Interface SVGTSpanElement 10.17.5 Interface SVGTRefElement 10.17.6 Interface SVGTextPathElement 10.17.7 Interface SVGAltGlyphElement 10.17.8 Interface SVGAltGlyphDefElement 10.17.9 Interface SVGAltGlyphItemElement 10.17.10 Interface SVGGlyphRefElement 11 Painting: Filling 11.1 Introduction 11.2 Specifying paint 11.3 Fill Properties 11.4 Stroke Properties 11.5 Controlling visibility 11.6 Markers 11.6.1 Introduction 11.6.2 The 憁arker?element 11.6.3 Marker properties 11.6.4 Details on how markers are rendered 11.7 Rendering properties 11.7.1 Color interpolation properties: 慶olor-interpolation?and 慶olor-interpolation-filters? 11.7.2 The 慶olor-rendering?property 11.7.3 The 憇hape-rendering?property 11.7.4 The 憈ext-rendering?property 11.7.5 The 慽mage-rendering?property 11.8 Inheritance of painting properties 11.9 DOM interfaces 11.9.1 Interface SVGPaint 11.9.2 Interface SVGMarkerElement 12 Color 12.1 Introduction 12.2 The 慶olor?property 12.3 Color profile descriptions 12.3.1 Overview of color profile descriptions 12.3.2 Alternative ways of defining a color profile description 12.3.3 The 慶olor-profile?element 12.3.4 The CSS @color-profile rule 12.3.5 The 慶olor-profile?property 12.4 DOM interfaces 12.4.1 Interface SVGColorProfileElement 12.4.2 Interface SVGColorProfileRule 13 Gradients and Patterns 13.1 Introduction 13.2 Gradients 13.2.1 Introduction 13.2.2 Linear gradients 13.2.3 Radial gradients 13.2.4 Gradient stops 13.3 Patterns 13.4 DOM interfaces 13.4.1 Interface SVGGradientElement 13.4.2 Interface SVGLinearGradientElement 13.4.3 Interface SVGRadialGradientElement 13.4.4 Interface SVGStopElement 13.4.5 Interface SVGPatternElement 14 Clipping 14.1 Introduction 14.2 Simple alpha compositing 14.3 Clipping paths 14.3.1 Introduction 14.3.2 The initial clipping path 14.3.3 The 憃verflow?and 慶lip?properties 14.3.4 Clip to viewport vs. clip to 憊iewBox? 14.3.5 Establishing a new clipping path: the 慶lipPath?element 14.3.6 Clipping paths 14.4 Masking 14.5 Object and group opacity: the 憃pacity?property 14.6 DOM interfaces 14.6.1 Interface SVGClipPathElement 14.6.2 Interface SVGMaskElement 15 Filter Effects 15.1 Introduction 15.2 An example 15.3 The 慺ilter?element 15.4 The 慺ilter?property 15.5 Filter effects region 15.6 Accessing the background image 15.7 Filter primitives overview 15.7.1 Overview 15.7.2 Common attributes 15.7.3 Filter primitive subregion 15.8 Light source elements and properties 15.8.1 Introduction 15.8.2 Light source 慺eDistantLight? 15.8.3 Light source 慺ePointLight? 15.8.4 Light source 慺eSpotLight? 15.8.5 The 憀ighting-color?property 15.9 Filter primitive 慺eBlend? 15.10 Filter primitive 慺eColorMatrix? 15.11 Filter primitive 慺eComponentTransfer? 15.12 Filter primitive 慺eComposite? 15.13 Filter primitive 慺eConvolveMatrix? 15.14 Filter primitive 慺eDiffuseLighting? 15.15 Filter primitive 慺eDisplacementMap? 15.16 Filter primitive 慺eFlood? 15.17 Filter primitive 慺eGaussianBlur? 15.18 Filter primitive 慺eImage? 15.19 Filter primitive 慺eMerge? 15.20 Filter primitive 慺eMorphology? 15.21 Filter primitive 慺eOffset? 15.22 Filter primitive 慺eSpecularLighting? 15.23 Filter primitive 慺eTile? 15.24 Filter primitive 慺eTurbulence? 15.25 DOM interfaces 15.25.1 Interface SVGFilterElement 15.25.2 Interface SVGFilterPrimitiveStandardAttributes 15.25.3 Interface SVGFEBlendElement 15.25.4 Interface SVGFEColorMatrixElement 15.25.5 Interface SVGFEComponentTransferElement 15.25.6 Interface SVGComponentTransferFunctionElement 15.25.7 Interface SVGFEFuncRElement 15.25.8 Interface SVGFEFuncGElement 15.25.9 Interface SVGFEFuncBElement 15.25.10 Interface SVGFEFuncAElement 15.25.11 Interface SVGFECompositeElement 15.25.12 Interface SVGFEConvolveMatrixElement 15.25.13 Interface SVGFEDiffuseLightingElement 15.25.14 Interface SVGFEDistantLightElement 15.25.15 Interface SVGFEPointLightElement 15.25.16 Interface SVGFESpotLightElement 15.25.17 Interface SVGFEDisplacementMapElement 15.25.18 Interface SVGFEFloodElement 15.25.19 Interface SVGFEGaussianBlurElement 15.25.20 Interface SVGFEImageElement 15.25.21 Interface SVGFEMergeElement 15.25.22 Interface SVGFEMergeNodeElement 15.25.23 Interface SVGFEMorphologyElement 15.25.24 Interface SVGFEOffsetElement 15.25.25 Interface SVGFESpecularLightingElement 15.25.26 Interface SVGFETileElement 15.25.27 Interface SVGFETurbulenceElement 16 Interactivity 16.1 Introduction 16.2 Complete list of supported events 16.3 User interface events 16.4 Pointer events 16.5 Hit-testing and processing order for user interface events 16.5.1 Hit-testing 16.5.2 Event processing 16.6 The 憄ointer-events?property 16.7 Magnification and panning 16.8 Cursors 16.8.1 Introduction to cursors 16.8.2 The 慶ursor?property 16.8.3 The 慶ursor?element 16.9 DOM interfaces 16.9.1 Interface SVGCursorElement 17 Linking 17.1 References 17.1.1 Overview 17.1.2 IRIs and URIs 17.1.3 Syntactic forms: IRI and FuncIRI 17.1.4 Processing of IRI references 17.1.5 IRI reference attributes 17.2 Links out of SVG content: the 慳?element 17.3 Linking into SVG content: IRI fragments and SVG views 17.3.1 Introduction: IRI fragments and SVG views 17.3.2 SVG fragment identifiers 17.3.3 Predefined views: the 憊iew?element 17.3.4 Highlighting views 17.4 DOM interfaces 17.4.1 Interface SVGAElement 17.4.2 Interface SVGViewElement 18 Scripting 18.1 Specifying the scripting language 18.1.1 Specifying the default scripting language 18.1.2 Local declaration of a scripting language 18.2 The 憇cript?element 18.3 Event handling 18.4 Event attributes 18.4.1 Event attribute for the SVGLoad event 18.4.2 Event attributes on graphics and container elements 18.4.3 Document-level event attributes 18.4.4 Animation event attributes 18.5 DOM interfaces 18.5.1 Interface SVGScriptElement 18.5.2 Interface SVGZoomEvent 19 Animation 19.1 Introduction 19.2 Animation elements 19.2.1 Overview 19.2.2 Relationship to SMIL Animation 19.2.3 Animation elements example 19.2.4 Attributes to identify the target element for an animation 19.2.5 Attributes to identify the target attribute or property for an animation 19.2.6 Animation with namespaces 19.2.7 Paced animation and complex types 19.2.8 Attributes to control the timing of the animation 19.2.8.1 Clock values 19.2.9 Attributes that define animation values over time 19.2.10 Attributes that control whether animations are additive 19.2.11 Inheritance 19.2.12 The 慳nimate?element 19.2.13 The 憇et?element 19.2.14 The 慳nimateMotion?element 19.2.15 The 慳nimateColor?element 19.2.16 The 慳nimateTransform?element 19.2.17 Elements 19.3 Animation using the SVG DOM 19.4 DOM interfaces 19.4.1 Interface ElementTimeControl 19.4.2 Interface TimeEvent 19.4.3 Interface SVGAnimationElement 19.4.4 Interface SVGAnimateElement 19.4.5 Interface SVGSetElement 19.4.6 Interface SVGAnimateMotionElement 19.4.7 Interface SVGMPathElement 19.4.8 Interface SVGAnimateColorElement 19.4.9 Interface SVGAnimateTransformElement 20 Fonts 20.1 Introduction 20.2 Overview of SVG fonts 20.3 The 慺ont?element 20.4 The 慻lyph?element 20.5 The 憁issing-glyph?element 20.6 Glyph selection rules 20.7 The 慼kern?and 憊kern?elements 20.8 Describing a font 20.8.1 Overview of font descriptions 20.8.2 Alternative ways for providing a font description 20.8.3 The 慺ont-face?element 20.8.4 The 慺ont-face-src?element 20.8.5 The 慺ont-face-uri?and 慺ont-face-format?elements 20.8.6 The 慺ont-face-name?element 20.9 DOM interfaces 20.9.1 Interface SVGFontElement 20.9.2 Interface SVGGlyphElement 20.9.3 Interface SVGMissingGlyphElement 20.9.4 Interface SVGHKernElement 20.9.5 Interface SVGVKernElement 20.9.6 Interface SVGFontFaceElement 20.9.7 Interface SVGFontFaceSrcElement 20.9.8 Interface SVGFontFaceUriElement 20.9.9 Interface SVGFontFaceFormatElement 20.9.10 Interface SVGFontFaceNameElement 21 Metadata 21.1 Introduction 21.2 The 憁etadata?element 21.3 An example 21.4 DOM interfaces 21.4.1 Interface SVGMetadataElement 22 Backwards Compatibility 23 Extensibility 23.1 Foreign namespaces and private data 23.2 Embedding foreign object types 23.3 The 慺oreignObject?element 23.4 An example 23.5 Adding private elements and attributes to the DTD 23.6 DOM interfaces 23.6.1 Interface SVGForeignObjectElement Appendix A: Document Type Definition A.1 Introduction A.2 Modularization A.2.1 Element and attribute collections A.2.2 Profiling the SVG specification A.2.3 Practical considerations A.3 SVG 1.1 module definitions and DTD implementations A.3.1 Modular Framework Module A.3.2 Datatypes Module A.3.3 Qualified Name Module A.3.4 Core Attribute Module A.3.5 Container Attribute Module A.3.6 Viewport Attribute Module A.3.7 Paint Attribute Module A.3.8 Basic Paint Attribute Module A.3.9 Paint Opacity Attribute Module A.3.10 Graphics Attribute Module A.3.11 Basic Graphics Attribute Module A.3.12 Document Events Attribute Module A.3.13 Graphical Element Events Attribute Module A.3.14 Animation Events Attribute Module A.3.15 XLink Attribute Module A.3.16 External Resources Attribute Module A.3.17 Structure Module A.3.18 Basic Structure Module A.3.19 Conditional Processing Module A.3.20 Image Module A.3.21 Style Module A.3.22 Shape Module A.3.23 Text Module A.3.24 Basic Text Module A.3.25 Marker Module A.3.26 Color Profile Module A.3.27 Gradient Module A.3.28 Pattern Module A.3.29 Clip Module A.3.30 Basic Clip Module A.3.31 Mask Module A.3.32 Filter Module A.3.33 Basic Filter Module A.3.34 Cursor Module A.3.35 Hyperlinking Module A.3.36 View Module A.3.37 Scripting Module A.3.38 Animation Module A.3.39 Font Module A.3.40 Basic Font Module A.3.41 Extensibility Module A.4 SVG 1.1 Document Type Definition A.4.1 SVG 1.1 DTD Driver A.4.2 SVG 1.1 Document Model A.4.3 SVG 1.1 Attribute Collection Appendix B: SVG Document Object Model (DOM) B.1 SVG DOM overview B.1.1 SVG DOM object initialization B.2 Elements in the SVG DOM B.3 Naming conventions B.4 Exception SVGException B.5 Feature strings for the hasFeature method call B.6 Relationship with DOM Level 2 Events B.7 Relationship with DOM Level 2 CSS B.7.1 Introduction B.7.2 User agents that do not support styling with CSS B.7.3 User agents that support styling with CSS B.7.4 Extended interfaces B.8 Read only nodes in the DOM B.9 Invalid values Appendix C: IDL Definitions Appendix D: Java Language Binding D.1 The Java language binding D.2 Using SVG with the Java language Appendix E: ECMAScript Language Binding E.1 Exceptions E.2 Constants E.3 Types E.4 Objects Appendix F: Implementation Requirements F.1 Introduction F.2 Error processing F.3 Version control F.4 Clamping values which are restricted to a particular range F.5 憄ath?element implementation notes F.6 Elliptical arc implementation notes F.6.1 Elliptical arc syntax F.6.2 Out-of-range parameters F.6.3 Parameterization alternatives F.6.4 Conversion from center to endpoint parameterization F.6.5 Conversion from endpoint to center parameterization F.6.6 Correction of out-of-range radii F.7 Text selection implementation notes F.8 Printing implementation notes Appendix G: Conformance Criteria G.1 Introduction G.2 Conforming SVG Document Fragments G.3 Conforming SVG Stand-Alone Files G.4 Conforming SVG Generators G.5 Conforming SVG Servers G.6 Conforming SVG DOM Subtree G.7 Conforming SVG Interpreters G.8 Conforming SVG Viewers Appendix H: Accessibility Support H.1 WAI Accessibility Guidelines H.2 SVG Content Accessibility Guidelines Appendix I: Internationalization Support I.1 Introduction I.2 Internationalization and SVG I.3 SVG Internationalization Guidelines Appendix J: Minimizing SVG File Sizes Appendix K: References K.1 Normative references K.2 Informative references Appendix L: Element Index Appendix M: Attribute Index M.1 Regular attributes M.2 Presentation attributes Appendix N: Property Index Appendix O: Feature Strings O.1 Introduction O.2 SVG 1.1 feature strings O.3 SVG 1.0 feature strings Appendix P: Media Type Registration for image/svg+xml P.1 Introduction P.2 Registration of media type image/svg+xml Appendix Q: Changes Check Update
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SVG 1.1 (Second Edition) – 16 August 2011Top ⋅ Contents ⋅ Previous ⋅ Next ⋅ Elements ⋅ Attributes ⋅ Properties

Appendix J: Minimizing SVG File Sizes

This appendix is informative, not normative.

Considerable effort has been made to make SVG file sizes as small as possible while still retaining the benefits of XML and achieving compatibility and leverage with other W3C specifications.

Here are some of the features in SVG that promote small file sizes:

  • SVG's path data definition was defined to produce a compact data stream for vector graphics data: all commands are one character in length; relative coordinates are available; separator characters do not have to be supplied when tokens can be identified implicitly; smooth curve formulations are available (cubic Béziers, quadratic Béziers and elliptical arcs) to prevent the need to tesselate into polylines; and shortcut formulations exist for common forms of cubic Bézier segments, quadratic Bézier segments, and horizontal and vertical straight line segments so that the minimum number of coordinates need to be specified.
  • Text can be specified using XML character data — no need to convert to outlines.
  • SVG contains a facility for defining symbols once and referencing them multiple times using different visual attributes and different sizing, positioning, clipping and client-side filter effects
  • User agents that support styling with CSS can use CSS selectors and property inheritance to define commonly used sets of attributes once as named styles.
  • Filter effects allow for compelling visual results and effects typically found only in image-authoring tools using small amounts of vector and/or raster data

Additionally, HTTP/1.1 allows for compressed data to be passed from server to client, which can result in significant file size reduction. Here are some sample compression results using gzip compression on SVG documents [RFC1952]:

Uncompressed SVG With gzip compression Compression ratio
12,912 2,463 81%
12,164 2,553 79%
11,613 2,617 77%
18,689 4,077 78%
13,024 2,041 84%

A related issue is progressive rendering. Some SVG viewers will support:

  • the ability to display the first parts of an SVG document fragments as the remainder of the document is downloaded from the server; thus, the user will see part of the SVG drawing right away and interact with it, even if the SVG file size is large.
  • delayed downloading of images and fonts. Just like some HTML browsers, some SVG viewers will download images and WebFonts ([CSS2], section 15.1) last, substituting a temporary image and system fonts, respectively, until the given image and/or font is available.

Here are techniques for minimizing SVG file sizes and minimizing the time before the user is able to start interacting with the SVG document fragments:

  • Construct the SVG file such that any links which the user might want to click on are included at the beginning of the SVG file
  • Use default values whenever possible rather than defining all attributes and properties explicitly.
  • Take advantage of the path data data compaction facilities: use relative coordinates; use h and v for horizontal and vertical lines; use s or t for cubic and quadratic Bézier segments whenever possible; eliminate extraneous white space and separators.
  • Utilize symbols if the same graphic appears multiple times in the document
  • For user agents that support styling with CSS, utilize CSS property inheritance and selectors to consolidate commonly used properties into named styles or to assign the properties to a parent ‘g’ element.
  • Utilize filter effects to help construct graphics via client-side graphics operations.
SVG 1.1 (Second Edition) – 16 August 2011Top ⋅ Contents ⋅ Previous ⋅ Next ⋅ Elements ⋅ Attributes ⋅ Properties
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