Monday, March 13, 2017

SVG - Quick Guide

SVG - Overview

What is SVG?

  • SVG, Scalable Vector Graphics is an XML based language to define vector based graphics.
  • SVG is intended to display images over the web.
  • Being vector images, SVG image never loses quality no matter how they are zoomed out or resized.
  • SVG images supports interactivity and animation.
  • SVG is a W3C standard.
  • Others image formats like raster images can also be clubbed with SVG images.
  • SVG integrates well with XSLT and DOM of HTML.

Advantages

  • Use any text editor to create and edit SVG images.
  • Being XML based, SVG images are searchable, indexable and can be scripted and compressed.
  • SVG images are highly scalable as they never loses quality no matter how they are zoomed out or resized
  • Good printing quality at any resolution
  • SVG is an Open Standard

Disadvantages

  • Being text format size is larger then compared to binary formatted raster images.
  • Size can be big even for small image.

Example

Following XML snippet can be used to draw a circle in web browser.
<svg width="100" height="100">
   <circle cx="50" cy="50" r="40" stroke="red" stroke-width="2" fill="green" />
</svg>
Embed the SVG XML directly in an HTML page.
testSVG.htm
<html>
   <title>SVG Image</title>
   <body>
   
      <h1>Sample SVG Image</h1>
      
      <svg width="100" height="100">
         <circle cx="50" cy="50" r="40" stroke="red" stroke-width="2" fill="green" />
      </svg>
   
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. In Internet Explorer, activeX controls are required to view SVG images.

How SVG integrates with HTML

  • <svg> element indicates the start of SVG image.
  • <svg> element's width and height attributes defines the height and width of the SVG image.
  • In above example, we've used a <circle> element to draw a circle.
  • cx and cy attribute represents center of the circle. Default value is (0,0). r attribute represents radius of circle.
  • Other attributes stroke and stroke-width controls the outlining of the circle.
  • fill attribute defines the fill color of the circle.
  • Closing</svg> tag indicates the end of SVG image.

SVG - Shapes

SVG provides number of shapes which can be used to draw images. Following are the common shapes.
Sr.No. Shape Type & Description
1 rect Used to draw a rectangle.
2 circle Used to draw a circle.
3 ellipse Used to draw a ellipse.
4 line Used to draw a line.
5 polygon Used to draw a closed shape consisting of connected straight lines.
6 polyline Used to draw a open shape consisting of connected straight lines.
7 path Used to draw any path.

SVG - Text

<text> element is used to draw text.

Declaration

Following is the syntax declaration of <text> element. We've shown main attributes only.
<text
  x="x-cordinates"
  y="y-cordinates"
  
  dx="list of lengths"
  dy="list of lengths"
  
  rotate="list of numbers"
  textlength="length"
  lengthAdjust="spacing" >
</text>

Attributes

Sr.No. Attribute & Description
1 x − x axis coordinates of glyphs.
2 y − y axis coordinates of glyphs.
3 dx − shift along with x-axis.
4 dy − shift along with y-axis.
5 rotate − rotation applied to all glyphs.
6 textlength − rendering length of the text.
7 lengthAdjust − type of adjustment with the rendered length of the text.

Example

testSVG.htm 
<html>
   <title>SVG Text</title>
   <body>
      
      <h1>Sample SVG Text</h1>
      
      <svg width="800" height="800">
         <g>
            <text x="30" y="12" >Text: </text>
            <text x="30" y="30" fill="rgb(121,0,121)">WWW.TutorialsPoint.COM</text>
         </g> 
      </svg>
   
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

Text with rotate

<html>
   <title>SVG Text</title>
   <body>
      <h1>Sample SVG Text</h1>
      
      <svg width="800" height="800">
         <g>
            <text x="30" y="12" >Multiline Text: </text>
            <text x="30" y="30" fill="rgb(121,0,121)">WWW.TutorialsPoint.COM
            <tspan x="30" y="50" font-weight="bold">Simply Easy learning.</tspan>
            <tspan x="30" y="70">We teach just for free.</tspan>
            </text>
         </g>
      </svg>
      
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

Multiline Text

<html>
   <title>SVG Text</title>
   <body>
      <h1>Sample SVG Text</h1>
      
      <svg width="570" height="100">
         <g>
            <text x="30" y="12" >Multiline Text: </text>
            <text x="30" y="30" fill="rgb(121,0,121)">WWW.TutorialsPoint.COM
               <tspan x="30" y="50" font-weight="bold">Simply Easy learning.</tspan>
               <tspan x="30" y="70">We teach just for free.</tspan>
            </text>
         </g>
      </svg>
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

Hyper link Text

<html>
   <title>SVG Text</title>
   <body>
      <h1>Sample SVG Text</h1>
      
      <svg width="800" height="800">
         <g>
            <text x="30" y="10" >Text as Link: </text>
         
            <a xlink:href="http://www.tutorialspoint.com/svg/" target="_blank">
               <text font-family="Verdana" font-size="20"  x="30" y="30" 
               fill="rgb(121,0,121)">WWW.TutorialsPoint.COM</text>
            </a>
         </g>
      </svg>
      
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

SVG - Stroke

SVG supports multiple stroke properties.
Following are the main stroke properties used.
Sr.No. Stroke Type & Description
1 stroke − defines color of text, line or outline of any element.
2 stroke-width − defines thickness of text, line or outline of any element.
3 stroke-linecap − defines different types of ending of a line or outline of any path.
4 stroke-dasharray − used to create dashed lines.

Example

testSVG.htm 
<html>
   <title>SVG Stroke</title>
   <body>
   
      <h1>Sample SVG Stroke</h1>
      
      <svg width="800" height="800">
         <g>
            <text x="30" y="30" >Using stroke: </text>
            <path stroke="red" d="M 50 50 L 300 50" />
            <path stroke="green" d="M 50 70 L 300 70" />
            <path stroke="blue" d="M 50 90 L 300 90" />
         </g> 
      </svg>
   
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

Stroke width

<html>
   <title>SVG Stroke</title>
   <body>
      
      <h1>Sample SVG Stroke</h1>
      
      <svg width="800" height="800">
         <text x="30" y="10" >Using stroke-width: </text>
         <path stroke-width="2" stroke="black" d="M 50 50 L 300 50" />
         <path stroke-width="4" stroke="black" d="M 50 70 L 300 70" />
         <path stroke-width="6" stroke="black" d="M 50 90 L 300 90" />
      </svg>
      
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

stroke-linecap

<html>
   <title>SVG Stroke</title>
   <body>
      
      <h1>Sample SVG Stroke</h1>
      
      <svg width="800" height="800">
         <g>
            <text x="30" y="30" >Using stroke-linecap: </text>
         
            <path stroke-linecap="butt" stroke-width="6" 
            stroke="black" d="M 50 50 L 300 50" />
         
            <path stroke-linecap="round" stroke-width="6" 
            stroke="black" d="M 50 70 L 300 70" />
         
            <path stroke-linecap="square" stroke-width="6"
            stroke="black" d="M 50 90 L 300 90" />
         </g>
      </svg>
   
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

stroke-dasharray

<html>
   <title>SVG Stroke</title>
   <body>
   
      <h1>Sample SVG Stroke</h1>
      
      <svg width="800" height="800">
         <g>
            <text x="30" y="30" >Using stroke-dasharray: </text>
            
            <path stroke-dasharray="5,5" stroke-width="6" 
            stroke="black" d="M 50 50 L 300 50" />
            
            <path stroke-dasharray="10,10" stroke-width="6" 
            stroke="black" d="M 50 70 L 300 70" />
            
            <path stroke-dasharray="20,10,5,5,5,10" stroke-width="6" 
            stroke="black" d="M 50 90 L 300 90" />
         </g>
      </svg>
   
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

SVG - Filters

SVG uses <filter> element to define filters. <filter> element uses an id attribute to uniquely identify it.Filters are defined within <def> elements and then are referenced by graphics elements by their ids.
SVG provides a rich set of filters. Following is the list of the commonly used filters.
  • feBlend
  • feColorMatrix
  • feComponentTransfer
  • feComposite
  • feConvolveMatrix
  • feDiffuseLighting
  • feDisplacementMap
  • feFlood
  • feGaussianBlur
  • feImage
  • feMerge
  • feMorphology
  • feOffset - filter for drop shadows
  • feSpecularLighting
  • feTile
  • feTurbulence
  • feDistantLight
  • fePointLight
  • feSpotLight

Declaration

Following is the syntax declaration of <filter> element. We've shown main attributes only.
<filter
   filterUnits="units to define filter effect region"
   primitiveUnits="units to define primitive filter subregion"
   
   x="x-axis co-ordinate" 
   y="y-axis co-ordinate"     
   
   width="length"
   height="length"
   
   filterRes="numbers for filter region"
   xlink:href="reference to another filter" >
</filter>

Attributes

Sr.No. Name & Description
1 filterUnits − units to define filter effect region. It specifies the coordinate system for the various length values within the filter and for the attributes defining the filter subregion. If filterUnits="userSpaceOnUse", values represent values in the current user coordinate system in place at the time when the 'filter' element is used. If filterUnits="objectBoundingBox", values represent values in fractions or percentages of the bounding box on the referencing element in place at the time when the 'filter' element is used. Default is userSpaceOnUse.
2 primitiveUnits − units to define filter effect region. It specifies the coordinate system for the various length values within the filter and for the attributes defining the filter subregion. If filterUnits="userSpaceOnUse", values represent values in the current user coordinate system in place at the time when the 'filter' element is used. If filterUnits="objectBoundingBox", values represent values in fractions or percentages of the bounding box on the referencing element in place at the time when the 'filter' element is used. Default is userSpaceOnUse.
3 x − x-axis co-ordinate of the filter bounding box. Defeault is 0.
4 y − y-axis co-ordinate of the filter bounding box. Default is 0.
5 width − width of the filter bounding box. Default is 0.
6 height − height of the filter bounding box. Default is 0.
7 filterRes − numbers representing filter regions.
8 xlink:href − used to refer to another filter.

Example

testSVG.htm 
<html>
   <title>SVG Filter</title>
   <body>
   
      <h1>Sample SVG Filter</h1>
   
      <svg width="800" height="800">
      
         <defs>
            <filter id="filter1" x="0" y="0">
               <feGaussianBlur in="SourceGraphic" stdDeviation="8" />
            </filter>
            
            <filter id="filter2" x="0" y="0" width="200%" height="200%">
               <feOffset result="offOut" in="SourceAlpha" dx="20" dy="20" />
               <feGaussianBlur result="blurOut" in="offOut" stdDeviation="10" />
               <feBlend in="SourceGraphic" in2="blurOut" mode="normal" />
            </filter>
         </defs>
         
         <g>
            <text x="30" y="50" >Using Filters (Blur Effect): </text>
            <rect x="100" y="100" width="90" height="90" stroke="green" stroke-width="3"
            fill="green" filter="url(#filter1)" />      
         </g> 
         
      </svg>
   
   </body>
</html>
  • Two <filter> elements defined as filter1 and filter2.
  • feGaussianBlur filter effect defines the blur effect with the amount of blur using stdDeviation.
  • in="SourceGraphic" defines that the effect is applicable for the entire element.
  • feOffset filter effect is used to create shadow effect. in="SourceAlpha" defines that the effect is applicable for the alpha part of RGBA graphics.
  • <rect> elements linked the filters using filter attribute.

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

Filter with Shadow effect

<html>
   <title>SVG Filter</title>
   <body>
      
      <h1>Sample SVG Filter</h1>
      
      <svg width="800" height="800">
      
         <defs>
            <filter id="filter1" x="0" y="0">
               <feGaussianBlur in="SourceGraphic" stdDeviation="8" />
            </filter>
            
            <filter id="filter2" x="0" y="0" width="200%" height="200%">
               <feOffset result="offOut" in="SourceAlpha" dx="20" dy="20" />
               <feGaussianBlur result="blurOut" in="offOut" stdDeviation="10" />
               <feBlend in="SourceGraphic" in2="blurOut" mode="normal" />
            </filter>
         </defs>
         
         <g>
            <text x="30" y="50" >Using Filters (Shadow Effect): </text>
            <rect x="100" y="100" width="90" height="90" stroke="green" stroke-width="3"
            fill="green" filter="url(#filter2)" />
         </g>
         
      </svg>
   
   </body>
</html>

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

SVG - Patterns

SVG uses <pattern> element to define patterns. Patterns are defined using <pattern> element and are used to fill graphics elements in tiled fashion.

Declaration

Following is the syntax declaration of <pattern> element. We've shown main attributes only.
<pattern
   patternUnits="units to define x,y, width and height attributes."
   patternContentUnits ="units to define co-ordinate system of contents of pattern"
   patternTransform = "definition of an additional transformation from the pattern coordinate system onto the target coordinate system"
   
   x="x-axis co-ordinate" 
   y="y-axis co-ordinate"     
   
   width="length"
   height="length"
   
   preserveAspectRatio="to preserve width/height ratio of original content"
   xlink:href="reference to another pattern" >
</pattern>

Attributes

Sr.No. Name & Description
1 patternUnits − units to define patterns effect region. It specifies the coordinate system for the various length values within the pattern and for the attributes defining the pattern subregion. If patternUnits="userSpaceOnUse", values represent values in the current user coordinate system in place at the time when the 'pattern' element is used. If patternUnits="objectBoundingBox", values represent values in fractions or percentages of the bounding box on the referencing element in place at the time when the 'pattern' element is used. Default is userSpaceOnUse.
2 patternContentUnits − units to define pattern content region. It specifies the coordinate system for the various length values within the pattern and for the attributes defining the pattern subregion. If patternContentUnits="userSpaceOnUse", values represent values in the current user coordinate system in place at the time when the 'pattern' element is used. If patternContentUnits="objectBoundingBox", values represent values in fractions or percentages of the bounding box on the referencing element in place at the time when the 'pattern' element is used. Default is userSpaceOnUse.
3 x − x-axis co-ordinate of the pattern bounding box. Defeault is 0.
4 y − y-axis co-ordinate of the pattern bounding box. Default is 0.
5 width − width of the pattern bounding box. Default is 0.
6 height − height of the pattern bounding box. Default is 0.
7 preserveAspectRatio - to preserve width/height ratio of original content.
8 xlink:href − used to refer to another pattern.

Example

testSVG.htm 
<html>
   <title>SVG Pattern</title>
   <body>
      <h1>Sample SVG Pattern</h1>
      
      <svg width="800" height="800">
         
         <defs>
            <pattern id="pattern1" patternUnits="userSpaceOnUse"
               x="0" y="0" width="100" height="100"
               viewBox="0 0 4 4" >
               <path d="M 0 0 L 3 0 L 1.5 3 z" fill="blue" stroke="green" />
            </pattern> 
         </defs>
         
         <g>
            <text x="30" y="50" >Using Pattern (Triangles): </text>
            <rect x="100" y="100" width="300" height="300" stroke="green" 
            stroke-width="3" fill="url(#pattern1)" />
         </g> 
         
      </svg>
   
   </body>
</html>
  • One <pattern> element defined as pattern1.
  • In pattern, a viewbox is defined and a path which is to be used as pattern is defined.
  • in rect element, in fill attribute, url of the pattern is specified to fill the rectangle with pattern created earlier.

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.

SVG - Gradients

Gradient refers to smooth transition of one color to another color within a shape. SVG provides two types of gradients.
  • Linear Gradients − Represents linear transition of one color to another from one direction to another.
  • Radial Gradients − Represents circular transition of one color to another from one direction to another.

Linear Gradients

Declaration

Following is the syntax declaration of <linearGradient> element. We've shown main attributes only.
<linearGradient
   gradientUnits ="units to define co-ordinate system of contents of gradient"
   gradientTransform = "definition of an additional transformation from the gradient coordinate system onto the target coordinate system"
   
   x1="x-axis co-ordinate" 
   y1="y-axis co-ordinate"     
   x2="x-axis co-ordinate" 
   y2="y-axis co-ordinate"     
   
   spreadMethod="indicates method of spreading the gradient within graphics element"
   xlink:href="reference to another gradient" >
</linearGradient>

Attributes

Sr.No. Name & Description
1 gradientUnits − units to define the coordinate system for the various length values within the gradient. If gradientUnits="userSpaceOnUse", values represent values in the current user coordinate system in place at the time when the gradient element is used. If patternContentUnits="objectBoundingBox", values represent values in fractions or percentages of the bounding box on the referencing element in place at the time when the gradient element is used. Default is userSpaceOnUse.
2 x1 − x-axis co-ordinate of the gradient vector. Defeault is 0.
3 y1 − y-axis co-ordinate of the gradient vector. Default is 0.
4 x2 − x-axis co-ordinate of the gradient vector. Defeault is 0.
5 y2 − y-axis co-ordinate of the gradient vector. Default is 0.
6 spreadMethod − indicates method of spreading the gradient within graphics element. Default is 'pad'.
7 xlink:href − used to refer to another gradient.

Example

testSVG.htm 
<html>
   <title>SVG Linear Gradient</title>
   <body>
   
      <h1>Sample SVG Linear Gradient</h1>
   
      <svg width="600" height="600">
      
         <defs>
            <linearGradient id="sampleGradient">
               <stop offset="0%" stop-color="#FF0000" />
               <stop offset="100%" stop-color="#00FFF00" />
            </linearGradient>
         </defs>
         
         <g>
            <text x="30" y="50" >Using Linear Gradient: </text>
            <rect x="100" y="100" width="200" height="200" stroke="green" stroke-width="3" 
            fill="url(#sampleGradient)" />
         </g>
         
      </svg>
   
   </body>
</html>
  • One <linearGradient> element defined as sampleGradient.
  • In linearGradient, two offsets are defined with two colors.
  • in rect element, in fill attribute, url of the gradient is specified to fill the rectangle with gradient created earlier.

Output

Open textSVG.htm in Chrome web browser. You can use Chrome/Firefox/Opera to view SVG image directly without any plugin. Internet Explorer 9 and higher also supports SVG image rendering.
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