revision:
SVG stands for scalable vector graphics (SVG). It defines vector-based graphics in XML format and is, essentially, to graphics what HTML is to text.
SVG is mostly useful for vector type diagrams like pie charts, two-dimensional graphs in an X,Y coordinate system, etc.
SVG images can be created with any text editor, but it is often more convenient to create SVG images with a drawing program, like Inkscape.(https://inkscape.org/)
SVG code explanation:
An SVG image begins with an "svg" element.
The "width" and "height" attributes of the "svg" element define the width and height of the SVG image.
The "d" attribute defines a path to be drawn.
A "path definition" is a list of path commands where each command is composed of a command letter and numbers that represent the command parameters.
The "circle" element is used to draw a circle.
The "cx" and "cy" attributes define the x and y coordinates of the center of the circle. If "cx" and "cy" are not set, the circle's center is set to (0, 0).
The "r" attribute defines the radius of the circle.
The "stroke" and "stroke-width" attributes control how the outline of a shape appears.
The "fill" attribute refers to the color inside the circle.
The closing "/svg" tag closes the SVG image
SVG viewBox: the "viewBox" attribute defines the position and dimension, in user space, of an SVG viewport.
The value of the "viewBox" attribute is a list of four numbers: min-x, min-y, width and height.
The numbers, which are separated by whitespace and/or a comma, specify a rectangle in user space which is mapped to the bounds of the viewport established for the associated SVG element (not the browser viewport).
For "svg", viewBox defines the position and dimension for the content of the "svg" element.
The "g" SVG element is a container used to group other SVG elements.
Transformations applied to the "g" element are performed on its child elements, and its attributes are inherited by its children.
It can also group multiple elements to be referenced later with the "use" element.
The SVG "tspan" element defines a subtext within a <text> element or another <tspan> element. It allows for adjustment of the style and/or position of that subtext as needed.
The "fill" property: the "fill" attribute is a presentation attribute, therefore it can be used as a CSS property.
Note: Since SVG is written in XML, all elements must be properly closed!
Note: the SVG image background in the examples here below is put in gray to better reflect the positioning based on the respective attributes.
<svg width="100" height="100">
<circle cx="50" cy="50" r="40" stroke="green" stroke-width="4" fill="orange"/>
Sorry, your browser does not support inline SVG.
</svg>
Container elements: <a>, <defs>, <g>, <marker>, <mask>, <pattern>, <svg>, <switch>, <symbol>.
Filter primitive elements: <feBlend>, <feColorMatrix>, <feComponentTransfer>, <feComposite>, <feConvolveMatrix>, <feDiffuseLighting>, <feDisplacementMap>, <feFlood>, <feGaussianBlur>, <feImage>, <feMerge>, <feMorphology>, <feOffset>, <feSpecularLighting>, <feTile>, <feTurbulence>.
Gradient elements:<linearGradient>, <radialGradient>, <stop>.
Graphics elements: <circle>, <ellipse>, <image>, <line>, <path>, <polygon>, <polyline>, <rect>, <text>, <use>.
Shape elements: <circle>, <ellipse>, <line>, <path>, <polygon>, <polyline>, <rect>.
Text content elements: <text>, <textPath>, <tspan>.
SVG element - <circle>: cx, cy, r.
SVG element - <ellipse>: cx, cy, rx, ry.
SVG element - <rect>: rx, ry, height, width, x, y.
SVG element - <path>: path.
SVG element - <image>: height, width, x, y.
SVG element - <foreignObject>: height, width, x, y,.
SVG element - <svg>: width, x, y.
The "rect" element is used to create a rectangle and variations of a rectangle shape:
codes
<svg width="400" height="110">
<rect width="300" height="100" style="fill:rgb(7, 117, 71);stroke-width:3;stroke:rgb(0,0,0)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "width" and "height" attributes of the "rect" element define the height and the width of the rectangle.
The "style" attribute is used to define CSS properties for the rectangle.
The CSS "fill" property defines the fill color of the rectangle.
The CSS "stroke-width" property defines the width of the border of the rectangle.
The CSS "stroke" property defines the color of the border of the rectangle.
codes:
<svg width="400" height="180">
<rect x="50" y="20" width="150" height="150" style="fill:blue;stroke:pink; stroke-width:5;
fill-opacity:0.1; stroke-opacity:0.9" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "x" attribute defines the left position of the rectangle (e.g. x="50" places the rectangle 50 px from the left margin).
The "y" attribute defines the top position of the rectangle (e.g. y="20" places the rectangle 20 px from the top margin).
The CSS "fill-opacity" property defines the opacity of the fill color (legal range: 0 to 1).
The CSS "stroke-opacity" property defines the opacity of the stroke color (legal range: 0 to 1).
codes:
<svg width="300" height="180">
<rect x="50" y="20" width="150" height="150" style="fill:blue;stroke:pink; stroke-width:5;
opacity: 0.5" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The CSS "opacity" property defines the opacity value for the whole element (legal range: 0 to 1)
codes:
<svg width="400" height="180">
<rect x="50" y="20" rx="20" ry="20" width="150" height="150" style="fill:red;stroke:black;
stroke-width:5; opacity:0.5" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "rx" and the "ry" attributes rounds the corners of the rectangle.
The "circle" element is used to create a circle:
codes:
<svg height="100" width="100">
<circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "cx" and "cy" attributes define the x and y coordinates of the center of the circle. If "cx" and "cy" are omitted, the circle's center is set to (0,0).
The "r" attribute defines the radius of the circle.
The "ellipse" element is used to create an ellipse. An ellipse is closely related to a circle. The difference is that an ellipse has an x and a y radius that differs from each other, while a circle has equal x and y radius.
codes:
<svg height="140" width="500">
<ellipse cx="200" cy="80" rx="100" ry="50" style="fill:yellow;stroke:purple;stroke-width:2" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "cx" attribute defines the x coordinate of the center of the ellipse.
The "cy" attribute defines the y coordinate of the center of the ellipse.
The "rx" attribute defines the horizontal radius.
The "ry" attribute defines the vertical radius.
codes:
<svg height="150" width="500">
<ellipse cx="240" cy="100" rx="220" ry="30" style="fill:purple" />
<ellipse cx="220" cy="70" rx="190" ry="20" style="fill:lime" />
<ellipse cx="210" cy="45" rx="170" ry="15" style="fill:yellow" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
Three ellipses are created on top of each other using different values for the defining attributes.
codes:
<svg height="100" width="500">
<ellipse cx="240" cy="50" rx="220" ry="30" style="fill:yellow" />
<ellipse cx="220" cy="50" rx="190" ry="20" style="fill:white" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "line" element is used to create a line:
codes:
<svg height="210" width="500">
<line x1="0" y1="0" x2="200" y2="200" style="stroke:rgb(255,0,0);stroke-width:2"/>
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "x1" attribute defines the start of the line on the x-axis.
The "y1" attribute defines the start of the line on the y-axis.
The "x2" attribute defines the end of the line on the x-axis.
The "y2" attribute defines the end of the line on the y-axis.
The "polygon" element is used to create a graphic that contains at least three sides. Polygons are made of straight lines, and the shape is "closed" (all the lines connect up).
codes
<svg height="210" width="500">
<polygon points="200,10 250,190 160,210" style="fill:lime;stroke:purple;
stroke-width:1" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The points attribute defines the x and y coordinates for each corner of the polygon.
codes
<svg height="250" width="500">
<polygon points="220,10 300,210 170,250 123,234" style="fill:lime;stroke:purple;
stroke-width:1" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
A polygon with four sides.
codes:>
<svg height="210" width="500">
<polygon points="100,10 40,198 190,78 10,78 160,198" style="fill:lime;stroke:purple;
stroke-width:5; fill-rule:nonzero;"/>
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "polygon" element is used to create a star.
codes:
<svg height="210" width="500">
<polygon points="100,10 40,198 190,78 10,78 160,198" style="fill:lime;stroke:purple;
stroke-width:5; fill-rule:evenodd;"/>
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "fill-rule" property has been changed to "evenodd".
The "polyline" element is used to create any shape that consists of only straight lines (that is connected at several points):
codes:
<svg height="200" width="500">
<polyline points="20,20 40,25 60,40 80,120 120,140 200,180" style="fill:none;stroke:black;
stroke-width:3" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "points" attribute defines the list of points (pairs of x and y coordinates) required to draw the polyline.
codes:
<svg height="180" width="500">
<polyline points="0,40 40,40 40,80 80,80 80,120 120,120 120,160" style="fill:white;stroke:red;
stroke-width:4" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "points" attribute defines the list of points (pairs of x and y coordinates) required to draw the polyline.
The "path" element is used to define a path.
The following commands are available for path data:
M = moveto
L = lineto
H = horizontal lineto
V = vertical lineto
C = curveto
S = smooth curveto
Q = quadratic Bézier curve
T = smooth quadratic Bézier curveto
A = elliptical Arc
Z = closepath
All of the commands above can also be expressed with lower letters. Capital letters means absolutely positioned, lower cases means relatively positioned.
codes:
<svg height="210" width="400">
<path d="M150 0 L75 200 L225 200 Z" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The example defines a path that starts at position 150,0 with a line to position 75,200, then from there a line to 225,200 and finally closing the path back to 150,0.
Bézier curves are used to model smooth curves that can be scaled indefinitely. Generally, the user selects two endpoints and >one or two control points. A Bézier curve with one control point is called a quadratic Bézier curve and the kind with two control points is called cubic.
codes:
<svg height="400" width="450" style="background-color: grey;">
<path id="lineAB" d="M 100 350 l 150 -300" stroke="red" stroke-width="3" fill="none" />
<path id="lineBC" d="M 250 50 l 150 300" stroke="red" stroke-width="3" fill="none" />
<path d="M 175 200 l 150 0" stroke="green" stroke-width="3" fill="none" />
<path d="M 100 350 q 150 -300 300 0" stroke="blue" stroke-width="5" fill="none" />
<g stroke="black" stroke-width="3" fill="black">
<circle id="pointA" cx="100" cy="350" r="4" />
<circle id="pointB" cx="250" cy="50" r="4" />
<circle id="pointC" cx="400" cy="350" r="4" />
</g>
<g font-size="30" font-family="sans-serif" fill="black" stroke="none" text-anchor=
"middle">
<text x="100" y="350" dx="-30">A</text>
<text x="250" y="50" dy="-10">B</text>
<text x="400" y="350" dx="30">C</text>
</g>
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The example creates a quadratic Bézier curve, where A and C are the start and end points, B is the control point.
P.S. Because of the complexity involved in drawing paths it is highly recommended to use an SVG editor to create complex graphics.
The "text" element is used to define a text.
codes:
<svg height="30" width="200">
<text x="0" y="15" fill="red">I love SVG!</text>
Sorry, your browser does not support inline SVG.
</svg>
codes:
<svg height="60" width="200">
<text x="0" y="15" fill="red" transform="rotate(30 20,40)">I love SVG</text>
Sorry, your browser does not support inline SVG.
</svg>
The "text" element can be arranged in any number of sub-groups with the "tspan" element. Each "tspan" element can contain different formatting and position.
codes:
<svg height="90" width="200">
<text x="10" y="20" style="fill:red;">Several lines:
<tspan x="10" y="45">First line.</tspan>
<tspan x="10" y="70">Second line.</tspan>
</text>
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
Text on several lines (with the <tspan> element):
Text as a link (with the "a" element):
codes:
<svg height="30" width="200" xmlns:xlink="http://www.w3.org/1999/xlink">
<a xlink:href="https://www.w3schools.com/graphics/" target="_blank">
<text x="0" y="15" fill="red">I love SVG!</text>
</a>
Sorry, your browser does not support inline SVG.
</svg>
SVG offers a wide range of stroke properties: stroke, stroke-width, stroke-linecap, stroke-dasharray.
All the "stroke" properties can be applied to any kind of lines, text and outlines of elements like a circle.
The "stroke" property defines the color of a line, text or outline of an element:
codes:
<svg height="80" width="300">
<g fill="none">
<path stroke="red" d="M5 20 l215 0" />
<path stroke="lightgreen" d="M5 40 l215 0" />
<path stroke="blue" d="M5 60 l215 0" />
</g>
Sorry, your browser does not support inline SVG.
</svg>
The "stroke-width" property defines the thickness of a line, text or outline of an element:
codes:
<svg height="80" width="300">
<g fill="none" stroke="black">
<path stroke-width="2" d="M5 20 l215 0" />
<path stroke-width="4" d="M5 40 l215 0" />
<path stroke-width="6" d="M5 60 l215 0" />
</g>
Sorry, your browser does not support inline SVG.
</svg>
The "stroke-linecap" property defines different types of endings to an open path:
codes:
<svg height="80" width="300">
<g fill="none" stroke="black" stroke-width="6">
<path stroke-linecap="butt" d="M5 20 l215 0" />
<path stroke-linecap="round" d="M5 40 l215 0" />
<path stroke-linecap="square" d="M5 60 l215 0" />
</g>
Sorry, your browser does not support inline SVG.
</svg>
The "stroke-dasharray" property is used to create dashed lines:
codes:
<svg height="80" width="300">
<g fill="none" stroke="black" stroke-width="4">
<path stroke-dasharray="5,5" d="M5 20 l215 0" />
<path stroke-dasharray="10,10" d="M5 40 l215 0" />
<path stroke-dasharray="20,10,5,5,5,10" d="M5 60 l215 0" />
</g>
Sorry, your browser does not support inline SVG.
</svg>
SVG filters are used to add special effects to SVG graphics.
The available filter elements in SVG are:
"feBlend> - filter for combining images
"feColorMatrix" - filter for color transforms
"feComponentTransfer"
"feComposite"
"feConvolveMatrix"
"feDiffuseLighting"
"feDisplacementMap"
"feFlood"
"feGaussianBlur"
"feImage"
"feMerge"
"feMorphology"
"feOffset" - filter for drop shadows
"feSpecularLighting"
"feTile"
"feTurbulence"
"feDistantLight" - filter for lighting
"fePointLight" - filter for lighting
'feSpotLight" - filter for lighting
Tip: You can use multiple filters on each SVG element!
All internet SVG filters are defined within a "defs" element.
The "defs" element is short for definitions and contains definition of special elements (such as filters).
The "filter" element is used to define an SVG filter. It has a required "id" attribute which identifies the filter. The graphic then points to the filter to use.
The "feGaussianBlur" element is used to create blur effects:
codes
<svg height="110" width="110">
<defs>
<filter id="f1" x="0" y="0">
<feGaussianBlur in="SourceGraphic" stdDeviation="15" />
</filter>
</defs>
<rect width="90" height="90" stroke="green" stroke-width="3" fill="yellow"
filter="url(#f1)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "id" attribute of the "filter" element defines a unique name for the filter.
The blur effect is defined with the "feGaussianBlur" element. The in="SourceGraphic" part defines that the effect is created for the entire element.
The stdDeviation attribute defines the amount of the blur.
The "filter" attribute of the "rect" element links the element to the "f1" filter
All internet SVG filters are defined within a "defs" element.
The "defs" element is short for definitions and contains definition of special elements (such as filters).
The "filter" element is used to define an SVG filter. It has a required "id" attribute which identifies the filter. The graphic then points to the filter to use.
The "feOffset" element is used to create drop shadow effects. The idea is to take an SVG graphic (image or element) and move it a little bit in the xy plane. The first example offsets a rectangle (with "feOffset"), then blend the original on top of the offset image (with "feBlend"):
codes
<svg height="120" width="120">
<defs>
<filter id="f2" x="0" y="0" width="200%" height="200%">
<feOffset result="offOut" in="SourceGraphic" dx="20" dy="20" />
<feBlend in="SourceGraphic" in2="offOut" mode="normal" />
</filter>
</defs>
<rect width="90" height="90" stroke="green" stroke-width="3" fill="yellow"
filter="url(#f2)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "id" attribute of the <filter> element defines a unique name for the filter.
The "filter" attribute of the <rect> element links the element to the "f1" filter.
codes:
<svg height="140" width="140">
<defs>
<filter id="f3" x="0" y="0" width="200%" height="200%">
<feOffset result="offOut" in="SourceGraphic" dx="20" dy="20" />
<feGaussianBlur result="blurOut" in="offOut" stdDeviation="10" />
<feBlend in="SourceGraphic" in2="blurOut" mode="normal" />
</filter>
</defs>
<rect width="90" height="90" stroke="green" stroke-width="3" fill="yellow"
filter="url(#f3)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The stdDeviation attribute of the <feGaussianBlur> element defines the amount of the blur.
A gradient is a smooth transition from one color to another and several color transitions can be applied to the same element.
The "linearGradient" element is used to define a linear gradient. It must be nested within a "defs" tag, which is short for definitions and contains definition of special elements (such as gradients).
Linear gradients can be defined as horizontal, vertical or angular gradients:
horizontal gradients are created when y1 and y2 are equal and x1 and x2 differ;
vertical gradients are created when x1 and x2 are equal and y1 and y2 differ;
angular gradients are created when x1 and x2 differ and y1 and y2 differ
codes:
<svg height="150" width="400">
<defs>
<linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:rgb(255,255,0);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
</defs>
<ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad1)" />
Sorry, your browser does not support inline SVG.
Code explanation:
The id attribute of the "linearGradient" tag defines a unique name for the gradient.
The "x1", "x2", "y1", "y2" attributes of the "linearGradient" tag define the start and end position of the gradient.
The color range for a gradient can be composed of two or more colors. Each color is specified with a "stop" tag.
The "offset" attribute is used to define where the gradient color begin and end.
The "fill" attribute links the ellipse element to the gradient.
codes:
<svg height="150" width="400">
<defs>
<linearGradient id="grad2" x1="0%" y1="0%" x2="0%" y2="100%">
<stop offset="0%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,255,0);stop-opacity:1" />
</linearGradient>
</defs>
<ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad2)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The example shows an ellipse with avertical linear gradient from yellow to red.
codes:
<svg height="150" width="400">
<defs>
<linearGradient id="grad3" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:rgb(255,255,0);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
</defs>
<ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad3)" />
<text fill="#ffffff" font-size="45" font-family="Verdana" x="150" y="86">SVG</text>
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The example shows an ellipse with a horizontal linear gradient from yellow to red, and add a text inside the ellipse.
The <text> element is used to add a text
The "radialGradient" element is used to define a radial gradient. The "radialGradient" element must be nested within a "defs" tag. The "defs" tag is short for definitions and contains definition of special elements (such as gradients).
codes:
<svg height="150" width="500">
<defs>
<radialGradient id="grad4" cx="50%" cy="50%" r="50%" fx="50%" fy="50%">
<stop offset="0%" style="stop-color:rgb(255,255,255);stop-opacity:0" />
<stop offset="100%" style="stop-color:rgb(0,0,255);stop-opacity:1" />
</radialGradient>
</defs>
<ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad4)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
The "id" attribute of the "radialGradient" tag defines a unique name for the gradient.
The "cx", "cy" and "r" attributes define the outermost circle and the "fx" and "fy" define the innermost circle.
The color range for a gradient can be composed of two or more colors. Each color is specified with a "stop" tag.
The "offset" attribute is used to define where the gradient color begin and end.
The "fill" attribute links the ellipse element to the gradient.
<svg height="150" width="500">
<defs>
<radialGradient id="grad5" cx="20%" cy="30%" r="30%" fx="50%" fy="50%">
<stop offset="0%" style="stop-color:rgb(255,255,255);stop-opacity:0" />
<stop offset="100%" style="stop-color:rgb(0,0,255);stop-opacity:1" />
</radialGradient>
</defs>
<ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad5)" />
Sorry, your browser does not support inline SVG.
</svg>
Code explanation:
the example shows another ellipse with a radial gradient from white to blue.