svg.filter.js

A plugin for svg.js adding filter functionality.

Svg.filter.js is licensed under the terms of the MIT License.

• Examples
• Furthermore
  • unfilter
  • referencing the filter node
  • Animating filter values
  • Chaining Effects
• Effect Classes

Usage

Include this plugin after including the svg.js library in your html document.

Here is how each filter effect on the example page is achieved.

Examples

• gaussian blur
• horizontal blur
• desaturate
• contrast
• sepiatone
• hue rotate 180
• luminance to alpha
• colorize
• posterize
• darken
• lighten
• invert
• gamma correct 1
• gamma correct 2
• drop shadow
• extrude

original

var image = draw.image('path/to/image.jpg').size(300, 300)

gaussian blur

image.filter(function(add) {
  add.gaussianBlur(30)
})

horizontal blur

image.filter(function(add) {
  add.gaussianBlur(30, 0)
})

desaturate

image.filter(function(add) {
  add.colorMatrix('saturate', 0)
})

contrast

image.filter(function(add) {
  var amount = 1.5

  add.componentTransfer({
    rgb: { type: 'linear', slope: amount, intercept: -(0.3 * amount) + 0.3 }
  })
})

sepiatone

image.filter(function(add) {
  add.colorMatrix('matrix', [ .343, .669, .119, 0, 0
                            , .249, .626, .130, 0, 0
                            , .172, .334, .111, 0, 0
                            , .000, .000, .000, 1, 0 ])
})

hue rotate 180

image.filter(function(add) {
  add.colorMatrix('hueRotate', 180)
})

luminance to alpha

image.filter(function(add) {
  add.colorMatrix('luminanceToAlpha')
})

colorize

image.filter(function(add) {
  add.colorMatrix('matrix', [ 1.0, 0,   0,   0,   0
                            , 0,   0.2, 0,   0,   0
                            , 0,   0,   0.2, 0,   0
                            , 0,   0,   0,   1.0, 0 ])
})

posterize

image.filter(function(add) {
  add.componentTransfer({
    rgb: { type: 'discrete', tableValues: [0, 0.2, 0.4, 0.6, 0.8, 1] }
  })
})

darken

image.filter(function(add) {
  add.componentTransfer({
    rgb: { type: 'linear', slope: 0.2 }
  })
})

lighten

image.filter(function(add) {
  add.componentTransfer({
    rgb: { type: 'linear', slope: 1.5, intercept: 0.2 }
  })
})

invert

image.filter(function(add) {
  add.componentTransfer({
    rgb: { type: 'table', tableValues: [1, 0] }
  })
})

gamma correct 1

image.filter(function(add) {
  add.componentTransfer({
    g: { type: 'gamma', amplitude: 1, exponent: 0.5 }
  })
})

gamma correct 2

image.filter(function(add) {
  add.componentTransfer({
    g: { type: 'gamma', amplitude: 1, exponent: 0.5, offset: -0.1 }
  })
})

drop shadow

You will notice that all the effect descriptions have a drop shadow. Here is how this drop shadow can be achieved:

var text = draw.text('SVG text with drop shadow').fill('#fff')

text.filter(function(add) {
  var blur = add.offset(0, 1).in(add.sourceAlpha).gaussianBlur(1)

  add.blend(add.source, blur)
})

This technique can be achieved on any other shape of course:

var rect = draw.rect(100,100).fill('#f09').stroke({ width: 3, color: '#0f9' }).move(10,10)

rect.filter(function(add) {
  var blur = add.offset(20, 20).in(add.sourceAlpha).gaussianBlur(5)

  add.blend(add.source, blur)

  this.size('200%','200%').move('-50%', '-50%')
})

If the drop shadow should get the colour of the shape so it appears like coloured glass:

var rect = draw.rect(100,100).fill('#f09').stroke({ width: 3, color: '#0f9' }).move(10,10)

rect.filter(function(add) {
  var blur = add.offset(20, 20).gaussianBlur(5)

  add.blend(add.source, blur)

  this.size('200%','200%').move('-50%', '-50%')
})

extrude

image.filter(function(add){
  var matrix = add.convolveMatrix([
    1,0,0,0,0,0,
    0,1,0,0,0,0,
    0,0,1,0,0,0,
    0,0,0,1,0,0,
    0,0,0,0,1,0,
    0,0,0,0,0,1
  ]).attr({
    devisor: '2',
    preserveAlpha: 'false'
  }).in(add.sourceAlpha)

  //recolor it
  var color = add.composite(add.flood('#ff2222'),matrix,'in');

  //merge all of them toggether
  add.merge(color,add.source);
})

Furthermore

Some more features you should know about.

unfilter

The unfilter method removes the filter attribute from the node:

image.unfilter()

This will return the element to its original state but will retain the filter in the defs node. If the filter node should be removed as well, simply pass the true as the first argument:

image.unfilter(true)

referencing the filter node

An internal reference to the filter node is made in the element:

image.filterer

This can also be very useful to reuse an existing filter on various elements:

otherImage.filter(image.filterer)

Animating filter values

Every filter value can be animated as well:

var hueRotate

image.filter(function(add) {
  hueRotate = add.colorMatrix('hueRotate', 0)
})

hueRotate.animate(3000).attr('values', 360)

Chaining Effects

Method chaining is a programing style where each function returns the object it belongs to, for an example look at JQuery.
it's possible to chain the effects on a filter when you are creating them, for example:

image.filter(function(add){
  add.flood('black',0.5).composite(add.sourceAlpha,'in').offset(10).merge(add.source)
})

this would create a basic shadow filter where the first input on the composite effect would be the flood effect, and the input on the offset effect would be the composite effect.
same with the merge effect, its first input would be the offset effect, and its second input would be add.source

some effects like Merge, Blend, Composite, DisplacementMap have thier arguments changed when they are chained, for example

image.filter(function(add){
  add.flood('black',0.5).composite(add.sourceAlpha,'in')
})

the composite effects first input is set to the flood effect and its second input becomes the first argument, this is the same for the merge, blend, composite, and displacmentMap effect.
for more details check out each effects doc below

Effect Classes

• Base Effect Class
• Blend
• ColorMatrix
• ComponentTransfer
• Composite
• ConvolveMatrix
• DiffuseLighting
• DisplacementMap
• Flood
• GaussianBlur
• Image
• Merge
• Morphology
• Offset
• SpecularLighting
• Tile
• Turbulence

Base Effect Class

in(effect)

gets or sets the in attribute of the effect

• effect: this can be another effect or a string
  if effect is not provided it will look for another effect on the same filter whose result is equal to this effects in attribute, else it will return the value of the in attribute

  image.filter(function(add){
    var offset = add.offset(10)
  
    //create the blur effect and then set its input
    var blur = add.gaussianBlur(3)
  
    //set the input to an effect
    blur.in(offset)
  
    //this will return the offset effect
    var input = blur.in()
  
    //set the input to a string
    blur.in('another-result-as-a-string')
  
    //this will return a string since there is no other effect which has a matching result attribute
    var input2 = blur.in()
  })

in2(effect)

gets or sets the in2 attribute of the effect
this function works the same as the in method.
it's only on effects (Blend, Composite, and DisplacementMap)

result(string)

gets or sets the result attribute of the effect

• string: if a string is provided it will set the value of the result attribute.
  if no arguments are provided it will act as a getter and return the value of the result attribute

Blend

W3 doc

filter.blend(in1, in2, mode)
//or
new SVG.BlendEffect(in1, in2, mode)

• in1: an effect or the result of effect
• in2: same as in1
• mode: "normal | multiply | screen | darken | lighten" defaults to "normal"

chaining when this effect is called right after another effect, for example:

filter.offset(10).blend(filter.source)

the first input is set to the offset effect and the second input is set to filter.source or what ever was passed as the first argument, and the second input becomes the mode

ColorMatrix

W3 doc

filter.colorMatrix(type, values);
//or
new SVG.ColorMatrixEffect(type, values);

• type: "matrix | saturate | hueRotate | luminanceToAlpha"
• values
  • type="matrix": values would be a matrix the size of 4x5
  • type="saturate": number (0 to 1)
  • type="hueRotate": number (0 to 360) deg
  • type="luminanceToAlpha": value not needed

ComponentTransfer

W3 doc

filter.componentTransfer(components);
//or
new SVG.ComponentTransferEffect(components);

• components: an object with one rgb property for the (r, g and b) chanels or r, g, b, a properties for each chanel

  {
    rgb: {
      type: "identity | table | discrete | linear | gamma",
  
      //type="table"
      tableValues: "0 0.5 2 1", //number separated by spaces
  
      //type="linear"
      slope: 1, //number
      intercept: 3,//number
  
      //type="gamma"
      amplitude: 0, //number
      exponent: 0, //number
      offset: 0 //number
    }
  }

Composite

W3 doc

filter.composite(in1, in2, operator);
//or
new SVG.CompositeEffect(in1, in2, operator);

• in1: an effect or the result of an effect
• in2: same as in1
• operator: "over | in | out | atop | xor | arithmetic" defaults to "over"

chaining when this effect is called right after another effect, for example:

filter.flood('black',0.5).composite(filter.sourceAlpha,'in')

the first input is set to the flood effect and the second input is set to filter.sourceAlpha or what ever was passed as the first argument.
also the second argument becomes the operator

ConvolveMatrix

W3 doc

filter.convolveMatrix(matrix);
//or
new SVG.ConvolveMatrixEffect(matrix);

• matrix: a square matrix of numbers that will be applied to the image
  • exmaple:

  [
    1,0,0,
    0,1,0,
    0,0,1
  ]

DiffuseLighting

W3 doc

filter.displacementMap(surfaceScale, diffuseConstant, kernelUnitLength);
//or
new SVG.DisplacementMapEffect(surfaceScale, diffuseConstant, kernelUnitLength);

very complicated, just check out the W3 doc

DisplacementMap

W3 doc

filter.displacementMap(in1, in2, scale, xChannelSelector, yChannelSelector);
//or
new SVG.DisplacementMapEffect(in1, in2, scale, xChannelSelector, yChannelSelector);

very complicated, just check out the W3 doc

chaining when this effect is called right after another effect, for example:

filter.offset(20,50).displacementMap(filter.source,2)

the first input is set to the offset effect and the second input is set to filter.source or what ever was passed as the first argument.
also the second argument becomes the scale, and the third argument is the xChannelSelector and so on

Flood

W3 doc

filter.flood(color,opacity);
//or
new SVG.FloodEffect(color,opacity);

• color: a named or hex color in string format
• opacity: number form 0 to 1

GaussianBlur

W3 doc

filter.gaussianBlur(x, y);
//or
new SVG.GaussianBlurEffect(x, y);

• x: blur on the X
• y: blur on the y, will default to the x if not provided

Image

W3 doc

filter.image(src);
//or
new SVG.ImageEffect(src);

Merge

W3 doc

filter.merge();
//or
new SVG.MergeEffect();

• Array: an Array of effects or effect results filter.merge([effectOne,"result-two",another_effect])
• SVG.Set: a set of effects
• arguments: pass each effect or result in as arguments filter.merge(effect,"some-result",anotherEffect)
• chianing you can also chain the merge effect filter.offset(10).merge(anotherEffect) which will result in a merge effect with its first input set to the offset effect and its second input set to anotherEffect

Morphology

W3 doc

filter.morphology(operator, radius);
//or
new SVG.MorphologyEffect(operator, radius);

• operator: "erode | dilate"
• radius: a single number or a string of two numbers separated by a space
  • the first number is the X
  • the second number is the Y, if no second number was provided it will default to the first number

Offset

W3 doc

filter.offset(x, y);
//or
new SVG.OffsetEffect(x, y);

• x: move on the X
• y: move on the y, will default to the x if not provided

SpecularLighting

W3 doc

filter.specularLighting(surfaceScale, diffuseConstant, specularExponent, kernelUnitLength);
//or
new SVG.SpecularLightingEffect(surfaceScale, diffuseConstant, specularExponent, kernelUnitLength);

very complicated, just check out the W3 doc

Tile

W3 doc

filter.tile();
//or
new SVG.TileEffect();

no arguments, but if you want to find out what it does check out the W3 doc

Turbulence

W3 doc

filter.turbulence(baseFrequency, numOctaves, seed, stitchTiles, type);
//or
new SVG.TurbulenceEffect(baseFrequency, numOctaves, seed, stitchTiles, type);

very complicated, just check out the W3 doc