<feColorMatrix>
The <feColorMatrix>
SVG filter element changes colors based on a transformation matrix. Every pixel's color value [R,G,B,A]
is matrix multiplied by a 5 by 5 color matrix to create new color [R',G',B',A']
.
Note: The prime symbol '
is used in mathematics indicate the result of a transformation.
| R' | | r1 r2 r3 r4 r5 | | R | | G' | | g1 g2 g3 g4 g5 | | G | | B' | = | b1 b2 b3 b4 b5 | * | B | | A' | | a1 a2 a3 a4 a5 | | A | | 1 | | 0 0 0 0 1 | | 1 |
In simplified terms, below is how each color channel in the new pixel is calculated. The last row is ignored because its values are constant.
R' = r1*R + r2*G + r3*B + r4*A + r5 G' = g1*R + g2*G + g3*B + g4*A + g5 B' = b1*R + b2*G + b3*B + b4*A + b5 A' = a1*R + a2*G + a3*B + a4*A + a5
Take the amount of red in the new pixel, or R'
:
It is the sum of:
r1
times the old pixel's redR
,r2
times the old pixel's greenG
,r3
times of the old pixel's blueB
,r4
times the old pixel's alphaA
,- plus a shift
r5
.
These specified amounts can be any real number, though the final R' will be clamped between 0 and 1. The same goes for G', B', and A'.
R' = r1 * R + r2 * G + r3 * B + r4 * A + r5 New red = [ r1 * old red ] + [ r2 * old green ] + [ r3 * old Blue ] + [ r4 * old Alpha ] + [ shift of r5 ]
If, say, we want to make a completely black image redder, we can make the r5
a positive real number x, boosting the redness on every pixel of the new image by x.
An identity matrix looks like this:
R G B A W R' | 1 0 0 0 0 | G' | 0 1 0 0 0 | B' | 0 0 1 0 0 | A' | 0 0 0 1 0 |
In it, every new value is exactly 1 times its old value, with nothing else added. It is recommended to start manipulating the matrix from here.
Usage context
Attributes
Global attributes
- Core attributes
- Presentation attributes
- Filter primitive attributes, including the
x
,y
,width
,height
, andresult
attributes. class
style
Specific attributes
DOM Interface
This element implements the SVGFEColorMatrixElement
interface.
Example
SVG
html
<svg
width="100%"
height="100%"
viewBox="0 0 150 500"
preserveAspectRatio="xMidYMid meet"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<!-- ref -->
<defs>
<g id="circles">
<circle cx="30" cy="30" r="20" fill="blue" fill-opacity="0.5" />
<circle cx="20" cy="50" r="20" fill="green" fill-opacity="0.5" />
<circle cx="40" cy="50" r="20" fill="red" fill-opacity="0.5" />
</g>
</defs>
<use href="#circles" />
<text x="70" y="50">Reference</text>
<!-- identity matrix -->
<filter id="colorMeTheSame">
<feColorMatrix
in="SourceGraphic"
type="matrix"
values="1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 1 0" />
</filter>
<use
href="#circles"
transform="translate(0 70)"
filter="url(#colorMeTheSame)" />
<text x="70" y="120">Identity matrix</text>
<!-- Combine RGB into green matrix -->
<filter id="colorMeGreen">
<feColorMatrix
in="SourceGraphic"
type="matrix"
values="0 0 0 0 0
1 1 1 1 0
0 0 0 0 0
0 0 0 1 0" />
</filter>
<use
href="#circles"
transform="translate(0 140)"
filter="url(#colorMeGreen)" />
<text x="70" y="190">rgbToGreen</text>
<!-- saturate -->
<filter id="colorMeSaturate">
<feColorMatrix in="SourceGraphic" type="saturate" values="0.2" />
</filter>
<use
href="#circles"
transform="translate(0 210)"
filter="url(#colorMeSaturate)" />
<text x="70" y="260">saturate</text>
<!-- hueRotate -->
<filter id="colorMeHueRotate">
<feColorMatrix in="SourceGraphic" type="hueRotate" values="180" />
</filter>
<use
href="#circles"
transform="translate(0 280)"
filter="url(#colorMeHueRotate)" />
<text x="70" y="330">hueRotate</text>
<!-- luminanceToAlpha -->
<filter id="colorMeLTA">
<feColorMatrix in="SourceGraphic" type="luminanceToAlpha" />
</filter>
<use href="#circles" transform="translate(0 350)" filter="url(#colorMeLTA)" />
<text x="70" y="400">luminanceToAlpha</text>
</svg>
Result
Screenshot | Live sample |
---|---|
Specifications
Specification |
---|
Filter Effects Module Level 1 # feColorMatrixElement |
Browser compatibility
BCD tables only load in the browser