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This reference is for Processing 3.0+. If you have a previous version, use the reference included with your software in the Help menu. If you see any errors or have suggestions, please let us know. If you prefer a more technical reference, visit the Processing Core Javadoc and Libraries Javadoc.

Name | ### filter()
Examples |
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(THRESHOLD);
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(GRAY);
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(INVERT);
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(POSTERIZE, 4);
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(BLUR, 6);
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(ERODE);
    PImage img;
    img = loadImage("apples.jpg");
    image(img, 0, 0);
    filter(DILATE);
    PShader blur;
    PImage img;

    void setup() {
      size(100, 100, P2D);
      blur = loadShader("blur.glsl");
      img = loadImage("apples.jpg");
      image(img, 0, 0);
    }

    void draw() {
      filter(blur); // Blurs more each time through draw()
    }
Description | Filters the display window using a preset filter or with a custom shader. Using a shader with filter() is much faster than without. Shaders require the P2D or P3D renderer in size(). The presets options are: THRESHOLD Converts the image to black and white pixels depending if they are above or below the threshold defined by the level parameter. The parameter must be between 0.0 (black) and 1.0 (white). If no level is specified, 0.5 is used. GRAY Converts any colors in the image to grayscale equivalents. No parameter is used. OPAQUE Sets the alpha channel to entirely opaque. No parameter is used. INVERT Sets each pixel to its inverse value. No parameter is used. POSTERIZE Limits each channel of the image to the number of colors specified as the parameter. The parameter can be set to values between 2 and 255, but results are most noticeable in the lower ranges. BLUR Executes a Guassian blur with the level parameter specifying the extent of the blurring. If no parameter is used, the blur is equivalent to Guassian blur of radius 1. Larger values increase the blur. ERODE Reduces the light areas. No parameter is used. DILATE Increases the light areas. No parameter is used.
Syntax |
    filter(shader)
    filter(kind)
    filter(kind, param)
Parameters |
shader | PShader: the fragment shader to apply
kind | int: Either THRESHOLD, GRAY, OPAQUE, INVERT, POSTERIZE, BLUR, ERODE, or DILATE
param | float: unique for each, see above
Returns | void

Updated on July 4, 2018 11:56:44am EDT