Image

WLJS

Execution environment

Supports dynamics

wljs-graphics-d3

Package

Represents a raster image and plots the list of pixel's colors to a canvas used in notebooks

Image[{row1_List, row2_List...} | n_NumericArray, encoding_:"Real32"]

where each row is a list of pixel colors. It it better to pass NumericArray for the best performance.

The following encoding is supported

• "Real32" each pixel is encoded using a real value from 0 up-to 1. Corresponding NumericArray format is "Real32" (if applicable).
• "Byte" each pixel is encoded using integer value from 0 up-to 255. Corresponding NumericArray format is "UnsignedInteger8".
• "Bit" each pixel is either 1 or 0 (integer). Corresponding NumericArray is "UnsignedInteger8"

The first two can be divided into groups by pixel format

• {R,G,B} - each pixel is a list of numbers
• {R,G,B,A} - each pixel is a list of numbers
• I grayscale - each pixel is a single number

Options

Magnification

Magnifies by an integer factor original pixels provided by an array

ImageSize

Acts similar to Magnification and scales an image to match the width of provided size

Antialiasing

By the default is True, which forces to use bilinear approximation when an image is shown scaled.

Examples

Direct

Show multiple iterations of a cellular automaton as a binary image

Image[CellularAutomaton[30, {{1}, 0}, 40], Magnification->4]

A random noise

Image[Table[RandomInteger[{0,1}], {i, 200}, {j, 350}]]

adding a color

Image[Table[RandomInteger[{0,255}, 3], {i, 200}, {j, 350}], "Byte"]

tip

Use NumericArray to provide and handle pixel data. It has to be a nested list of lists as usual. There is a following correspondence. Byte and UnsignedInteger8 combo is the most efficient. ::

Indirect

One can also use Rasterize function to show any expressions as an image

x + y // Rasterize

Dynamics

It does support dynamic variables. For example

Puffer = {{1, 4}, {2, 5}, {3, 1}, {3, 5}, {4, 2}, {4, 3}, {4, 4}, {4,
     5}, {8, 1}, {9, 2}, {9, 3}, {10, 3}, {11, 3}, {12, 2}, {15, 1}, {15,
     4}, {16, 5}, {17, 1}, {17, 5}, {18, 2}, {18, 3}, {18, 4}, {18, 5}};

board = NumericArray[
  CellularAutomaton["GameOfLife", {SparseArray[Puffer
     -> 1], 0}, {{500}}] // First
, "UnsignedInteger8"];

Image[board // Offload, "Bit", Magnification -> 3, Antialiasing->False]

and now we can run the simulation with a desired speed

task = SetInterval[board = NumericArray[CellularAutomaton["GameOfLife",
     board // Normal, {{1}}] // First, "UnsignedInteger8"], 50];

SetTimeout[TaskRemove[task], 5000];

See more examples in Raster animation

Supported output forms

• StandardForm
• WLXForm