net.freeutils.scrollphat

Class Canvas

java.lang.Object

net.freeutils.scrollphat.Canvas

public class Canvas
extends Object

A convenience class for manipulating a LED matrix buffer and preparing the display content.

Constructor Summary

Constructors

Constructor and Description
Canvas(byte[] matrix, int height) Constructs a Canvas which wraps the given matrix.
Canvas(int width, int height) Constructs a Canvas with a new matrix of the given width and height.

Method Summary

Modifier and Type	Method and Description
static byte[]	crop(byte[] matrix, int x, int y, int width, int height, byte[] out) Crops the given pixel matrix.
static byte[]	cropX(byte[] matrix, int x, int width, byte[] out) Crops the given pixel matrix horizontally.
static byte[]	cropY(byte[] matrix, int y, int height, byte[] out) Crops the given pixel matrix vertically.
void	empty() Empty the matrix (fill it with empty columns).
static byte[]	empty(byte[] matrix) Empties a byte array by filling it with zeros.
static byte[]	fill(byte[] matrix) Fills a byte array with 0xFF bytes (i.e.
static byte[]	fill(byte[] matrix, int value) Fills a byte array with a single value.
void	fill(int value) Fills the matrix with the given column value.
static byte	flip(byte b) Flips the order of bits in a byte.
static byte[]	flip(byte[] matrix, int height, byte[] out) Flips the order of the least-significant bits in an array of bytes.
static byte	flip(byte b, int height) Flips the order of the least-significant bits in a byte.
int	getHeight() Returns the canvas height in pixels.
byte[]	getMatrix() Returns the wrapped matrix bytes.
int	getWidth() Returns the canvas width in pixels.
static void	graph(byte[] matrix, int width, int height, float[] values, Float low, Float high, boolean bars) Draws a graph with the given width and height in pixels from the given data values and boundaries.
static void	graph(byte[] matrix, int width, int height, int[] values, Float low, Float high, boolean bars) Draws a graph with the given width and height in pixels from the given data values and boundaries.
void	graph(int[] values, Float low, Float high, boolean bars) Draws a graph with the given width and height in pixels from the given data values and boundaries.
byte[]	render() Render the matrix into a returned buffer, with transformations applied (flip, reverse, crop, etc.)
static byte[]	reverse(byte[] matrix, byte[] out) Reverses the order of bytes in an array.
void	scroll(int delta) Scrolls the rendered columns by the given number of columns (positive or negative delta).
static void	setBit(byte[] matrix, int x, int y, boolean value) Sets the value of a single bit within a matrix of bits represented by a byte array.
void	setColumn(int column, int value) Sets the value of a column.
void	setColumns(int startColumn, byte[] columns, int offset, int length) Sets the value of a sequence of columns.
void	setFlip(boolean flip) Sets whether the rendered matrix should be flipped vertically.
void	setMatrix(byte[] matrix) Sets the wrapped matrix bytes.
void	setOffset(int offset) Sets the offset of the column within the matrix at which the rendering will start.
void	setPixel(int x, int y, boolean value) Sets the value of a pixel.
void	setReverse(boolean reverse) Sets whether the rendered matrix should be reversed horizontally.
static String	toAsciiArt(byte[] matrix, int height) Converts the pixel matrix represented by a given byte array to a string containing the ASCII-art representation of the pixels.
static String	toAsciiArt(byte[] matrix, int offset, int len, int height) Converts the pixel matrix represented by a given byte array to a string containing the ASCII-art representation of the pixels.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Canvas

public Canvas(byte[] matrix,
              int height)
       throws IOException

Constructs a Canvas which wraps the given matrix.

Parameters:

matrix - the matrix to wrap

height - the height of the pixel matrix in pixels (max 8)

Throws:

IOException - if an error occurs

Canvas

public Canvas(int width,
              int height)
       throws IOException

Constructs a Canvas with a new matrix of the given width and height.

Parameters:

width - the width of the pixel matrix in pixels

height - the height of the pixel matrix in pixels (max 8)

Throws:

IOException - if an error occurs

Method Detail

toAsciiArt

public static String toAsciiArt(byte[] matrix,
                                int offset,
                                int len,
                                int height)

Converts the pixel matrix represented by a given byte array to a string containing the ASCII-art representation of the pixels.

Parameters:

matrix - the pixel matrix

offset - the offset within the matrix where the data to convert starts

len - the length in bytes of the data to convert

height - the height of the pixel matrix in pixels (max 8)

Returns:

an ASCII-art string representing the pixel matrix

toAsciiArt

public static String toAsciiArt(byte[] matrix,
                                int height)

Converts the pixel matrix represented by a given byte array to a string containing the ASCII-art representation of the pixels.

Parameters:

matrix - the pixel matrix

height - the height of the pixel matrix in pixels (max 8)

Returns:

an ASCII-art string representing the pixel matrix

flip

public static byte flip(byte b)

Flips the order of bits in a byte.

Parameters:

b - a byte

Returns:

the flipped byte

flip

public static byte flip(byte b,
                        int height)

Flips the order of the least-significant bits in a byte.

Parameters:

b - a byte

height - the number of least-significant bits to flip (all higher bits are set to zero)

Returns:

the flipped byte

flip

public static byte[] flip(byte[] matrix,
                          int height,
                          byte[] out)

Flips the order of the least-significant bits in an array of bytes.

Parameters:

matrix - the bytes to flip

height - the number of least-significant bits to flip (all higher bits are set to zero)

out - an array into which the flipped bits are written (can be identical to the given source array)

Returns:

the output array

reverse

public static byte[] reverse(byte[] matrix,
                             byte[] out)

Reverses the order of bytes in an array.

Parameters:

matrix - the bytes to flip

out - an array into which the reversed bytes are written (can be identical to the given source array)

Returns:

the output array

cropX

public static byte[] cropX(byte[] matrix,
                           int x,
                           int width,
                           byte[] out)

Crops the given pixel matrix horizontally.

Parameters:

matrix - the pixel matrix to crop

x - the X position to start cropping at (left side of cropped rectangle)

width - the number of pixels to crop horizontally

out - an array into which the cropped bytes are written (can be identical to the given source array)

Returns:

the output array

cropY

public static byte[] cropY(byte[] matrix,
                           int y,
                           int height,
                           byte[] out)

Crops the given pixel matrix vertically.

Parameters:

matrix - the pixel matrix to crop

y - the Y position to start cropping at (top side of cropped rectangle)

height - the number of pixels to crop vertically

out - an array into which the cropped bytes are written (can be identical to the given source array)

Returns:

the output array

crop

public static byte[] crop(byte[] matrix,
                          int x,
                          int y,
                          int width,
                          int height,
                          byte[] out)

Crops the given pixel matrix.

Parameters:

matrix - the pixel matrix to crop

x - the X position to start cropping at (left side of cropped rectangle)

y - the Y position to start cropping at (top side of cropped rectangle)

width - the number of pixels to crop horizontally

height - the number of pixels to crop vertically

out - an array into which the cropped bytes are written (can be identical to the given source array)

Returns:

the output array

empty

public static byte[] empty(byte[] matrix)

Empties a byte array by filling it with zeros.

Parameters:

matrix - a byte array

Returns:

the byte array

fill

public static byte[] fill(byte[] matrix,
                          int value)

Fills a byte array with a single value.

Parameters:

matrix - a byte array

value - the value to fill with

Returns:

the byte array

fill

public static byte[] fill(byte[] matrix)

Fills a byte array with 0xFF bytes (i.e. all bits set to 1).

Parameters:

matrix - a byte array

Returns:

the byte array

setBit

public static void setBit(byte[] matrix,
                          int x,
                          int y,
                          boolean value)

Sets the value of a single bit within a matrix of bits represented by a byte array.

Parameters:

matrix - a byte array (matrix of bits)

x - the x coordinate of the bit to set (left to right)

y - the y coordinate of the bit to set (top to bottom)

value - the value to set (true means 1, false means 0)

graph

public static void graph(byte[] matrix,
                         int width,
                         int height,
                         float[] values,
                         Float low,
                         Float high,
                         boolean bars)

Draws a graph with the given width and height in pixels from the given data values and boundaries.

Parameters:

matrix - the pixel matrix to draw on

width - the graph width in pixels

height - the graph height in pixels

values - the data values

low - the value represented at the bottom of the graph, or null if the minimum data value should be used

high - the value represented at the top of the graph, or null if the maximum data value should be used

bars - specifies whether the graph is a bar graph (with filled area under the value), or a scatter plot (single point per value)

graph

public static void graph(byte[] matrix,
                         int width,
                         int height,
                         int[] values,
                         Float low,
                         Float high,
                         boolean bars)

Draws a graph with the given width and height in pixels from the given data values and boundaries.

Parameters:

matrix - the pixel matrix to draw on

width - the graph width in pixels

height - the graph height in pixels

values - the data values

low - the value represented at the bottom of the graph, or null if the minimum data value should be used

high - the value represented at the top of the graph, or null if the maximum data value should be used

bars - specifies whether the graph is a bar graph (with filled area under the value), or a scatter plot (single point per value)

getWidth

public int getWidth()

Returns the canvas width in pixels.

Returns:

the canvas width in pixels

getHeight

public int getHeight()

Returns the canvas height in pixels.

Returns:

the canvas height in pixels

setFlip

public void setFlip(boolean flip)

Sets whether the rendered matrix should be flipped vertically.

Parameters:

flip - true if the rendered matrix should be flipped vertically; false otherwise

setReverse

public void setReverse(boolean reverse)

Sets whether the rendered matrix should be reversed horizontally.

Parameters:

reverse - true if the rendered matrix should be reversed horizontally; false otherwise

getMatrix

public byte[] getMatrix()

Returns the wrapped matrix bytes.

Returns:

the wrapped matrix bytes

setMatrix

public void setMatrix(byte[] matrix)

Sets the wrapped matrix bytes.

Parameters:

matrix - the wrapped matrix bytes

setColumn

public void setColumn(int column,
                      int value)

Sets the value of a column.

Parameters:

column - the column to set

value - the column value

setColumns

public void setColumns(int startColumn,
                       byte[] columns,
                       int offset,
                       int length)

Sets the value of a sequence of columns.

Parameters:

startColumn - the first target column

columns - the column values

offset - the start offset of the column values

length - the length of the column values

setPixel

public void setPixel(int x,
                     int y,
                     boolean value)

Sets the value of a pixel.

Parameters:

x - the X coordinate of the pixel

y - the Y coordinate of the pixel

value - the pixel value (true for on, false for off)

fill

public void fill(int value)

Fills the matrix with the given column value.

Parameters:

value - the column value to fill the matrix with

empty

public void empty()
           throws IOException

Empty the matrix (fill it with empty columns).

Throws:

IOException - if an error occurs

render

public byte[] render()
              throws IOException

Render the matrix into a returned buffer, with transformations applied (flip, reverse, crop, etc.)

Returns:

the rendered buffer

Throws:

IOException - if an error occurs

setOffset

public void setOffset(int offset)

Sets the offset of the column within the matrix at which the rendering will start.

Parameters:

offset - the offset of the column within the matrix

scroll

public void scroll(int delta)

Scrolls the rendered columns by the given number of columns (positive or negative delta). This sets the offset relative to the current offset.

Parameters:

delta - the number of columns to scroll by

graph

public void graph(int[] values,
                  Float low,
                  Float high,
                  boolean bars)

Draws a graph with the given width and height in pixels from the given data values and boundaries.

Parameters:

values - the data values

low - the value represented at the bottom of the graph, or null if the minimum data value should be used

high - the value represented at the top of the graph, or null if the maximum data value should be used

bars - specifies whether the graph is a bar graph (with filled area under the value), or a scatter plot (single point per value)