Package jexer.bits

Class ImageUtils

java.lang.Object

jexer.bits.ImageUtils

public class ImageUtils
extends java.lang.Object

ImageUtils contains methods to: - Check if an image is fully transparent. - Scale an image and preserve aspect ratio. - Break an image up into cells and optionally convert to Unicode glyphs. - Open an animated image as an Animation. - Compute the distance between two colors in RGB space. - Compute the partial movement between two colors in RGB space.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ImageUtils.DisplayMode	Selections for approximating an image as text cells.
static class	ImageUtils.Scale	Selections for fitting an image to the text cells.

Method Summary

Modifier and Type	Method	Description
static boolean	canDrawUnicodeBlockDrawingChar(int ch)	Check if a Unicode block-drawing character is drawable by drawUnicodeBlockDrawingChar().
static java.awt.image.BufferedImage	createImage(java.awt.image.BufferedImage image, int width, int height)	Create a BufferedImage using the same color model as another image.
static void	drawUnicodeBlockDrawingChar(int ch, java.awt.Color foreColor, java.awt.Color backColor, java.awt.image.BufferedImage image)	Draw a Unicode block-drawing character to an image.
static Animation	getAnimation(java.io.File file)	Open an image as an Animation.
static Animation	getAnimation(java.io.InputStream inputStream)	Open an image as an Animation.
static Animation	getAnimation(java.lang.String filename)	Open an image as an Animation.
static Animation	getAnimation(java.net.URL url)	Open an image as an Animation.
static Cell[][]	imageToCells(Backend backend, java.awt.image.BufferedImage image, int textWidth, int textHeight, ImageUtils.DisplayMode displayMode, java.awt.Color backColor, boolean bleedThrough)	Convert an image to a 2D array of cells.
static boolean	isFullyOpaque(java.awt.image.BufferedImage image)	Check if any pixels in an image have not-100% alpha value.
static boolean	isFullyTransparent(java.awt.image.BufferedImage image)	Check if any pixels in an image have not-0% alpha value.
static int	rgbAverage(java.awt.image.BufferedImage image)	Compute the average RGB value of an entire image, including pixels that may be partially or fully transparent.
static int	rgbAverage(java.awt.image.BufferedImage image, boolean onlyOpaque)	Compute the average RGB value of an entire image.
static int	rgbDistance(int first, int second)	Report the absolute distance in RGB space between two RGB colors.
static int	rgbMove(int start, int end, double fraction)	Move from one point in RGB space to another, by a certain fraction.
static double	rgbStdDev(java.awt.image.BufferedImage image, java.awt.image.BufferedImage averageImage)	Compute the standard deviation of RGB values of an entire image.
static java.awt.image.BufferedImage	scaleImage(java.awt.image.BufferedImage image, int width, int height, ImageUtils.Scale scale, java.awt.Color backColor)	Scale an image to be scaleFactor size and/or stretch it to fit a target box.

Methods inherited from class java.lang.Object

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

Method Detail

isFullyTransparent

public static boolean isFullyTransparent(java.awt.image.BufferedImage image)

Check if any pixels in an image have not-0% alpha value.

Parameters:

image - the image to check

Returns:

true if every pixel is fully transparent

isFullyOpaque

public static boolean isFullyOpaque(java.awt.image.BufferedImage image)

Check if any pixels in an image have not-100% alpha value.

Parameters:

image - the image to check

Returns:

true if every pixel is fully transparent

scaleImage

public static java.awt.image.BufferedImage scaleImage(java.awt.image.BufferedImage image,
                                                      int width,
                                                      int height,
                                                      ImageUtils.Scale scale,
                                                      java.awt.Color backColor)

Scale an image to be scaleFactor size and/or stretch it to fit a target box.

Parameters:

image - the image to scale

width - the width in pixels for the destination image

height - the height in pixels for the destination image

scale - the scaling type

backColor - the background color to use for Scale.SCALE

Returns:

the scaled image

imageToCells

public static Cell[][] imageToCells(Backend backend,
                                    java.awt.image.BufferedImage image,
                                    int textWidth,
                                    int textHeight,
                                    ImageUtils.DisplayMode displayMode,
                                    java.awt.Color backColor,
                                    boolean bleedThrough)

Convert an image to a 2D array of cells.

Parameters:

image - the image to convert

backend - the backend that can obtain the correct background color for a text cell

textWidth - the width of a cell in pixels

textHeight - the height of a cell in pixels

displayMode - option to convert image to Unicode glyphs

backColor - the color to use for the right and bottom padding to the text cell boundary

bleedThrough - if true, then image cells that are fully covered by a single color will be replaced by empty text cells of that color, permitting text "behind" that cell to bleed through if translucence is enabled

Returns:

a two-dimensional array of cells (cells[x][y])

getAnimation

public static Animation getAnimation(java.lang.String filename)

Open an image as an Animation.

Parameters:

filename - the name of the file that contains an animation

Returns:

the animation, or null on error

getAnimation

public static Animation getAnimation(java.io.File file)

Open an image as an Animation.

Parameters:

file - the file that contains an animation

Returns:

the animation, or null on error

getAnimation

public static Animation getAnimation(java.net.URL url)

Open an image as an Animation.

Parameters:

url - the URK that contains an animation

Returns:

the animation, or null on error

getAnimation

public static Animation getAnimation(java.io.InputStream inputStream)

Open an image as an Animation.

Parameters:

inputStream - the inputStream that contains an animation

Returns:

the animation, or null on error

rgbDistance

public static int rgbDistance(int first,
                              int second)

Report the absolute distance in RGB space between two RGB colors.

Parameters:

first - the first color

second - the second color

Returns:

the distance

rgbMove

public static int rgbMove(int start,
                          int end,
                          double fraction)

Move from one point in RGB space to another, by a certain fraction.

Parameters:

start - the starting point color

end - the ending point color

fraction - the amount of movement between start and end, between 0.0 (start) and 1.0 (end).

Returns:

the final color

rgbAverage

public static int rgbAverage(java.awt.image.BufferedImage image)

Compute the average RGB value of an entire image, including pixels that may be partially or fully transparent.

Parameters:

image - the image to check

Returns:

the average color

rgbAverage

public static int rgbAverage(java.awt.image.BufferedImage image,
                             boolean onlyOpaque)

Compute the average RGB value of an entire image.

Parameters:

image - the image to check

onlyOpaque - if true, only count pixels that are fully opaque

Returns:

the average color

rgbStdDev

public static double rgbStdDev(java.awt.image.BufferedImage image,
                               java.awt.image.BufferedImage averageImage)

Compute the standard deviation of RGB values of an entire image.

Parameters:

image - the image to check

averageImage - the image's "average" pixel values

Returns:

the average color

Throws:

java.lang.IllegalArgumentException - if the two images are of different dimensions

createImage

public static java.awt.image.BufferedImage createImage(java.awt.image.BufferedImage image,
                                                       int width,
                                                       int height)

Create a BufferedImage using the same color model as another image.

Parameters:

image - the original image

width - the width of the new image

height - the height of the new image

Returns:

the new image

canDrawUnicodeBlockDrawingChar

public static boolean canDrawUnicodeBlockDrawingChar(int ch)

Check if a Unicode block-drawing character is drawable by drawUnicodeBlockDrawingChar().

Parameters:

ch - the character to draw

Returns:

true if drawUnicodeBlockDrawingChar() can draw that character

drawUnicodeBlockDrawingChar

public static void drawUnicodeBlockDrawingChar(int ch,
                                               java.awt.Color foreColor,
                                               java.awt.Color backColor,
                                               java.awt.image.BufferedImage image)

Draw a Unicode block-drawing character to an image.

Parameters:

ch - the character to draw

foreColor - the foreground color

backColor - the background color

image - the image to draw onto