com.antelmann.image
Class ImageUtils

java.lang.Object
  com.antelmann.image.ImageUtils

public class ImageUtils
extends Object

implements several useful image-related functions

Author:

Holger Antelmann

Nested Class Summary

static class

ImageUtils.Axis

Method Summary

static String	asHexString(Color c)
static BufferedImage	captureComponent(Component c)
static BufferedImage	centerImageOnImage(Image foreground, Image background) the returned Image is as large as needed to fully show both, foreground and background
static BufferedImage	centerTextOnImage(Image background, String text, Font font, Paint paint, boolean antiAlias) the image is exactly as big as the background; if the text is larger, it is cut off
static BufferedImage	convertCMYK2RGB(Image img) very useful when writing jpeg images
static void	copyToClipboard(Image image)
static Image	createGreyscale(Image image)
static ImageIcon	createIcon(String chars) uses the default label font and a standard icon dimension of 16x16; useful for a single character
static ImageIcon	createIcon(String chars, Font font, Dimension dim)
static BufferedImage	createImage(Component c)
static BufferedImage	createImage(Component c, int width, int height)
static Image	createImage(Icon icon)
static ImageIcon	createImageIcon(Icon icon)
static Image	createNegative(Image image)
static byte[]	createThumbnail(Image image, int maxSize, float quality) convenience method to create thumbnail
static Image	createTransparentImage(Image image, Color transparentColor)
static Image	crop(Image image, RectangularShape rect)
static BufferedImage	deserialize(byte[] imageData)
static Iterator<BufferedImage>	extractFrames(InputStream animatedGifStream)
static BufferedImage	extractImage(URL url) makes a thorough attempt to extract an image from the given location.
static Image	filterImage(Image image, ImageFilter filter)
static AffineTransform	findUpperLeftTranslation(AffineTransform at, Image image) checks the four corners of the image and returns an AffineTransform that makes sure that the upper-left corner of the image is painted at the coordintates (0/0).
static BufferedImage	flip(Image image, ImageUtils.Axis axis)
static BufferedImage	generateBarcodeImage(String code, String type, boolean showLabel)
static BufferedImage	generateBarcodeImage(String code, String type, int dpi, boolean showLabel) if type is null, Code128 is assumed.
static BufferedImage	generateTextImage(String text) generates an image based on the given text.
static BufferedImage	generateTextImage(String text, Font font, Paint textColor, Paint backgroundColor, boolean antiAlias) generates an image based on the given text.
static BufferedImage	generateTransparentImage(int width, int height)
static Color	getColorByName(String color) first, this method looks for a field name (such as 'green') to derive the color, then it calls Color.decode(String).
static String	getImageFormat(InputStream stream)
static Dimension	getImageSize(InputStream stream)
static RGBImageFilter	getNegativeFilter()
static RGBImageFilter	getTransparentColorFilter(Color color) makes the given Color transparent; already existing transparency is preserved
static boolean	hasAlpha(Image image)
static Image	makeColorTransparent(Image image, Color c)
static Image	makeTransparent(Image image, float scaleFactor) returns a transparent version of the given image
static BufferedImage	paintImage(Paint paint, Dimension d)
static Image	pasteFromClipboard() returns null if the clipboard content cannot be read into an image
static BufferedImage	renderImage(Image image) allows to convert an Image to a BufferedImage
static BufferedImage	rewriteImage(Image image, int bufferedImageType)
static Image	rotate(Image image, double degrees)
static Image	scale(Image image, double factor) scales the image based on one given factor while preserving its ratio
static Image	scaleToFit(Image image, int size) scales the image so that it fits into a square of the given size; if the image is smaller than the given boundary, it's returned with a scale of 1
static Image	scaleToFit(Image image, int size, int renderHints)
static byte[]	serialize(Image image, String format)
static Image	transformImage(Image image, AffineTransform xform)
static Image	transformImage(Image image, BufferedImageOp bio)
static void	writeJpeg(Image image, File file, float quality)
static void	writeJpeg(Image image, OutputStream out, float quality)

Methods inherited from class java.lang.Object

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

Method Detail

getColorByName

public static Color getColorByName(String color)

first, this method looks for a field name (such as 'green') to derive the color, then it calls Color.decode(String). If both fails, null is returned.

asHexString

public static String asHexString(Color c)

See Also:

Color.decode(String)

deserialize

public static BufferedImage deserialize(byte[] imageData)
                                 throws IOException

Throws:

IOException

serialize

public static byte[] serialize(Image image,
                               String format)
                        throws IOException

Throws:

IOException

createThumbnail

public static byte[] createThumbnail(Image image,
                                     int maxSize,
                                     float quality)
                              throws IOException

convenience method to create thumbnail

Throws:

IOException

writeJpeg

public static void writeJpeg(Image image,
                             File file,
                             float quality)
                      throws IOException

Parameters:

quality - a number between 0 and 1 where 1 is the highest quality

Throws:

IOException

writeJpeg

public static void writeJpeg(Image image,
                             OutputStream out,
                             float quality)
                      throws IOException

Parameters:

quality - a number between 0 and 1 where 1 is the highest quality

Throws:

IOException

convertCMYK2RGB

public static BufferedImage convertCMYK2RGB(Image img)
                                     throws IOException

very useful when writing jpeg images

Throws:

IOException

generateBarcodeImage

public static BufferedImage generateBarcodeImage(String code,
                                                 String type,
                                                 boolean showLabel)

generateBarcodeImage

@ThirdParty(value="net.sourceforge.barbecue.BarcodeFactory")
public static BufferedImage generateBarcodeImage(String code,
                                                                 String type,
                                                                 int dpi,
                                                                 boolean showLabel)
                                          throws IllegalArgumentException

if type is null, Code128 is assumed.

Throws:

IllegalArgumentException

See Also:

BarcodeFactory

createIcon

public static ImageIcon createIcon(String chars)

uses the default label font and a standard icon dimension of 16x16; useful for a single character

createIcon

public static ImageIcon createIcon(String chars,
                                   Font font,
                                   Dimension dim)

captureComponent

public static BufferedImage captureComponent(Component c)

createImageIcon

public static ImageIcon createImageIcon(Icon icon)

createImage

public static Image createImage(Icon icon)

createImage

public static BufferedImage createImage(Component c)

createImage

public static BufferedImage createImage(Component c,
                                        int width,
                                        int height)

getImageFormat

public static String getImageFormat(InputStream stream)
                             throws IOException

Throws:

IOException

getImageSize

public static Dimension getImageSize(InputStream stream)
                              throws IOException

Throws:

IOException

pasteFromClipboard

public static Image pasteFromClipboard()

returns null if the clipboard content cannot be read into an image

copyToClipboard

public static void copyToClipboard(Image image)
                            throws IOException

Throws:

IOException

generateTransparentImage

public static BufferedImage generateTransparentImage(int width,
                                                     int height)

generateTextImage

public static BufferedImage generateTextImage(String text)

generates an image based on the given text. Uses black on white w/ the default font and no antiAlias.

generateTextImage

public static BufferedImage generateTextImage(String text,
                                              Font font,
                                              Paint textColor,
                                              Paint backgroundColor,
                                              boolean antiAlias)

generates an image based on the given text. Particularly useful for web apps.

Parameters:

font - may be null (in which case the default font is used)

backgroundColor - may be null, in which case the picture would be transparant

centerTextOnImage

public static BufferedImage centerTextOnImage(Image background,
                                              String text,
                                              Font font,
                                              Paint paint,
                                              boolean antiAlias)

the image is exactly as big as the background; if the text is larger, it is cut off

centerImageOnImage

public static BufferedImage centerImageOnImage(Image foreground,
                                               Image background)

the returned Image is as large as needed to fully show both, foreground and background

paintImage

public static BufferedImage paintImage(Paint paint,
                                       Dimension d)

scale

public static Image scale(Image image,
                          double factor)

scales the image based on one given factor while preserving its ratio

Parameters:

factor - a factor of 1 returns an image of the same size

scaleToFit

public static Image scaleToFit(Image image,
                               int size)

scales the image so that it fits into a square of the given size; if the image is smaller than the given boundary, it's returned with a scale of 1

scaleToFit

public static Image scaleToFit(Image image,
                               int size,
                               int renderHints)

Parameters:

renderHints - example: Image.SCALE_DEFAULT

crop

public static Image crop(Image image,
                         RectangularShape rect)

rotate

public static Image rotate(Image image,
                           double degrees)

flip

public static BufferedImage flip(Image image,
                                 ImageUtils.Axis axis)

makeColorTransparent

public static Image makeColorTransparent(Image image,
                                         Color c)

makeTransparent

public static Image makeTransparent(Image image,
                                    float scaleFactor)

returns a transparent version of the given image

Parameters:

scaleFactor - a number between 0 and 1; 0 means complete transparaency and 1 means complete opacity.

findUpperLeftTranslation

public static AffineTransform findUpperLeftTranslation(AffineTransform at,
                                                       Image image)

checks the four corners of the image and returns an AffineTransform that makes sure that the upper-left corner of the image is painted at the coordintates (0/0).

transformImage

public static Image transformImage(Image image,
                                   AffineTransform xform)

transformImage

public static Image transformImage(Image image,
                                   BufferedImageOp bio)

rewriteImage

public static BufferedImage rewriteImage(Image image,
                                         int bufferedImageType)

renderImage

public static BufferedImage renderImage(Image image)

allows to convert an Image to a BufferedImage

hasAlpha

public static boolean hasAlpha(Image image)

createGreyscale

public static Image createGreyscale(Image image)

filterImage

public static Image filterImage(Image image,
                                ImageFilter filter)

createNegative

public static Image createNegative(Image image)

createTransparentImage

public static Image createTransparentImage(Image image,
                                           Color transparentColor)

getTransparentColorFilter

public static RGBImageFilter getTransparentColorFilter(Color color)

makes the given Color transparent; already existing transparency is preserved

getNegativeFilter

public static RGBImageFilter getNegativeFilter()

extractFrames

public static Iterator<BufferedImage> extractFrames(InputStream animatedGifStream)
                                             throws IOException

Throws:

IOException

extractImage

@Todo(value="may not fully load images that are embedded into the html due to the stupid HTMLEditorKit")
public static BufferedImage extractImage(URL url)

makes a thorough attempt to extract an image from the given location. First, it tries to directly read an image from the url; if that fails, a JEditorPane is employed to create a component for it.

Returns:

an image representing the given content or null if no known useful representation exists