org.jdesktop.swingx.graphics
Class GraphicsUtilities

java.lang.Object
  org.jdesktop.swingx.graphics.GraphicsUtilities

public class GraphicsUtilities
extends Object

GraphicsUtilities contains a set of tools to perform common graphics operations easily. These operations are divided into several themes, listed below.

Compatible Images

Compatible images can, and should, be used to increase drawing performance. This class provides a number of methods to load compatible images directly from files or to convert existing images to compatibles images.

Creating Thumbnails

This class provides a number of methods to easily scale down images. Some of these methods offer a trade-off between speed and result quality and shouuld be used all the time. They also offer the advantage of producing compatible images, thus automatically resulting into better runtime performance.

All these methodes are both faster than Image.getScaledInstance(int, int, int) and produce better-looking results than the various drawImage() methods in Graphics, which can be used for image scaling.

Image Manipulation

This class provides two methods to get and set pixels in a buffered image. These methods try to avoid unmanaging the image in order to keep good performance.

Method Summary

static BufferedImage	convertToBufferedImage(Image img) Converts the specified image into a compatible buffered image.
static BufferedImage	createColorModelCompatibleImage(BufferedImage image) Returns a new BufferedImage using the same color model as the image passed as a parameter.
static BufferedImage	createCompatibleImage(BufferedImage image) Returns a new compatible image with the same width, height and transparency as the image specified as a parameter.
static BufferedImage	createCompatibleImage(BufferedImage image, int width, int height) Returns a new compatible image of the specified width and height, and the same transparency setting as the image specified as a parameter.
static BufferedImage	createCompatibleImage(int width, int height) Returns a new opaque compatible image of the specified width and height.
static BufferedImage	createCompatibleTranslucentImage(int width, int height) Returns a new translucent compatible image of the specified width and height.
static BufferedImage	createThumbnail(BufferedImage image, int newSize) Returns a thumbnail of a source image.
static BufferedImage	createThumbnail(BufferedImage image, int newWidth, int newHeight) Returns a thumbnail of a source image.
static BufferedImage	createThumbnailFast(BufferedImage image, int newSize) Returns a thumbnail of a source image.
static BufferedImage	createThumbnailFast(BufferedImage image, int newWidth, int newHeight) Returns a thumbnail of a source image.
static int[]	getPixels(BufferedImage img, int x, int y, int w, int h, int[] pixels) Returns an array of pixels, stored as integers, from a BufferedImage.
static BufferedImage	loadCompatibleImage(InputStream in) Returns a new compatible image from a stream.
static BufferedImage	loadCompatibleImage(URL resource) Returns a new compatible image from a URL.
static Shape	mergeClip(Graphics g, Shape clip) Sets the clip on a graphics object by merging a supplied clip with the existing one.
static void	setPixels(BufferedImage img, int x, int y, int w, int h, int[] pixels) Writes a rectangular area of pixels in the destination BufferedImage.
static BufferedImage	toCompatibleImage(BufferedImage image) Return a new compatible image that contains a copy of the specified image.

Methods inherited from class java.lang.Object

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

Method Detail

convertToBufferedImage

public static BufferedImage convertToBufferedImage(Image img)

Converts the specified image into a compatible buffered image.

Parameters:

img - the image to convert

Returns:

a compatible buffered image of the input

createColorModelCompatibleImage

public static BufferedImage createColorModelCompatibleImage(BufferedImage image)

Returns a new BufferedImage using the same color model as the image passed as a parameter. The returned image is only compatible with the image passed as a parameter. This does not mean the returned image is compatible with the hardware.

Parameters:

image - the reference image from which the color model of the new image is obtained

Returns:

a new BufferedImage, compatible with the color model of image

createCompatibleImage

public static BufferedImage createCompatibleImage(BufferedImage image)

Returns a new compatible image with the same width, height and transparency as the image specified as a parameter. That is, the returned BufferedImage will be compatible with the graphics hardware. If this method is called in a headless environment, then the returned BufferedImage will be compatible with the source image.

Parameters:

image - the reference image from which the dimension and the transparency of the new image are obtained

Returns:

a new compatible BufferedImage with the same dimension and transparency as image

See Also:

Transparency, createCompatibleImage(int, int), createCompatibleImage(java.awt.image.BufferedImage, int, int), createCompatibleTranslucentImage(int, int), loadCompatibleImage(java.net.URL), toCompatibleImage(java.awt.image.BufferedImage)

createCompatibleImage

public static BufferedImage createCompatibleImage(BufferedImage image,
                                                  int width,
                                                  int height)

Returns a new compatible image of the specified width and height, and the same transparency setting as the image specified as a parameter. That is, the returned BufferedImage is compatible with the graphics hardware. If the method is called in a headless environment, then the returned BufferedImage will be compatible with the source image.

Parameters:

width - the width of the new image

height - the height of the new image

image - the reference image from which the transparency of the new image is obtained

Returns:

a new compatible BufferedImage with the same transparency as image and the specified dimension

See Also:

Transparency, createCompatibleImage(java.awt.image.BufferedImage), createCompatibleImage(int, int), createCompatibleTranslucentImage(int, int), loadCompatibleImage(java.net.URL), toCompatibleImage(java.awt.image.BufferedImage)

createCompatibleImage

public static BufferedImage createCompatibleImage(int width,
                                                  int height)

Returns a new opaque compatible image of the specified width and height. That is, the returned BufferedImage is compatible with the graphics hardware. If the method is called in a headless environment, then the returned BufferedImage will be compatible with the source image.

Parameters:

width - the width of the new image

height - the height of the new image

Returns:

a new opaque compatible BufferedImage of the specified width and height

See Also:

createCompatibleImage(java.awt.image.BufferedImage), createCompatibleImage(java.awt.image.BufferedImage, int, int), createCompatibleTranslucentImage(int, int), loadCompatibleImage(java.net.URL), toCompatibleImage(java.awt.image.BufferedImage)

createCompatibleTranslucentImage

public static BufferedImage createCompatibleTranslucentImage(int width,
                                                             int height)

Returns a new translucent compatible image of the specified width and height. That is, the returned BufferedImage is compatible with the graphics hardware. If the method is called in a headless environment, then the returned BufferedImage will be compatible with the source image.

Parameters:

width - the width of the new image

height - the height of the new image

Returns:

a new translucent compatible BufferedImage of the specified width and height

See Also:

createCompatibleImage(java.awt.image.BufferedImage), createCompatibleImage(java.awt.image.BufferedImage, int, int), createCompatibleImage(int, int), loadCompatibleImage(java.net.URL), toCompatibleImage(java.awt.image.BufferedImage)

loadCompatibleImage

public static BufferedImage loadCompatibleImage(InputStream in)
                                         throws IOException

Returns a new compatible image from a stream. The image is loaded from the specified stream and then turned, if necessary into a compatible image.

Parameters:

in - the stream of the picture to load as a compatible image

Returns:

a new translucent compatible BufferedImage of the specified width and height

Throws:

IOException - if the image cannot be read or loaded

See Also:

createCompatibleImage(java.awt.image.BufferedImage), createCompatibleImage(java.awt.image.BufferedImage, int, int), createCompatibleImage(int, int), createCompatibleTranslucentImage(int, int), toCompatibleImage(java.awt.image.BufferedImage)

loadCompatibleImage

public static BufferedImage loadCompatibleImage(URL resource)
                                         throws IOException

Returns a new compatible image from a URL. The image is loaded from the specified location and then turned, if necessary into a compatible image.

Parameters:

resource - the URL of the picture to load as a compatible image

Returns:

a new translucent compatible BufferedImage of the specified width and height

Throws:

IOException - if the image cannot be read or loaded

See Also:

createCompatibleImage(java.awt.image.BufferedImage), createCompatibleImage(java.awt.image.BufferedImage, int, int), createCompatibleImage(int, int), createCompatibleTranslucentImage(int, int), toCompatibleImage(java.awt.image.BufferedImage)

toCompatibleImage

public static BufferedImage toCompatibleImage(BufferedImage image)

Return a new compatible image that contains a copy of the specified image. This method ensures an image is compatible with the hardware, and therefore optimized for fast blitting operations.

If the method is called in a headless environment, then the returned BufferedImage will be the source image.

Parameters:

image - the image to copy into a new compatible image

Returns:

a new compatible copy, with the same width and height and transparency and content, of image

See Also:

createCompatibleImage(java.awt.image.BufferedImage), createCompatibleImage(java.awt.image.BufferedImage, int, int), createCompatibleImage(int, int), createCompatibleTranslucentImage(int, int), loadCompatibleImage(java.net.URL)

createThumbnailFast

public static BufferedImage createThumbnailFast(BufferedImage image,
                                                int newSize)

Returns a thumbnail of a source image. newSize defines the length of the longest dimension of the thumbnail. The other dimension is then computed according to the dimensions ratio of the original picture.

This method favors speed over quality. When the new size is less than half the longest dimension of the source image, createThumbnail(BufferedImage, int) or createThumbnail(BufferedImage, int, int) should be used instead to ensure the quality of the result without sacrificing too much performance.

Parameters:

image - the source image

newSize - the length of the largest dimension of the thumbnail

Returns:

a new compatible BufferedImage containing a thumbnail of image

Throws:

IllegalArgumentException - if newSize is larger than the largest dimension of image or <= 0

See Also:

createThumbnailFast(java.awt.image.BufferedImage, int, int), createThumbnail(java.awt.image.BufferedImage, int), createThumbnail(java.awt.image.BufferedImage, int, int)

createThumbnailFast

public static BufferedImage createThumbnailFast(BufferedImage image,
                                                int newWidth,
                                                int newHeight)

Returns a thumbnail of a source image.

This method favors speed over quality. When the new size is less than half the longest dimension of the source image, createThumbnail(BufferedImage, int) or createThumbnail(BufferedImage, int, int) should be used instead to ensure the quality of the result without sacrificing too much performance.

Parameters:

image - the source image

newWidth - the width of the thumbnail

newHeight - the height of the thumbnail

Returns:

a new compatible BufferedImage containing a thumbnail of image

Throws:

IllegalArgumentException - if newWidth is larger than the width of image or if code>newHeight is larger than the height of image or if one of the dimensions is <= 0

See Also:

createThumbnailFast(java.awt.image.BufferedImage, int), createThumbnail(java.awt.image.BufferedImage, int), createThumbnail(java.awt.image.BufferedImage, int, int)

createThumbnail

public static BufferedImage createThumbnail(BufferedImage image,
                                            int newSize)

Returns a thumbnail of a source image. newSize defines the length of the longest dimension of the thumbnail. The other dimension is then computed according to the dimensions ratio of the original picture.

This method offers a good trade-off between speed and quality. The result looks better than createThumbnailFast(java.awt.image.BufferedImage, int) when the new size is less than half the longest dimension of the source image, yet the rendering speed is almost similar.

Parameters:

image - the source image

newSize - the length of the largest dimension of the thumbnail

Returns:

a new compatible BufferedImage containing a thumbnail of image

Throws:

IllegalArgumentException - if newSize is larger than the largest dimension of image or <= 0

See Also:

createThumbnailFast(java.awt.image.BufferedImage, int, int), createThumbnailFast(java.awt.image.BufferedImage, int), createThumbnail(java.awt.image.BufferedImage, int, int)

createThumbnail

public static BufferedImage createThumbnail(BufferedImage image,
                                            int newWidth,
                                            int newHeight)

Returns a thumbnail of a source image.

This method offers a good trade-off between speed and quality. The result looks better than createThumbnailFast(java.awt.image.BufferedImage, int) when the new size is less than half the longest dimension of the source image, yet the rendering speed is almost similar.

Parameters:

image - the source image

newWidth - the width of the thumbnail

newHeight - the height of the thumbnail

Returns:

a new compatible BufferedImage containing a thumbnail of image

Throws:

IllegalArgumentException - if newWidth is larger than the width of image or if code>newHeight is larger than the height of image or if one the dimensions is not > 0

See Also:

createThumbnailFast(java.awt.image.BufferedImage, int), createThumbnailFast(java.awt.image.BufferedImage, int, int), createThumbnail(java.awt.image.BufferedImage, int)

getPixels

public static int[] getPixels(BufferedImage img,
                              int x,
                              int y,
                              int w,
                              int h,
                              int[] pixels)

Returns an array of pixels, stored as integers, from a BufferedImage. The pixels are grabbed from a rectangular area defined by a location and two dimensions. Calling this method on an image of type different from BufferedImage.TYPE_INT_ARGB and BufferedImage.TYPE_INT_RGB will unmanage the image.

Parameters:

img - the source image

x - the x location at which to start grabbing pixels

y - the y location at which to start grabbing pixels

w - the width of the rectangle of pixels to grab

h - the height of the rectangle of pixels to grab

pixels - a pre-allocated array of pixels of size w*h; can be null

Returns:

pixels if non-null, a new array of integers otherwise

Throws:

IllegalArgumentException - is pixels is non-null and of length < w*h

setPixels

public static void setPixels(BufferedImage img,
                             int x,
                             int y,
                             int w,
                             int h,
                             int[] pixels)

Writes a rectangular area of pixels in the destination BufferedImage. Calling this method on an image of type different from BufferedImage.TYPE_INT_ARGB and BufferedImage.TYPE_INT_RGB will unmanage the image.

Parameters:

img - the destination image

x - the x location at which to start storing pixels

y - the y location at which to start storing pixels

w - the width of the rectangle of pixels to store

h - the height of the rectangle of pixels to store

pixels - an array of pixels, stored as integers

Throws:

IllegalArgumentException - is pixels is non-null and of length < w*h

mergeClip

public static Shape mergeClip(Graphics g,
                              Shape clip)

Sets the clip on a graphics object by merging a supplied clip with the existing one. The new clip will be an intersection of the old clip and the supplied clip. The old clip shape will be returned. This is useful for resetting the old clip after an operation is performed.

Parameters:

g - the graphics object to update

clip - a new clipping region to add to the graphics clip. This may return null if the current clip is null.

Returns:

the current clipping region of the supplied graphics object

Throws:

NullPointerException - if any parameter is null