org.eclipse.swt.graphics
Class ImageData

java.lang.Object
  org.eclipse.swt.graphics.ImageData

public final class ImageData
extends java.lang.Object

Instances of this class are device-independent descriptions of images. They are typically used as an intermediate format between loading from or writing to streams and creating an Image.

Note that the public fields x, y, disposalMethod and delayTime are typically only used when the image is in a set of images used for animation.

Since:

1.3

See Also:

Image, ImageLoader

Field Summary

int	alpha The global alpha value to be used for every pixel.
byte[]	alphaData The alpha data of the image.
int	bytesPerLine The number of bytes per scanline.
byte[]	data The pixel data of the image.
int	delayTime The time to delay before displaying the next image in an animation (this field corresponds to the GIF89a Delay Time value).
int	depth The color depth of the image, in bits per pixel.
int	disposalMethod A description of how to dispose of the current image before displaying the next.
int	height The height of the image, in pixels.
byte[]	maskData An icon-specific field containing the data from the icon mask.
int	maskPad An icon-specific field containing the scanline pad of the mask.
PaletteData	palette The color table for the image.
int	scanlinePad The scanline padding.
int	transparentPixel The transparent pixel.
int	type The type of file from which the image was read.
int	width The width of the image, in pixels.
int	x The x coordinate of the top left corner of the image within the logical screen (this field corresponds to the GIF89a Image Left Position value).
int	y The y coordinate of the top left corner of the image within the logical screen (this field corresponds to the GIF89a Image Top Position value).

Constructor Summary

ImageData(java.io.InputStream stream)
Constructs an ImageData loaded from the specified input stream.

ImageData(int width, int height, int depth, PaletteData palette)
Constructs a new, empty ImageData with the given width, height, depth and palette.

ImageData(int width, int height, int depth, PaletteData palette, int scanlinePad, byte[] data)
Constructs a new, empty ImageData with the given width, height, depth, palette, scanlinePad and data.

ImageData(java.lang.String filename)
Constructs an ImageData loaded from a file with the specified name.

Method Summary

java.lang.Object	clone() Returns a new instance of the same class as the receiver, whose slots have been filled in with copies of the values in the slots of the receiver.
int	getAlpha(int x, int y) Returns the alpha value at offset x in scanline y in the receiver's alpha data.
void	getAlphas(int x, int y, int getWidth, byte[] alphas, int startIndex) Returns getWidth alpha values starting at offset x in scanline y in the receiver's alpha data starting at startIndex.
int	getPixel(int x, int y) Returns the pixel value at offset x in scanline y in the receiver's data.
void	getPixels(int x, int y, int getWidth, byte[] pixels, int startIndex) Returns getWidth pixel values starting at offset x in scanline y in the receiver's data starting at startIndex.
void	getPixels(int x, int y, int getWidth, int[] pixels, int startIndex) Returns getWidth pixel values starting at offset x in scanline y in the receiver's data starting at startIndex.
RGB[]	getRGBs() Returns an array of RGBs which comprise the indexed color table of the receiver, or null if the receiver has a direct color model.
ImageData	getTransparencyMask() Returns an ImageData which specifies the transparency mask information for the receiver.
int	getTransparencyType() Returns the image transparency type, which will be one of SWT.TRANSPARENCY_NONE, SWT.TRANSPARENCY_MASK, SWT.TRANSPARENCY_PIXEL or SWT.TRANSPARENCY_ALPHA.
static ImageData	internal_new(int width, int height, int depth, PaletteData palette, int scanlinePad, byte[] data, int maskPad, byte[] maskData, byte[] alphaData, int alpha, int transparentPixel, int type, int x, int y, int disposalMethod, int delayTime) Invokes internal SWT functionality to create a new instance of this class.
ImageData	scaledTo(int width, int height) Returns a copy of the receiver which has been stretched or shrunk to the specified size.
void	setAlpha(int x, int y, int alpha) Sets the alpha value at offset x in scanline y in the receiver's alpha data.
void	setAlphas(int x, int y, int putWidth, byte[] alphas, int startIndex) Sets the alpha values starting at offset x in scanline y in the receiver's alpha data to the values from the array alphas starting at startIndex.
void	setPixel(int x, int y, int pixelValue) Sets the pixel value at offset x in scanline y in the receiver's data.
void	setPixels(int x, int y, int putWidth, byte[] pixels, int startIndex) Sets the pixel values starting at offset x in scanline y in the receiver's data to the values from the array pixels starting at startIndex.
void	setPixels(int x, int y, int putWidth, int[] pixels, int startIndex) Sets the pixel values starting at offset x in scanline y in the receiver's data to the values from the array pixels starting at startIndex.

Methods inherited from class java.lang.Object

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

Field Detail

width

public int width

The width of the image, in pixels.

height

public int height

The height of the image, in pixels.

depth

public int depth

The color depth of the image, in bits per pixel.

Note that a depth of 8 or less does not necessarily mean that the image is palette indexed, or conversely that a depth greater than 8 means that the image is direct color. Check the associated PaletteData's isDirect field for such determinations.

scanlinePad

public int scanlinePad

The scanline padding.

If one scanline of the image is not a multiple of this number, it will be padded with zeros until it is.

bytesPerLine

public int bytesPerLine

The number of bytes per scanline.

This is a multiple of the scanline padding.

data

public byte[] data

The pixel data of the image.

Note that for 16 bit depth images the pixel data is stored in least significant byte order; however, for 24bit and 32bit depth images the pixel data is stored in most significant byte order.

palette

public PaletteData palette

The color table for the image.

transparentPixel

public int transparentPixel

The transparent pixel.

Pixels with this value are transparent.

The default is -1 which means 'no transparent pixel'.

maskData

public byte[] maskData

An icon-specific field containing the data from the icon mask.

This is a 1 bit bitmap stored with the most significant bit first. The number of bytes per scanline is '((width + 7) / 8 + (maskPad - 1)) / maskPad * maskPad'.

The default is null which means 'no transparency mask'.

maskPad

public int maskPad

An icon-specific field containing the scanline pad of the mask.

If one scanline of the transparency mask is not a multiple of this number, it will be padded with zeros until it is.

alphaData

public byte[] alphaData

The alpha data of the image.

Every pixel can have an alpha blending value that varies from 0, meaning fully transparent, to 255 meaning fully opaque. The number of bytes per scanline is 'width'.

alpha

public int alpha

The global alpha value to be used for every pixel.

If this value is set, the alphaData field is ignored and when the image is rendered each pixel will be blended with the background an amount proportional to this value.

The default is -1 which means 'no global alpha value'

type

public int type

The type of file from which the image was read. It is expressed as one of the following values:

IMAGE_BMP

Windows BMP file format, no compression

IMAGE_BMP_RLE

Windows BMP file format, RLE compression if appropriate

IMAGE_GIF

GIF file format

IMAGE_ICO

Windows ICO file format

IMAGE_JPEG

JPEG file format

IMAGE_PNG

PNG file format

x

public int x

The x coordinate of the top left corner of the image within the logical screen (this field corresponds to the GIF89a Image Left Position value).

y

public int y

The y coordinate of the top left corner of the image within the logical screen (this field corresponds to the GIF89a Image Top Position value).

disposalMethod

public int disposalMethod

A description of how to dispose of the current image before displaying the next. It is expressed as one of the following values:

DM_UNSPECIFIED

disposal method not specified

DM_FILL_NONE

do nothing - leave the image in place

DM_FILL_BACKGROUND

fill with the background color

DM_FILL_PREVIOUS

restore the previous picture

(this field corresponds to the GIF89a Disposal Method value)

delayTime

public int delayTime

The time to delay before displaying the next image in an animation (this field corresponds to the GIF89a Delay Time value).

Constructor Detail

ImageData

public ImageData(int width,
                 int height,
                 int depth,
                 PaletteData palette)

Constructs a new, empty ImageData with the given width, height, depth and palette. The data will be initialized to an (all zero) array of the appropriate size.

Parameters:

width - the width of the image

height - the height of the image

depth - the depth of the image

palette - the palette of the image (must not be null)

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the width or height is zero or negative, or if the depth is not one of 1, 2, 4, 8, 16, 24 or 32
• ERROR_NULL_ARGUMENT - if the palette is null

ImageData

public ImageData(int width,
                 int height,
                 int depth,
                 PaletteData palette,
                 int scanlinePad,
                 byte[] data)

Constructs a new, empty ImageData with the given width, height, depth, palette, scanlinePad and data.

Parameters:

width - the width of the image

height - the height of the image

depth - the depth of the image

palette - the palette of the image

scanlinePad - the padding of each line, in bytes

data - the data of the image

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the width or height is zero or negative, or if the depth is not one of 1, 2, 4, 8, 16, 24 or 32, or the data array is too small to contain the image data
• ERROR_NULL_ARGUMENT - if the palette or data is null
• ERROR_CANNOT_BE_ZERO - if the scanlinePad is zero

ImageData

public ImageData(java.io.InputStream stream)

Constructs an ImageData loaded from the specified input stream. Throws an error if an error occurs while loading the image, or if the image has an unsupported type. Application code is still responsible for closing the input stream.

This constructor is provided for convenience when loading a single image only. If the stream contains multiple images, only the first one will be loaded. To load multiple images, use ImageLoader.load().

This constructor may be used to load a resource as follows:

     static ImageData loadImageData (Class clazz, String string) {
          InputStream stream = clazz.getResourceAsStream (string);
          if (stream == null) return null;
          ImageData imageData = null;
          try {
               imageData = new ImageData (stream);
          } catch (SWTException ex) {
          } finally {
               try {
                    stream.close ();
               } catch (IOException ex) {}
          }
          return imageData;
     }
 

Parameters:

stream - the input stream to load the image from (must not be null)

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the stream is null

SWTException -

• ERROR_IO - if an IO error occurs while reading from the stream
• ERROR_INVALID_IMAGE - if the image stream contains invalid data
• ERROR_UNSUPPORTED_FORMAT - if the image stream contains an unrecognized format

See Also:

ImageLoader.load(InputStream)

ImageData

public ImageData(java.lang.String filename)

Constructs an ImageData loaded from a file with the specified name. Throws an error if an error occurs loading the image, or if the image has an unsupported type.

This constructor is provided for convenience when loading a single image only. If the file contains multiple images, only the first one will be loaded. To load multiple images, use ImageLoader.load().

Parameters:

filename - the name of the file to load the image from (must not be null)

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the file name is null

SWTException -

• ERROR_IO - if an IO error occurs while reading from the file
• ERROR_INVALID_IMAGE - if the image file contains invalid data
• ERROR_UNSUPPORTED_FORMAT - if the image file contains an unrecognized format

Method Detail

internal_new

public static ImageData internal_new(int width,
                                     int height,
                                     int depth,
                                     PaletteData palette,
                                     int scanlinePad,
                                     byte[] data,
                                     int maskPad,
                                     byte[] maskData,
                                     byte[] alphaData,
                                     int alpha,
                                     int transparentPixel,
                                     int type,
                                     int x,
                                     int y,
                                     int disposalMethod,
                                     int delayTime)

Invokes internal SWT functionality to create a new instance of this class.

IMPORTANT: This method is not part of the public API for ImageData. It is marked public only so that it can be shared within the packages provided by SWT. It is subject to change without notice, and should never be called from application code.

This method is for internal use, and is not described further.

clone

public java.lang.Object clone()

Returns a new instance of the same class as the receiver, whose slots have been filled in with copies of the values in the slots of the receiver. That is, the returned object is a deep copy of the receiver.

Overrides:

clone in class java.lang.Object

Returns:

a copy of the receiver.

getAlpha

public int getAlpha(int x,
                    int y)

Returns the alpha value at offset x in scanline y in the receiver's alpha data. The alpha value is between 0 (transparent) and 255 (opaque).

Parameters:

x - the x coordinate of the pixel to get the alpha value of

y - the y coordinate of the pixel to get the alpha value of

Returns:

the alpha value at the given coordinates

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if either argument is out of range

getAlphas

public void getAlphas(int x,
                      int y,
                      int getWidth,
                      byte[] alphas,
                      int startIndex)

Returns getWidth alpha values starting at offset x in scanline y in the receiver's alpha data starting at startIndex. The alpha values are unsigned, between (byte)0 (transparent) and (byte)255 (opaque).

Parameters:

x - the x position of the pixel to begin getting alpha values

y - the y position of the pixel to begin getting alpha values

getWidth - the width of the data to get

alphas - the buffer in which to put the alpha values

startIndex - the offset into the image to begin getting alpha values

Throws:

java.lang.IndexOutOfBoundsException - if getWidth is too large

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if pixels is null
• ERROR_INVALID_ARGUMENT - if x or y is out of bounds
• ERROR_INVALID_ARGUMENT - if getWidth is negative

getPixel

public int getPixel(int x,
                    int y)

Returns the pixel value at offset x in scanline y in the receiver's data.

Parameters:

x - the x position of the pixel to get

y - the y position of the pixel to get

Returns:

the pixel at the given coordinates

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if either argument is out of bounds

SWTException -

• ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8, 16, 24 or 32

getPixels

public void getPixels(int x,
                      int y,
                      int getWidth,
                      byte[] pixels,
                      int startIndex)

Returns getWidth pixel values starting at offset x in scanline y in the receiver's data starting at startIndex.

Parameters:

x - the x position of the first pixel to get

y - the y position of the first pixel to get

getWidth - the width of the data to get

pixels - the buffer in which to put the pixels

startIndex - the offset into the byte array to begin storing pixels

Throws:

java.lang.IndexOutOfBoundsException - if getWidth is too large

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if pixels is null
• ERROR_INVALID_ARGUMENT - if x or y is out of bounds
• ERROR_INVALID_ARGUMENT - if getWidth is negative

SWTException -

• ERROR_UNSUPPORTED_DEPTH - if the depth is not one of 1, 2, 4 or 8 (For higher depths, use the int[] version of this method.)

getPixels

public void getPixels(int x,
                      int y,
                      int getWidth,
                      int[] pixels,
                      int startIndex)

Returns getWidth pixel values starting at offset x in scanline y in the receiver's data starting at startIndex.

Parameters:

x - the x position of the first pixel to get

y - the y position of the first pixel to get

getWidth - the width of the data to get

pixels - the buffer in which to put the pixels

startIndex - the offset into the buffer to begin storing pixels

Throws:

java.lang.IndexOutOfBoundsException - if getWidth is too large

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if pixels is null
• ERROR_INVALID_ARGUMENT - if x or y is out of bounds
• ERROR_INVALID_ARGUMENT - if getWidth is negative

SWTException -

• ERROR_UNSUPPORTED_DEPTH - if the depth is not one of 1, 2, 4, 8, 16, 24 or 32

getRGBs

public RGB[] getRGBs()

Returns an array of RGBs which comprise the indexed color table of the receiver, or null if the receiver has a direct color model.

Returns:

the RGB values for the image or null if direct color

See Also:

PaletteData.getRGBs()

getTransparencyMask

public ImageData getTransparencyMask()

Returns an ImageData which specifies the transparency mask information for the receiver. If the receiver has no transparency or is not an icon, returns an opaque mask.

Returns:

the transparency mask

getTransparencyType

public int getTransparencyType()

Returns the image transparency type, which will be one of SWT.TRANSPARENCY_NONE, SWT.TRANSPARENCY_MASK, SWT.TRANSPARENCY_PIXEL or SWT.TRANSPARENCY_ALPHA.

Returns:

the receiver's transparency type

scaledTo

public ImageData scaledTo(int width,
                          int height)

Returns a copy of the receiver which has been stretched or shrunk to the specified size. If either the width or height is negative, the resulting image will be inverted in the associated axis.

Parameters:

width - the width of the new ImageData

height - the height of the new ImageData

Returns:

a scaled copy of the image

setAlpha

public void setAlpha(int x,
                     int y,
                     int alpha)

Sets the alpha value at offset x in scanline y in the receiver's alpha data. The alpha value must be between 0 (transparent) and 255 (opaque).

Parameters:

x - the x coordinate of the alpha value to set

y - the y coordinate of the alpha value to set

alpha - the value to set the alpha to

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if x or y is out of bounds

setAlphas

public void setAlphas(int x,
                      int y,
                      int putWidth,
                      byte[] alphas,
                      int startIndex)

Sets the alpha values starting at offset x in scanline y in the receiver's alpha data to the values from the array alphas starting at startIndex. The alpha values must be between (byte)0 (transparent) and (byte)255 (opaque)

Parameters:

x - the x coordinate of the pixel to being setting the alpha values

y - the y coordinate of the pixel to being setting the alpha values

putWidth - the width of the alpha values to set

alphas - the alpha values to set

startIndex - the index at which to begin setting

Throws:

java.lang.IndexOutOfBoundsException - if putWidth is too large

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if pixels is null
• ERROR_INVALID_ARGUMENT - if x or y is out of bounds
• ERROR_INVALID_ARGUMENT - if putWidth is negative

setPixel

public void setPixel(int x,
                     int y,
                     int pixelValue)

Sets the pixel value at offset x in scanline y in the receiver's data.

Parameters:

x - the x coordinate of the pixel to set

y - the y coordinate of the pixel to set

pixelValue - the value to set the pixel to

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if x or y is out of bounds

SWTException -

• ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8, 16, 24 or 32

setPixels

public void setPixels(int x,
                      int y,
                      int putWidth,
                      byte[] pixels,
                      int startIndex)

Sets the pixel values starting at offset x in scanline y in the receiver's data to the values from the array pixels starting at startIndex.

Parameters:

x - the x position of the pixel to set

y - the y position of the pixel to set

putWidth - the width of the pixels to set

pixels - the pixels to set

startIndex - the index at which to begin setting

Throws:

java.lang.IndexOutOfBoundsException - if putWidth is too large

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if pixels is null
• ERROR_INVALID_ARGUMENT - if x or y is out of bounds
• ERROR_INVALID_ARGUMENT - if putWidth is negative

SWTException -

• ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8 (For higher depths, use the int[] version of this method.)

setPixels

public void setPixels(int x,
                      int y,
                      int putWidth,
                      int[] pixels,
                      int startIndex)

Sets the pixel values starting at offset x in scanline y in the receiver's data to the values from the array pixels starting at startIndex.

Parameters:

x - the x position of the pixel to set

y - the y position of the pixel to set

putWidth - the width of the pixels to set

pixels - the pixels to set

startIndex - the index at which to begin setting

Throws:

java.lang.IndexOutOfBoundsException - if putWidth is too large

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if pixels is null
• ERROR_INVALID_ARGUMENT - if x or y is out of bounds
• ERROR_INVALID_ARGUMENT - if putWidth is negative

SWTException -

• ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8, 16, 24 or 32