Package org.eclipse.swt.graphics

Class Image

java.lang.Object
org.eclipse.swt.graphics.Resource
org.eclipse.swt.graphics.Image
All Implemented Interfaces:
Drawable
public final class Image extends Resource implements Drawable
Instances of this class are graphics which have been prepared for display on a specific device. That is, they are ready to paint using methods such as GC.drawImage() and display on widgets with, for example, Button.setImage().

If loaded from a file format that supports it, an Image may have transparency, meaning that certain pixels are specified as being transparent when drawn. Examples of file formats that support transparency are GIF and PNG.

There are two primary ways to use Images. The first is to load a graphic file from disk and create an Image from it. This is done using an Image constructor, for example: 

    Image i = new Image(device, "C:\\graphic.bmp");
A graphic file may contain a color table specifying which colors the image was intended to possess. In the above example, these colors will be mapped to the closest available color in SWT. It is possible to get more control over the mapping of colors as the image is being created, using code of the form: 
    ImageData data = new ImageData("C:\\graphic.bmp");
    RGB[] rgbs = data.getRGBs();
    // At this point, rgbs contains specifications of all
    // the colors contained within this image. You may
    // allocate as many of these colors as you wish by
    // using the Color constructor Color(RGB), then
    // create the image:
    Image i = new Image(device, data);

Applications which require even greater control over the image loading process should use the support provided in class ImageLoader.

Application code must explicitly invoke the Image.dispose() method to release the operating system resources managed by each instance when those instances are no longer required.

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    long
    handle
    the handle to the OS image resource (Warning: This field is platform dependent)
    int
    type
    specifies whether the receiver is a bitmap or an icon (one of SWT.BITMAP, SWT.ICON)

  • Constructor Summary

    Constructors
    Constructor
    Description
    Image(Device device, int width, int height)
    Constructs an empty instance of this class with the specified width and height.
    Image(Device device, InputStream stream)
    Constructs an instance of this class by loading its representation from the specified input stream.
    Image(Device device, String filename)
    Constructs an instance of this class by loading its representation from the file with the specified name.
    Image(Device device, ImageData data)
    Constructs an instance of this class from the given ImageData.
    Image(Device device, ImageDataProvider imageDataProvider)
    Constructs an instance of this class by loading its representation from the ImageData retrieved from the ImageDataProvider.
    Image(Device device, ImageData source, ImageData mask)
    Constructs an instance of this class, whose type is SWT.ICON, from the two given ImageData objects.
    Image(Device device, ImageFileNameProvider imageFileNameProvider)
    Constructs an instance of this class by loading its representation from the file retrieved from the ImageFileNameProvider.
    Image(Device device, Image srcImage, int flag)
    Constructs a new instance of this class based on the provided image, with an appearance that varies depending on the value of the flag.
    Image(Device device, Rectangle bounds)
    Constructs an empty instance of this class with the width and height of the specified rectangle.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    equals(Object object)
    Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
    Color
    getBackground()
    Returns the color to which to map the transparent pixel, or null if the receiver has no transparent pixel.
    Rectangle
    getBounds()
    Returns the bounds of the receiver.
    Rectangle
    getBoundsInPixels()
    Deprecated.
    This API doesn't serve the purpose in an environment having multiple monitors with different DPIs, hence deprecated.
    ImageData
    getImageData()
    Returns an ImageData based on the receiver.
    ImageData
    getImageData(int zoom)
    Returns an ImageData for the given zoom level based on the receiver.
    ImageData
    getImageDataAtCurrentZoom()
    Deprecated.
    This API doesn't serve the purpose in an environment having multiple monitors with different DPIs, hence deprecated.
    int
    hashCode()
    Returns an integer hash code for the receiver.
    void
    internal_dispose_GC(long hDC, GCData data)
    Invokes platform specific functionality to dispose a GC handle.
    long
    internal_new_GC(GCData data)
    Invokes platform specific functionality to allocate a new GC handle.
    boolean
    isDisposed()
    Returns true if the image has been disposed, and false otherwise.
    void
    setBackground(Color color)
    Sets the color to which to map the transparent pixel.
    String
    toString()
    Returns a string containing a concise, human-readable description of the receiver.
    static Long
    win32_getHandle(Image image, int zoom)
    IMPORTANT: This method is not part of the public API for Image.
    static Image
    win32_new(Device device, int type, long handle)
    Invokes platform specific functionality to allocate a new image.

    Methods inherited from class org.eclipse.swt.graphics.Resource

    dispose, getDevice, setNonDisposeHandler

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    Methods inherited from interface org.eclipse.swt.graphics.Drawable

    isAutoScalable

  • Field Details

    • type

      public int type
      specifies whether the receiver is a bitmap or an icon (one of SWT.BITMAP, SWT.ICON)

      IMPORTANT: This field is not part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms and should never be accessed from application code.

      Restriction:
      This field is not intended to be referenced by clients.

    • handle

      public long handle
      the handle to the OS image resource (Warning: This field is platform dependent)

      IMPORTANT: This field is not part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms and should never be accessed from application code.

      Restriction:
      This field is not intended to be referenced by clients.

  • Constructor Details

    • Image

      public Image(Device device, int width, int height)
      Constructs an empty instance of this class with the specified width and height. The result may be drawn upon by creating a GC and using any of its drawing operations, as shown in the following example: 
          Image i = new Image(device, width, height);
    GC gc = new GC(i);
    gc.drawRectangle(0, 0, 50, 50);
    gc.dispose();

      Note: Some platforms may have a limitation on the size of image that can be created (size depends on width, height, and depth). For example, Windows 95, 98, and ME do not allow images larger than 16M.

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the image
      width - the width of the new image
      height - the height of the new image
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_INVALID_ARGUMENT - if either the width or height is negative or zero
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, Image srcImage, int flag)
      Constructs a new instance of this class based on the provided image, with an appearance that varies depending on the value of the flag. The possible flag values are:
      SWT.IMAGE_COPY
      the result is an identical copy of srcImage
      SWT.IMAGE_DISABLE
      the result is a copy of srcImage which has a disabled look
      SWT.IMAGE_GRAY
      the result is a copy of srcImage which has a gray scale look

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the image
      srcImage - the image to use as the source
      flag - the style, either IMAGE_COPY, IMAGE_DISABLE or IMAGE_GRAY
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_NULL_ARGUMENT - if srcImage is null
      • ERROR_INVALID_ARGUMENT - if the flag is not one of IMAGE_COPY, IMAGE_DISABLE or IMAGE_GRAY
      • ERROR_INVALID_ARGUMENT - if the image has been disposed
      SWTException -
      • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon, or is otherwise in an invalid state
      • ERROR_UNSUPPORTED_DEPTH - if the depth of the image is not supported
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, Rectangle bounds)
      Constructs an empty instance of this class with the width and height of the specified rectangle. The result may be drawn upon by creating a GC and using any of its drawing operations, as shown in the following example: 
          Image i = new Image(device, boundsRectangle);
    GC gc = new GC(i);
    gc.drawRectangle(0, 0, 50, 50);
    gc.dispose();

      Note: Some platforms may have a limitation on the size of image that can be created (size depends on width, height, and depth). For example, Windows 95, 98, and ME do not allow images larger than 16M.

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the image
      bounds - a rectangle specifying the image's width and height (must not be null)
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_NULL_ARGUMENT - if the bounds rectangle is null
      • ERROR_INVALID_ARGUMENT - if either the rectangle's width or height is negative
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, ImageData data)
      Constructs an instance of this class from the given ImageData.

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the image
      data - the image data to create the image from (must not be null)
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_NULL_ARGUMENT - if the image data is null
      SWTException -
      • ERROR_UNSUPPORTED_DEPTH - if the depth of the ImageData is not supported
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, ImageData source, ImageData mask)
      Constructs an instance of this class, whose type is SWT.ICON, from the two given ImageData objects. The two images must be the same size. Pixel transparency in either image will be ignored.

      The mask image should contain white wherever the icon is to be visible, and black wherever the icon is to be transparent. In addition, the source image should contain black wherever the icon is to be transparent.

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the icon
      source - the color data for the icon
      mask - the mask data for the icon
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_NULL_ARGUMENT - if either the source or mask is null
      • ERROR_INVALID_ARGUMENT - if source and mask are different sizes
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, InputStream stream)
      Constructs an instance of this class by loading its representation from the specified input stream. Throws an error if an error occurs while loading the image, or if the result is an image of 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 Image loadImage (Display display, Class clazz, String string) {
          InputStream stream = clazz.getResourceAsStream (string);
          if (stream == null) return null;
          Image image = null;
          try {
               image = new Image (display, stream);
          } catch (SWTException ex) {
          } finally {
               try {
                    stream.close ();
               } catch (IOException ex) {}
          }
          return image;
     }

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the image
      stream - the input stream to load the image from
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • 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_DEPTH - if the image stream describes an image with an unsupported depth
      • ERROR_UNSUPPORTED_FORMAT - if the image stream contains an unrecognized format
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, String filename)
      Constructs an instance of this class by loading its representation from the file with the specified name. Throws an error if an error occurs while loading the image, or if the result is an image of an unsupported type.

      This constructor is provided for convenience when loading a single image only. If the specified file contains multiple images, only the first one will be used.

      You must dispose the image when it is no longer required.

      Parameters:
      device - the device on which to create the image
      filename - the name of the file to load the image from
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • 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_DEPTH - if the image file describes an image with an unsupported depth
      • ERROR_UNSUPPORTED_FORMAT - if the image file contains an unrecognized format
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      See Also:

    • Image

      public Image(Device device, ImageFileNameProvider imageFileNameProvider)
      Constructs an instance of this class by loading its representation from the file retrieved from the ImageFileNameProvider. Throws an error if an error occurs while loading the image, or if the result is an image of an unsupported type.

      This constructor is provided for convenience for loading image as per DPI level.

      Parameters:
      device - the device on which to create the image
      imageFileNameProvider - the ImageFileNameProvider object that is to be used to get the file name
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_NULL_ARGUMENT - if the ImageFileNameProvider is null
      • ERROR_INVALID_ARGUMENT - if the fileName provided by ImageFileNameProvider is null at 100% zoom
      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_DEPTH - if the image file describes an image with an unsupported depth
      • ERROR_UNSUPPORTED_FORMAT - if the image file contains an unrecognized format
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      Since:
      3.104

    • Image

      public Image(Device device, ImageDataProvider imageDataProvider)
      Constructs an instance of this class by loading its representation from the ImageData retrieved from the ImageDataProvider. Throws an error if an error occurs while loading the image, or if the result is an image of an unsupported type.

      This constructor is provided for convenience for loading image as per DPI level.

      Parameters:
      device - the device on which to create the image
      imageDataProvider - the ImageDataProvider object that is to be used to get the ImageData
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if device is null and there is no current device
      • ERROR_NULL_ARGUMENT - if the ImageDataProvider is null
      • ERROR_INVALID_ARGUMENT - if the ImageData provided by ImageDataProvider is null at 100% zoom
      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_DEPTH - if the image file describes an image with an unsupported depth
      • ERROR_UNSUPPORTED_FORMAT - if the image file contains an unrecognized format
      SWTError -
      • ERROR_NO_HANDLES if a handle could not be obtained for image creation
      Since:
      3.104

  • Method Details

    • win32_getHandle

      public static Long win32_getHandle(Image image, int zoom)
      IMPORTANT: This method is not part of the public API for Image. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code. Updates zoom and refresh the Image based on the native zoom level, if required.
      Parameters:
      image - the image to get the handle of
      zoom - device zoom in % of the monitor on which the image is painted
      Returns:
      true if image is refreshed
      Restriction:
      This method is not intended to be referenced by clients.

    • equals

      public boolean equals(Object object)
      Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
      Overrides:
      equals in class Object
      Parameters:
      object - the object to compare with this object
      Returns:
      true if the object is the same as this object and false otherwise
      See Also:

    • getBackground

      public Color getBackground()
      Returns the color to which to map the transparent pixel, or null if the receiver has no transparent pixel.

      There are certain uses of Images that do not support transparency (for example, setting an image into a button or label). In these cases, it may be desired to simulate transparency by using the background color of the widget to paint the transparent pixels of the image. Use this method to check which color will be used in these cases in place of transparency. This value may be set with setBackground().

      Returns:
      the background color of the image, or null if there is no transparency in the image
      Throws:
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

    • getBounds

      public Rectangle getBounds()
      Returns the bounds of the receiver. The rectangle will always have x and y values of 0, and the width and height of the image.
      Returns:
      a rectangle specifying the image's bounds in points.
      Throws:
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
      • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon

    • getBoundsInPixels

      @Deprecated public Rectangle getBoundsInPixels()
      Deprecated.
      This API doesn't serve the purpose in an environment having multiple monitors with different DPIs, hence deprecated.
      Returns the bounds of the receiver. The rectangle will always have x and y values of 0, and the width and height of the image in pixels.
      Returns:
      a rectangle specifying the image's bounds in pixels.
      Throws:
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
      • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon
      Since:
      3.105

    • getImageData

      public ImageData getImageData()
      Returns an ImageData based on the receiver. Modifications made to this ImageData will not affect the Image.
      Returns:
      an ImageData containing the image's data and attributes at 100% zoom level.
      Throws:
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
      • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon
      See Also:

    • getImageData

      public ImageData getImageData(int zoom)
      Returns an ImageData for the given zoom level based on the receiver.

      Note that this method is mainly intended to be used by custom implementations of ImageDataProvider that draw a composite image at the requested zoom level based on other images. For custom zoom levels, the image data may be an auto-scaled version of the native image and may look more blurred or mangled than expected.

      Modifications made to the returned ImageData will not affect this Image.

      Parameters:
      zoom - The zoom level in % of the standard resolution (which is 1 physical monitor pixel == 1 SWT logical point). Typically 100, 150, or 200.
      Returns:
      an ImageData containing the image's data and attributes at the given zoom level
      Throws:
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
      • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon
      Since:
      3.106

    • getImageDataAtCurrentZoom

      @Deprecated public ImageData getImageDataAtCurrentZoom()
      Deprecated.
      This API doesn't serve the purpose in an environment having multiple monitors with different DPIs, hence deprecated. Use getImageData(int) instead.
      Returns an ImageData based on the receiver. Modifications made to this ImageData will not affect the Image.
      Returns:
      an ImageData containing the image's data and attributes at the current zoom level.
      Throws:
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
      • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon
      Since:
      3.105
      See Also:

    • hashCode

      public int hashCode()
      Returns an integer hash code for the receiver. Any two objects that return true when passed to equals must return the same value for this method.
      Overrides:
      hashCode in class Object
      Returns:
      the receiver's hash
      See Also:

    • internal_new_GC

      public long internal_new_GC(GCData data)
      Invokes platform specific functionality to allocate a new GC handle.

      IMPORTANT: This method is not part of the public API for Image. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

      Specified by:
      internal_new_GC in interface Drawable
      Parameters:
      data - the platform specific GC data
      Returns:
      the platform specific GC handle
      Restriction:
      This method is not intended to be referenced by clients.

    • internal_dispose_GC

      public void internal_dispose_GC(long hDC, GCData data)
      Invokes platform specific functionality to dispose a GC handle.

      IMPORTANT: This method is not part of the public API for Image. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

      Specified by:
      internal_dispose_GC in interface Drawable
      Parameters:
      hDC - the platform specific GC handle
      data - the platform specific GC data
      Restriction:
      This method is not intended to be referenced by clients.

    • isDisposed

      public boolean isDisposed()
      Returns true if the image has been disposed, and false otherwise.

      This method gets the dispose state for the image. When an image has been disposed, it is an error to invoke any other method (except Resource.dispose()) using the image.

      Specified by:
      isDisposed in class Resource
      Returns:
      true when the image is disposed and false otherwise

    • setBackground

      public void setBackground(Color color)
      Sets the color to which to map the transparent pixel.

      There are certain uses of Images that do not support transparency (for example, setting an image into a button or label). In these cases, it may be desired to simulate transparency by using the background color of the widget to paint the transparent pixels of the image. This method specifies the color that will be used in these cases. For example:

          Button b = new Button();
    image.setBackground(b.getBackground());
    b.setImage(image);

      The image may be modified by this operation (in effect, the transparent regions may be filled with the supplied color). Hence this operation is not reversible and it is not legal to call this function twice or with a null argument.

      This method has no effect if the receiver does not have a transparent pixel value.

      Parameters:
      color - the color to use when a transparent pixel is specified
      Throws:
      IllegalArgumentException -
      • ERROR_NULL_ARGUMENT - if the color is null
      • ERROR_INVALID_ARGUMENT - if the color has been disposed
      SWTException -
      • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

    • toString

      public String toString()
      Returns a string containing a concise, human-readable description of the receiver.
      Overrides:
      toString in class Object
      Returns:
      a string representation of the receiver

    • win32_new

      public static Image win32_new(Device device, int type, long handle)
      Invokes platform specific functionality to allocate a new image.

      IMPORTANT: This method is not part of the public API for Image. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

      Parameters:
      device - the device on which to allocate the color
      type - the type of the image (SWT.BITMAP or SWT.ICON)
      handle - the OS handle for the image
      Returns:
      a new image object containing the specified device, type and handle
      Restriction:
      This method is not intended to be referenced by clients.