Package org.eclipse.swt.graphics

Class Image

  • All Implemented Interfaces:
    Drawable
    public 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 to 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.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      InternalImage internalImage
      The internal resource.

    • 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, 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.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      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.
      ImageData getImageData()
      Returns an ImageData based on the receiver Modifications made to this ImageData will not affect the Image.
      void setBackground​(Color color)
      Sets the color to which to map the transparent pixel.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • internalImage

        public final InternalImage internalImage
        The internal 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.

    • Constructor Detail

      • 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
        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:
        java.lang.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
        Since:
        1.3

      • 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.

        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:
        java.lang.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
        Since:
        1.4

    • Method Detail

      • 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
        Throws:
        SWTException -
        • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
        • ERROR_INVALID_IMAGE - if the image is not a bitmap or an icon

      • 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
        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:
        1.3
        See Also:
        ImageData

      • 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:
        java.lang.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
        Since:
        1.3

      • 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
        Since:
        1.3