Package ej.microui.display

Class ResourceImage

  • All Implemented Interfaces:
    Closeable, AutoCloseable
    Direct Known Subclasses:
    BufferedImage
    public class ResourceImage
extends Image
implements Closeable
    A ResourceImage represents an image which may require dynamic allocation in order to be created.

    A resource image should be closed in order to free the dynamic allocation used to store the image pixels.

    This class provides statics method in order to load an image from a resource or from a given input stream.

    • Constructor Detail

      • ResourceImage

        public ResourceImage()

    • Method Detail

      • canLoadImage

        public static boolean canLoadImage​(String path)
        Returns whether an image can be loaded from a resource.

        This method may be used to know whether calling loadImage(String) with the given path would be successful or not.

        Parameters:
        path - the resource path.
        Returns:
        true if the image can be loaded, false otherwise.
        Throws:
        MicroUIException - if the resource path doesn't start with "/".
        MicroUIException - if MicroUI is not started.
        SecurityException - if a security manager exists and does not allow the caller to load an image.
        Since:
        3.0
        See Also:
        loadImage(String)

      • loadImage

        public static ResourceImage loadImage​(String path)
        Loads an immutable image from a resource.

        This method can load images which are in the internal image format defined by the MicroUI implementation, and images which are in standard image formats (such as PNG), depending on the capabilities of the MicroUI implementation (such as having a PNG decoder).

        The MicroUI implementation is responsible for retrieving the correct image load/decoder in order to load the image.

        The output format of the returned image is the best format for the input format. For example, the output format for PNG images is ResourceImage.OutputFormat.ARGB8888. The output format for images in internal MicroUI image format is the output format specified in the images.list file.

        Calling this method is equivalent to calling loadImage(name, null).

        Parameters:
        path - the resource path.
        Returns:
        the loaded image.
        Throws:
        MicroUIException - if the image could not be loaded for any reason (see MicroUIException.getErrorCode()).
        MicroUIException - if the resource path doesn't start with "/".
        MicroUIException - if MicroUI is not started.
        SecurityException - if a security manager exists and does not allow the caller to load an image.
        Since:
        2.0

      • loadImage

        public static ResourceImage loadImage​(String path,
                                      @Nullable
                                      ResourceImage.OutputFormat format)
        Loads an immutable image from a resource.

        This method can load images which are in the internal image format defined by the MicroUI implementation, and images which are in standard image formats (such as PNG), depending on the capabilities of the MicroUI implementation (such as having a PNG decoder).

        The MicroUI implementation is responsible for retrieving the correct image load/decoder in order to load the image.

        The output format of the image is the output format given as parameter. This format may be different from the default output format (@see loadImage(String)).

        Parameters:
        path - the resource path.
        format - the desired output format, or null to use the default output format.
        Returns:
        the loaded image.
        Throws:
        MicroUIException - if the image could not be loaded for any reason (see MicroUIException.getErrorCode()).
        MicroUIException - if the resource path doesn't start with "/".
        MicroUIException - if MicroUI is not started.
        SecurityException - if a security manager exists and does not allow the caller to load an image.
        Since:
        2.0

      • loadImage

        public static ResourceImage loadImage​(InputStream stream,
                                      int size)
        Loads an immutable image from an InputStream.

        Refer to loadImage(String) for more information.

        Calling this method is equivalent to calling loadImage(stream, size, null).

        Parameters:
        stream - the input stream providing the image data.
        size - the number of bytes to read from the input stream.
        Returns:
        the loaded image.
        Throws:
        MicroUIException - if the image could not be loaded for any reason (see MicroUIException.getErrorCode()).
        MicroUIException - if MicroUI is not started.
        SecurityException - if a security manager exists and does not allow the caller to load an image.
        Since:
        2.0

      • isClosed

        public boolean isClosed()
        Returns whether this image has been closed.
        Returns:
        true if the image has been closed, false otherwise.

      • close

        public void close()
        Closes this image and its associated resources.

        Calling this method on an image which has already been closed has no effect.

        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable