com.arsdigita.mimetypes.image
Class ImageSizer

java.lang.Object
  com.arsdigita.mimetypes.image.ImageSizer

Direct Known Subclasses:

BMPImageSizer, GIFImageSizer, JPEGImageSizer

public abstract class ImageSizer

extends Object

A class which is capable of reading an image and spitting out its size. Child classes should implement the computeImageSize(java.lang.String) method in order to provide image-format-specific functionality.

This class and its subclasses are used in the MimeType class.

Note that the only legal way to obtain an instance of this class is to call ImageSizerFactory.getImageSizer(java.lang.String)

Version:

$Id: //core-platform/dev/src/com/arsdigita/mimetypes/image/ImageSizer.java#6 $

Author:

Stanislav Freidin

Field Summary

static String

versionId

Constructor Summary

protected

ImageSizer() This constructor is protected since the only way to get an instance of the ImageSizer is to call ImageSizerFactory.getImageSizer(java.lang.String)

Method Summary

Dimension	computeImageSize(File file) Construct a new ImageSizer.
Dimension	computeImageSize(String path) Read a file from the filesystem and try to determine its size
abstract Dimension	computeSize(DataInputStream in) Read the input stream, determine the size of the image, and return it
static Dimension	getScaledSize(Dimension d, int maxWidth, int maxHeight) Scale width and height down to fit within the specified dimensions.
static Dimension	getScaledSize(int width, int height, int maxWidth, int maxHeight) Scale the specified dimensions down to fit within the maximum dimensions.
protected static short	toShort(byte highOrder, byte lowOrder) Utility method to convert 2 bytes to a short integer

Methods inherited from class java.lang.Object

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

Field Detail

versionId

public static final String versionId

See Also:

Constant Field Values

Constructor Detail

ImageSizer

protected ImageSizer()

This constructor is protected since the only way to get an instance of the ImageSizer is to call ImageSizerFactory.getImageSizer(java.lang.String)

Method Detail

computeImageSize

public Dimension computeImageSize(String path)
                           throws IOException

Read a file from the filesystem and try to determine its size

Parameters:

path - The path of the file to read

Returns:

a Dimension which will hold the size of an image

Throws:

IOException

computeImageSize

public Dimension computeImageSize(File file)
                           throws IOException

Construct a new ImageSizer. Read a file from the filesystem and try to determine its size

Parameters:

file - The fike to read

Throws:

IOException

getScaledSize

public static Dimension getScaledSize(Dimension d,
                                      int maxWidth,
                                      int maxHeight)

Scale width and height down to fit within the specified dimensions. Maintain aspect ratio. If the image already fits within the specified dimensions, then return the image dimensions unchanged.

Parameters:

d - a Dimension which holds the size of the image

maxWidth - the maximum width

maxHeight - the maximum height

getScaledSize

public static Dimension getScaledSize(int width,
                                      int height,
                                      int maxWidth,
                                      int maxHeight)

Scale the specified dimensions down to fit within the maximum dimensions. Maintain aspect ratio. If the original dimensions already fit within the maximum dimensions, return the original dimensions

Parameters:

width - The current width

height - The current height

maxWidth - the maximum width

maxHeight - the maximum height

computeSize

public abstract Dimension computeSize(DataInputStream in)
                               throws IOException

Read the input stream, determine the size of the image, and return it

Parameters:

in - The InputStream to read

Returns:

The size of the image, or null on failure

Throws:

IOException

toShort

protected static short toShort(byte highOrder,
                               byte lowOrder)

Utility method to convert 2 bytes to a short integer