Class ImageIO

java.lang.Object

com.codename1.ui.util.ImageIO

public abstract class ImageIO
extends Object

Enable simple operations on image file & image objects such as dynamic scaling and storage to binary formats such as JPEG. Use Display.getImageIO() to get an instance of this class.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	FORMAT_JPEG	Indicates the JPEG output format
static final String	FORMAT_PNG	Indicates the PNG output format

Constructor Summary

Constructors

Constructor	Description
ImageIO()

Method Summary

Modifier and Type	Method	Description
static ImageIO	getImageIO()	Gets the ImageIO instance
Dimension	getImageSize(String imageFilePath)	Returns the image size in pixels
abstract boolean	isFormatSupported(String format)	Indicates if the given format for output is supported by this implementation
void	save(Image img, OutputStream response, String format, float quality)	Saves an image object to the given format
abstract void	save(InputStream image, OutputStream response, String format, int width, int height, float quality)	Saves an image file at the given resolution, scaling if necessary
void	save(String imageFilePath, OutputStream response, String format, int width, int height, float quality)	Saves an image file at the given resolution, scaling if necessary
String	saveAndKeepAspect(String imageFilePath, String preferredOutputPath, String format, int width, int height, float quality, boolean onlyDownscale, boolean scaleToFill)	Scales an image on disk while maintaining an aspect ratio, the appropriate aspect size will be picked based on the status of scaleToFill
protected abstract void	saveImage(Image img, OutputStream response, String format, float quality)	Saves an image object to the given format

Methods inherited from class Object

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

Field Details

FORMAT_JPEG

public static final String FORMAT_JPEG

Indicates the JPEG output format

See Also:

• Constant Field Values

FORMAT_PNG

public static final String FORMAT_PNG

Indicates the PNG output format

See Also:

• Constant Field Values

Constructor Details

ImageIO

public ImageIO()

Method Details

getImageIO

public static ImageIO getImageIO()

Gets the ImageIO instance

Returns

Returns:

the image IO instance or null if image IO isn't supported for the given platform

save

public abstract void save(InputStream image,
 OutputStream response,
 String format,
 int width,
 int height,
 float quality)
                   throws IOException

Saves an image file at the given resolution, scaling if necessary

Parameters

• image: source image stream

• response: resulting image output will be written to this stream

• format: the format for the image either FORMAT_PNG or FORMAT_JPEG

• width: the width for the resulting image, use -1 to not scale

• height: the height of the resulting image, use -1 to not scale

• quality: @param quality the quality for the resulting image output (applicable mostly for JPEG), a value between 0 and 1 notice that this isn't implemented in all platforms.

Throws:

IOException

save

public void save(Image img,
 OutputStream response,
 String format,
 float quality)
          throws IOException

Saves an image object to the given format

Parameters

• img: the image object

• response: resulting image output will be written to this stream

• format: the format for the image either FORMAT_PNG or FORMAT_JPEG

• quality: @param quality the quality for the resulting image output (applicable mostly for JPEG), a value between 0 and 1 notice that this isn't implemented in all platforms.

Throws:

IOException

save

public void save(String imageFilePath,
 OutputStream response,
 String format,
 int width,
 int height,
 float quality)
          throws IOException

Saves an image file at the given resolution, scaling if necessary

Parameters

• imageFilePath: the image file path

• response: resulting image output will be written to this stream

• format: the format for the image either FORMAT_PNG or FORMAT_JPEG

• width: the width for the resulting image, use -1 to not scale

• height: the height of the resulting image, use -1 to not scale

• quality: @param quality the quality for the resulting image output (applicable mostly for JPEG), a value between 0 and 1 notice that this isn't implemented in all platforms.

Throws:

IOException

getImageSize

public Dimension getImageSize(String imageFilePath)
                       throws IOException

Returns the image size in pixels

Parameters

• imageFilePath: the path to the image

Returns

the size in pixels

Throws:

IOException

saveAndKeepAspect

public String saveAndKeepAspect(String imageFilePath,
 String preferredOutputPath,
 String format,
 int width,
 int height,
 float quality,
 boolean onlyDownscale,
 boolean scaleToFill)
                         throws IOException

Scales an image on disk while maintaining an aspect ratio, the appropriate aspect size will be picked based on the status of scaleToFill

Parameters

• imageFilePath: the path to the image

• preferredOutputPath: the url where the image will be saved

• format: the format for the image either FORMAT_JPEG or FORMAT_PNG

• width: the desired width, either width or height will be respected based on aspect dimensions

• height: the desired height, either width or height will be respected based on aspect dimensions

• quality: @param quality the quality for the resulting image output (applicable mostly for JPEG), a value between 0 and 1 notice that this isn't implemented in all platforms.

• onlyDownscale: will not scale if the resolution to scale will be higher in this case will return the imageFilePath

• scaleToFill: @param scaleToFill when set to true will pick the larger value so the resulting image will be at least as big as width x height, when set to false will create an image that is no bigger than width x height

Returns

the url for the scaled image or the url of the unscaled image

Throws

• IOException: if the operation fails

Throws:

IOException

saveImage

protected abstract void saveImage(Image img,
 OutputStream response,
 String format,
 float quality)
                           throws IOException

Saves an image object to the given format

Parameters

• img: the image object

• response: resulting image output will be written to this stream

• format: the format for the image either FORMAT_PNG or FORMAT_JPEG

• quality: @param quality the quality for the resulting image output (applicable mostly for JPEG), a value between 0 and 1 notice that this isn't implemented in all platforms.

Throws:

IOException

isFormatSupported

public abstract boolean isFormatSupported(String format)

Indicates if the given format for output is supported by this implementation

Parameters

• format: the format for the image either FORMAT_PNG or FORMAT_JPEG

Returns

true if supported