org.apache.myfaces.trinidadinternal.image.painter.ImageUtils Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.myfaces.trinidadinternal.image.painter;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URL;
/**
* A utility class for working with images.
*
* ImageUtils contains utility functions for:
*
* - Forcing images to load synchronously
*
- Loading image resources
*
- Creating a filtered version of an image
*
- Creating a disabled version of an image
*
- Creating a "not loaded" image that doesn't rely on any
* resources external to the class.
*
*
* @version $Name: $ ($Revision: adfrt/faces/adf-faces-impl/src/main/java/oracle/adfinternal/view/faces/image/painter/ImageUtils.java#0 $) $Date: 10-nov-2005.19:04:58 $
*/
public class ImageUtils
{
/**
* Given an image and a filter, creates the resulting image.
* @param baseImage the base image
* @param imageFilter the image filter
*/
public static Image createFilteredImage(
Image baseImage,
ImageFilter imageFilter
)
{
// get the filtered image producer
ImageProducer producer = new FilteredImageSource(baseImage.getSource(),
imageFilter);
// return the filtered image
return Toolkit.getDefaultToolkit().createImage(producer);
}
/**
* Gets an image resource. If the image cannot be loaded,
* returns the special "not loaded" image.
* @param cl the class used to load the resource
* @param name the path to the resource, relative to the class
*/
static public Image getImageResource(Class cl, String name)
{
Image image = _getImageResource(cl, name);
if (image == null)
{
image = getNotLoadedImage();
}
return image;
}
/**
* Gets an image from a InputStream of image data.
* If the image cannot be loaded, returns null.
*
* @param in The InputStream to use for loading image data. The
* InputStream is automatically closed once the image data
* is read.
*/
static public Image getImageFromStream(InputStream in)
{
return _getImageFromStream(in);
}
/**
* Returns the special "not loaded" image, indicating that
* an image failed to be loaded properly.
*/
static public Image getNotLoadedImage()
{
if (_sNotLoadedImage == null)
{
_sNotLoadedImage = _createImage(_NOLOAD_DATA);
}
return _sNotLoadedImage;
}
/**
* Return true if the Image has been successfully loaded.
*
* @param image Image to check for sucessful loading
*
* @return True if the image has been sucessfully loaded.
*/
static public boolean isImageLoaded(
Image image
)
{
Toolkit tk = Toolkit.getDefaultToolkit();
int status = tk.checkImage(image, -1, -1, null);
return ((status & (ImageObserver.ALLBITS |ImageObserver.FRAMEBITS)) != 0);
}
/**
* Synchronously loads a single image.
* @return true if the image loaded successfully, false if it
* failed.
*/
static public boolean loadImage(Image image)
{
if (!isImageLoaded(image))
{
ImageLoader load = new ImageLoader(image);
load.start();
return load.waitFor();
}
else
{
return true;
}
}
/**
* Synchronously loads multiple images.
* @return true if all images loaded successfully, false if any failed
*/
static public boolean loadImages(Image[] images)
{
boolean value = true;
ImageLoader loaders[] = new ImageLoader[images.length];
for (int i = 0; i < images.length; i++)
{
loaders[i] = new ImageLoader(images[i]);
loaders[i].start();
}
for (int i = 0; i < images.length; i++)
value = (value && loaders[i].waitFor());
/*
// We could use an array of loaders, but this is only
// minimally less efficient, since we're only waiting on
// one image at any one time - it'll just woken up a bit
// more than necessary
ImageLoader load = new ImageLoader();
// Start each image loading, so each'll be loading in
// its own thread.
for (int i = 0; i < images.length; i++)
load.start(images[i]);
// Now wait for each image in turn - they'll be loading
// simultaneously, so this is more multithreaded than it looks
for (int i = 0; i < images.length; i++)
value = (value && load.waitFor(images[i]));
*/
return value;
}
/**
* Gets an image resource - won't substitute the "not loaded"
* image.
* @param cl the class used to load the resource
* @param name the path to the resource, relative to the class
*/
static private Image _getImageResource(Class cl, String name)
{
//
// =-= bts completely rewrite this method to use getResourceAsStream()
// rather than getResource(). There are two reasons for this.
// 1) Netscape Navigator 4.0 always returns null from getResource(),
// while allowing getResourceAsStream() to work
//
// 2) The appletviewer's code for loading images from JARs
// doesn't work correctly with getResource() if the image
// has been purged from memory.
//
// Calling getResourceAsStream() instead of getResource() solves both
// of these problems at the cost of:
//
// 1) Slower performance since we have to slurp the stream into a byte
// array first.
//
// 2) Not being able to purge images from memory.
//
// Hopefully, at some point in the future, we will be able to go back
// to the original code.
//
// assume that we won;t have any image to return
Image outImage = null;
// get a stream for the specified resource
InputStream inStream = cl.getResourceAsStream(name);
if (inStream != null)
{
outImage = _getImageFromStream(inStream);
if (outImage != null)
return outImage;
}
// =-= bwa restoring the original code in order to give the Appletviewer a
// second chance to succeed when images are not in a JAR -- the previous
// strategy fails in that case
URL imageURL = cl.getResource(name);
if (imageURL != null)
{
try
{
Object urlContent = imageURL.getContent();
// Sun VM's return ImageProducers
if (urlContent instanceof ImageProducer)
{
ImageProducer producer = (ImageProducer) urlContent;
outImage = Toolkit.getDefaultToolkit().createImage(producer);
}
// Microsoft VM's return Images
else if (urlContent instanceof Image)
{
outImage = (Image) urlContent;
}
if (outImage != null)
{
if (ImageUtils.loadImage(outImage))
return outImage;
else
return null;
}
}
catch (IOException e)
{
;
}
}
return null;
}
// Creates an Image using data from the InputStream
static private Image _getImageFromStream(InputStream inStream)
{
// assume that we won;t have any image to return
Image outImage = null;
// assume that we won't have any imageBuffer to turn into an image
byte[] imageBuffer = null;
//
// load the entire stream into the imageBuffer byte array
//
try
{
BufferedInputStream inBuffer = new BufferedInputStream(inStream);
ByteArrayOutputStream out =
new ByteArrayOutputStream(1024);
imageBuffer = new byte[1024];
int n;
while ((n = inBuffer.read(imageBuffer)) > 0)
out.write(imageBuffer, 0, n);
out.flush();
imageBuffer = out.toByteArray();
}
catch (IOException e)
{
;
}
finally
{
try
{
// make sure that we close the stream no matter what
inStream.close();
}
catch (IOException e)
{
;
}
}
//
// if we managed to load the byte array from the stream,
// create an image from it and synchronously load the image
//
if (imageBuffer != null)
{
outImage = Toolkit.getDefaultToolkit().createImage(imageBuffer);
if (!ImageUtils.loadImage(outImage))
{
// synchronous loading of image failded, so don't return any image
//
// =-= bts it might be better to still return the image in this
// case. What are we hurting by doing so?
outImage = null;
}
}
// return the image
return outImage;
}
// Private constructor to prevent clients from creating
// instances of this utility class.
private ImageUtils()
{
}
// Creates an image from a string representation of the
// byte data. This implementation currently only uses
// the bottom 8 bits of each character (i.e., one byte
// per character) - this is efficient on disk, given its
// UTF-8 representation, but twice as big as necessary
// in memory. OTOH, it means we don't need any special
// case code for odd lengths!
static private Image _createImage(String string)
{
int length = string.length();
byte[] data = new byte[length];
for (int i = 0; i < length; i++)
data[i] = (byte) string.charAt(i);
return Toolkit.getDefaultToolkit().createImage(data);
}
// Inline version of the "This image couldn't be loaded" image
private static final String _NOLOAD_DATA =
"\u0047\u0049\u0046\u0038\u0039\u0061\u000e\u0000\u0010\u0000\u00b3" +
"\u0000\u0000\u0000\u0000\u0000\u0080\u0000\u0000\u0000\u0080\u0000" +
"\u0080\u0080\u0000\u0000\u0000\u0080\u0080\u0000\u0080\u0000\u0080" +
"\u0080\u00c0\u00c0\u00c0\u0080\u0080\u0080\u00ff\u0000\u0000\u0000" +
"\u00ff\u0000\u00ff\u00ff\u0000\u0000\u0000\u00ff\u00ff\u0000\u00ff" +
"\u0000\u00ff\u00ff\u00ff\u00ff\u00ff\u0021\u00f9\u0004\u0001\u0000" +
"\u0000\u000f\u0000\u002c\u0000\u0000\u0000\u0000\u000e\u0000\u0010" +
"\u0000\u0000\u0004\u0049\u0010\u00c8\u0049\u00d1\u00bb\u00e0\u00ea" +
"\u008d\u00ec\u00cb\u0047\u0028\u0086\u0096\u0005\u0086\u0082\u0020" +
"\u007a\u00c8\u0029\u0028\u0002\u0010\u0052\u006e\u002a\u008b\u00df" +
"\u0079\u0048\u00e3\u0091\u003f\u00bd\u0003\u0063\u0098\u0091\u0000" +
"\u0013\u0023\u0086\u0083\u0051\u0004\u0035\u0090\u00a1\u0021\u00a1" +
"\u0009\u006c\u003c\u0067\u0093\u00df\u00c1\u007a\u001d\u0069\u0069" +
"\u005e\u0063\u0030\u009c\u00d9\u0098\u0031\u00b4\u00f4\u0024\u0002" +
"\u0000\u003b";
// Image cache for common images
static private Image _sNotLoadedImage;
}