/*
*
*
* Copyright 1990-2009 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package javax.microedition.lcdui;
import java.io.InputStream;
import java.io.IOException;
import javax.microedition.lcdui.game.Sprite;
/**
* The <code>Image</code> class is used to hold graphical image
* data. <code>Image</code>
* objects exist independently of the display device. They exist only in
* off-screen memory and will not be painted on the display unless an explicit
* command is issued by the application (such as within the
* <code>paint()</code> method of
* a <code>Canvas</code>) or when an <code>Image</code> object is
* placed within a <code>Form</code> screen or an
* <code>Alert</code> screen and that screen is made current.
*
* <p>Images are either <em>mutable</em> or <em>immutable</em> depending upon
* how they are created. Immutable images are generally created by loading
* image data from resource bundles, from files, or from the network. They may
* not be modified once created. Mutable images are created as blank images
* containing only white pixels. The application may render on a mutable image
* by calling {@link #getGraphics} on the <code>Image</code> to obtain
* a <code>Graphics</code> object
* expressly for this purpose.</p>
*
* <p><code>Images</code> may be placed within <code>Alert</code>,
* <code>Choice</code>, <code>Form</code>, or <code>ImageItem</code>
* objects.
* The high-level user interface implementation may need to update the display
* at any time, without notifying the application. In order to provide
* predictable behavior, the high-level user interface
* objects provide snapshot semantics for the image. That is, when a mutable
* image is placed within an <code>Alert</code>, <code>Choice</code>,
* <code>Form</code>, or <code>ImageItem</code> object,
* the effect is as if a snapshot is taken of its current contents. This
* snapshot is then used for all subsequent painting of the high-level user
* interface component. If the application modifies the contents of the
* image, the application must update the component containing the image (for
* example, by calling <code>ImageItem.setImage</code>) in order to
* make the modified
* contents visible.</p>
*
* <p>An immutable image may be created from a mutable image through the
* use of the {@link #createImage(Image) createImage} method. It is possible
* to create a mutable copy of an immutable image using a technique similar
* to the following: </p>
*
* <TABLE BORDER="2">
* <TR>
* <TD ROWSPAN="1" COLSPAN="1">
* <pre><code>
* Image source; // the image to be copied
* source = Image.createImage(...);
* Image copy = Image
* .createImage(source.getWidth(), source.getHeight());
* Graphics g = copy.getGraphics();
* g.drawImage(source, 0, 0, TOP|LEFT); </code></pre>
* </TD>
* </TR>
* </TABLE>
* <a name="alpha"></a>
* <h3>Alpha Processing</h3>
*
* <p>Every pixel within a mutable image is always fully opaque. Immutable
* images may contain a combination of fully opaque pixels
* <code>(alpha = 2<sup><em>bitdepth</em></sup> - 1)</code>, fully
* transparent pixels (<code>alpha = 0</code>), and
* semitransparent pixels
* (<code>0 < alpha <
* 2<sup><em>bitdepth</em></sup> - 1</code>),
* where <em>bitdepth</em> is the number of bits per sample in the source data.
*
* <p>Implementations must support storage, processing, and rendering of fully
* opaque pixels and fully transparent pixels in immutable images. When
* creating an image from source data (whether from a PNG file or from an
* array of ARGB data), a fully opaque pixel in the source data must always
* result in a fully opaque pixel in the new image, and a fully transparent
* pixel in the source data must always result in a fully transparent pixel in
* the new image.
*
* <p>The required treatment of semitransparent pixel data depends upon
* whether the implementation supports alpha blending at rendering time. If
* the implementation supports alpha blending, a semitransparent pixel in the
* source data must result in a semitransparent pixel in the new image. The
* resulting alpha value may be modified to accommodate the number of levels
* of semitransparency supported by the platform. (See the {@link
* Display#numAlphaLevels() Display.numAlphaLevels()} method.) If an
* implementation does not support alpha blending, any semitransparent pixels
* in the source data must be replaced with fully transparent pixels in the
* new image.
*
* <a name="PNG"></a>
* <h3>PNG Image Format</h3>
*
* <p>Implementations are required to support images stored in the PNG format,
* as specified by the <em>PNG (Portable Network Graphics) Specification,
* Version 1.0.</em> All conforming MIDP implementations are also conformant
* to the minimum set of requirements given by the <em>PNG Specification</em>.
* MIDP implementations also must conform to additional requirements given
* here with respect to handling of PNG images. Note that the requirements
* listed here take precedence over any conflicting recommendations given in
* the <em>PNG Specification</em>.</p>
*
* <h4>Critical Chunks</h4>
*
* <p>All of the 'critical' chunks specified by PNG must be supported. The
* paragraphs below describe these critical chunks.</p>
*
* <p>The IHDR chunk. MIDP devices must handle the following values in
* the IHDR chunk:</p>
*
* <ul>
* <li>All positive values of width and height are supported; however, a
* very large image may not be readable because of memory constraints. The
* dimensions of the resulting <code>Image</code> object must match
* the dimensions of the PNG image. That is, the values returned by
* {@link #getWidth() getWidth()} and {@link #getHeight() getHeight()}
* and the rendered width and height must
* equal the width and height specified in the IHDR chunk.</li>
*
* <li>All color types are supported, although the appearance of the image will
* be dependent on the capabilities of the device's screen. Color types that
* include alpha channel data are supported.</li>
*
* <li> For color types <code>4</code> & <code>6</code> (grayscale
* with alpha and RGB with alpha,
* respectively) the alpha channel must be decoded. Any pixels with an alpha
* value of zero must be treated as transparent. Any pixels with an alpha
* value of <code>255</code> (for images with <code>8</code> bits per
* sample) or <code>65535</code> (for images with
* <code>16</code> bits per sample) must be treated as opaque. If
* rendering with alpha
* blending is supported, any pixels with intermediate alpha values must be
* carried through to the resulting image. If alpha blending is not
* supported, any pixels with intermediate alpha values must be replaced with
* fully transparent pixels.</li>
*
* <li>All bit depth values for the given color type are supported.</li>
*
* <li>Compression method <code>0</code> (deflate) is the only
* supported compression method.
* This method utilizes the "zlib" compression scheme, which
* is also used for
* jar files; thus, the decompression (inflate) code may be shared between the
* jar decoding and PNG decoding implementations. As noted in the PNG
* specification, the compressed data stream may comprised internally of both
* compressed and uncompressed (raw) data.
* </li>
*
* <li>The filter method represents a series of encoding schemes that may be
* used to optimize compression. The PNG spec currently defines a single
* filter method (method <code>0</code>) that is an adaptive filtering
* scheme with five
* basic filter types. Filtering is essential for optimal compression since it
* allows the deflate algorithm to exploit spatial similarities within the
* image. Therefore, MIDP devices must support all five filter types defined
* by filter method <code>0</code>.</li>
*
* <li> MIDP devices are required to read PNG images that are encoded with
* either interlace method <code>0</code> (None) or interlace method
* <code>1</code> (Adam7). Image
* loading in MIDP is synchronous and cannot be overlapped with image
* rendering, and so there is no advantage for an application to use interlace
* method <code>1</code>. Support for decoding interlaced images is
* required for
* compatibility with PNG and for the convenience of developers who may already
* have interlaced images available.</li>
*
* </ul>
*
* <p>The PLTE chunk. Palette-based images must be supported.</p>
*
* <p>The IDAT chunk. Image data may be encoded using any of the
* <code>5</code> filter
* types defined by filter method <code>0</code> (None, Sub, Up,
* Average, Paeth).</p>
*
* <p>The IEND chunk. This chunk must be found in order for the image to be
* considered valid.</p>
*
* <h4>Ancillary Chunks</h4>
*
* <p>PNG defines several 'ancillary' chunks that may be present in a
* PNG image but are not critical for image decoding.</p>
*
* <p>The tRNS chunk. All implementations must support the tRNS chunk.
* This chunk is used to implement transparency without providing alpha
* channel data for each pixel. For color types <code>0</code> and
* <code>2</code>, a particular
* gray or RGB value is defined to be a transparent pixel. In this case, the
* implementation must treat pixels with this value as fully transparent.
* Pixel value comparison must be based on the actual pixel values using the
* original sample depth; that is, this comparison must be performed before
* the pixel values are resampled to reflect the display capabilities
* of the device. For color type <code>3</code> (indexed color),
* <code>8</code>-bit alpha values are
* potentially provided for each entry in the color palette. In this case,
* the implementation must treat pixels with an alpha value of
* <code>0</code> as fully
* transparent, and it must treat pixels with an alpha value of
* <code>255</code> as fully
* opaque. If rendering with alpha blending is supported, any pixels with
* intermediate alpha values must be carried through to the resulting image.
* If alpha blending is not supported, any pixels with intermediate alpha
* values must be replaced with fully transparent pixels.</p>
*
* <p>The implementation <em>may</em> (but is not required to) support
* any of the other ancillary chunks. The implementation <em>must</em>
* silently ignore any unsupported ancillary chunks that it encounters.
* The currently defined optional ancillary chunks are:</p>
*
* <PRE>
* cHRM gAMA hIST iCCP iTXt pHYs
* sBIT sPLT sRGB tEXt tIME zTXt </PRE>
*
* <h3>Reference</h3>
*
* <p><em>PNG (Portable Network Graphics) Specification, Version 1.0.</em>
* W3C Recommendation, October 1, 1996. http://www.w3.org/TR/REC-png.html.
* Also available as RFC 2083, http://www.ietf.org/rfc/rfc2083.txt.</p>
* @since MIDP 1.0
*/
public class Image {
/**
* Width of the image in pixels.
*/
private int width;
/**
* Height of the image in pixels.
*/
private int height;
/**
* <code>ImageData</code> instance associated with this <code>Image</code>.
*/
private ImageData imageData;
/**
* Valid transforms possible are 0 - 7
*/
static final int INVALID_TRANSFORM_BITS = 0xFFFFFFF8;
/**
* Transform swap axis bit is the 3 bit
*/
static final int TRANSFORM_SWAP_AXIS = 4;
/**
* Creates a new, mutable image for off-screen drawing. Every pixel
* within the newly created image is white. The width and height of the
* image must both be greater than zero.
*
* @param width the width of the new image, in pixels
* @param height the height of the new image, in pixels
* @return the created image
*
* @throws IllegalArgumentException if either <code>width</code> or
* <code>height</code> is zero or less
*/
public static Image createImage(int width, int height) {
if (width <= 0 || height <= 0) {
throw new IllegalArgumentException();
}
// SYNC NOTE: Not accessing any shared data, no locking necessary
return new Image(ImageDataFactory.getImageDataFactory().
createOffScreenImageData(width, height));
}
/**
* Creates an immutable image from a source image.
* If the source image is mutable, an immutable copy is created and
* returned. If the source image is immutable, the implementation may
* simply return it without creating a new image. If an immutable source
* image contains transparency information, this information is copied to
* the new image unchanged.
*
* <p> This method is useful for placing the contents of mutable images
* into <code>Choice</code> objects. The application can create
* an off-screen image
* using the
* {@link #createImage(int, int) createImage(w, h)}
* method, draw into it using a <code>Graphics</code> object
* obtained with the
* {@link #getGraphics() getGraphics()}
* method, and then create an immutable copy of it with this method.
* The immutable copy may then be placed into <code>Choice</code>
* objects. </p>
*
* @param source the source image to be copied
* @return the new, immutable image
*
* @throws NullPointerException if <code>source</code> is <code>null</code>
*/
public static Image createImage(Image source) {
// SYNC NOTE: Not accessing any shared data, no locking necessary
if (source.isMutable()) {
return new Image(ImageDataFactory.getImageDataFactory().
createImmutableCopy(source.imageData));
} else {
return source;
}
}
/**
* Creates an immutable image from decoded image data obtained from the
* named resource. The name parameter is a resource name as defined by
* {@link Class#getResourceAsStream(String)
* Class.getResourceAsStream(name)}. The rules for resolving resource
* names are defined in the
* <a href="../../../java/lang/package-summary.html">
* Application Resource Files</a> section of the
* <code>java.lang</code> package documentation.
*
* @param name the name of the resource containing the image data in one of
* the supported image formats
* @return the created image
* @throws NullPointerException if <code>name</code> is <code>null</code>
* @throws java.io.IOException if the resource does not exist,
* the data cannot
* be loaded, or the image data cannot be decoded
*/
public static Image createImage(java.lang.String name)
throws java.io.IOException {
return new Image(ImageDataFactory.getImageDataFactory().
createResourceImageData(name));
}
/**
* Creates an immutable image which is decoded from the data stored in
* the specified byte array at the specified offset and length. The data
* must be in a self-identifying image file format supported by the
* implementation, such as <a href="#PNG">PNG</A>.
*
* <p>The <code>imageoffset</code> and <code>imagelength</code>
* parameters specify a range of
* data within the <code>imageData</code> byte array. The
* <code>imageOffset</code> parameter
* specifies the
* offset into the array of the first data byte to be used. It must
* therefore lie within the range
* <code>[0..(imageData.length-1)]</code>. The
* <code>imageLength</code>
* parameter specifies the number of data bytes to be used. It must be a
* positive integer and it must not cause the range to extend beyond
* the end
* of the array. That is, it must be true that
* <code>imageOffset + imageLength < imageData.length</code>. </p>
*
* <p> This method is intended for use when loading an
* image from a variety of sources, such as from
* persistent storage or from the network.</p>
*
* @param imageData the array of image data in a supported image format
* @param imageOffset the offset of the start of the data in the array
* @param imageLength the length of the data in the array
*
* @return the created image
* @throws ArrayIndexOutOfBoundsException if <code>imageOffset</code>
* and <code>imageLength</code>
* specify an invalid range
* @throws NullPointerException if <code>imageData</code> is
* <code>null</code>
* @throws IllegalArgumentException if <code>imageData</code> is incorrectly
* formatted or otherwise cannot be decoded
*/
public static Image createImage(byte[] imageData, int imageOffset,
int imageLength) {
if (imageOffset < 0 || imageOffset >= imageData.length ||
imageLength < 0 ||
imageOffset + imageLength > imageData.length) {
throw new ArrayIndexOutOfBoundsException();
}
return new Image(ImageDataFactory.getImageDataFactory().
createImmutableImageData(imageData,
imageOffset,
imageLength));
}
/**
* Creates an immutable image using pixel data from the specified
* region of a source image, transformed as specified.
*
* <p>The source image may be mutable or immutable. For immutable source
* images, transparency information, if any, is copied to the new
* image unchanged.</p>
*
* <p>On some devices, pre-transformed images may render more quickly
* than images that are transformed on the fly using
* <code>drawRegion</code>.
* However, creating such images does consume additional heap space,
* so this technique should be applied only to images whose rendering
* speed is critical.</p>
*
* <p>The transform function used must be one of the following, as defined
* in the {@link javax.microedition.lcdui.game.Sprite Sprite} class:<br>
*
* <code>Sprite.TRANS_NONE</code> - causes the specified image
* region to be copied unchanged<br>
* <code>Sprite.TRANS_ROT90</code> - causes the specified image
* region to be rotated clockwise by 90 degrees.<br>
* <code>Sprite.TRANS_ROT180</code> - causes the specified image
* region to be rotated clockwise by 180 degrees.<br>
* <code>Sprite.TRANS_ROT270</code> - causes the specified image
* region to be rotated clockwise by 270 degrees.<br>
* <code>Sprite.TRANS_MIRROR</code> - causes the specified image
* region to be reflected about its vertical center.<br>
* <code>Sprite.TRANS_MIRROR_ROT90</code> - causes the specified image
* region to be reflected about its vertical center and then rotated
* clockwise by 90 degrees.<br>
* <code>Sprite.TRANS_MIRROR_ROT180</code> - causes the specified image
* region to be reflected about its vertical center and then rotated
* clockwise by 180 degrees.<br>
* <code>Sprite.TRANS_MIRROR_ROT270</code> - causes the specified image
* region to be reflected about its vertical center and then rotated
* clockwise by 270 degrees.<br></p>
*
* <p>
* The size of the returned image will be the size of the specified region
* with the transform applied. For example, if the region is
* <code>100 x 50</code> pixels and the transform is
* <code>TRANS_ROT90</code>, the
* returned image will be <code>50 x 100</code> pixels.</p>
*
* <p><strong>Note:</strong> If all of the following conditions
* are met, this method may
* simply return the source <code>Image</code> without creating a
* new one:</p>
* <ul>
* <li>the source image is immutable;</li>
* <li>the region represents the entire source image; and</li>
* <li>the transform is <code>TRANS_NONE</code>.</li>
* </ul>
*
* @param image the source image to be copied from
* @param x the horizontal location of the region to be copied
* @param y the vertical location of the region to be copied
* @param width the width of the region to be copied
* @param height the height of the region to be copied
* @param transform the transform to be applied to the region
* @return the new, immutable image
*
* @throws NullPointerException if <code>image</code> is <code>null</code>
* @throws IllegalArgumentException if the region to be copied exceeds
* the bounds of the source image
* @throws IllegalArgumentException if either <code>width</code> or
* <code>height</code> is zero or less
* @throws IllegalArgumentException if the <code>transform</code>
* is not valid
*
*/
public static Image createImage(Image image,
int x, int y, int width, int height,
int transform) {
if ((transform & INVALID_TRANSFORM_BITS) != 0) {
throw new IllegalArgumentException();
}
if (x < 0 || y < 0 ||
(x + width) > image.getWidth() || // throws NPE if image is null
(y + height) > image.getHeight() ||
width <= 0 || height <= 0) {
throw new IllegalArgumentException();
}
if (x == 0 && y == 0
&& width == image.getWidth() && height == image.getHeight()
&& transform == Sprite.TRANS_NONE) {
return createImage(image);
} else {
return
new Image(ImageDataFactory.getImageDataFactory().
createImmutableImageData(image.imageData,
x, y,
width, height,
transform));
}
}
/**
* Creates an immutable image from decoded image data obtained froH an
* <code>InputStream</code>. This method blocks until all image data has
* been read and decoded. After this method completes (whether by
* returning or by throwing an exception) the stream is left open and its
* current position is undefined.
*
* @param stream the name of the resource containing the image data
* in one of the supported image formats
*
* @return the created image
* @throws NullPointerException if <code>stream</code> is <code>null</code>
* @throws java.io.IOException if an I/O error occurs, if the image data
* cannot be loaded, or if the image data cannot be decoded
*
*/
public static Image createImage(InputStream stream)
throws java.io.IOException {
if (stream == null) {
throw new java.lang.NullPointerException();
}
try {
return new Image(ImageDataFactory.getImageDataFactory().
createImmutableImageData(stream));
} catch (IllegalArgumentException e) {
throw new java.io.IOException();
}
}
/**
* Creates an immutable image from a sequence of ARGB values, specified
* as <code>0xAARRGGBB</code>.
* The ARGB data within the <code>rgb</code> array is arranged
* horizontally from left to right within each row,
* row by row from top to bottom.
* If <code>processAlpha</code> is <code>true</code>,
* the high-order byte specifies opacity; that is,
* <code>0x00RRGGBB</code> specifies
* a fully transparent pixel and <code>0xFFRRGGBB</code> specifies
* a fully opaque
* pixel. Intermediate alpha values specify semitransparency. If the
* implementation does not support alpha blending for image rendering
* operations, it must replace any semitransparent pixels with fully
* transparent pixels. (See <a href="#alpha">Alpha Processing</a>
* for further discussion.) If <code>processAlpha</code> is
* <code>false</code>, the alpha values
* are ignored and all pixels must be treated as fully opaque.
*
* <p>Consider <code>P(a,b)</code> to be the value of the pixel
* located at column <code>a</code> and row <code>b</code> of the
* Image, where rows and columns are numbered downward from the
* top starting at zero, and columns are numbered rightward from
* the left starting at zero. This operation can then be defined
* as:</p>
*
* <TABLE BORDER="2">
* <TR>
* <TD ROWSPAN="1" COLSPAN="1">
* <pre><code>
* P(a, b) = rgb[a + b * width]; </code></pre>
* </TD>
* </TR>
* </TABLE>
* <p>for</p>
*
* <TABLE BORDER="2">
* <TR>
* <TD ROWSPAN="1" COLSPAN="1">
* <pre><code>
* 0 <= a < width
* 0 <= b < height </code></pre>
* </TD>
* </TR>
* </TABLE>
* <p> </p>
*
* @param rgb an array of ARGB values that composes the image
* @param width the width of the image
* @param height the height of the image
* @param processAlpha <code>true</code> if <code>rgb</code>
* has an alpha channel,
* <code>false</code> if all pixels are fully opaque
* @return the created image
* @throws NullPointerException if <code>rgb</code> is <code>null</code>.
* @throws IllegalArgumentException if either <code>width</code> or
* <code>height</code> is zero or less
* @throws ArrayIndexOutOfBoundsException if the length of
* <code>rgb</code> is
* less than<code> width * height</code>.
*
*/
public static Image createRGBImage(int rgb[], int width,
int height, boolean processAlpha) {
if (width <= 0 || height <= 0) {
throw new IllegalArgumentException();
}
if ((width * height) > rgb.length) {
throw new ArrayIndexOutOfBoundsException();
}
return new Image(ImageDataFactory.getImageDataFactory().
createImmutableImageData(rgb,
width, height,
processAlpha));
}
/**
* Creates a new <code>Graphics</code> object that renders to this
* image. This image
* must be
* mutable; it is illegal to call this method on an immutable image.
* The mutability of an image may be tested
* with the <code>isMutable()</code> method.
*
* <P>The newly created <code>Graphics</code> object has the
* following properties:
* </P>
* <UL>
* <LI>the destination is this <code>Image</code> object;</LI>
* <LI>the clip region encompasses the entire <code>Image</code>;</LI>
* <LI>the current color is black;</LI>
* <LI>the font is the same as the font returned by
* {@link Font#getDefaultFont() Font.getDefaultFont()};</LI>
* <LI>the stroke style is {@link Graphics#SOLID SOLID}; and
* </LI>
* <LI>the origin of the coordinate system is located at the upper-left
* corner of the Image.</LI>
* </UL>
*
* <P>The lifetime of <code>Graphics</code> objects created using
* this method is
* indefinite. They may be used at any time, by any thread.</P>
*
* @return a <code>Graphics</code> object with this image as its destination
* @throws IllegalStateException if the image is immutable
*/
public Graphics getGraphics() {
if (isMutable()) {
// SYNC NOTE: no locking necessary as getGraphics() only allocates
// a new object
return Graphics.getImageGraphics(this);
} else {
// SYNC NOTE: Not accessing any shared data, no locking necessary
throw new IllegalStateException();
}
}
/**
* Gets the width of the image in pixels. The value returned
* must reflect the actual width of the image when rendered.
* @return width of the image
*/
public int getWidth() {
return width;
}
/**
* Gets the height of the image in pixels. The value returned
* must reflect the actual height of the image when rendered.
* @return height of the image
*/
public int getHeight() {
return height;
}
/**
* Check if this image is mutable. Mutable images can be modified by
* rendering to them through a <code>Graphics</code> object
* obtained from the
* <code>getGraphics()</code> method of this object.
* @return <code>true</code> if the image is mutable,
* <code>false</code> otherwise
*/
public boolean isMutable() {
return imageData.isMutable();
}
/**
* Obtains ARGB pixel data from the specified region of this image and
* stores it in the provided array of integers. Each pixel value is
* stored in <code>0xAARRGGBB</code> format, where the high-order
* byte contains the
* alpha channel and the remaining bytes contain color components for
* red, green and blue, respectively. The alpha channel specifies the
* opacity of the pixel, where a value of <code>0x00</code>
* represents a pixel that
* is fully transparent and a value of <code>0xFF</code>
* represents a fully opaque
* pixel.
*
* <p> The returned values are not guaranteed to be identical to values
* from the original source, such as from
* <code>createRGBImage</code> or from a PNG
* image. Color values may be resampled to reflect the display
* capabilities of the device (for example, red, green or blue pixels may
* all be represented by the same gray value on a grayscale device). On
* devices that do not support alpha blending, the alpha value will be
* <code>0xFF</code> for opaque pixels and <code>0x00</code> for
* all other pixels (see <a
* href="#alpha">Alpha Processing</a> for further discussion.) On devices
* that support alpha blending, alpha channel values may be resampled to
* reflect the number of levels of semitransparency supported.</p>
*
* <p>The <code>scanlength</code> specifies the relative offset within the
* array between the corresponding pixels of consecutive rows. In order
* to prevent rows of stored pixels from overlapping, the absolute value
* of <code>scanlength</code> must be greater than or equal to
* <code>width</code>. Negative values of <code>scanlength</code> are
* allowed. In all cases, this must result in every reference being
* within the bounds of the <code>rgbData</code> array.</p>
*
* <p>Consider <code>P(a,b)</code> to be the value of the pixel
* located at column <code>a</code> and row <code>b</code> of the
* Image, where rows and columns are numbered downward from the
* top starting at zero, and columns are numbered rightward from
* the left starting at zero. This operation can then be defined
* as:</p>
*
* <TABLE BORDER="2">
* <TR>
* <TD ROWSPAN="1" COLSPAN="1">
* <pre><code>
* rgbData[offset + (a - x) + (b - y) * scanlength] = P(a, b);
* </code></pre>
* </TD>
* </TR>
* </TABLE>
* <p>for</p>
*
* <TABLE BORDER="2">
* <TR>
* <TD ROWSPAN="1" COLSPAN="1">
* <pre><code>
* x <= a < x + width
* y <= b < y + height </code></pre>
* </TD>
* </TR>
* </TABLE>
*
* <p>The source rectangle is required to not exceed the bounds of
* the image. This means: </p>
* <TABLE BORDER="2">
* <TR>
* <TD ROWSPAN="1" COLSPAN="1">
* <pre><code>
* x >= 0
* y >= 0
* x + width <= image width
* y + height <= image height </code></pre>
* </TD>
* </TR>
* </TABLE>
* <p>
* If any of these conditions is not met an
* <code>IllegalArgumentException</code> is thrown. Otherwise, in
* cases where <code>width <= 0</code> or <code>height <= 0</code>,
* no exception is thrown, and no pixel data is copied to
* <code>rgbData</code>.</p>
*
* @param rgbData an array of integers in which the ARGB pixel data is
* stored
* @param offset the index into the array where the first ARGB value
* is stored
* @param scanlength the relative offset in the array between
* corresponding pixels in consecutive rows of the region
* @param x the x-coordinate of the upper left corner of the region
* @param y the y-coordinate of the upper left corner of the region
* @param width the width of the region
* @param height the height of the region
*
* @throws ArrayIndexOutOfBoundsException if the requested operation would
* attempt to access an element in the <code>rgbData</code> array
* whose index is either
* negative or beyond its length (the contents of the array are unchanged)
*
* @throws IllegalArgumentException if the area being retrieved
* exceeds the bounds of the source image
*
* @throws IllegalArgumentException if the absolute value of
* <code>scanlength</code> is less than <code>width</code>
*
* @throws NullPointerException if <code>rgbData</code> is <code>null</code>
*
* @since MIDP 2.0
*/
public void getRGB(int[] rgbData, int offset, int scanlength,
int x, int y, int width, int height) {
int img_width = imageData.getWidth();
int img_height = imageData.getHeight();
// see if absolute value of scanlength is greater than or
// equal to width
if (scanlength >= 0 && scanlength < width) {
throw new IllegalArgumentException();
} else if (scanlength < 0 && (0 - scanlength) < width) {
throw new IllegalArgumentException();
} else if((y < 0) || (x < 0) || (x + width > img_width) ||
(y + height > img_height)) {
throw new IllegalArgumentException();
} else if (height < 0 || width < 0 ) {
/* spec says noop in this case */
} else {
// will throw a NullPointerException
int buflen = rgbData.length;
if (offset < 0
|| offset + ((height - 1) * scanlength) + width > buflen
|| offset + ((height - 1) * scanlength) < 0) {
throw new ArrayIndexOutOfBoundsException();
}
imageData.getRGB(rgbData, offset, scanlength,
x, y, width, height);
}
}
/**
* Returns <code>ImageData</code> associated with this
* <code>Image</code>.
*
* @return The <code>ImageData </code> associated with this
* <code>Image</code>.
*/
ImageData getImageData() {
return imageData;
}
/**
* Function to load an romized Image.
*
* @param imageDataArrayPtr native pointer to image data as Java int
* @param imageDataArrayLength length of image data array
* @return image created. Null if no romized image matches the id.
*/
static Image getRomizedImage(int imageDataArrayPtr,
int imageDataArrayLength) {
try {
AbstractImageDataFactory f =
ImageDataFactory.getImageDataFactory();
ImageData data = f.createImmutableImageData(imageDataArrayPtr,
imageDataArrayLength);
return new Image(data);
} catch (IllegalArgumentException iae) {
return null;
}
}
/**
* Creates an Immutable image from the given ImageData.
* @param imageData <code>ImageData</code> instance to be used to
* create new Image
*/
private Image(ImageData imageData) {
this.imageData = imageData;
this.width = imageData.getWidth();
this.height = imageData.getHeight();
}
/**
* Resize Image optionally saving its content clipped according
* to the new geometry
*
* @param width new width of the Image
* @param height new height of the Image
* @param keepContent keep current content of the image
* binded to the (0, 0) of the resized image and clipped
* according to the new image dimensions
*/
void resize(int width, int height, boolean keepContent) {
if (!imageData.isMutable() || width <= 0 || height <= 0) {
throw new IllegalArgumentException();
}
// IMPL_NOTE: In the case content is not kept it is possible
// to resize the image more efficiently, especially for the
// case of rotation, when the memory reallocation is not needed.
// However, now there are no scenarios when resize is needed
// without content saving.
Image newImage = createImage(width, height);
synchronized(this) {
if (keepContent) {
Graphics.getImageGraphics(newImage).render(this, 0, 0,
Graphics.TOP | Graphics.LEFT);
}
this.width = width;
this.height = height;
imageData = newImage.getImageData();
}
}
}