| /* IIOParam.java -- |
| Copyright (C) 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package javax.imageio; |
| |
| import java.awt.Point; |
| import java.awt.Rectangle; |
| |
| /** |
| * An IIOParam stores parameters used when encoding or decoding image |
| * streams. ImageReadParam and ImageWriteParam extend this abstract |
| * base class. |
| * |
| * IIOParams allow control over how source pixels converted into |
| * destination pixels. This conversion can take place between a |
| * stream and in-memory image data, when an image reader is doing the |
| * conversion, or a writer can be doing the conversion from an |
| * in-memory source to a stream destination. |
| * |
| * An image reader can be restricted to only read from a given region; |
| * likewise a writer can be restricted to only write output to a given |
| * region. |
| * |
| * For image readers and writers, IIOParam supports image pixelation |
| * -- where the input image is approximated by the output image using |
| * larger-sized pixel blocks. For example: FIXME |
| * |
| * IIOParams can control how pixels are combined into larger blocks |
| * using sub-sampling matrices. For example: FIXME |
| * |
| * They can also control which source bands are read and written; this |
| * example reads the RGBA (red, green, blue, transparency) data from a |
| * PNG image and outputs just the red and transparency bands: FIXME |
| * |
| * @author Thomas Fitzsimmons (fitzsim@redhat.com) |
| * @author Michael Koch (konqueror@gmx.de) |
| */ |
| public abstract class IIOParam |
| { |
| /** |
| * The controller called by this IIOParam to retrieve parameters. |
| */ |
| protected IIOParamController controller = null; |
| |
| /** |
| * The default controller called by this IIOParam to retrieve |
| * parameters. |
| */ |
| protected IIOParamController defaultController = null; |
| |
| /** |
| * The offset in the destination where the upper-left |
| * decoded/encoded pixel should be located. |
| */ |
| protected Point destinationOffset = new Point(0, 0); |
| |
| /** |
| * Sets the output colour type when writing or the destination image |
| * type when reading. |
| */ |
| protected ImageTypeSpecifier destinationType = null; |
| |
| /** |
| * An array indicating which source bands will be used or null. |
| */ |
| protected int[] sourceBands = null; |
| |
| /** |
| * The source pixel region or null. |
| */ |
| protected Rectangle sourceRegion = null; |
| |
| /** |
| * Sample every sourceXSubsampling'th pixel in the source image when |
| * pixelating the destination image in the horizontal direction. |
| */ |
| protected int sourceXSubsampling = 1; |
| |
| /** |
| * Sample every sourceYSubsampling'th pixel in the source image when |
| * pixelating the destination image in the vertical direction. |
| */ |
| protected int sourceYSubsampling = 1; |
| |
| /** |
| * Start sampling at this horizontal offset within the source region |
| * when pixelating the destination image in the horizontal |
| * direction. |
| */ |
| protected int subsamplingXOffset = 0; |
| |
| /** |
| * Start sampling at this vertical offset within the source region |
| * when pixelating the destination image in the vertical direction. |
| */ |
| protected int subsamplingYOffset = 0; |
| |
| /** |
| * Indicates whether or not the controller has been explicitly set |
| * to null. |
| */ |
| private boolean no_controller = false; |
| |
| /** |
| * Constructs an IIOParam object. |
| */ |
| protected IIOParam() |
| { |
| } |
| |
| /** |
| * Activates the parameter controller by calling its activate method |
| * and passing it this IIOParam. A true return value indicates that |
| * this IIOParam's values are ready for the next read or write |
| * operation. A return value of false means that this IIOParam's |
| * values have not been affected because the controller operations |
| * were cancelled. |
| * |
| * @return true if parameters were successfully set, false if |
| * parameters were not changed |
| */ |
| public boolean activateController() |
| { |
| if (controller == null) |
| { |
| if (defaultController == null || no_controller) |
| return false; |
| else |
| return defaultController.activate (this); |
| } |
| else |
| return controller.activate(this); |
| } |
| |
| /** |
| * Retrieve the currently set controller if one has been set, or the |
| * default controller, or null if the controller has been explicitly |
| * set to null. |
| * |
| * @return the currently used controller or null |
| */ |
| public IIOParamController getController() |
| { |
| return controller == null ? |
| (no_controller ? null : defaultController) : controller; |
| } |
| |
| /** |
| * Retrieve the default controller regardless of whether or not a |
| * non-default controller has been set. The default controller may |
| * be null. |
| * |
| * @return the default controller or null |
| */ |
| public IIOParamController getDefaultController() |
| { |
| return defaultController; |
| } |
| |
| /** |
| * Retrieve the offset in the destination where the upper-left |
| * decoded/encoded pixel should be located. (0, 0) by default. |
| * |
| * @return the destination offset |
| */ |
| public Point getDestinationOffset() |
| { |
| return destinationOffset; |
| } |
| |
| /** |
| * Retrieve the currently set image-type specifier or null if none |
| * has been set. |
| * |
| * @return the current image-type specifier or null |
| */ |
| public ImageTypeSpecifier getDestinationType() |
| { |
| return destinationType; |
| } |
| |
| /** |
| * Retrieve the current source band values or null if source band |
| * values have not been set. |
| * |
| * The returned array is a copy of this IIOParam's source band |
| * array. |
| * |
| * @return the current set of source band values or null |
| */ |
| public int[] getSourceBands() |
| { |
| if (sourceBands == null) |
| return null; |
| |
| int[] sourceBandsCopy = new int[sourceBands.length]; |
| System.arraycopy (sourceBands, 0, sourceBandsCopy, 0, sourceBands.length); |
| return sourceBandsCopy; |
| } |
| |
| /** |
| * Retrieve the source rectangle from which pixels should be read or |
| * null if no source region has been set. |
| * |
| * @return the current source region or null |
| */ |
| public Rectangle getSourceRegion() |
| { |
| return sourceRegion; |
| } |
| |
| /** |
| * Retrieve the number of pixel columns to advance before taking a |
| * pixel sample. |
| * |
| * @return the horizontal sub-sampling interval |
| */ |
| public int getSourceXSubsampling() |
| { |
| return sourceXSubsampling; |
| } |
| |
| /** |
| * Retrieve the number of pixel rows to advance before taking a |
| * pixel sample. |
| * |
| * @return the vertical sub-sampling interval |
| */ |
| public int getSourceYSubsampling() |
| { |
| return sourceYSubsampling; |
| } |
| |
| /** |
| * Retrieve the number of pixel columns to advance before taking any |
| * pixel samples. |
| * |
| * @return the horizontal sub-sampling offset |
| */ |
| public int getSubsamplingXOffset() |
| { |
| return subsamplingXOffset; |
| } |
| |
| /** |
| * Retrieve the number of pixel rows to advance before taking any |
| * pixel samples. |
| * |
| * @return the vertical sub-sampling offset |
| */ |
| public int getSubsamplingYOffset() |
| { |
| return subsamplingYOffset; |
| } |
| |
| /** |
| * Check if a non-null controller is currently available. |
| * |
| * @return true if getController returns a non-null value, false if |
| * getController returns null |
| */ |
| public boolean hasController() |
| { |
| return getController() != null; |
| } |
| |
| /** |
| * Sets the controller for this IIOParam. This is the controller |
| * that will be activated when activateController is called. The |
| * argument controller overrides this IIOParam's default controller. |
| * If the argument is null then no controller will be set, not even |
| * the default one. To reset the default controller call |
| * setController(getDefaultController()). |
| * |
| * @param controller the controller to set or null |
| */ |
| public void setController(IIOParamController controller) |
| { |
| if (controller == defaultController) |
| { |
| this.controller = null; |
| no_controller = false; |
| } |
| else |
| { |
| no_controller = (controller == null); |
| this.controller = controller; |
| } |
| } |
| |
| /** |
| * Set the destination image type. |
| * |
| * If this value is set on an image reader then its read method will |
| * return a new BufferedImage of the specified destination type. In |
| * this case any destination image set using setDestination() is |
| * ignored. |
| * |
| * If this is set on an image writer then the destination type |
| * affects only the colour model of the destination image. The |
| * destination type's SampleModel is ignored. The destination |
| * type's ColorModel will override the source image's colour model. |
| * |
| * @param destinationType the sample and colour models of the |
| * destination image |
| */ |
| public void setDestinationType (ImageTypeSpecifier destinationType) |
| { |
| this.destinationType = destinationType; |
| } |
| |
| /** |
| * Specify the destination pixel offset. Image writers are only |
| * affected by this setting when ImageWriter.replacePixels is called |
| * in which case the offset is into the region of pixels being |
| * changed. |
| * |
| * @param destinationOffset the offset where pixel writing should |
| * begin |
| */ |
| public void setDestinationOffset(Point destinationOffset) |
| { |
| if (destinationOffset == null) |
| throw new IllegalArgumentException("destinationOffset is null"); |
| |
| this.destinationOffset = destinationOffset; |
| } |
| |
| /** |
| * Set the indices of the source bands to be used. Duplicate |
| * indices are not allowed. A value of null means use all source |
| * bands. The argument array is copied and stored, so subsequent |
| * updates to it will not be reflected in this IIOParam. |
| * |
| * @param sourceBands the array of source bands to use |
| */ |
| public void setSourceBands(int[] sourceBands) |
| { |
| int[] sourceBandsCopy = new int[sourceBands.length]; |
| System.arraycopy (sourceBands, 0, sourceBandsCopy, 0, sourceBands.length); |
| this.sourceBands = sourceBandsCopy; |
| } |
| |
| /** |
| * Set the source region from which to read. The number of pixels |
| * sampled from the source region depends on the source sub-sampling |
| * settings. If the combination of this sourceRegion and the |
| * current sub-sampling settings would result in no pixels being |
| * sampled then an IllegalStateException will be thrown. |
| * |
| * The source region is specified in the source image coordinate |
| * system which has point (0, 0) at the top-left and increases down |
| * and to the right. The argument source region is clipped to the |
| * image boundaries at read-time. |
| * |
| * A null argument sets the source region to null meaning that the |
| * whole image should be read. |
| * |
| * @param sourceRegion the rectangular source region |
| * |
| * @exception IllegalArgumentException if sourceRegion has width or |
| * height <= 0 or x or y < 0 |
| * @exception IllegalStateException if the given sourceRegion and |
| * the current sampling settings would produce zero samples |
| */ |
| public void setSourceRegion(Rectangle sourceRegion) |
| { |
| if (sourceRegion != null |
| && (sourceRegion.x < 0 |
| || sourceRegion.y < 0 |
| || sourceRegion.width <= 0 |
| || sourceRegion.height <= 0)) |
| throw new IllegalArgumentException("illegal source region"); |
| |
| if (sourceRegion != null) |
| { |
| int num_rows = |
| (sourceRegion.height - subsamplingYOffset + sourceYSubsampling - 1) |
| / sourceYSubsampling; |
| |
| int num_columns = |
| (sourceRegion.width - subsamplingXOffset + sourceXSubsampling - 1) |
| / sourceXSubsampling; |
| |
| if (num_rows <= 0 || num_columns <= 0) |
| throw new IllegalStateException("zero pixels in source region"); |
| } |
| |
| this.sourceRegion = sourceRegion; |
| } |
| |
| /** |
| * Set the source sampling intervals and offsets. Every |
| * sourceXSubsampling'th pixel horizontally and |
| * sourceYSubsampling'th pixel vertically will be sampled. Sampling |
| * will being a the subsamplingXOffset'th column and the |
| * subsamplingYOffset'th row. |
| * |
| * Horizontally, the number of sampled pixels will be: |
| * |
| * floor((width - subsamplingXOffset + sourceXSubsampling - 1) / sourceXSubsampling) |
| * |
| * Vertically: |
| * |
| * floor((height - subsamplingYOffset + sourceYSubsampling - 1) / sourceYSubsampling) |
| * |
| * If the current source region setting is such that the given |
| * sub-sampling arguments would produce zero pixel samples, an |
| * IllegalStateException is thrown. |
| * |
| * The offset parameters can be used to make source regions overlap |
| * when tiling across an image. This can eliminate seams and |
| * better-tile images whose width or height is not a multiple of the |
| * sampling interval. |
| * |
| * @param sourceXSubsampling the horizontal sampling interval |
| * @param sourceYSubsampling the vertical sampling interval |
| * @param subsamplingXOffset the horizontal offset of the initial |
| * sample |
| * @param subsamplingYOffset the vertical offset of the initial |
| * sample |
| * |
| * @exception IllegalArgumentException if either subsamplingXOffset |
| * or subsamplingYOffset is < 0 |
| * @exception IllegalStateException if the current source region |
| * combined with the given sub-sampling parameters would produce |
| * zero pixel samples |
| */ |
| public void setSourceSubsampling(int sourceXSubsampling, int sourceYSubsampling, |
| int subsamplingXOffset, int subsamplingYOffset) |
| { |
| if (subsamplingXOffset < 0 || subsamplingYOffset < 0) |
| throw new IllegalArgumentException("subsampling offset < 0"); |
| |
| if (sourceRegion != null) |
| { |
| int num_rows = |
| (sourceRegion.height - subsamplingYOffset + sourceYSubsampling - 1) |
| / sourceYSubsampling; |
| |
| int num_columns = |
| (sourceRegion.width - subsamplingXOffset + sourceXSubsampling - 1) |
| / sourceXSubsampling; |
| |
| if (num_rows <= 0 || num_columns <= 0) |
| throw new IllegalStateException("subsampling parameters would" |
| + " produce zero pixel samples" |
| + " in source region"); |
| } |
| |
| this.sourceXSubsampling = sourceXSubsampling; |
| this.sourceYSubsampling = sourceYSubsampling; |
| this.subsamplingXOffset = subsamplingXOffset; |
| this.subsamplingYOffset = subsamplingYOffset; |
| } |
| } |