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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.awt;

import java.util.Map;
import java.util.Set;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import sun.awt.SunHints;
import java.lang.ref.WeakReference;

/**
 * The {@code RenderingHints} class defines and manages collections of
 * keys and associated values which allow an application to provide input
 * into the choice of algorithms used by other classes which perform
 * rendering and image manipulation services.
 * The {@link java.awt.Graphics2D} class, and classes that implement
 * {@link java.awt.image.BufferedImageOp} and
 * {@link java.awt.image.RasterOp} all provide methods to get and
 * possibly to set individual or groups of {@code RenderingHints}
 * keys and their associated values.
 * When those implementations perform any rendering or image manipulation
 * operations they should examine the values of any {@code RenderingHints}
 * that were requested by the caller and tailor the algorithms used
 * accordingly and to the best of their ability.
 * <p>
 * Note that since these keys and values are <i>hints</i>, there is
 * no requirement that a given implementation supports all possible
 * choices indicated below or that it can respond to requests to
 * modify its choice of algorithm.
 * The values of the various hint keys may also interact such that
 * while all variants of a given key are supported in one situation,
 * the implementation may be more restricted when the values associated
 * with other keys are modified.
 * For example, some implementations may be able to provide several
 * types of dithering when the antialiasing hint is turned off, but
 * have little control over dithering when antialiasing is on.
 * The full set of supported keys and hints may also vary by destination
 * since runtimes may use different underlying modules to render to
 * the screen, or to {@link java.awt.image.BufferedImage} objects,
 * or while printing.
 * <p>
 * Implementations are free to ignore the hints completely, but should
 * try to use an implementation algorithm that is as close as possible
 * to the request.
 * If an implementation supports a given algorithm when any value is used
 * for an associated hint key, then minimally it must do so when the
 * value for that key is the exact value that specifies the algorithm.
 * <p>
 * The keys used to control the hints are all special values that
 * subclass the associated {@link RenderingHints.Key} class.
 * Many common hints are expressed below as static constants in this
 * class, but the list is not meant to be exhaustive.
 * Other hints may be created by other packages by defining new objects
 * which subclass the {@code Key} class and defining the associated values.
 */
public class RenderingHints
 implements Map<Object,Object>, Cloneable
{
 /**
 * Defines the base type of all keys used along with the
 * {@link RenderingHints} class to control various
 * algorithm choices in the rendering and imaging pipelines.
 * Instances of this class are immutable and unique which
 * means that tests for matches can be made using the
 * {@code ==} operator instead of the more expensive
 * {@code equals()} method.
 */
 public abstract static class Key {
 private static HashMap<Object,Object> identitymap = new HashMap<>(17);

 private String getIdentity() {
 // Note that the identity string is dependent on 3 variables:
 // - the name of the subclass of Key
 // - the identityHashCode of the subclass of Key
 // - the integer key of the Key
 // It is theoretically possible for 2 distinct keys to collide
 // along all 3 of those attributes in the context of multiple
 // class loaders, but that occurrence will be extremely rare and
 // we account for that possibility below in the recordIdentity
 // method by slightly relaxing our uniqueness guarantees if we
 // end up in that situation.
 return getClass().getName()+"@"+
 Integer.toHexString(System.identityHashCode(getClass()))+":"+
 Integer.toHexString(privatekey);
 }

 private synchronized static void recordIdentity(Key k) {
 Object identity = k.getIdentity();
 Object otherref = identitymap.get(identity);
 if (otherref != null) {
 Key otherkey = (Key) ((WeakReference) otherref).get();
 if (otherkey != null && otherkey.getClass() == k.getClass()) {
 throw new IllegalArgumentException(identity+
 " already registered");
 }
 // Note that this system can fail in a mostly harmless
 // way. If we end up generating the same identity
 // String for 2 different classes (a very rare case)
 // then we correctly avoid throwing the exception above,
 // but we are about to drop through to a statement that
 // will replace the entry for the old Key subclass with
 // an entry for the new Key subclass. At that time the
 // old subclass will be vulnerable to someone generating
 // a duplicate Key instance for it. We could bail out
 // of the method here and let the old identity keep its
 // record in the map, but we are more likely to see a
 // duplicate key go by for the new class than the old
 // one since the new one is probably still in the
 // initialization stage. In either case, the probability
 // of loading 2 classes in the same VM with the same name
 // and identityHashCode should be nearly impossible.
 }
 // Note: Use a weak reference to avoid holding on to extra
 // objects and classes after they should be unloaded.
 identitymap.put(identity, new WeakReference<Key>(k));
 }

 private int privatekey;

 /**
 * Construct a key using the indicated private key. Each
 * subclass of Key maintains its own unique domain of integer
 * keys. No two objects with the same integer key and of the
 * same specific subclass can be constructed. An exception
 * will be thrown if an attempt is made to construct another
 * object of a given class with the same integer key as a
 * pre-existing instance of that subclass of Key.
 * @param privatekey the specified key
 */
 protected Key(int privatekey) {
 this.privatekey = privatekey;
 recordIdentity(this);
 }

 /**
 * Returns true if the specified object is a valid value
 * for this Key.
 * @param val the <code>Object</code> to test for validity
 * @return <code>true</code> if <code>val</code> is valid;
 * <code>false</code> otherwise.
 */
 public abstract boolean isCompatibleValue(Object val);

 /**
 * Returns the private integer key that the subclass
 * instantiated this Key with.
 * @return the private integer key that the subclass
 * instantiated this Key with.
 */
 protected final int intKey() {
 return privatekey;
 }

 /**
 * The hash code for all Key objects will be the same as the
 * system identity code of the object as defined by the
 * System.identityHashCode() method.
 */
 public final int hashCode() {
 return super.hashCode();
 }

 /**
 * The equals method for all Key objects will return the same
 * result as the equality operator '=='.
 */
 public final boolean equals(Object o) {
 return this == o;
 }
 }

 HashMap<Object,Object> hintmap = new HashMap<>(7);

 /**
 * Antialiasing hint key.
 * The {@code ANTIALIASING} hint controls whether or not the
 * geometry rendering methods of a {@link Graphics2D} object
 * will attempt to reduce aliasing artifacts along the edges
 * of shapes.
 * <p>
 * A typical antialiasing algorithm works by blending the existing
 * colors of the pixels along the boundary of a shape with the
 * requested fill paint according to the estimated partial pixel
 * coverage of the shape.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_ANTIALIAS_ON}
 * <li>{@link #VALUE_ANTIALIAS_OFF}
 * <li>{@link #VALUE_ANTIALIAS_DEFAULT}
 * </ul>
 */
 public static final Key KEY_ANTIALIASING =
 SunHints.KEY_ANTIALIASING;

 /**
 * Antialiasing hint value -- rendering is done with antialiasing.
 * @see #KEY_ANTIALIASING
 */
 public static final Object VALUE_ANTIALIAS_ON =
 SunHints.VALUE_ANTIALIAS_ON;

 /**
 * Antialiasing hint value -- rendering is done without antialiasing.
 * @see #KEY_ANTIALIASING
 */
 public static final Object VALUE_ANTIALIAS_OFF =
 SunHints.VALUE_ANTIALIAS_OFF;

 /**
 * Antialiasing hint value -- rendering is done with a default
 * antialiasing mode chosen by the implementation.
 * @see #KEY_ANTIALIASING
 */
 public static final Object VALUE_ANTIALIAS_DEFAULT =
 SunHints.VALUE_ANTIALIAS_DEFAULT;

 /**
 * Rendering hint key.
 * The {@code RENDERING} hint is a general hint that provides
 * a high level recommendation as to whether to bias algorithm
 * choices more for speed or quality when evaluating tradeoffs.
 * This hint could be consulted for any rendering or image
 * manipulation operation, but decisions will usually honor
 * other, more specific hints in preference to this hint.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_RENDER_SPEED}
 * <li>{@link #VALUE_RENDER_QUALITY}
 * <li>{@link #VALUE_RENDER_DEFAULT}
 * </ul>
 */
 public static final Key KEY_RENDERING =
 SunHints.KEY_RENDERING;

 /**
 * Rendering hint value -- rendering algorithms are chosen
 * with a preference for output speed.
 * @see #KEY_RENDERING
 */
 public static final Object VALUE_RENDER_SPEED =
 SunHints.VALUE_RENDER_SPEED;

 /**
 * Rendering hint value -- rendering algorithms are chosen
 * with a preference for output quality.
 * @see #KEY_RENDERING
 */
 public static final Object VALUE_RENDER_QUALITY =
 SunHints.VALUE_RENDER_QUALITY;

 /**
 * Rendering hint value -- rendering algorithms are chosen
 * by the implementation for a good tradeoff of performance
 * vs. quality.
 * @see #KEY_RENDERING
 */
 public static final Object VALUE_RENDER_DEFAULT =
 SunHints.VALUE_RENDER_DEFAULT;

 /**
 * Dithering hint key.
 * The {@code DITHERING} hint controls how closely to approximate
 * a color when storing into a destination with limited color
 * resolution.
 * <p>
 * Some rendering destinations may support a limited number of
 * color choices which may not be able to accurately represent
 * the full spectrum of colors that can result during rendering
 * operations.
 * For such a destination the {@code DITHERING} hint controls
 * whether rendering is done with a flat solid fill of a single
 * pixel value which is the closest supported color to what was
 * requested, or whether shapes will be filled with a pattern of
 * colors which combine to better approximate that color.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_DITHER_DISABLE}
 * <li>{@link #VALUE_DITHER_ENABLE}
 * <li>{@link #VALUE_DITHER_DEFAULT}
 * </ul>
 */
 public static final Key KEY_DITHERING =
 SunHints.KEY_DITHERING;

 /**
 * Dithering hint value -- do not dither when rendering geometry.
 * @see #KEY_DITHERING
 */
 public static final Object VALUE_DITHER_DISABLE =
 SunHints.VALUE_DITHER_DISABLE;

 /**
 * Dithering hint value -- dither when rendering geometry, if needed.
 * @see #KEY_DITHERING
 */
 public static final Object VALUE_DITHER_ENABLE =
 SunHints.VALUE_DITHER_ENABLE;

 /**
 * Dithering hint value -- use a default for dithering chosen by
 * the implementation.
 * @see #KEY_DITHERING
 */
 public static final Object VALUE_DITHER_DEFAULT =
 SunHints.VALUE_DITHER_DEFAULT;

 /**
 * Text antialiasing hint key.
 * The {@code TEXT_ANTIALIASING} hint can control the use of
 * antialiasing algorithms for text independently of the
 * choice used for shape rendering.
 * Often an application may want to use antialiasing for text
 * only and not for other shapes.
 * Additionally, the algorithms for reducing the aliasing
 * artifacts for text are often more sophisticated than those
 * that have been developed for general rendering so this
 * hint key provides additional values which can control
 * the choices of some of those text-specific algorithms.
 * If left in the {@code DEFAULT} state, this hint will
 * generally defer to the value of the regular
 * {@link #KEY_ANTIALIASING} hint key.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_TEXT_ANTIALIAS_ON}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_OFF}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_DEFAULT}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_GASP}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_LCD_HRGB}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_LCD_HBGR}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_LCD_VRGB}
 * <li>{@link #VALUE_TEXT_ANTIALIAS_LCD_VBGR}
 * </ul>
 */
 public static final Key KEY_TEXT_ANTIALIASING =
 SunHints.KEY_TEXT_ANTIALIASING;

 /**
 * Text antialiasing hint value -- text rendering is done with
 * some form of antialiasing.
 * @see #KEY_TEXT_ANTIALIASING
 */
 public static final Object VALUE_TEXT_ANTIALIAS_ON =
 SunHints.VALUE_TEXT_ANTIALIAS_ON;

 /**
 * Text antialiasing hint value -- text rendering is done without
 * any form of antialiasing.
 * @see #KEY_TEXT_ANTIALIASING
 */
 public static final Object VALUE_TEXT_ANTIALIAS_OFF =
 SunHints.VALUE_TEXT_ANTIALIAS_OFF;

 /**
 * Text antialiasing hint value -- text rendering is done according
 * to the {@link #KEY_ANTIALIASING} hint or a default chosen by the
 * implementation.
 * @see #KEY_TEXT_ANTIALIASING
 */
 public static final Object VALUE_TEXT_ANTIALIAS_DEFAULT =
 SunHints.VALUE_TEXT_ANTIALIAS_DEFAULT;

 /**
 * Text antialiasing hint value -- text rendering is requested to
 * use information in the font resource which specifies for each point
 * size whether to apply {@link #VALUE_TEXT_ANTIALIAS_ON} or
 * {@link #VALUE_TEXT_ANTIALIAS_OFF}.
 * <p>
 * TrueType fonts typically provide this information in the 'gasp' table.
 * In the absence of this information, the behaviour for a particular
 * font and size is determined by implementation defaults.
 * <p>
 * <i>Note:</i>A font designer will typically carefully hint a font for
 * the most common user interface point sizes. Consequently the 'gasp'
 * table will likely specify to use only hinting at those sizes and not
 * "smoothing". So in many cases the resulting text display is
 * equivalent to {@code VALUE_TEXT_ANTIALIAS_OFF}.
 * This may be unexpected but is correct.
 * <p>
 * Logical fonts which are composed of multiple physical fonts will for
 * consistency will use the setting most appropriate for the overall
 * composite font.
 *
 * @see #KEY_TEXT_ANTIALIASING
 * @since 1.6
 */
 public static final Object VALUE_TEXT_ANTIALIAS_GASP =
 SunHints.VALUE_TEXT_ANTIALIAS_GASP;

 /**
 * Text antialiasing hint value -- request that text be displayed
 * optimised for an LCD display with subpixels in order from display
 * left to right of R,G,B such that the horizontal subpixel resolution
 * is three times that of the full pixel horizontal resolution (HRGB).
 * This is the most common configuration.
 * Selecting this hint for displays with one of the other LCD subpixel
 * configurations will likely result in unfocused text.
 * <p>
 * <i>Notes:</i><br>
 * An implementation when choosing whether to apply any of the
 * LCD text hint values may take into account factors including requiring
 * color depth of the destination to be at least 15 bits per pixel
 * (ie 5 bits per color component),
 * characteristics of a font such as whether embedded bitmaps may
 * produce better results, or when displaying to a non-local networked
 * display device enabling it only if suitable protocols are available,
 * or ignoring the hint if performing very high resolution rendering
 * or the target device is not appropriate: eg when printing.
 * <p>
 * These hints can equally be applied when rendering to software images,
 * but these images may not then be suitable for general export, as the
 * text will have been rendered appropriately for a specific subpixel
 * organisation. Also lossy images are not a good choice, nor image
 * formats such as GIF which have limited colors.
 * So unless the image is destined solely for rendering on a
 * display device with the same configuration, some other text
 * anti-aliasing hint such as
 * {@link #VALUE_TEXT_ANTIALIAS_ON}
 * may be a better choice.
 * <p>Selecting a value which does not match the LCD display in use
 * will likely lead to a degradation in text quality.
 * On display devices (ie CRTs) which do not have the same characteristics
 * as LCD displays, the overall effect may appear similar to standard text
 * anti-aliasing, but the quality may be degraded by color distortion.
 * Analog connected LCD displays may also show little advantage over
 * standard text-antialiasing and be similar to CRTs.
 * <p>
 * In other words for the best results use an LCD display with a digital
 * display connector and specify the appropriate sub-pixel configuration.
 *
 * @see #KEY_TEXT_ANTIALIASING
 * @since 1.6
 */
 public static final Object VALUE_TEXT_ANTIALIAS_LCD_HRGB =
 SunHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB;

 /**
 * Text antialiasing hint value -- request that text be displayed
 * optimised for an LCD display with subpixels in order from display
 * left to right of B,G,R such that the horizontal subpixel resolution
 * is three times that of the full pixel horizontal resolution (HBGR).
 * This is a much less common configuration than HRGB.
 * Selecting this hint for displays with one of the other LCD subpixel
 * configurations will likely result in unfocused text.
 * See {@link #VALUE_TEXT_ANTIALIAS_LCD_HRGB},
 * for more information on when this hint is applied.
 *
 * @see #KEY_TEXT_ANTIALIASING
 * @since 1.6
 */
 public static final Object VALUE_TEXT_ANTIALIAS_LCD_HBGR =
 SunHints.VALUE_TEXT_ANTIALIAS_LCD_HBGR;

 /**
 * Text antialiasing hint value -- request that text be displayed
 * optimised for an LCD display with subpixel organisation from display
 * top to bottom of R,G,B such that the vertical subpixel resolution is
 * three times that of the full pixel vertical resolution (VRGB).
 * Vertical orientation is very uncommon and probably mainly useful
 * for a physically rotated display.
 * Selecting this hint for displays with one of the other LCD subpixel
 * configurations will likely result in unfocused text.
 * See {@link #VALUE_TEXT_ANTIALIAS_LCD_HRGB},
 * for more information on when this hint is applied.
 *
 * @see #KEY_TEXT_ANTIALIASING
 * @since 1.6
 */
 public static final Object VALUE_TEXT_ANTIALIAS_LCD_VRGB =
 SunHints.VALUE_TEXT_ANTIALIAS_LCD_VRGB;

 /**
 * Text antialiasing hint value -- request that text be displayed
 * optimised for an LCD display with subpixel organisation from display
 * top to bottom of B,G,R such that the vertical subpixel resolution is
 * three times that of the full pixel vertical resolution (VBGR).
 * Vertical orientation is very uncommon and probably mainly useful
 * for a physically rotated display.
 * Selecting this hint for displays with one of the other LCD subpixel
 * configurations will likely result in unfocused text.
 * See {@link #VALUE_TEXT_ANTIALIAS_LCD_HRGB},
 * for more information on when this hint is applied.
 *
 * @see #KEY_TEXT_ANTIALIASING
 * @since 1.6
 */
 public static final Object VALUE_TEXT_ANTIALIAS_LCD_VBGR =
 SunHints.VALUE_TEXT_ANTIALIAS_LCD_VBGR;


 /**
 * LCD text contrast rendering hint key.
 * The value is an <code>Integer</code> object which is used as a text
 * contrast adjustment when used in conjunction with an LCD text
 * anti-aliasing hint such as
 * {@link #VALUE_TEXT_ANTIALIAS_LCD_HRGB}.
 * <ul>
 * <li>Values should be a positive integer in the range 100 to 250.
 * <li>A lower value (eg 100) corresponds to higher contrast text when
 * displaying dark text on a light background.
 * <li>A higher value (eg 200) corresponds to lower contrast text when
 * displaying dark text on a light background.
 * <li>A typical useful value is in the narrow range 140-180.
 * <li>If no value is specified, a system or implementation default value
 * will be applied.
 * </ul>
 * The default value can be expected to be adequate for most purposes,
 * so clients should rarely need to specify a value for this hint unless
 * they have concrete information as to an appropriate value.
 * A higher value does not mean a higher contrast, in fact the opposite
 * is true.
 * The correction is applied in a similar manner to a gamma adjustment
 * for non-linear perceptual luminance response of display systems, but
 * does not indicate a full correction for this.
 *
 * @see #KEY_TEXT_ANTIALIASING
 * @since 1.6
 */
 public static final Key KEY_TEXT_LCD_CONTRAST =
 SunHints.KEY_TEXT_ANTIALIAS_LCD_CONTRAST;

 /**
 * Font fractional metrics hint key.
 * The {@code FRACTIONALMETRICS} hint controls whether the positioning
 * of individual character glyphs takes into account the sub-pixel
 * accuracy of the scaled character advances of the font or whether
 * such advance vectors are rounded to an integer number of whole
 * device pixels.
 * This hint only recommends how much accuracy should be used to
 * position the glyphs and does not specify or recommend whether or
 * not the actual rasterization or pixel bounds of the glyph should
 * be modified to match.
 * <p>
 * Rendering text to a low resolution device like a screen will
 * necessarily involve a number of rounding operations as the
 * high quality and very precise definition of the shape and
 * metrics of the character glyphs must be matched to discrete
 * device pixels.
 * Ideally the positioning of glyphs during text layout would be
 * calculated by scaling the design metrics in the font according
 * to the point size, but then the scaled advance width will not
 * necessarily be an integer number of pixels.
 * If the glyphs are positioned with sub-pixel accuracy according
 * to these scaled design metrics then the rasterization would
 * ideally need to be adjusted for each possible sub-pixel origin.
 * <p>
 * Unfortunately, scaling each glyph customized to its exact
 * subpixel origin during text layout would be prohibitively
 * expensive so a simplified system based on integer device
 * positions is typically used to lay out the text.
 * The rasterization of the glyph and the scaled advance width
 * are both adjusted together to yield text that looks good at
 * device resolution and has consistent integer pixel distances
 * between glyphs that help the glyphs look uniformly and
 * consistently spaced and readable.
 * <p>
 * This process of rounding advance widths for rasterized glyphs
 * to integer distances means that the character density and the
 * overall length of a string of text will be different from the
 * theoretical design measurements due to the accumulation of
 * a series of small differences in the adjusted widths of
 * each glyph.
 * The specific differences will be different for each glyph,
 * some being wider and some being narrower than their theoretical
 * design measurements.
 * Thus the overall difference in character density and length
 * will vary by a number of factors including the font, the
 * specific device resolution being targeted, and the glyphs
 * chosen to represent the string being rendered.
 * As a result, rendering the same string at multiple device
 * resolutions can yield widely varying metrics for whole strings.
 * <p>
 * When {@code FRACTIONALMETRICS} are enabled, the true font design
 * metrics are scaled by the point size and used for layout with
 * sub-pixel accuracy.
 * The average density of glyphs and total length of a long
 * string of characters will therefore more closely match the
 * theoretical design of the font, but readability may be affected
 * since individual pairs of characters may not always appear to
 * be consistent distances apart depending on how the sub-pixel
 * accumulation of the glyph origins meshes with the device pixel
 * grid.
 * Enabling this hint may be desirable when text layout is being
 * performed that must be consistent across a wide variety of
 * output resolutions.
 * Specifically, this hint may be desirable in situations where
 * the layout of text is being previewed on a low resolution
 * device like a screen for output that will eventually be
 * rendered on a high resolution printer or typesetting device.
 * <p>
 * When disabled, the scaled design metrics are rounded or adjusted
 * to integer distances for layout.
 * The distances between any specific pair of glyphs will be more
 * uniform on the device, but the density and total length of long
 * strings may no longer match the theoretical intentions of the
 * font designer.
 * Disabling this hint will typically produce more readable results
 * on low resolution devices like computer monitors.
 * <p>
 * The allowable values for this key are
 * <ul>
 * <li>{@link #VALUE_FRACTIONALMETRICS_OFF}
 * <li>{@link #VALUE_FRACTIONALMETRICS_ON}
 * <li>{@link #VALUE_FRACTIONALMETRICS_DEFAULT}
 * </ul>
 */
 public static final Key KEY_FRACTIONALMETRICS =
 SunHints.KEY_FRACTIONALMETRICS;

 /**
 * Font fractional metrics hint value -- character glyphs are
 * positioned with advance widths rounded to pixel boundaries.
 * @see #KEY_FRACTIONALMETRICS
 */
 public static final Object VALUE_FRACTIONALMETRICS_OFF =
 SunHints.VALUE_FRACTIONALMETRICS_OFF;

 /**
 * Font fractional metrics hint value -- character glyphs are
 * positioned with sub-pixel accuracy.
 * @see #KEY_FRACTIONALMETRICS
 */
 public static final Object VALUE_FRACTIONALMETRICS_ON =
 SunHints.VALUE_FRACTIONALMETRICS_ON;

 /**
 * Font fractional metrics hint value -- character glyphs are
 * positioned with accuracy chosen by the implementation.
 * @see #KEY_FRACTIONALMETRICS
 */
 public static final Object VALUE_FRACTIONALMETRICS_DEFAULT =
 SunHints.VALUE_FRACTIONALMETRICS_DEFAULT;

 /**
 * Interpolation hint key.
 * The {@code INTERPOLATION} hint controls how image pixels are
 * filtered or resampled during an image rendering operation.
 * <p>
 * Implicitly images are defined to provide color samples at
 * integer coordinate locations.
 * When images are rendered upright with no scaling onto a
 * destination, the choice of which image pixels map to which
 * device pixels is obvious and the samples at the integer
 * coordinate locations in the image are transfered to the
 * pixels at the corresponding integer locations on the device
 * pixel grid one for one.
 * When images are rendered in a scaled, rotated, or otherwise
 * transformed coordinate system, then the mapping of device
 * pixel coordinates back to the image can raise the question
 * of what color sample to use for the continuous coordinates
 * that lie between the integer locations of the provided image
 * samples.
 * Interpolation algorithms define functions which provide a
 * color sample for any continuous coordinate in an image based
 * on the color samples at the surrounding integer coordinates.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_INTERPOLATION_NEAREST_NEIGHBOR}
 * <li>{@link #VALUE_INTERPOLATION_BILINEAR}
 * <li>{@link #VALUE_INTERPOLATION_BICUBIC}
 * </ul>
 */
 public static final Key KEY_INTERPOLATION =
 SunHints.KEY_INTERPOLATION;

 /**
 * Interpolation hint value -- the color sample of the nearest
 * neighboring integer coordinate sample in the image is used.
 * Conceptually the image is viewed as a grid of unit-sized
 * square regions of color centered around the center of each
 * image pixel.
 * <p>
 * As the image is scaled up, it will look correspondingly blocky.
 * As the image is scaled down, the colors for source pixels will
 * be either used unmodified, or skipped entirely in the output
 * representation.
 *
 * @see #KEY_INTERPOLATION
 */
 public static final Object VALUE_INTERPOLATION_NEAREST_NEIGHBOR =
 SunHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR;

 /**
 * Interpolation hint value -- the color samples of the 4 nearest
 * neighboring integer coordinate samples in the image are
 * interpolated linearly to produce a color sample.
 * Conceptually the image is viewed as a set of infinitely small
 * point color samples which have value only at the centers of
 * integer coordinate pixels and the space between those pixel
 * centers is filled with linear ramps of colors that connect
 * adjacent discrete samples in a straight line.
 * <p>
 * As the image is scaled up, there are no blocky edges between
 * the colors in the image as there are with
 * {@link #VALUE_INTERPOLATION_NEAREST_NEIGHBOR NEAREST_NEIGHBOR},
 * but the blending may show some subtle discontinuities along the
 * horizontal and vertical edges that line up with the samples
 * caused by a sudden change in the slope of the interpolation
 * from one side of a sample to the other.
 * As the image is scaled down, more image pixels have their
 * color samples represented in the resulting output since each
 * output pixel receives color information from up to 4 image
 * pixels.
 *
 * @see #KEY_INTERPOLATION
 */
 public static final Object VALUE_INTERPOLATION_BILINEAR =
 SunHints.VALUE_INTERPOLATION_BILINEAR;

 /**
 * Interpolation hint value -- the color samples of 9 nearby
 * integer coordinate samples in the image are interpolated using
 * a cubic function in both {@code X} and {@code Y} to produce
 * a color sample.
 * Conceptually the view of the image is very similar to the view
 * used in the {@link #VALUE_INTERPOLATION_BILINEAR BILINEAR}
 * algorithm except that the ramps of colors that connect between
 * the samples are curved and have better continuity of slope
 * as they cross over between sample boundaries.
 * <p>
 * As the image is scaled up, there are no blocky edges and the
 * interpolation should appear smoother and with better depictions
 * of any edges in the original image than with {@code BILINEAR}.
 * As the image is scaled down, even more of the original color
 * samples from the original image will have their color information
 * carried through and represented.
 *
 * @see #KEY_INTERPOLATION
 */
 public static final Object VALUE_INTERPOLATION_BICUBIC =
 SunHints.VALUE_INTERPOLATION_BICUBIC;

 /**
 * Alpha interpolation hint key.
 * The {@code ALPHA_INTERPOLATION} hint is a general hint that
 * provides a high level recommendation as to whether to bias
 * alpha blending algorithm choices more for speed or quality
 * when evaluating tradeoffs.
 * <p>
 * This hint could control the choice of alpha blending
 * calculations that sacrifice some precision to use fast
 * lookup tables or lower precision SIMD instructions.
 * This hint could also control whether or not the color
 * and alpha values are converted into a linear color space
 * during the calculations for a more linear visual effect
 * at the expense of additional per-pixel calculations.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_ALPHA_INTERPOLATION_SPEED}
 * <li>{@link #VALUE_ALPHA_INTERPOLATION_QUALITY}
 * <li>{@link #VALUE_ALPHA_INTERPOLATION_DEFAULT}
 * </ul>
 */
 public static final Key KEY_ALPHA_INTERPOLATION =
 SunHints.KEY_ALPHA_INTERPOLATION;

 /**
 * Alpha interpolation hint value -- alpha blending algorithms
 * are chosen with a preference for calculation speed.
 * @see #KEY_ALPHA_INTERPOLATION
 */
 public static final Object VALUE_ALPHA_INTERPOLATION_SPEED =
 SunHints.VALUE_ALPHA_INTERPOLATION_SPEED;

 /**
 * Alpha interpolation hint value -- alpha blending algorithms
 * are chosen with a preference for precision and visual quality.
 * @see #KEY_ALPHA_INTERPOLATION
 */
 public static final Object VALUE_ALPHA_INTERPOLATION_QUALITY =
 SunHints.VALUE_ALPHA_INTERPOLATION_QUALITY;

 /**
 * Alpha interpolation hint value -- alpha blending algorithms
 * are chosen by the implementation for a good tradeoff of
 * performance vs. quality.
 * @see #KEY_ALPHA_INTERPOLATION
 */
 public static final Object VALUE_ALPHA_INTERPOLATION_DEFAULT =
 SunHints.VALUE_ALPHA_INTERPOLATION_DEFAULT;

 /**
 * Color rendering hint key.
 * The {@code COLOR_RENDERING} hint controls the accuracy of
 * approximation and conversion when storing colors into a
 * destination image or surface.
 * <p>
 * When a rendering or image manipulation operation produces
 * a color value that must be stored into a destination, it
 * must first convert that color into a form suitable for
 * storing into the destination image or surface.
 * Minimally, the color components must be converted to bit
 * representations and ordered in the correct order or an
 * index into a color lookup table must be chosen before
 * the data can be stored into the destination memory.
 * Without this minimal conversion, the data in the destination
 * would likely represent random, incorrect or possibly even
 * unsupported values.
 * Algorithms to quickly convert the results of rendering
 * operations into the color format of most common destinations
 * are well known and fairly optimal to execute.
 * <p>
 * Simply performing the most basic color format conversion to
 * store colors into a destination can potentially ignore a
 * difference in the calibration of the
 * {@link java.awt.color.ColorSpace}
 * of the source and destination or other factors such as the
 * linearity of the gamma correction.
 * Unless the source and destination {@code ColorSpace} are
 * identical, to correctly perform a rendering operation with
 * the most care taken for the accuracy of the colors being
 * represented, the source colors should be converted to a
 * device independent {@code ColorSpace} and the results then
 * converted back to the destination {@code ColorSpace}.
 * Furthermore, if calculations such as the blending of multiple
 * source colors are to be performed during the rendering
 * operation, greater visual clarity can be achieved if the
 * intermediate device independent {@code ColorSpace} is
 * chosen to have a linear relationship between the values
 * being calculated and the perception of the human eye to
 * the response curves of the output device.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_COLOR_RENDER_SPEED}
 * <li>{@link #VALUE_COLOR_RENDER_QUALITY}
 * <li>{@link #VALUE_COLOR_RENDER_DEFAULT}
 * </ul>
 */
 public static final Key KEY_COLOR_RENDERING =
 SunHints.KEY_COLOR_RENDERING;

 /**
 * Color rendering hint value -- perform the fastest color
 * conversion to the format of the output device.
 * @see #KEY_COLOR_RENDERING
 */
 public static final Object VALUE_COLOR_RENDER_SPEED =
 SunHints.VALUE_COLOR_RENDER_SPEED;

 /**
 * Color rendering hint value -- perform the color conversion
 * calculations with the highest accuracy and visual quality.
 * @see #KEY_COLOR_RENDERING
 */
 public static final Object VALUE_COLOR_RENDER_QUALITY =
 SunHints.VALUE_COLOR_RENDER_QUALITY;

 /**
 * Color rendering hint value -- perform color conversion
 * calculations as chosen by the implementation to represent
 * the best available tradeoff between performance and
 * accuracy.
 * @see #KEY_COLOR_RENDERING
 */
 public static final Object VALUE_COLOR_RENDER_DEFAULT =
 SunHints.VALUE_COLOR_RENDER_DEFAULT;

 /**
 * Stroke normalization control hint key.
 * The {@code STROKE_CONTROL} hint controls whether a rendering
 * implementation should or is allowed to modify the geometry
 * of rendered shapes for various purposes.
 * <p>
 * Some implementations may be able to use an optimized platform
 * rendering library which may be faster than traditional software
 * rendering algorithms on a given platform, but which may also
 * not support floating point coordinates.
 * Some implementations may also have sophisticated algorithms
 * which perturb the coordinates of a path so that wide lines
 * appear more uniform in width and spacing.
 * <p>
 * If an implementation performs any type of modification or
 * "normalization" of a path, it should never move the coordinates
 * by more than half a pixel in any direction.
 * <p>
 * The allowable values for this hint are
 * <ul>
 * <li>{@link #VALUE_STROKE_NORMALIZE}
 * <li>{@link #VALUE_STROKE_PURE}
 * <li>{@link #VALUE_STROKE_DEFAULT}
 * </ul>
 * @since 1.3
 */
 public static final Key KEY_STROKE_CONTROL =
 SunHints.KEY_STROKE_CONTROL;

 /**
 * Stroke normalization control hint value -- geometry may be
 * modified or left pure depending on the tradeoffs in a given
 * implementation.
 * Typically this setting allows an implementation to use a fast
 * integer coordinate based platform rendering library, but does
 * not specifically request normalization for uniformity or
 * aesthetics.
 *
 * @see #KEY_STROKE_CONTROL
 * @since 1.3
 */
 public static final Object VALUE_STROKE_DEFAULT =
 SunHints.VALUE_STROKE_DEFAULT;

 /**
 * Stroke normalization control hint value -- geometry should
 * be normalized to improve uniformity or spacing of lines and
 * overall aesthetics.
 * Note that different normalization algorithms may be more
 * successful than others for given input paths.
 *
 * @see #KEY_STROKE_CONTROL
 * @since 1.3
 */
 public static final Object VALUE_STROKE_NORMALIZE =
 SunHints.VALUE_STROKE_NORMALIZE;

 /**
 * Stroke normalization control hint value -- geometry should
 * be left unmodified and rendered with sub-pixel accuracy.
 *
 * @see #KEY_STROKE_CONTROL
 * @since 1.3
 */
 public static final Object VALUE_STROKE_PURE =
 SunHints.VALUE_STROKE_PURE;

 /**
 * Constructs a new object with keys and values initialized
 * from the specified Map object which may be null.
 * @param init a map of key/value pairs to initialize the hints
 * or null if the object should be empty
 */
 public RenderingHints(Map<Key,?> init) {
 if (init != null) {
 hintmap.putAll(init);
 }
 }

 /**
 * Constructs a new object with the specified key/value pair.
 * @param key the key of the particular hint property
 * @param value the value of the hint property specified with
 * <code>key</code>
 */
 public RenderingHints(Key key, Object value) {
 hintmap.put(key, value);
 }

 /**
 * Returns the number of key-value mappings in this
 * <code>RenderingHints</code>.
 *
 * @return the number of key-value mappings in this
 * <code>RenderingHints</code>.
 */
 public int size() {
 return hintmap.size();
 }

 /**
 * Returns <code>true</code> if this
 * <code>RenderingHints</code> contains no key-value mappings.
 *
 * @return <code>true</code> if this
 * <code>RenderingHints</code> contains no key-value mappings.
 */
 public boolean isEmpty() {
 return hintmap.isEmpty();
 }

 /**
 * Returns {@code true} if this {@code RenderingHints}
 * contains a mapping for the specified key.
 *
 * @param key key whose presence in this
 * {@code RenderingHints} is to be tested.
 * @return {@code true} if this {@code RenderingHints}
 * contains a mapping for the specified key.
 * @exception ClassCastException if the key can not
 * be cast to {@code RenderingHints.Key}
 */
 public boolean containsKey(Object key) {
 return hintmap.containsKey((Key) key);
 }

 /**
 * Returns true if this RenderingHints maps one or more keys to the
 * specified value.
 * More formally, returns <code>true</code> if and only
 * if this <code>RenderingHints</code>
 * contains at least one mapping to a value <code>v</code> such that
 * <pre>
 * (value==null ? v==null : value.equals(v))
 * </pre>.
 * This operation will probably require time linear in the
 * <code>RenderingHints</code> size for most implementations
 * of <code>RenderingHints</code>.
 *
 * @param value value whose presence in this
 * <code>RenderingHints</code> is to be tested.
 * @return <code>true</code> if this <code>RenderingHints</code>
 * maps one or more keys to the specified value.
 */
 public boolean containsValue(Object value) {
 return hintmap.containsValue(value);
 }

 /**
 * Returns the value to which the specified key is mapped.
 * @param key a rendering hint key
 * @return the value to which the key is mapped in this object or
 * {@code null} if the key is not mapped to any value in
 * this object.
 * @exception ClassCastException if the key can not
 * be cast to {@code RenderingHints.Key}
 * @see #put(Object, Object)
 */
 public Object get(Object key) {
 return hintmap.get((Key) key);
 }

 /**
 * Maps the specified {@code key} to the specified
 * {@code value} in this {@code RenderingHints} object.
 * Neither the key nor the value can be {@code null}.
 * The value can be retrieved by calling the {@code get} method
 * with a key that is equal to the original key.
 * @param key the rendering hint key.
 * @param value the rendering hint value.
 * @return the previous value of the specified key in this object
 * or {@code null} if it did not have one.
 * @exception NullPointerException if the key is
 * {@code null}.
 * @exception ClassCastException if the key can not
 * be cast to {@code RenderingHints.Key}
 * @exception IllegalArgumentException if the
 * {@link Key#isCompatibleValue(java.lang.Object)
 * Key.isCompatibleValue()}
 * method of the specified key returns false for the
 * specified value
 * @see #get(Object)
 */
 public Object put(Object key, Object value) {
 if (!((Key) key).isCompatibleValue(value)) {
 throw new IllegalArgumentException(value+
 " incompatible with "+
 key);
 }
 return hintmap.put((Key) key, value);
 }

 /**
 * Adds all of the keys and corresponding values from the specified
 * <code>RenderingHints</code> object to this
 * <code>RenderingHints</code> object. Keys that are present in
 * this <code>RenderingHints</code> object, but not in the specified
 * <code>RenderingHints</code> object are not affected.
 * @param hints the set of key/value pairs to be added to this
 * <code>RenderingHints</code> object
 */
 public void add(RenderingHints hints) {
 hintmap.putAll(hints.hintmap);
 }

 /**
 * Clears this <code>RenderingHints</code> object of all key/value
 * pairs.
 */
 public void clear() {
 hintmap.clear();
 }

 /**
 * Removes the key and its corresponding value from this
 * {@code RenderingHints} object. This method does nothing if the
 * key is not in this {@code RenderingHints} object.
 * @param key the rendering hints key that needs to be removed
 * @exception ClassCastException if the key can not
 * be cast to {@code RenderingHints.Key}
 * @return the value to which the key had previously been mapped in this
 * {@code RenderingHints} object, or {@code null}
 * if the key did not have a mapping.
 */
 public Object remove(Object key) {
 return hintmap.remove((Key) key);
 }

 /**
 * Copies all of the mappings from the specified {@code Map}
 * to this {@code RenderingHints}. These mappings replace
 * any mappings that this {@code RenderingHints} had for any
 * of the keys currently in the specified {@code Map}.
 * @param m the specified {@code Map}
 * @exception ClassCastException class of a key or value
 * in the specified {@code Map} prevents it from being
 * stored in this {@code RenderingHints}.
 * @exception IllegalArgumentException some aspect
 * of a key or value in the specified {@code Map}
 * prevents it from being stored in
 * this {@code RenderingHints}.
 */
 public void putAll(Map<?,?> m) {
 // ## javac bug?
 //if (m instanceof RenderingHints) {
 if (RenderingHints.class.isInstance(m)) {
 //hintmap.putAll(((RenderingHints) m).hintmap);
 for (Map.Entry<?,?> entry : m.entrySet())
 hintmap.put(entry.getKey(), entry.getValue());
 } else {
 // Funnel each key/value pair through our protected put method
 for (Map.Entry<?,?> entry : m.entrySet())
 put(entry.getKey(), entry.getValue());
 }
 }

 /**
 * Returns a <code>Set</code> view of the Keys contained in this
 * <code>RenderingHints</code>. The Set is backed by the
 * <code>RenderingHints</code>, so changes to the
 * <code>RenderingHints</code> are reflected in the <code>Set</code>,
 * and vice-versa. If the <code>RenderingHints</code> is modified
 * while an iteration over the <code>Set</code> is in progress,
 * the results of the iteration are undefined. The <code>Set</code>
 * supports element removal, which removes the corresponding
 * mapping from the <code>RenderingHints</code>, via the
 * <code>Iterator.remove</code>, <code>Set.remove</code>,
 * <code>removeAll</code> <code>retainAll</code>, and
 * <code>clear</code> operations. It does not support
 * the <code>add</code> or <code>addAll</code> operations.
 *
 * @return a <code>Set</code> view of the keys contained
 * in this <code>RenderingHints</code>.
 */
 public Set<Object> keySet() {
 return hintmap.keySet();
 }

 /**
 * Returns a <code>Collection</code> view of the values
 * contained in this <code>RenderinHints</code>.
 * The <code>Collection</code> is backed by the
 * <code>RenderingHints</code>, so changes to
 * the <code>RenderingHints</code> are reflected in
 * the <code>Collection</code>, and vice-versa.
 * If the <code>RenderingHints</code> is modified while
 * an iteration over the <code>Collection</code> is
 * in progress, the results of the iteration are undefined.
 * The <code>Collection</code> supports element removal,
 * which removes the corresponding mapping from the
 * <code>RenderingHints</code>, via the
 * <code>Iterator.remove</code>,
 * <code>Collection.remove</code>, <code>removeAll</code>,
 * <code>retainAll</code> and <code>clear</code> operations.
 * It does not support the <code>add</code> or
 * <code>addAll</code> operations.
 *
 * @return a <code>Collection</code> view of the values
 * contained in this <code>RenderingHints</code>.
 */
 public Collection<Object> values() {
 return hintmap.values();
 }

 /**
 * Returns a <code>Set</code> view of the mappings contained
 * in this <code>RenderingHints</code>. Each element in the
 * returned <code>Set</code> is a <code>Map.Entry</code>.
 * The <code>Set</code> is backed by the <code>RenderingHints</code>,
 * so changes to the <code>RenderingHints</code> are reflected
 * in the <code>Set</code>, and vice-versa. If the
 * <code>RenderingHints</code> is modified while
 * while an iteration over the <code>Set</code> is in progress,
 * the results of the iteration are undefined.
 * <p>
 * The entrySet returned from a <code>RenderingHints</code> object
 * is not modifiable.
 *
 * @return a <code>Set</code> view of the mappings contained in
 * this <code>RenderingHints</code>.
 */
 public Set<Map.Entry<Object,Object>> entrySet() {
 return Collections.unmodifiableMap(hintmap).entrySet();
 }

 /**
 * Compares the specified <code>Object</code> with this
 * <code>RenderingHints</code> for equality.
 * Returns <code>true</code> if the specified object is also a
 * <code>Map</code> and the two <code>Map</code> objects represent
 * the same mappings. More formally, two <code>Map</code> objects
 * <code>t1</code> and <code>t2</code> represent the same mappings
 * if <code>t1.keySet().equals(t2.keySet())</code> and for every
 * key <code>k</code> in <code>t1.keySet()</code>,
 * <pre>
 * (t1.get(k)==null ? t2.get(k)==null : t1.get(k).equals(t2.get(k)))
 * </pre>.
 * This ensures that the <code>equals</code> method works properly across
 * different implementations of the <code>Map</code> interface.
 *
 * @param o <code>Object</code> to be compared for equality with
 * this <code>RenderingHints</code>.
 * @return <code>true</code> if the specified <code>Object</code>
 * is equal to this <code>RenderingHints</code>.
 */
 public boolean equals(Object o) {
 if (o instanceof RenderingHints) {
 return hintmap.equals(((RenderingHints) o).hintmap);
 } else if (o instanceof Map) {
 return hintmap.equals(o);
 }
 return false;
 }

 /**
 * Returns the hash code value for this <code>RenderingHints</code>.
 * The hash code of a <code>RenderingHints</code> is defined to be
 * the sum of the hashCodes of each <code>Entry</code> in the
 * <code>RenderingHints</code> object's entrySet view. This ensures that
 * <code>t1.equals(t2)</code> implies that
 * <code>t1.hashCode()==t2.hashCode()</code> for any two <code>Map</code>
 * objects <code>t1</code> and <code>t2</code>, as required by the general
 * contract of <code>Object.hashCode</code>.
 *
 * @return the hash code value for this <code>RenderingHints</code>.
 * @see java.util.Map.Entry#hashCode()
 * @see Object#hashCode()
 * @see Object#equals(Object)
 * @see #equals(Object)
 */
 public int hashCode() {
 return hintmap.hashCode();
 }

 /**
 * Creates a clone of this <code>RenderingHints</code> object
 * that has the same contents as this <code>RenderingHints</code>
 * object.
 * @return a clone of this instance.
 */
 @SuppressWarnings("unchecked")
 public Object clone() {
 RenderingHints rh;
 try {
 rh = (RenderingHints) super.clone();
 if (hintmap != null) {
 rh.hintmap = (HashMap<Object,Object>) hintmap.clone();
 }
 } catch (CloneNotSupportedException e) {
 // this shouldn't happen, since we are Cloneable
 throw new InternalError(e);
 }

 return rh;
 }

 /**
 * Returns a rather long string representation of the hashmap
 * which contains the mappings of keys to values for this
 * <code>RenderingHints</code> object.
 * @return a string representation of this object.
 */
 public String toString() {
 if (hintmap == null) {
 return getClass().getName() + "@" +
 Integer.toHexString(hashCode()) +
 " (0 hints)";
 }

 return hintmap.toString();
 }
}