* Typically, a {@code Color} or {@code ColorModel} would be associated with an * ICC Profile which is either an input, display, or output profile (see the ICC * specification). There are other types of ICC Profiles, e.g. abstract * profiles, device link profiles, and named color profiles, which do not * contain information appropriate for representing the color space of a color, * image, or device (see {@code ICC_Profile}). Attempting to create an * {@code ICC_ColorSpace} object from an inappropriate ICC Profile is an error. *
* ICC Profiles represent transformations from the color space of the profile * (e.g. a monitor) to a Profile Connection Space (PCS). Profiles of interest * for tagging images or colors have a PCS which is one of the device * independent spaces (one CIEXYZ space and two CIELab spaces) defined in the * ICC Profile Format Specification. Most profiles of interest either have * invertible transformations or explicitly specify transformations going both * directions. Should an {@code ICC_ColorSpace} object be used in a way * requiring a conversion from PCS to the profile's native space and there is * inadequate data to correctly perform the conversion, the * {@code ICC_ColorSpace} object will produce output in the specified type of * color space (e.g. {@code TYPE_RGB}, {@code TYPE_CMYK}, etc.), but the * specific color values of the output data will be undefined. *
* The details of this class are not important for simple applets, which draw in * a default color space or manipulate and display imported images with a known * color space. At most, such applets would need to get one of the default color * spaces via {@link ColorSpace#getInstance}. * * @see ColorSpace * @see ICC_Profile */ public class ICC_ColorSpace extends ColorSpace { static final long serialVersionUID = 3455889114070431483L; private ICC_Profile thisProfile; private float[] minVal; private float[] maxVal; private float[] diffMinMax; private float[] invDiffMinMax; private boolean needScaleInit = true; // {to,from}{RGB,CIEXYZ} methods create and cache these when needed private transient ColorTransform this2srgb; private transient ColorTransform srgb2this; private transient ColorTransform this2xyz; private transient ColorTransform xyz2this; /** * Constructs a new {@code ICC_ColorSpace} from an {@code ICC_Profile} * object. * * @param profile the specified {@code ICC_Profile} object * @throws IllegalArgumentException if profile is inappropriate for * representing a {@code ColorSpace} */ public ICC_ColorSpace (ICC_Profile profile) { super (profile.getColorSpaceType(), profile.getNumComponents()); int profileClass = profile.getProfileClass(); /* REMIND - is NAMEDCOLOR OK? */ if ((profileClass != ICC_Profile.CLASS_INPUT) && (profileClass != ICC_Profile.CLASS_DISPLAY) && (profileClass != ICC_Profile.CLASS_OUTPUT) && (profileClass != ICC_Profile.CLASS_COLORSPACECONVERSION) && (profileClass != ICC_Profile.CLASS_NAMEDCOLOR) && (profileClass != ICC_Profile.CLASS_ABSTRACT)) { throw new IllegalArgumentException("Invalid profile type"); } thisProfile = profile; setMinMax(); } /** * Validate an ICC_ColorSpace read from an object input stream */ private void readObject(java.io.ObjectInputStream s) throws ClassNotFoundException, java.io.IOException { s.defaultReadObject(); if (thisProfile == null) { thisProfile = ICC_Profile.getInstance(ColorSpace.CS_sRGB); } } /** * Returns the {@code ICC_Profile} for this {@code ICC_ColorSpace}. * * @return the {@code ICC_Profile} for this {@code ICC_ColorSpace} */ public ICC_Profile getProfile() { return thisProfile; } /** * Transforms a color value assumed to be in this {@code ColorSpace} into a * value in the default {@code CS_sRGB} color space. *
* This method transforms color values using algorithms designed to produce * the best perceptual match between input and output colors. In order to do * colorimetric conversion of color values, you should use the * {@code toCIEXYZ} method of this color space to first convert from the * input color space to the {@code CS_CIEXYZ} color space, and then use the * {@code fromCIEXYZ} method of the {@code CS_sRGB} color space to convert * from {@code CS_CIEXYZ} to the output color space. See * {@link #toCIEXYZ(float[]) toCIEXYZ} and * {@link #fromCIEXYZ(float[]) fromCIEXYZ} for further information. * * @param colorvalue a float array with length of at least the number of * components in this {@code ColorSpace} * @return a float array of length 3 * @throws ArrayIndexOutOfBoundsException if array length is not at least * the number of components in this {@code ColorSpace} */ public float[] toRGB (float[] colorvalue) { if (this2srgb == null) { ColorTransform[] transformList = new ColorTransform [2]; ICC_ColorSpace srgbCS = (ICC_ColorSpace) ColorSpace.getInstance (CS_sRGB); PCMM mdl = CMSManager.getModule(); transformList[0] = mdl.createTransform( thisProfile, ColorTransform.Any, ColorTransform.In); transformList[1] = mdl.createTransform( srgbCS.getProfile(), ColorTransform.Any, ColorTransform.Out); this2srgb = mdl.createTransform(transformList); if (needScaleInit) { setComponentScaling(); } } int nc = this.getNumComponents(); short[] tmp = new short[nc]; for (int i = 0; i < nc; i++) { tmp[i] = (short) ((colorvalue[i] - minVal[i]) * invDiffMinMax[i] + 0.5f); } tmp = this2srgb.colorConvert(tmp, null); float[] result = new float [3]; for (int i = 0; i < 3; i++) { result[i] = ((float) (tmp[i] & 0xffff)) / 65535.0f; } return result; } /** * Transforms a color value assumed to be in the default {@code CS_sRGB} * color space into this {@code ColorSpace}. *
* This method transforms color values using algorithms designed to produce * the best perceptual match between input and output colors. In order to do * colorimetric conversion of color values, you should use the * {@code toCIEXYZ} method of the {@code CS_sRGB} color space to first * convert from the input color space to the {@code CS_CIEXYZ} color space, * and then use the {@code fromCIEXYZ} method of this color space to convert * from {@code CS_CIEXYZ} to the output color space. See * {@link #toCIEXYZ(float[]) toCIEXYZ} and * {@link #fromCIEXYZ(float[]) fromCIEXYZ} for further information. * * @param rgbvalue a float array with length of at least 3 * @return a float array with length equal to the number of components in * this {@code ColorSpace} * @throws ArrayIndexOutOfBoundsException if array length is not at least 3 */ public float[] fromRGB(float[] rgbvalue) { if (srgb2this == null) { ColorTransform[] transformList = new ColorTransform [2]; ICC_ColorSpace srgbCS = (ICC_ColorSpace) ColorSpace.getInstance (CS_sRGB); PCMM mdl = CMSManager.getModule(); transformList[0] = mdl.createTransform( srgbCS.getProfile(), ColorTransform.Any, ColorTransform.In); transformList[1] = mdl.createTransform( thisProfile, ColorTransform.Any, ColorTransform.Out); srgb2this = mdl.createTransform(transformList); if (needScaleInit) { setComponentScaling(); } } short[] tmp = new short[3]; for (int i = 0; i < 3; i++) { tmp[i] = (short) ((rgbvalue[i] * 65535.0f) + 0.5f); } tmp = srgb2this.colorConvert(tmp, null); int nc = this.getNumComponents(); float[] result = new float [nc]; for (int i = 0; i < nc; i++) { result[i] = (((float) (tmp[i] & 0xffff)) / 65535.0f) * diffMinMax[i] + minVal[i]; } return result; } /** * Transforms a color value assumed to be in this {@code ColorSpace} into * the {@code CS_CIEXYZ} conversion color space. *
* This method transforms color values using relative colorimetry, as * defined by the ICC Specification. This means that the XYZ values returned * by this method are represented relative to the D50 white point of the * {@code CS_CIEXYZ} color space. This representation is useful in a * two-step color conversion process in which colors are transformed from an * input color space to {@code CS_CIEXYZ} and then to an output color space. * This representation is not the same as the XYZ values that would be * measured from the given color value by a colorimeter. A further * transformation is necessary to compute the XYZ values that would be * measured using current CIE recommended practices. The paragraphs below * explain this in more detail. *
* The ICC standard uses a device independent color space (DICS) as the * mechanism for converting color from one device to another device. In this * architecture, colors are converted from the source device's color space * to the ICC DICS and then from the ICC DICS to the destination device's * color space. The ICC standard defines device profiles which contain * transforms which will convert between a device's color space and the ICC * DICS. The overall conversion of colors from a source device to colors of * a destination device is done by connecting the device-to-DICS transform * of the profile for the source device to the DICS-to-device transform of * the profile for the destination device. For this reason, the ICC DICS is * commonly referred to as the profile connection space (PCS). The color * space used in the methods {@code toCIEXYZ} and {@code fromCIEXYZ} is the * CIEXYZ PCS defined by the ICC Specification. This is also the color space * represented by {@code ColorSpace.CS_CIEXYZ}. *
* The XYZ values of a color are often represented as relative to some white * point, so the actual meaning of the XYZ values cannot be known without * knowing the white point of those values. This is known as relative * colorimetry. The PCS uses a white point of D50, so the XYZ values of the * PCS are relative to D50. For example, white in the PCS will have the XYZ * values of D50, which is defined to be X=.9642, Y=1.000, and Z=0.8249. * This white point is commonly used for graphic arts applications, but * others are often used in other applications. *
* To quantify the color characteristics of a device such as a printer or * monitor, measurements of XYZ values for particular device colors are * typically made. For purposes of this discussion, the term device XYZ * values is used to mean the XYZ values that would be measured from device * colors using current CIE recommended practices. *
* Converting between device XYZ values and the PCS XYZ values returned by * this method corresponds to converting between the device's color space, * as represented by CIE colorimetric values, and the PCS. There are many * factors involved in this process, some of which are quite subtle. The * most important, however, is the adjustment made to account for * differences between the device's white point and the white point of the * PCS. There are many techniques for doing this and it is the subject of * much current research and controversy. Some commonly used methods are XYZ * scaling, the von Kries transform, and the Bradford transform. The proper * method to use depends upon each particular application. *
* The simplest method is XYZ scaling. In this method each device XYZ value * is converted to a PCS XYZ value by multiplying it by the ratio of the PCS * white point (D50) to the device white point. *
*
* Xd, Yd, Zd are the device XYZ values
* Xdw, Ydw, Zdw are the device XYZ white point values
* Xp, Yp, Zp are the PCS XYZ values
* Xd50, Yd50, Zd50 are the PCS XYZ white point values
*
* Xp = Xd * (Xd50 / Xdw)
* Yp = Yd * (Yd50 / Ydw)
* Zp = Zd * (Zd50 / Zdw)
*
*
* * Conversion from the PCS to the device would be done by inverting these * equations: *
*
* Xd = Xp * (Xdw / Xd50)
* Yd = Yp * (Ydw / Yd50)
* Zd = Zp * (Zdw / Zd50)
*
*
* * Note that the media white point tag in an ICC profile is not the same as * the device white point. The media white point tag is expressed in PCS * values and is used to represent the difference between the XYZ of device * illuminant and the XYZ of the device media when measured under that * illuminant. The device white point is expressed as the device XYZ values * corresponding to white displayed on the device. For example, displaying * the RGB color (1.0, 1.0, 1.0) on an sRGB device will result in a measured * device XYZ value of D65. This will not be the same as the media white * point tag XYZ value in the ICC profile for an sRGB device. * * @param colorvalue a float array with length of at least the number of * components in this {@code ColorSpace} * @return a float array of length 3 * @throws ArrayIndexOutOfBoundsException if array length is not at least * the number of components in this {@code ColorSpace} */ public float[] toCIEXYZ(float[] colorvalue) { if (this2xyz == null) { ColorTransform[] transformList = new ColorTransform [2]; ICC_ColorSpace xyzCS = (ICC_ColorSpace) ColorSpace.getInstance (CS_CIEXYZ); PCMM mdl = CMSManager.getModule(); try { transformList[0] = mdl.createTransform( thisProfile, ICC_Profile.icRelativeColorimetric, ColorTransform.In); } catch (CMMException e) { transformList[0] = mdl.createTransform( thisProfile, ColorTransform.Any, ColorTransform.In); } transformList[1] = mdl.createTransform( xyzCS.getProfile(), ColorTransform.Any, ColorTransform.Out); this2xyz = mdl.createTransform (transformList); if (needScaleInit) { setComponentScaling(); } } int nc = this.getNumComponents(); short[] tmp = new short[nc]; for (int i = 0; i < nc; i++) { tmp[i] = (short) ((colorvalue[i] - minVal[i]) * invDiffMinMax[i] + 0.5f); } tmp = this2xyz.colorConvert(tmp, null); float ALMOST_TWO = 1.0f + (32767.0f / 32768.0f); // For CIEXYZ, min = 0.0, max = ALMOST_TWO for all components float[] result = new float [3]; for (int i = 0; i < 3; i++) { result[i] = (((float) (tmp[i] & 0xffff)) / 65535.0f) * ALMOST_TWO; } return result; } /** * Transforms a color value assumed to be in the {@code CS_CIEXYZ} * conversion color space into this ColorSpace. *
* This method transforms color values using relative colorimetry, as * defined by the ICC Specification. This means that the XYZ argument values * taken by this method are represented relative to the D50 white point of * the {@code CS_CIEXYZ} color space. This representation is useful in a * two-step color conversion process in which colors are transformed from an * input color space to {@code CS_CIEXYZ} and then to an output color space. * The color values returned by this method are not those that would produce * the XYZ value passed to the method when measured by a colorimeter. If you * have XYZ values corresponding to measurements made using current CIE * recommended practices, they must be converted to D50 relative values * before being passed to this method. The paragraphs below explain this in * more detail. *
* The ICC standard uses a device independent color space (DICS) as the * mechanism for converting color from one device to another device. In this * architecture, colors are converted from the source device's color space * to the ICC DICS and then from the ICC DICS to the destination device's * color space. The ICC standard defines device profiles which contain * transforms which will convert between a device's color space and the ICC * DICS. The overall conversion of colors from a source device to colors of * a destination device is done by connecting the device-to-DICS transform * of the profile for the source device to the DICS-to-device transform of * the profile for the destination device. For this reason, the ICC DICS is * commonly referred to as the profile connection space (PCS). The color * space used in the methods {@code toCIEXYZ} and {@code fromCIEXYZ} is the * CIEXYZ PCS defined by the ICC Specification. This is also the color space * represented by {@code ColorSpace.CS_CIEXYZ}. *
* The XYZ values of a color are often represented as relative to some white * point, so the actual meaning of the XYZ values cannot be known without * knowing the white point of those values. This is known as relative * colorimetry. The PCS uses a white point of D50, so the XYZ values of the * PCS are relative to D50. For example, white in the PCS will have the XYZ * values of D50, which is defined to be X=.9642, Y=1.000, and Z=0.8249. * This white point is commonly used for graphic arts applications, but * others are often used in other applications. *
* To quantify the color characteristics of a device such as a printer or * monitor, measurements of XYZ values for particular device colors are * typically made. For purposes of this discussion, the term device XYZ * values is used to mean the XYZ values that would be measured from device * colors using current CIE recommended practices. *
* Converting between device XYZ values and the PCS XYZ values taken as * arguments by this method corresponds to converting between the device's * color space, as represented by CIE colorimetric values, and the PCS. * There are many factors involved in this process, some of which are quite * subtle. The most important, however, is the adjustment made to account * for differences between the device's white point and the white point of * the PCS. There are many techniques for doing this and it is the subject * of much current research and controversy. Some commonly used methods are * XYZ scaling, the von Kries transform, and the Bradford transform. The * proper method to use depends upon each particular application. *
* The simplest method is XYZ scaling. In this method each device XYZ value * is converted to a PCS XYZ value by multiplying it by the ratio of the PCS * white point (D50) to the device white point. *
*
* Xd, Yd, Zd are the device XYZ values
* Xdw, Ydw, Zdw are the device XYZ white point values
* Xp, Yp, Zp are the PCS XYZ values
* Xd50, Yd50, Zd50 are the PCS XYZ white point values
*
* Xp = Xd * (Xd50 / Xdw)
* Yp = Yd * (Yd50 / Ydw)
* Zp = Zd * (Zd50 / Zdw)
*
*
* * Conversion from the PCS to the device would be done by inverting these * equations: *
*
* Xd = Xp * (Xdw / Xd50)
* Yd = Yp * (Ydw / Yd50)
* Zd = Zp * (Zdw / Zd50)
*
*
* * Note that the media white point tag in an ICC profile is not the same as * the device white point. The media white point tag is expressed in PCS * values and is used to represent the difference between the XYZ of device * illuminant and the XYZ of the device media when measured under that * illuminant. The device white point is expressed as the device XYZ values * corresponding to white displayed on the device. For example, displaying * the RGB color (1.0, 1.0, 1.0) on an sRGB device will result in a measured * device XYZ value of D65. This will not be the same as the media white * point tag XYZ value in the ICC profile for an sRGB device. * * @param colorvalue a float array with length of at least 3 * @return a float array with length equal to the number of components in * this {@code ColorSpace} * @throws ArrayIndexOutOfBoundsException if array length is not at least 3 */ public float[] fromCIEXYZ(float[] colorvalue) { if (xyz2this == null) { ColorTransform[] transformList = new ColorTransform [2]; ICC_ColorSpace xyzCS = (ICC_ColorSpace) ColorSpace.getInstance (CS_CIEXYZ); PCMM mdl = CMSManager.getModule(); transformList[0] = mdl.createTransform ( xyzCS.getProfile(), ColorTransform.Any, ColorTransform.In); try { transformList[1] = mdl.createTransform( thisProfile, ICC_Profile.icRelativeColorimetric, ColorTransform.Out); } catch (CMMException e) { transformList[1] = CMSManager.getModule().createTransform( thisProfile, ColorTransform.Any, ColorTransform.Out); } xyz2this = mdl.createTransform(transformList); if (needScaleInit) { setComponentScaling(); } } short[] tmp = new short[3]; float ALMOST_TWO = 1.0f + (32767.0f / 32768.0f); float factor = 65535.0f / ALMOST_TWO; // For CIEXYZ, min = 0.0, max = ALMOST_TWO for all components for (int i = 0; i < 3; i++) { tmp[i] = (short) ((colorvalue[i] * factor) + 0.5f); } tmp = xyz2this.colorConvert(tmp, null); int nc = this.getNumComponents(); float[] result = new float [nc]; for (int i = 0; i < nc; i++) { result[i] = (((float) (tmp[i] & 0xffff)) / 65535.0f) * diffMinMax[i] + minVal[i]; } return result; } /** * Returns the minimum normalized color component value for the specified * component. For {@code TYPE_XYZ} spaces, this method returns minimum * values of 0.0 for all components. For {@code TYPE_Lab} spaces, this * method returns 0.0 for L and -128.0 for a and b components. This is * consistent with the encoding of the XYZ and Lab Profile Connection Spaces * in the ICC specification. For all other types, this method returns 0.0 * for all components. When using an {@code ICC_ColorSpace} with a profile * that requires different minimum component values, it is necessary to * subclass this class and override this method. * * @param component the component index * @return the minimum normalized component value * @throws IllegalArgumentException if component is less than 0 or greater * than {@code numComponents - 1} * @since 1.4 */ public float getMinValue(int component) { if ((component < 0) || (component > this.getNumComponents() - 1)) { throw new IllegalArgumentException( "Component index out of range: " + component); } return minVal[component]; } /** * Returns the maximum normalized color component value for the specified * component. For {@code TYPE_XYZ} spaces, this method returns maximum * values of 1.0 + (32767.0 / 32768.0) for all components. For * {@code TYPE_Lab} spaces, this method returns 100.0 for L and 127.0 for a * and b components. This is consistent with the encoding of the XYZ and Lab * Profile Connection Spaces in the ICC specification. For all other types, * this method returns 1.0 for all components. When using an * {@code ICC_ColorSpace} with a profile that requires different maximum * component values, it is necessary to subclass this class and override * this method. * * @param component the component index * @return the maximum normalized component value * @throws IllegalArgumentException if component is less than 0 or greater * than {@code numComponents - 1} * @since 1.4 */ public float getMaxValue(int component) { if ((component < 0) || (component > this.getNumComponents() - 1)) { throw new IllegalArgumentException( "Component index out of range: " + component); } return maxVal[component]; } private void setMinMax() { int nc = this.getNumComponents(); int type = this.getType(); minVal = new float[nc]; maxVal = new float[nc]; if (type == ColorSpace.TYPE_Lab) { minVal[0] = 0.0f; // L maxVal[0] = 100.0f; minVal[1] = -128.0f; // a maxVal[1] = 127.0f; minVal[2] = -128.0f; // b maxVal[2] = 127.0f; } else if (type == ColorSpace.TYPE_XYZ) { minVal[0] = minVal[1] = minVal[2] = 0.0f; // X, Y, Z maxVal[0] = maxVal[1] = maxVal[2] = 1.0f + (32767.0f/ 32768.0f); } else { for (int i = 0; i < nc; i++) { minVal[i] = 0.0f; maxVal[i] = 1.0f; } } } private void setComponentScaling() { int nc = this.getNumComponents(); diffMinMax = new float[nc]; invDiffMinMax = new float[nc]; for (int i = 0; i < nc; i++) { minVal[i] = this.getMinValue(i); // in case getMinVal is overridden maxVal[i] = this.getMaxValue(i); // in case getMaxVal is overridden diffMinMax[i] = maxVal[i] - minVal[i]; invDiffMinMax[i] = 65535.0f / diffMinMax[i]; } needScaleInit = false; } }