[10547] | 1 | // License: GPL. For details, see LICENSE file.
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| 2 | package org.openstreetmap.josm.gui.layer.imagery;
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| 3 |
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| 4 | import java.awt.Transparency;
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| 5 | import java.awt.image.BufferedImage;
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| 6 | import java.awt.image.LookupOp;
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| 7 | import java.awt.image.ShortLookupTable;
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[12594] | 8 | import java.util.Collections;
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| 9 | import java.util.Map;
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[10547] | 10 |
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| 11 | import org.openstreetmap.josm.Main;
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| 12 | import org.openstreetmap.josm.gui.layer.ImageProcessor;
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[12594] | 13 | import org.openstreetmap.josm.io.session.SessionAwareReadApply;
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| 14 | import org.openstreetmap.josm.tools.Utils;
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[10547] | 15 |
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| 16 | /**
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| 17 | * An image processor which adjusts the gamma value of an image.
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| 18 | * @since 10547
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| 19 | */
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[12594] | 20 | public class GammaImageProcessor implements ImageProcessor, SessionAwareReadApply {
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| 21 | private double gamma = 1.0;
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[10547] | 22 | final short[] gammaChange = new short[256];
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| 23 | private final LookupOp op3 = new LookupOp(
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| 24 | new ShortLookupTable(0, new short[][]{gammaChange, gammaChange, gammaChange}), null);
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| 25 | private final LookupOp op4 = new LookupOp(
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| 26 | new ShortLookupTable(0, new short[][]{gammaChange, gammaChange, gammaChange, gammaChange}), null);
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| 27 |
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| 28 | /**
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| 29 | * Returns the currently set gamma value.
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| 30 | * @return the currently set gamma value
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| 31 | */
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| 32 | public double getGamma() {
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| 33 | return gamma;
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| 34 | }
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| 35 |
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| 36 | /**
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| 37 | * Sets a new gamma value, {@code 1} stands for no correction.
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| 38 | * @param gamma new gamma value
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| 39 | */
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| 40 | public void setGamma(double gamma) {
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| 41 | this.gamma = gamma;
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| 42 | for (int i = 0; i < 256; i++) {
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| 43 | gammaChange[i] = (short) (255 * Math.pow(i / 255., gamma));
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| 44 | }
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| 45 | }
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| 46 |
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| 47 | @Override
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| 48 | public BufferedImage process(BufferedImage image) {
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[12594] | 49 | if (gamma == 1.0) {
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[10547] | 50 | return image;
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| 51 | }
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| 52 | try {
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| 53 | final int bands = image.getRaster().getNumBands();
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| 54 | if (image.getType() != BufferedImage.TYPE_CUSTOM && bands == 3) {
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| 55 | return op3.filter(image, null);
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| 56 | } else if (image.getType() != BufferedImage.TYPE_CUSTOM && bands == 4) {
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| 57 | return op4.filter(image, null);
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| 58 | }
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| 59 | } catch (IllegalArgumentException ignore) {
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| 60 | Main.trace(ignore);
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| 61 | }
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| 62 | final int type = image.getTransparency() == Transparency.OPAQUE ? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
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| 63 | final BufferedImage to = new BufferedImage(image.getWidth(), image.getHeight(), type);
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| 64 | to.getGraphics().drawImage(image, 0, 0, null);
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| 65 | return process(to);
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| 66 | }
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| 67 |
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| 68 | @Override
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[12594] | 69 | public void applyFromPropertiesMap(Map<String, String> properties) {
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| 70 | String cStr = properties.get("gamma");
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| 71 | if (cStr != null) {
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| 72 | try {
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| 73 | setGamma(Double.parseDouble(cStr));
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| 74 | } catch (NumberFormatException e) {
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| 75 | // nothing
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| 76 | }
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| 77 | }
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| 78 | }
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| 79 |
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| 80 | @Override
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| 81 | public Map<String, String> toPropertiesMap() {
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| 82 | if (Utils.equalsEpsilon(gamma, 1.0))
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| 83 | return Collections.emptyMap();
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| 84 | else
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| 85 | return Collections.singletonMap("gamma", Double.toString(gamma));
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| 86 | }
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| 87 |
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| 88 | @Override
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[10547] | 89 | public String toString() {
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| 90 | return "GammaImageProcessor [gamma=" + gamma + ']';
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| 91 | }
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| 92 | }
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