Java 1.2 How-To/JavaHowTo.iso/3rdParty/jbuilder/unsupported/JDK1.2beta3/SOURCE/SRC.ZIP/java/awt/GradientPaintContext.java

Java Source | 1998-03-20 | 4.6 KB | 191 lines

/*
 * @(#)GradientPaintContext.java    1.12 98/03/18
 *
 * Copyright 1997 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */

package java.awt;

import java.awt.color.ColorSpace;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import sun.awt.image.IntegerComponentRaster;
import java.awt.image.ColorModel;
import java.awt.image.DirectColorModel;
import java.awt.geom.Point2D;

class GradientPaintContext implements PaintContext {
    static ColorModel xrgbmodel =
    new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);

    double x1;
    double y1;
    double dx;
    double dy;
    boolean cyclic;
    int interp[];
    Raster saved;
    ColorModel model;

    public GradientPaintContext(Point2D p1, Point2D p2,
                Color c1, Color c2,
                boolean cyclic) {
    double x1, y1, x2, y2;
    int rgb1, rgb2;
    x1 = p1.getX();
    x2 = p2.getX();
    if (x1 > x2) {
        y1 = x1;
        x1 = x2;
        x2 = y1;
        y1 = p2.getY();
        y2 = p1.getY();
        rgb1 = c2.getRGBA();
        rgb2 = c1.getRGBA();
    } else {
        y1 = p1.getY();
        y2 = p2.getY();
        rgb1 = c1.getRGBA();
        rgb2 = c2.getRGBA();
    }
    double dx = x2 - x1;
    double dy = y2 - y1;
    double lenSq = dx * dx + dy * dy;
    this.x1 = x1;
    this.y1 = y1;
    if (lenSq >= Double.MIN_VALUE) {
        dx = dx / lenSq;
        dy = dy / lenSq;
        if (cyclic) {
        dx = dx % 1.0;
        dy = dy % 1.0;
        }
    }
    this.dx = dx;
    this.dy = dy;
    this.cyclic = cyclic;
    int a1 = (rgb1 >> 24) & 0xff;
    int r1 = (rgb1 >> 16) & 0xff;
    int g1 = (rgb1 >>  8) & 0xff;
    int b1 = (rgb1      ) & 0xff;
    int da = ((rgb2 >> 24) & 0xff) - a1;
    int dr = ((rgb2 >> 16) & 0xff) - r1;
    int dg = ((rgb2 >>  8) & 0xff) - g1;
    int db = ((rgb2      ) & 0xff) - b1;
    if (((rgb1 & rgb2) >>> 24) == 0xff) {
        model = xrgbmodel;
    } else {
        model = ColorModel.getRGBdefault();
    }
    interp = new int[cyclic ? 513 : 257];
    for (int i = 0; i <= 256; i++) {
        float rel = i / 256.0f;
        int rgb =
        (((int) (a1 + da * rel)) << 24) |
        (((int) (r1 + dr * rel)) << 16) |
        (((int) (g1 + dg * rel)) <<  8) |
        (((int) (b1 + db * rel))      );
        interp[i] = rgb;
        if (cyclic) {
        interp[512 - i] = rgb;
        }
    }
    }

    /**
     * Release the resources allocated for the operation.
     */
    public void dispose() {
    saved = null;
    }

    /**
     * Return the ColorModel of the output.
     */
    public ColorModel getColorModel() {
        return model;
    }

    /**
     * Return a Raster containing the colors generated for the graphics
     * operation.
     * @param x,y,w,h The area in device space for which colors are
     * generated.
     */
    public Raster getRaster(int x, int y, int w, int h) {
    double rowrel = (x - x1) * dx + (y - y1) * dy;

    Raster rast = saved;
    if (rast == null || rast.getWidth() < w || rast.getHeight() < h) {
        rast = getColorModel().createCompatibleWritableRaster(w, h);
        saved = rast;
    }
    IntegerComponentRaster irast = (IntegerComponentRaster) rast;
    int off = irast.getDataOffset(0);
    int adjust = irast.getScanlineStride() - w;
    int[] pixels = irast.getDataStorage();

    if (cyclic) {
        cycleFillRaster(pixels, off, adjust, w, h, rowrel, dx, dy);
    } else {
        clipFillRaster(pixels, off, adjust, w, h, rowrel, dx, dy);
    }

    return rast;
    }

    void cycleFillRaster(int[] pixels, int off, int adjust, int w, int h,
             double rowrel, double dx, double dy) {
    rowrel = rowrel % 2.0;
    int irowrel = ((int) (rowrel * (1 << 30))) << 1;
    int idx = (int) (-dx * (1 << 31));
    int idy = (int) (-dy * (1 << 31));
    while (--h >= 0) {
        int icolrel = irowrel;
        for (int j = w; j > 0; j--) {
        pixels[off++] = interp[icolrel >>> 23];
        icolrel += idx;
        }

        off += adjust;
        irowrel += idy;
        }
    }

    void clipFillRaster(int[] pixels, int off, int adjust, int w, int h,
            double rowrel, double dx, double dy) {
    while (--h >= 0) {
        double colrel = rowrel;
        int j = w;
        if (colrel <= 0.0) {
        int rgb = interp[0];
        do {
            pixels[off++] = rgb;
            colrel += dx;
        } while (--j > 0 && colrel <= 0.0);
        }
        while (colrel < 1.0 && --j >= 0) {
        pixels[off++] = interp[(int) (colrel * 256)];
        colrel += dx;
        }
        if (j > 0) {
        int rgb = interp[256];
        do {
            pixels[off++] = rgb;
        } while (--j > 0);
        }

        off += adjust;
        rowrel += dy;
        }
    }
}