Java example source code file (img_dcm8.h)

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Java - Java tags/keywords

classjava_awt_image_directcolormodel, declaredcm8vars, declaredecodevars, decodedeclared, ifalpha, initpixeldcm8, initpixeldecode, pixeldcm8decode

The img_dcm8.h Java example source code

/*
 * Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * This file contains macro definitions for the Decoding category of
 * the macros used by the generic scaleloop function.
 *
 * This implementation can decode the pixel information associated
 * with Java DirectColorModel objects where the color masks are
 * guaranteed to be at least 8-bits wide each.  It is slightly more
 * efficient then the generic DCM parsing code since it does not need
 * to store or test component scaling values.  This implementation
 * examines some of the private fields of the DirectColorModel
 * object and decodes the red, green, blue, and possibly alpha values
 * directly rather than calling the getRGB method on the Java object.
 */

/*
 * These definitions vector the standard macro names to the "DCM8"
 * versions of those macros only if the "DecodeDeclared" keyword has
 * not yet been defined elsewhere.  The "DecodeDeclared" keyword is
 * also defined here to claim ownership of the primary implementation
 * even though this file does not rely on the definitions in any other
 * files.
 */
#ifndef DecodeDeclared
#define DeclareDecodeVars       DeclareDCM8Vars
#define InitPixelDecode(CM)     InitPixelDCM8(unhand(CM))
#define PixelDecode             PixelDCM8Decode
#define DecodeDeclared
#endif

#define DeclareDCM8Vars                                         \
    IfAlpha(unsigned int alpha_off;)                            \
    unsigned int red_off, green_off, blue_off;

#define InitPixelDCM8(CM)                                               \
    do {                                                                \
        Classjava_awt_image_DirectColorModel *dcm =                     \
            (Classjava_awt_image_DirectColorModel *) CM;                \
        red_off = dcm->red_offset;                                      \
        green_off = dcm->green_offset;                                  \
        blue_off = dcm->blue_offset;                                    \
        IfAlpha(alpha_off = (dcm->alpha_mask == 0                       \
                             ? -1                                       \
                             : dcm->alpha_offset);)                     \
    } while (0)

#define PixelDCM8Decode(CM, pixel, red, green, blue, alpha)             \
    do {                                                                \
        IfAlpha(alpha = ((alpha_off < 0)                                \
                         ? 255                                          \
                         : (pixel >> alpha_off) & 0xff);)               \
        red = (pixel >> red_off) & 0xff;                                \
        green = (pixel >> green_off) & 0xff;                            \
        blue = (pixel >> blue_off) & 0xff;                              \
    } while (0)