1 /*
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8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
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11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24  */
25 
26 /*
27  * This file contains macro definitions for the Decoding category of
28  * the macros used by the generic scaleloop function.
29  *
30  * This implementation can decode the pixel information associated
31  * with any Java DirectColorModel object.  This implementation will
32  * scale the decoded color components to 8-bit quantities if needed.
33  * Another file is provided to optimize DCM parsing when the masks
34  * are guaranteed to be at least 8-bits wide.  This implementation
35  * examines some of the private fields of the DirectColorModel
36  * object and decodes the red, green, blue, and possibly alpha values
37  * directly rather than calling the getRGB method on the Java object.
38  */
39 
40 /*
41  * These definitions vector the standard macro names to the "DCM"
42  * versions of those macros only if the "DecodeDeclared" keyword has
43  * not yet been defined elsewhere.  The "DecodeDeclared" keyword is
44  * also defined here to claim ownership of the primary implementation
45  * even though this file does not rely on the definitions in any other
46  * files.
47  */
48 #ifndef DecodeDeclared
49 #define DeclareDecodeVars       DeclareDCMVars
50 #define InitPixelDecode(CM)     InitPixelDCM(unhand(CM))
51 #define PixelDecode             PixelDCMDecode
52 #define DecodeDeclared
53 #endif
54 
55 #define DeclareDCMVars                                          \
56     IfAlpha(int alpha_mask;                                     \
57             int alpha_scale;                                    \
58             unsigned int alpha_off;)                            \
59     int red_mask, green_mask, blue_mask;                        \
60     int red_scale, green_scale, blue_scale;                     \
61     unsigned int red_off, green_off, blue_off;                  \
62     int scale;
63 
64 #define InitPixelDCM(CM)                                                \
65     do {                                                                \
66         Classjava_awt_image_DirectColorModel *dcm =                     \
67             (Classjava_awt_image_DirectColorModel *) CM;                \
68         red_mask = dcm->red_mask;                                       \
69         red_off = dcm->red_offset;                                      \
70         red_scale = dcm->red_scale;                                     \
71         green_mask = dcm->green_mask;                                   \
72         green_off = dcm->green_offset;                                  \
73         green_scale = dcm->green_scale;                                 \
74         blue_mask = dcm->blue_mask;                                     \
75         blue_off = dcm->blue_offset;                                    \
76         blue_scale = dcm->blue_scale;                                   \
77         IfAlpha(alpha_mask = dcm->alpha_mask;                           \
78                 alpha_off = dcm->alpha_offset;                          \
79                 alpha_scale = dcm->alpha_scale;)                        \
80         scale = (red_scale | green_scale | blue_scale                   \
81                  IfAlpha(| alpha_scale));                               \
82     } while (0)
83 
84 #define PixelDCMDecode(CM, pixel, red, green, blue, alpha)              \
85     do {                                                                \
86         IfAlpha(alpha = ((alpha_mask == 0)                              \
87                          ? 255                                          \
88                          : ((pixel & alpha_mask) >> alpha_off));)       \
89         red = ((pixel & red_mask) >> red_off);                          \
90         green = ((pixel & green_mask) >> green_off);                    \
91         blue = ((pixel & blue_mask) >> blue_off);                       \
92         if (scale) {                                                    \
93             if (red_scale) {                                            \
94                 red = red * 255 / (red_scale);                          \
95             }                                                           \
96             if (green_scale) {                                          \
97                 green = green * 255 / (green_scale);                    \
98             }                                                           \
99             if (blue_scale) {                                           \
100                 blue = blue * 255 / (blue_scale);                       \
101             }                                                           \
102             IfAlpha(if (alpha_scale) {                                  \
103                 alpha = alpha * 255 / (alpha_scale);                    \
104             })                                                          \
105         }                                                               \
106     } while (0)
107