| /* |
| * Copyright (c) 1996, 1998, 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 defines some of the standard utility macros and definitions |
| * used throughout the image conversion package header files. |
| */ |
| |
| #include "img_globals.h" |
| |
| #define ALPHASHIFT 24 |
| #define REDSHIFT 16 |
| #define GREENSHIFT 8 |
| #define BLUESHIFT 0 |
| |
| /* |
| * The following mapping is used between coordinates when scaling an |
| * image: |
| * |
| * srcXY = floor(((dstXY + .5) * srcWH) / dstWH) |
| * = floor((dstXY * srcWH + .5 * srcWH) / dstWH) |
| * = floor((2 * dstXY * srcWH + srcWH) / (2 * dstWH)) |
| * |
| * Since the numerator can always be assumed to be non-negative for |
| * all values of dstXY >= 0 and srcWH,dstWH >= 1, then the floor |
| * function can be calculated using the standard C integer division |
| * operator. |
| * |
| * To calculate back from a source range of pixels to the destination |
| * range of pixels that they will affect, we need to find a srcXY |
| * that satisfies the following inequality based upon the above mapping |
| * function: |
| * |
| * srcXY <= (2 * dstXY * srcWH + srcWH) / (2 * dstWH) < (srcXY+1) |
| * 2 * srcXY * dstWH <= 2 * dstXY * srcWH + srcWH < 2 * (srcXY+1) * dstWH |
| * |
| * To calculate the lowest dstXY that satisfies these constraints, we use |
| * the first half of the inequality: |
| * |
| * 2 * dstXY * srcWH + srcWH >= 2 * srcXY * dstWH |
| * 2 * dstXY * srcWH >= 2 * srcXY * dstWH - srcWH |
| * dstXY >= (2 * srcXY * dstWH - srcWH) / (2 * srcWH) |
| * dstXY = ceil((2 * srcXY * dstWH - srcWH) / (2 * srcWH)) |
| * dstXY = floor((2 * srcXY * dstWH - srcWH + 2*srcWH - 1) / (2 * srcWH)) |
| * dstXY = floor((2 * srcXY * dstWH + srcWH - 1) / (2 * srcWH)) |
| * |
| * Since the numerator can be shown to be non-negative, we can calculate |
| * this with the standard C integer division operator. |
| * |
| * To calculate the highest dstXY that satisfies these constraints, we use |
| * the second half of the inequality: |
| * |
| * 2 * dstXY * srcWH + srcWH < 2 * (srcXY+1) * dstWH |
| * 2 * dstXY * srcWH < 2 * (srcXY+1) * dstWH - srcWH |
| * dstXY < (2 * (srcXY+1) * dstWH - srcWH) / (2 * srcWH) |
| * dstXY = ceil((2 * (srcXY+1) * dstWH - srcWH) / (2 * srcWH)) - 1 |
| * dstXY = floor((2 * (srcXY+1) * dstWH - srcWH + 2 * srcWH - 1) |
| * / (2 * srcWH)) - 1 |
| * dstXY = floor((2 * (srcXY+1) * dstWH + srcWH - 1) / (2 * srcWH)) - 1 |
| * |
| * Again, the numerator is always non-negative so we can use integer division. |
| */ |
| |
| #define SRC_XY(dstXY, srcWH, dstWH) \ |
| (((2 * (dstXY) * (srcWH)) + (srcWH)) / (2 * (dstWH))) |
| |
| #define DEST_XY_RANGE_START(srcXY, srcWH, dstWH) \ |
| (((2 * (srcXY) * (dstWH)) + (srcWH) - 1) / (2 * (srcWH))) |
| |
| #define DEST_XY_RANGE_END(srcXY, srcWH, dstWH) \ |
| (((2 * ((srcXY) + 1) * (dstWH)) + (srcWH) - 1) / (2 * (srcWH)) - 1) |
| |
| /* |
| * This union is a utility structure for manipulating pixel pointers |
| * of variable depths. |
| */ |
| typedef union { |
| void *vp; |
| unsigned char *bp; |
| unsigned short *sp; |
| unsigned int *ip; |
| } pixptr; |
| |
| #define RGBTOGRAY(r, g, b) ((int) (.299 * r + .587 * g + .114 * b)) |
| |
| #define ComponentBound(c) \ |
| (((c) < 0) ? 0 : (((c) > 255) ? 255 : (c))) |
| |
| #define paddedwidth(number, boundary) \ |
| (((number) + ((boundary) - 1)) & (~((boundary) - 1))) |
