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https://github.com/gryf/wmaker.git
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390 lines
9.0 KiB
C
390 lines
9.0 KiB
C
/* rotate.c - image rotation
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*
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* Raster graphics library
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*
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* Copyright (c) 2000-2003 Alfredo K. Kojima
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <config.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <X11/Xlib.h>
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#include "wraster.h"
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#include <math.h>
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#ifndef PI
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#define PI 3.14159265358979323846
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#endif
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static RImage *rotateImage(RImage *image, float angle);
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RImage*
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RRotateImage(RImage *image, float angle)
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{
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RImage *img;
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int nwidth, nheight;
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int x, y;
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int bpp = image->format == RRGBAFormat ? 4 : 3;
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angle = ((int)angle % 360) + (angle - (int)angle);
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if (angle == 0.0) {
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return RCloneImage(image);
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} else if (angle == 90.0) {
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nwidth = image->height;
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nheight = image->width;
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img = RCreateImage(nwidth, nheight, True);
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if (!img) {
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return NULL;
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}
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if (bpp == 3) {
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unsigned char *optr, *nptr;
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unsigned offs;
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offs = nwidth * 4;
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optr = image->data;
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nptr = img->data;
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for (x = 0; x < nwidth; x++) {
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nptr = img->data + x*4;
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for (y = nheight; y; y--) {
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nptr[0] = *optr++;
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nptr[1] = *optr++;
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nptr[2] = *optr++;
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nptr[3] = 255;
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nptr += offs;
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}
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}
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} else {
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unsigned *optr, *nptr;
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unsigned *p;
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optr = (unsigned*)image->data;
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p = (unsigned*)img->data;
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for (x = 0; x < nwidth; x++) {
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nptr = p++;
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for (y = nheight; y; y--) {
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*nptr = *optr++;
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nptr += nwidth;
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}
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}
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}
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} else if (angle == 180.0) {
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nwidth = image->width;
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nheight = image->height;
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img = RCreateImage(nwidth, nheight, True);
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if (!img) {
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return NULL;
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}
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if (bpp == 3) {
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unsigned char *optr, *nptr;
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optr = image->data;
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nptr = img->data + nwidth * nheight * 4 - 4;
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for (y = 0; y < nheight; y++) {
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for (x = 0; x < nwidth; x++) {
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nptr[0] = optr[0];
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nptr[1] = optr[1];
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nptr[2] = optr[2];
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nptr[3] = 255;
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optr += 3;
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nptr -= 4;
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}
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}
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} else {
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unsigned *optr, *nptr;
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optr = (unsigned*)image->data;
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nptr = (unsigned*)img->data + nwidth * nheight - 1;
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for (y = nheight*nwidth-1; y >= 0; y--) {
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*nptr = *optr;
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optr++;
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nptr--;
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}
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}
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} else if (angle == 270.0) {
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nwidth = image->height;
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nheight = image->width;
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img = RCreateImage(nwidth, nheight, True);
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if (!img) {
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return NULL;
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}
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if (bpp == 3) {
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unsigned char *optr, *nptr;
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unsigned offs;
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offs = nwidth * 4;
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optr = image->data;
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nptr = img->data;
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for (x = 0; x < nwidth; x++) {
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nptr = img->data + x*4;
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for (y = nheight; y; y--) {
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nptr[0] = *optr++;
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nptr[1] = *optr++;
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nptr[2] = *optr++;
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nptr[3] = 255;
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nptr += offs;
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}
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}
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} else {
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unsigned *optr, *nptr;
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unsigned *p;
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optr = (unsigned*)image->data;
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p = (unsigned*)img->data + nwidth*nheight;
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for (x = 0; x < nwidth; x++) {
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nptr = p--;
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for (y = nheight; y; y--) {
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*nptr = *optr++;
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nptr -= nwidth;
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}
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}
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}
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} else {
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img = rotateImage(image, angle);
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}
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return img;
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}
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/*
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* Image rotation through Bresenham's line algorithm:
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*
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* If a square must be rotate by angle a, like in:
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* _______
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* | B |
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* | /4\ |
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* | /3 8\|
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* | /2 7 /|
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* |A1 6 / | A_______B
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* | \5 / a| <--- |1 2 3 4|
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* |__C/_)_| |5 6 7 8|
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* C-------
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*
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* for each point P1 in the line from C to A
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* for each point P2 in the perpendicular line starting at P1
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* get pixel from the source and plot at P2
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* increment pixel location from source
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*
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*/
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static void
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copyLine(int x1, int y1, int x2, int y2, int nwidth, int format,
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unsigned char *dst, unsigned char **src)
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{
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unsigned char *s = *src;
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int dx, dy;
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int xi, yi;
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int offset;
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int dpr, dpru, p;
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dx = abs(x2 - x1);
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dy = abs(y2 - y1);
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if (x1 > x2) xi = -1; else xi = 1;
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if (y1 > y2) yi = -1; else yi = 1;
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if (dx >= dy) {
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dpr = dy << 1;
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dpru = dpr - (dx << 1);
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p = dpr - dx;
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while (dx-- >= 0) {
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/* fetch and draw the pixel */
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offset = (x1 + y1 * nwidth) << 2;
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dst[offset++] = *s++;
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dst[offset++] = *s++;
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dst[offset++] = *s++;
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if (format == RRGBAFormat)
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dst[offset++] = *s++;
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else
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dst[offset++] = 255;
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/* calc next step */
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if (p > 0) {
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x1 += xi;
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y1 += yi;
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p += dpru;
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} else {
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x1 += xi;
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p += dpr;
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}
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}
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} else {
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dpr = dx << 1;
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dpru = dpr - (dy << 1);
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p = dpr - dy;
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while (dy-- >= 0) {
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/* fetch and draw the pixel */
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offset = (x1 + y1 * nwidth) << 2;
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dst[offset++] = *s++;
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dst[offset++] = *s++;
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dst[offset++] = *s++;
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if (format == RRGBAFormat)
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dst[offset++] = *s++;
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else
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dst[offset++] = 255;
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/* calc next step */
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if (p > 0) {
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x1 += xi;
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y1 += yi;
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p += dpru;
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} else {
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y1 += yi;
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p += dpr;
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}
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}
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}
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*src = s;
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}
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static RImage*
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rotateImage(RImage *image, float angle)
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{
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RImage *img;
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int nwidth, nheight;
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int x1, y1;
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int x2, y2;
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int dx, dy;
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int xi, yi;
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int xx, yy;
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unsigned char *src, *dst;
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int dpr, dpru, p;
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/* only 180o for now */
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if (angle > 180.0)
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angle -= 180.0;
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angle = (angle * PI) / 180.0;
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nwidth = ceil(abs(cos(angle) * image->width))
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+ ceil(abs(cos(PI/2 - angle) * image->width));
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nheight = ceil(abs(sin(angle) * image->height))
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+ ceil(abs(cos(PI/2 - angle) * image->height));
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img = RCreateImage(nwidth, nheight, True);
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if (!img)
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return NULL;
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src = image->data;
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dst = img->data;
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x1 = floor(abs(cos(PI/2 - angle)*image->width));
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y1 = 0;
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x2 = 0;
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y2 = floor(abs(sin(PI/2 - angle)*image->width));
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xx = floor(abs(cos(angle)*image->height)) - 1;
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yy = nheight - 1;
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printf("%ix%i, %i %i %i %i %i\n",
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nwidth, nheight, x1, y1, x2, y2, (int)((angle*180.0)/PI));
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dx = abs(x2 - x1);
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dy = abs(y2 - y1);
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if (x1 > x2) xi = -1; else xi = 1;
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if (y1 > y2) yi = -1; else yi = 1;
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if (dx >= dy) {
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dpr = dy << 1;
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dpru = dpr - (dx << 1);
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p = dpr - dx;
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while (dx-- >= 0) {
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copyLine(x1, y1, xx, yy, nwidth, image->format, dst, &src);
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/* calc next step */
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if (p > 0) {
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x1 += xi;
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y1 += yi;
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xx += xi;
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yy += yi;
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p += dpru;
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} else {
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x1 += xi;
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xx += xi;
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p += dpr;
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}
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}
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} else {
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puts("NOT IMPLEMTENED");
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return img;
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dpr = dx << 1;
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dpru = dpr - (dy << 1);
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p = dpr - dy;
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while (dy-- >= 0) {
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xx = abs(x1*sin(angle*PI/180.0));
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yy = abs(y1*cos(angle*PI/180.0));
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copyLine(x1, y1, xx, yy, nwidth, image->format, dst, &src);
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/* calc next step*/
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if (p > 0) {
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x1 += xi;
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y1 += yi;
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p += dpru;
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} else {
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y1 += yi;
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p += dpr;
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}
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}
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}
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return img;
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}
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