rotate.c

motion motion

/*
 *	rotate.c
 *
 *	Module for handling image rotation.
 *
 *	Copyright 2004-2005, Per Jonsson ([e-mail])
 *	
 *	This software is distributed under the GNU Public license
 *	Version 2.  See also the file 'COPYING'.
 *
 *	Image rotation is a feature of Motion that can be used when the
 *	camera is mounted upside-down or on the side. The module only
 *	supports rotation in multiples of 90 degrees. Using rotation 
 *	increases the Motion CPU usage slightly.
 *
 *	Version history:
 *	  v6 (29-Aug-2005) - simplified the code as Motion now requires
 *	                     that width and height are multiples of 16
 *	  v5 (3-Aug-2005)  - cleanup in code comments
 *	                   - better adherence to coding standard
 *	                   - fix for __bswap_32 macro collision
 *	                   - fixed bug where initialization would be
 *	                     incomplete for invalid degrees of rotation
 *	                   - now uses motion_log for error reporting
 *	  v4 (26-Oct-2004) - new fix for width/height from imgs/conf due to 
 *	                     earlier misinterpretation
 *	  v3 (11-Oct-2004) - cleanup of width/height from imgs/conf
 *	  v2 (26-Sep-2004) - separation of capture/internal dimensions
 *	                   - speed optimization, including bswap
 *	  v1 (28-Aug-2004) - initial version
 */
#include "rotate.h"

#ifndef __uint32
/**
 * We don't have a 32-bit unsigned integer type, so define it, given
 * a 32-bit type was found by configure.
 */
#	ifdef TYPE_32BIT
typedef unsigned TYPE_32BIT __uint32;
#	else
#		error "Failed to find a 32-bit integer type."
#	endif
#endif

/*=============================================================================
                    Start of code from bits/byteswap.h
 =============================================================================*/

/**
 * The code below is copied (with modification) from bits/byteswap.h. It provides
 * a macro/function named rot__bswap_32 that swaps the bytes in a 32-bit integer, 
 * preferably using the bswap assembler instruction if configure found support
 * for it.
 *
 * It would be neater to simply include byteswap.h and use the bswap_32 macro
 * defined there, but the problem is that the bswap asm instruction would then
 * only be used for certain processor architectures, excluding athlon (and 
 * probably athlon64 as well). Moreover, byteswap.h doesn't seem to exist on
 * FreeBSD. So, we rely on the HAVE_BSWAP macro defined by configure instead.
 *
 * Note that the macro names have been prefixed with "rot" in order to avoid 
 * collision since we have the include chain rotate.h -> motion.h -> netcam.h -> 
 * netinet/in.h -> ... -> byteswap.h -> bits/byteswap.h.
 */

/* Swap bytes in 32 bit value. This is used as a fallback and for constants. */
#define rot__bswap_constant_32(x) \
	((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) | \
	 (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))

#ifdef __GNUC__
#	if (__GNUC__ >= 2) && (i386 || __i386 || __i386__)
/* We're on an Intel-compatible platform, so we can use inline Intel assembler 
 * for the swapping. 
 */
#		ifndef HAVE_BSWAP
/* Bswap is not available, we have to use three instructions instead. */
#			define rot__bswap_32(x)                                         \
				(__extension__                                          \
				({ register __uint32 __v, __x = (x);                    \
				if (__builtin_constant_p (__x))                         \
					__v = rot__bswap_constant_32 (__x);             \
				else                                                    \
					__asm__ ("rorw $8, %w0;"                        \
							"rorl $16, %0;"                 \
							"rorw $8, %w0"                  \
							: "=r" (__v)                    \
							: "0" (__x)                     \
							: "cc");                        \
				__v; }))
#		else
#			define rot__bswap_32(x)                                         \
				(__extension__                                          \
				({ register __uint32 __v, __x = (x);                    \
				if (__builtin_constant_p (__x))                         \
					__v = rot__bswap_constant_32 (__x);             \
				else                                                    \
					__asm__ ("bswap %0" : "=r" (__v) : "0" (__x));  \
				__v; }))
#		endif
#	else
/* Non-Intel platform or too old version of gcc. */
#		define rot__bswap_32(x)                                                 \
			(__extension__                                                  \
			({ register __uint32 __x = (x);                                 \
			rot__bswap_constant_32 (__x); }))
#	endif
#else
/* Not a GNU compiler. */
static inline __uint32 rot__bswap_32(__uint32 __bsx) 
{
	return __bswap_constant_32 (__bsx);
}
#endif

/*=============================================================================
                     End of code from bits/byteswap.h
 =============================================================================*/

/* Finally define a macro with a more appropriate name, to be used below. */
#define swap_bytes(x) rot__bswap_32(x)

/**
 * reverse_inplace_quad
 * 
 *  Reverses a block of memory in-place, 4 bytes at a time. This function
 *  requires the __uint32 type, which is 32 bits wide.
 *
 * Parameters:
 * 
 *   src  - the memory block to reverse
 *   size - the size (in bytes) of the memory block
 *
 * Returns: nothing
 */
static void reverse_inplace_quad(unsigned char *src, int size) 
{
	__uint32 *nsrc = (__uint32 *)src;              /* first quad */
	__uint32 *ndst = (__uint32 *)(src + size - 4); /* last quad */
	register __uint32 tmp;

	while (nsrc < ndst) {
		tmp = swap_bytes(*ndst);
		*ndst-- = swap_bytes(*nsrc);
		*nsrc++ = tmp;
	}
}

/**
 * rot90cw
 * 
 *  Performs a 90 degrees clockwise rotation of the memory block pointed to 
 *  by src. The rotation is NOT performed in-place; dst must point to a 
 *  receiving memory block the same size as src.
 *
 * Parameters:
 * 
 *   src    - pointer to the memory block (image) to rotate clockwise
 *   dst    - where to put the rotated memory block
 *   size   - the size (in bytes) of the memory blocks (both src and dst)
 *   width  - the width of the memory block when seen as an image
 *   height - the height of the memory block when seen as an image
 *
 * Returns: nothing
 */
static void rot90cw(unsigned char *src, register unsigned char *dst, int size,
                    int width, int height) 
{
	unsigned char *endp;
	register unsigned char *base;
	int j;

	endp = src + size;
	for (base = endp - width; base < endp; base++) {
		src = base;
		for (j = 0; j < height; j++, src -= width) {
			*dst++ = *src;
		}
	}
}

/**
 * rot90ccw
 * 
 *  Performs a 90 degrees counterclockwise rotation of the memory block pointed
 *  to by src. The rotation is not performed in-place; dst must point to a 
 *  receiving memory block the same size as src. 
 *
 * Parameters:
 * 
 *   src    - pointer to the memory block (image) to rotate counterclockwise
 *   dst    - where to put the rotated memory block
 *   size   - the size (in bytes) of the memory blocks (both src and dst)
 *   width  - the width of the memory block when seen as an image
 *   height - the height of the memory block when seen as an image
 *
 * Returns: nothing
 */
static inline void rot90ccw(unsigned char *src, register unsigned char *dst,
                            int size, int width, int height) 
{
	unsigned char *endp;
	register unsigned char *base;
	int j;

	endp = src + size;
	dst = dst + size - 1;
	for(base = endp - width; base < endp; base++) {
		src = base;
		for(j = 0; j < height; j++, src -= width) {
			*dst-- = *src;
		}
	}
}

/**
 * rotate_init
 * 
 *  Initializes rotation data - allocates memory and determines which function
 *  to use for 180 degrees rotation.
 *
 * Parameters:
 * 
 *   cnt - the current thread's context structure
 *
 * Returns: nothing
 */
void rotate_init(struct context *cnt) 
{
	int size;
	
	/* Make sure temp_buf isn't freed if it hasn't been allocated. */
	cnt->rotate_data.temp_buf = NULL;

	/* Assign the value in conf.rotate_deg to rotate_data.degrees. This way,
	 * we have a value that is safe from changes caused by motion-control.
	 */
	if((cnt->conf.rotate_deg % 90) > 0) {
		motion_log(LOG_ERR, 0, "Config option \"rotate\" not a multiple of 90: %d",
		           cnt->conf.rotate_deg);
		cnt->conf.rotate_deg = 0;     /* disable rotation */
		cnt->rotate_data.degrees = 0; /* force return below */
	} else {
		cnt->rotate_data.degrees = cnt->conf.rotate_deg % 360; /* range: 0..359 */
	}

	/* Upon entrance to this function, imgs.width and imgs.height contain the
	 * capture dimensions (as set in the configuration file, or read from a 
	 * netcam source). 
	 *
	 * If rotating 90 or 270 degrees, the capture dimensions and output dimensions
	 * are not the same. Capture dimensions will be contained in cap_width and
	 * cap_height in cnt->rotate_data, while output dimensions will be contained
	 * in imgs.width and imgs.height.
	 */

	/* 1. Transfer capture dimensions into cap_width and cap_height. */
	cnt->rotate_data.cap_width  = cnt->imgs.width;
	cnt->rotate_data.cap_height = cnt->imgs.height;

	if((cnt->rotate_data.degrees == 90) || (cnt->rotate_data.degrees == 270)) {
		/* 2. "Swap" imgs.width and imgs.height. */
		cnt->imgs.width = cnt->rotate_data.cap_height;
		cnt->imgs.height = cnt->rotate_data.cap_width;
	}

	/* If we're not rotating, let's exit once we have setup the capture dimensions
	 * and output dimensions properly.
	 */
	if(cnt->rotate_data.degrees == 0) {
		return;
	}

	switch(cnt->imgs.type)
	{
	case VIDEO_PALETTE_YUV420P:
		/* For YUV 4:2:0 planar, the memory block used for 90/270 degrees
		 * rotation needs to be width x height x 1.5 bytes large. 
		 */
		size = cnt->imgs.width * cnt->imgs.height * 3 / 2;
		break;
	case VIDEO_PALETTE_GREY:
		/* For greyscale, the memory block used for 90/270 degrees rotation
		 * needs to be width x height bytes large.
		 */
		size = cnt->imgs.width * cnt->imgs.height;
		break;
	default:
		cnt->rotate_data.degrees = 0;
		motion_log(LOG_ERR, 0, "Unsupported palette (%d), rotation is disabled",
		           cnt->imgs.type);
		return;
	}

	/* Allocate memory if rotating 90 or 270 degrees, because those rotations 
	 * cannot be performed in-place (they can, but it would be too slow).
	 */
	if((cnt->rotate_data.degrees == 90) || (cnt->rotate_data.degrees == 270)) {
		cnt->rotate_data.temp_buf = mymalloc(size);
	}
}

/** 
 * rotate_deinit
 * 
 *  Frees resources previously allocated by rotate_init. 
 *
 * Parameters:
 * 
 *   cnt - the current thread's context structure
 *
 * Returns: nothing
 */
void rotate_deinit(struct context *cnt) 
{
	if(cnt->rotate_data.temp_buf) {
		free(cnt->rotate_data.temp_buf);
	}
}

/**
 * rotate_map
 * 
 *  Main entry point for rotation. This is the function that is called from
 *  video.c/video_freebsd.c to perform the rotation.
 *
 * Parameters:
 * 
 *   map - pointer to the image/data to rotate
 *   cnt - the current thread's context structure
 *
 * Returns: 
 * 
 *   0  - success
 *   -1 - failure (shouldn't happen)
 */
int rotate_map(struct context *cnt, unsigned char *map)
{
	/* The image format is either YUV 4:2:0 planar, in which case the pixel 
	 * data is divided in three parts:
	 *	Y - width x height bytes
	 *	U - width x height / 4 bytes
	 *	V - as U
	 * or, it is in greyscale, in which case the pixel data simply consists 
	 * of width x height bytes.
	 */
	int wh, wh4 = 0, w2 = 0, h2 = 0;  /* width*height, width*height/4 etc. */
	int size, deg;
	int width, height;

	deg = cnt->rotate_data.degrees;
	width = cnt->rotate_data.cap_width;
	height = cnt->rotate_data.cap_height;

	/* Pre-calculate some stuff:
	 *  wh   - size of the Y plane, or the entire greyscale image
	 *  size - size of the entire memory block
	 *  wh4  - size of the U plane, and the V plane
	 *  w2   - width of the U plane, and the V plane
	 *  h2   - as w2, but height instead
	 */
	wh = width * height;
	if(cnt->imgs.type == VIDEO_PALETTE_YUV420P) {
		size = wh * 3 / 2;
		wh4 = wh / 4;
		w2 = width / 2;
		h2 = height / 2;
	}
	else { /* VIDEO_PALETTE_GREY */
		size = wh;
	}

	switch (deg) {
	case 90:
		/* first do the Y part */
		rot90cw(map, cnt->rotate_data.temp_buf, wh, width, height);
		if(cnt->imgs.type == VIDEO_PALETTE_YUV420P) {
			/* then do U and V */
			rot90cw(map + wh, cnt->rotate_data.temp_buf + wh, wh4, w2, h2);
			rot90cw(map + wh + wh4, cnt->rotate_data.temp_buf + wh + wh4,
			        wh4, w2, h2);
		}
		
		/* then copy back from the temp buffer to map */
		memcpy(map, cnt->rotate_data.temp_buf, size);

		break;
		
	case 180:
		/* 180 degrees is easy - just reverse the data within
		 * Y, U and V.
		 */
		reverse_inplace_quad(map, wh);
		if(cnt->imgs.type == VIDEO_PALETTE_YUV420P) {
			reverse_inplace_quad(map + wh, wh4);
			reverse_inplace_quad(map + wh + wh4, wh4);
		}
		break;

	case 270:

		/* first do the Y part */
		rot90ccw(map, cnt->rotate_data.temp_buf, wh, width, height);
		if(cnt->imgs.type == VIDEO_PALETTE_YUV420P) {
			/* then do U and V */
			rot90ccw(map + wh, cnt->rotate_data.temp_buf + wh, wh4, w2, h2);
			rot90ccw(map + wh + wh4, cnt->rotate_data.temp_buf + wh + wh4, 
			         wh4, w2, h2);
		}
		
		/* then copy back from the temp buffer to map */
		memcpy(map, cnt->rotate_data.temp_buf, size);
		break;
		
	default:
		/* invalid */
		return -1;
	}
	
	return 0;
}