transforms.c

一个已经移植到嵌入式平台上的图象处理程序源代码,可以处理gif,bmp,jpg,png

/*
    fbv  --  simple image viewer for the linux framebuffer
    Copyright (C) 2000, 2001, 2003  Mateusz Golicz

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program 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 for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

unsigned char *simple_resize(unsigned char * orgin,int ox,int oy,int dx,int dy)
{
	unsigned char *cr,*p,*l;
	int i,j,k,ip;
	assert(cr = (unsigned char*) malloc(dx*dy*3));
	l=cr;    
	for(j=0;j<dy;j++,l+=dx*3)
	{
		p=orgin+(j*oy/dy*ox*3);
		for(i=0,k=0;i<dx;i++,k+=3)
		{
			ip=i*ox/dx*3;
			l[k]=p[ip];
			l[k+1]=p[ip+1];
			l[k+2]=p[ip+2];
		}
	}
	return(cr);
}

unsigned char *alpha_resize(unsigned char * alpha,int ox,int oy,int dx,int dy)
{
	unsigned char *cr,*p,*l;
  int i,j,k;
  cr=(unsigned char*) malloc(dx*dy); 
	l=cr;
  for(j=0;j<dy;j++,l+=dx)
  {
		p = alpha+(j*oy/dy*ox);
		for(i=0,k=0;i<dx;i++)
	    l[k++]=p[i*ox/dx];
	}
  return(cr);
}

unsigned char *color_average_resize(unsigned char *orgin,int ox,int oy,int dx,int dy)
{
    unsigned char *cr,*p,*q;
    int i,j,k,l,xa,xb,ya,yb;
    int sq,r,g,b;
    assert(cr=(unsigned char*)malloc(dx*dy*3)); 
		p=cr;
    for(j=0;j<dy;j++)
    {
			for(i=0;i<dx;i++,p+=3)
			{
			    xa=i*ox/dx;
		   	 	ya=j*oy/dy;
		   	 	xb=(i+1)*ox/dx; 
					if(xb>=ox) 
						xb=ox-1;
		    	yb=(j+1)*oy/dy; 
					if(yb>=oy) 
						yb=oy-1;
		    	for(l=ya,r=0,g=0,b=0,sq=0;l<=yb;l++)
		    	{
						q=orgin+((l*ox+xa)*3);
						for(k=xa;k<=xb;k++,q+=3,sq++)
						    r+=q[0]; g+=q[1]; b+=q[2];
		    	}
		    	p[0]=r/sq; p[1]=g/sq; p[2]=b/sq;
			}
    }
    return(cr);
}

unsigned char *rotate(unsigned char *i, int ox, int oy, int rot)
{
	unsigned char * n, * p;
	int x, y;
	assert(n = (unsigned char*) malloc(ox * oy * 3));
	switch(rot)
	{
		case 1: /* 90 deg right */
			p = n + (oy - 1) * 3;
			for(y = 0; y<oy; y++, p -= 3)
			{
				unsigned char * r = p;
				for(x = 0; x<ox; x++, r += oy * 3)
				{
					r[0] = *(i++);
					r[1] = *(i++);
					r[2] = *(i++);
				}
			}
			break;
		case 2: /* 180 deg */
			i += ox * oy * 3; p = n;
			for(y = ox * oy; y > 0; y--)
			{
				i -= 3;
				p[0] = i[0];
				p[1] = i[1];
				p[2] = i[2];
				p += 3;
			}
			break;
		case 3: /* 90 deg left */
			p = n;
			for(y = 0; y<oy; y++, p += 3)
			{
				unsigned char *r = p + ((ox * 3) * oy);
				for(x = 0; x<ox; x++)
				{
					r -= oy * 3;
					r[0] = *(i++);
					r[1] = *(i++);
					r[2] = *(i++);
				}
			}
			break;
	}
	return(n);
}

unsigned char *alpha_rotate(unsigned char *i, int ox, int oy, int rot)
{
	unsigned char * n, * p;
	int x, y;
	assert(n = (unsigned char*) malloc(ox * oy));	
	switch(rot)
	{
		case 1: /* 90 deg right */
			p = n + (oy - 1);
			for(y = 0; y<oy; y++, p --)
			{
				unsigned char * r = p;
				for(x = 0; x<ox; x++, r += oy)
					*r = *(i++);
			}
			break;
		case 2: /* 180 deg */
			i += ox * oy; p = n;
			for(y = ox * oy; y > 0; y--)
				*(p++) = *(i--);
			break;
		case 3: /* 90 deg left */
			p = n;
			for(y = 0; y<oy; y++, p++)
			{
				unsigned char * r = p + (ox * oy);
				for(x = 0; x<ox; x++)
				{
					r -= oy;
					*r = *(i++);
				}
			}
			break;
	}
	return(n);
}