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FBdraw.c

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/* 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; version 2 of the License. */
 
#include <math.h>
#include "FBlib.h"
#include "FBpriv.h"
#include <stdlib.h> // for abort()

//
// TODO: Should really rename this to something else
//
int GETPOS(int a, int b)
{
        int pos = 0;
        switch(FB_getrotation())
        {
                case FB_ROTATE_NONE:
                        pos = (a*inc_x) + (b*inc_y);
                        break;
                case FB_ROTATE_90:
                        pos = (b*inc_x) + ((work_var_info.yres-a-1)*inc_y);
                        break;
                case FB_ROTATE_180:
                        pos = screensize-((a*inc_x) + (b*inc_y));
                        break;
                case FB_ROTATE_270:
                        pos = ((work_var_info.xres-b-1)*inc_x) + (a*inc_y);
                        break;
                default:
                        printf("Trying to create rotation coordinate with invalid rotation: FB_getrotation()=%d\n",FB_getrotation());
                        abort();
        }

        // sanity checking
        if(pos>screensize || pos<0)
                pos = 0;
        return pos;
}

inline void setpixel(char *pos, FB_pixel col)
{
        char *abs_pos;
        
        abs_pos = fb_visp + (long int)pos;
        if(FB_getbpp() == 16)
        {
                *abs_pos = (u_char)col;
                *(abs_pos + 1) = (u_char)(col>>8);
        }
        else if (FB_getbpp() == 32)
        {
                *abs_pos = (u_char)col;
                *(abs_pos + 1) = (col>>8);
                *(abs_pos + 2) = (u_char)(col>>16);
                *(abs_pos + 3) = (u_char)(col>>24);
        }

        return;
}

inline void FB_putpixel(int x, int y, FB_pixel color)
{
        char *pos;
        
        if(x < 0 || x > FB_getxres())
                return;
        if(y < 0 || y > FB_getyres())
                return;
        
        pos = (char*)(GETPOS(x,y));
        setpixel(pos, color);

        return;
}

FB_pixel FB_getpixel(int x, int y)
{
        long int location;
        FB_pixel tmp;
        
        location=x * (FB_getbpp()/8) + y * (fb_fix_info.line_length);
        if(location > visiblesize)
                return 0; /* return black if out of bounds (weird) */
        tmp = *(fb_visp + location) | (*(fb_visp + location + 1)<<8);
        if(FB_getbpp() == 32)
                tmp |= (*(fb_visp + location + 2)<<16) + (*(fb_visp + location + 3)<<24);
        return tmp;
}

//
// TODO: replace this with something independent of inc_*
//
void FB_vline(int x, int sy, int ey, FB_pixel color)
{
        int i;

        /* Parameter sanity checks */
        if(x < 0 || x > FB_getxres())
                return;
        
        if(sy > ey)
        {
                i=sy;
                sy=ey;
                ey=i;
        }

        if(sy < 0)
                sy = 0;

        if(ey > FB_getyres())
                ey = FB_getyres();
        /* end of checks */

        for(i = sy; i <= ey; i++)
        {
                FB_putpixel(x,i,color);
        }
        return;
}

//
// TODO: replace this with something independent of inc_*
//
void FB_hline(int sx, int ex, int y, FB_pixel color)
{
        int i;
        
        if(y < 0 || y > FB_getyres())
                return;
        
        if(sx > ex)
        {
                i=sx;
                sx=ex;
                ex=i;
        }

        if(sx < 0)
                sx = 0;
        if(ex > FB_getxres())
                ex = FB_getxres();
        
        for(i = sx; i <= ex; i++)
        {
                FB_putpixel(i,y,color);
        }
        return;
}

//
// TODO: replace this with something independent of inc_*
//
/* This is Bresenham's line algorithm */
void FB_line(int sx, int sy, int ex, int ey, FB_pixel color)
{
        int dx,dy;
        int x,y,incx,incy;
        int balance;
        
        if(sx == ex)
                FB_vline(sx,sy,ey,color);
        if(sy == ey)
                FB_hline(sx,ex,sy,color);
        
        if (ex >= sx)
        {
                dx = ex - sx;
                incx = 1;
        }
        else
        {
                dx = sx - ex;
                incx = -1;
        }

        if (ey >= sy)
        {
                dy = ey - sy;
                incy = 1;
        }
        else
        {
                dy = sy - ey;
                incy = -1;
        }

        x = sx;
        y = sy;

        if (dx >= dy)
        {
                dy <<= 1;
                balance = dy - dx;
                dx <<= 1;

                while (x != ex)
                {
                        FB_putpixel(x, y, color);
                        if (balance >= 0)
                        {
                                y += incy;
                                balance -= dx;
                        }
                        balance += dy;
                        x += incx;
                } FB_putpixel(x, y, color);
        }
        else
        {
                dx <<= 1;
                balance = dx - dy;
                dy <<= 1;

                while (y != ey)
                {
                        FB_putpixel(x, y, color);
                        if (balance >= 0)
                        {
                                x += incx;
                                balance -= dy;
                        }
                        balance += dx;
                        y += incy;
                } FB_putpixel(x, y, color);
        }

        return;
}

void FB_rect(int sx, int sy, int ex, int ey, FB_pixel color)
{
        FB_hline(sx,ex,sy,color);
        FB_hline(sx,ex,ey,color);
        FB_vline(sx,sy,ey,color);
        FB_vline(ex,sy,ey,color);
        return;
}

//
// TODO: replace this with something independent of inc_*
//
void FB_rectfill(int sx, int sy, int ex, int ey, FB_pixel color)
{
        int i,j;
        
        if(sx > ex)
        {
                i=sx;
                sx=ex;
                ex=i;
        }
        if(sy > ey)
        {
                i=sy;
                sy=ey;
                ey=i;
        }
        if(sx < 0)
                sx = 0;
        if(sy < 0)
                sy = 0;
        if(ex > FB_getxres())
                ex = FB_getxres();
        if(ey > FB_getyres())
                ey = FB_getyres();
        
        for(i = sy; i <= ey; i++)
        {
                for(j = sx; j <= ex; j++ )
                {
                        FB_putpixel(j,i,color);
                }
        }
        return;
}

void FB_triangle(int x1,int y1,int x2,int y2,int x3,int y3,FB_pixel col)
{
        FB_line(x1, y1, x2, y2, col);
        FB_line(x3, y3, x2, y2, col);
        FB_line(x1, y1, x3, y3, col);
        
        return;
}

void FB_circle(int cx, int cy, int radius, FB_pixel color)
{
        double cosval;
        double sinval;
        double inc = (M_PI)/(radius*3.6); // Is this ok for all circles ?
        double angle=0;
        int x,y;

        while(angle <= M_PI)
        {
                cosval = radius*cos(angle);
                sinval = radius*sin(angle);
                x = (int)(cosval + cx);
                y = (int)(sinval + cy);
                FB_putpixel(x, y, color);
                x = (int)(-cosval + cx);
                y = (int)(-sinval + cy);
                FB_putpixel(x, y, color);
                angle+=inc;
        }
        return;
}

void FB_clear_screen(FB_pixel color)
{
        int i,j;
        
        for(i = 0; i <= FB_getyres(); i++)
        {
                for(j = 0; j <= FB_getxres(); j++ )
                {
                        FB_putpixel(j,i,color);
                }
        }

        return;
}

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