/
draw.c
1422 lines (1129 loc) · 31.9 KB
/
draw.c
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#include "imager.h"
#include "draw.h"
#include "log.h"
#include "imageri.h"
#include <limits.h>
void
i_mmarray_cr(i_mmarray *ar,int l) {
int i;
int alloc_size;
ar->lines=l;
alloc_size = sizeof(minmax) * l;
/* check for overflow */
if (alloc_size / l != sizeof(minmax)) {
fprintf(stderr, "overflow calculating memory allocation");
exit(3);
}
ar->data=mymalloc(alloc_size); /* checked 5jul05 tonyc */
for(i=0;i<l;i++) { ar->data[i].max=-1; ar->data[i].min=MAXINT; }
}
void
i_mmarray_dst(i_mmarray *ar) {
ar->lines=0;
if (ar->data != NULL) { myfree(ar->data); ar->data=NULL; }
}
void
i_mmarray_add(i_mmarray *ar,int x,int y) {
if (y>-1 && y<ar->lines)
{
if (x<ar->data[y].min) ar->data[y].min=x;
if (x>ar->data[y].max) ar->data[y].max=x;
}
}
int
i_mmarray_gmin(i_mmarray *ar,int y) {
if (y>-1 && y<ar->lines) return ar->data[y].min;
else return -1;
}
int
i_mmarray_getm(i_mmarray *ar,int y) {
if (y>-1 && y<ar->lines) return ar->data[y].max;
else return MAXINT;
}
void
i_mmarray_render(i_img *im,i_mmarray *ar,i_color *val) {
int i,x;
for(i=0;i<ar->lines;i++) if (ar->data[i].max!=-1) for(x=ar->data[i].min;x<ar->data[i].max;x++) i_ppix(im,x,i,val);
}
void
i_mmarray_render_fill(i_img *im,i_mmarray *ar,i_fill_t *fill) {
int x, w, y;
if (im->bits == i_8_bits && fill->fill_with_color) {
i_color *line = mymalloc(sizeof(i_color) * im->xsize); /* checked 5jul05 tonyc */
i_color *work = NULL;
if (fill->combine)
work = mymalloc(sizeof(i_color) * im->xsize); /* checked 5jul05 tonyc */
for(y=0;y<ar->lines;y++) {
if (ar->data[y].max!=-1) {
x = ar->data[y].min;
w = ar->data[y].max-ar->data[y].min;
if (fill->combine) {
i_glin(im, x, x+w, y, line);
(fill->fill_with_color)(fill, x, y, w, im->channels, work);
(fill->combine)(line, work, im->channels, w);
}
else {
(fill->fill_with_color)(fill, x, y, w, im->channels, line);
}
i_plin(im, x, x+w, y, line);
}
}
myfree(line);
if (work)
myfree(work);
}
else {
i_fcolor *line = mymalloc(sizeof(i_fcolor) * im->xsize); /* checked 5jul05 tonyc */
i_fcolor *work = NULL;
if (fill->combinef)
work = mymalloc(sizeof(i_fcolor) * im->xsize); /* checked 5jul05 tonyc */
for(y=0;y<ar->lines;y++) {
if (ar->data[y].max!=-1) {
x = ar->data[y].min;
w = ar->data[y].max-ar->data[y].min;
if (fill->combinef) {
i_glinf(im, x, x+w, y, line);
(fill->fill_with_fcolor)(fill, x, y, w, im->channels, work);
(fill->combinef)(line, work, im->channels, w);
}
else {
(fill->fill_with_fcolor)(fill, x, y, w, im->channels, line);
}
i_plinf(im, x, x+w, y, line);
}
}
myfree(line);
if (work)
myfree(work);
}
}
static
void
i_arcdraw(int x1, int y1, int x2, int y2, i_mmarray *ar) {
double alpha;
double dsec;
int temp;
alpha=(double)(y2-y1)/(double)(x2-x1);
if (fabs(alpha) <= 1)
{
if (x2<x1) { temp=x1; x1=x2; x2=temp; temp=y1; y1=y2; y2=temp; }
dsec=y1;
while(x1<=x2)
{
i_mmarray_add(ar,x1,(int)(dsec+0.5));
dsec+=alpha;
x1++;
}
}
else
{
alpha=1/alpha;
if (y2<y1) { temp=x1; x1=x2; x2=temp; temp=y1; y1=y2; y2=temp; }
dsec=x1;
while(y1<=y2)
{
i_mmarray_add(ar,(int)(dsec+0.5),y1);
dsec+=alpha;
y1++;
}
}
}
void
i_mmarray_info(i_mmarray *ar) {
int i;
for(i=0;i<ar->lines;i++)
if (ar->data[i].max!=-1) printf("line %d: min=%d, max=%d.\n",i,ar->data[i].min,ar->data[i].max);
}
static void
i_arc_minmax(i_int_hlines *hlines,int x,int y,float rad,float d1,float d2) {
i_mmarray dot;
float f,fx,fy;
int x1,y1;
/*mm_log((1,"i_arc(im* 0x%x,x %d,y %d,rad %.2f,d1 %.2f,d2 %.2f,val 0x%x)\n",im,x,y,rad,d1,d2,val));*/
i_mmarray_cr(&dot, hlines->limit_y);
x1=(int)(x+0.5+rad*cos(d1*PI/180.0));
y1=(int)(y+0.5+rad*sin(d1*PI/180.0));
fx=(float)x1; fy=(float)y1;
/* printf("x1: %d.\ny1: %d.\n",x1,y1); */
i_arcdraw(x, y, x1, y1, &dot);
x1=(int)(x+0.5+rad*cos(d2*PI/180.0));
y1=(int)(y+0.5+rad*sin(d2*PI/180.0));
for(f=d1;f<=d2;f+=0.01) i_mmarray_add(&dot,(int)(x+0.5+rad*cos(f*PI/180.0)),(int)(y+0.5+rad*sin(f*PI/180.0)));
/* printf("x1: %d.\ny1: %d.\n",x1,y1); */
i_arcdraw(x, y, x1, y1, &dot);
/* render the minmax values onto the hlines */
for (y = 0; y < dot.lines; y++) {
if (dot.data[y].max!=-1) {
int minx, width;
minx = dot.data[y].min;
width = dot.data[y].max - dot.data[y].min + 1;
i_int_hlines_add(hlines, y, minx, width);
}
}
/* dot.info(); */
i_mmarray_dst(&dot);
}
static void
i_arc_hlines(i_int_hlines *hlines,int x,int y,float rad,float d1,float d2) {
if (d1 <= d2) {
i_arc_minmax(hlines, x, y, rad, d1, d2);
}
else {
i_arc_minmax(hlines, x, y, rad, d1, 360);
i_arc_minmax(hlines, x, y, rad, 0, d2);
}
}
/*
=item i_arc(im, x, y, rad, d1, d2, color)
=category Drawing
=synopsis i_arc(im, 50, 50, 20, 45, 135, &color);
Fills an arc centered at (x,y) with radius I<rad> covering the range
of angles in degrees from d1 to d2, with the color.
=cut
*/
void
i_arc(i_img *im,int x,int y,float rad,float d1,float d2,const i_color *val) {
i_int_hlines hlines;
i_int_init_hlines_img(&hlines, im);
i_arc_hlines(&hlines, x, y, rad, d1, d2);
i_int_hlines_fill_color(im, &hlines, val);
i_int_hlines_destroy(&hlines);
}
/*
=item i_arc_cfill(im, x, y, rad, d1, d2, fill)
=category Drawing
=synopsis i_arc_cfill(im, 50, 50, 35, 90, 135, fill);
Fills an arc centered at (x,y) with radius I<rad> covering the range
of angles in degrees from d1 to d2, with the fill object.
=cut
*/
#define MIN_CIRCLE_STEPS 8
#define MAX_CIRCLE_STEPS 360
void
i_arc_cfill(i_img *im,int x,int y,float rad,float d1,float d2,i_fill_t *fill) {
i_int_hlines hlines;
i_int_init_hlines_img(&hlines, im);
i_arc_hlines(&hlines, x, y, rad, d1, d2);
i_int_hlines_fill_fill(im, &hlines, fill);
i_int_hlines_destroy(&hlines);
}
static void
arc_poly(int *count, double **xvals, double **yvals,
double x, double y, double rad, double d1, double d2) {
double d1_rad, d2_rad;
double circum;
int steps, point_count;
double angle_inc;
/* normalize the angles */
d1 = fmod(d1, 360);
if (d1 == 0) {
if (d2 >= 360) { /* default is 361 */
d2 = 360;
}
else {
d2 = fmod(d2, 360);
if (d2 < d1)
d2 += 360;
}
}
else {
d2 = fmod(d2, 360);
if (d2 < d1)
d2 += 360;
}
d1_rad = d1 * PI / 180;
d2_rad = d2 * PI / 180;
/* how many segments for the curved part?
we do a maximum of one per degree, with a minimum of 8/circle
we try to aim at having about one segment per 2 pixels
Work it out per circle to get a step size.
I was originally making steps = circum/2 but that looked horrible.
I think there might be an issue in the polygon filler.
*/
circum = 2 * PI * rad;
steps = circum;
if (steps > MAX_CIRCLE_STEPS)
steps = MAX_CIRCLE_STEPS;
else if (steps < MIN_CIRCLE_STEPS)
steps = MIN_CIRCLE_STEPS;
angle_inc = 2 * PI / steps;
point_count = steps + 5; /* rough */
/* point_count is always relatively small, so allocation won't overflow */
*xvals = mymalloc(point_count * sizeof(double)); /* checked 17feb2005 tonyc */
*yvals = mymalloc(point_count * sizeof(double)); /* checked 17feb2005 tonyc */
/* from centre to edge at d1 */
(*xvals)[0] = x;
(*yvals)[0] = y;
(*xvals)[1] = x + rad * cos(d1_rad);
(*yvals)[1] = y + rad * sin(d1_rad);
*count = 2;
/* step around the curve */
while (d1_rad < d2_rad) {
(*xvals)[*count] = x + rad * cos(d1_rad);
(*yvals)[*count] = y + rad * sin(d1_rad);
++*count;
d1_rad += angle_inc;
}
/* finish off the curve */
(*xvals)[*count] = x + rad * cos(d2_rad);
(*yvals)[*count] = y + rad * sin(d2_rad);
++*count;
}
/*
=item i_arc_aa(im, x, y, rad, d1, d2, color)
=category Drawing
=synopsis i_arc_aa(im, 50, 50, 35, 90, 135, &color);
Antialias fills an arc centered at (x,y) with radius I<rad> covering
the range of angles in degrees from d1 to d2, with the color.
=cut
*/
void
i_arc_aa(i_img *im, double x, double y, double rad, double d1, double d2,
const i_color *val) {
double *xvals, *yvals;
int count;
arc_poly(&count, &xvals, &yvals, x, y, rad, d1, d2);
i_poly_aa(im, count, xvals, yvals, val);
myfree(xvals);
myfree(yvals);
}
/*
=item i_arc_aa_cfill(im, x, y, rad, d1, d2, fill)
=category Drawing
=synopsis i_arc_aa_cfill(im, 50, 50, 35, 90, 135, fill);
Antialias fills an arc centered at (x,y) with radius I<rad> covering
the range of angles in degrees from d1 to d2, with the fill object.
=cut
*/
void
i_arc_aa_cfill(i_img *im, double x, double y, double rad, double d1, double d2,
i_fill_t *fill) {
double *xvals, *yvals;
int count;
arc_poly(&count, &xvals, &yvals, x, y, rad, d1, d2);
i_poly_aa_cfill(im, count, xvals, yvals, fill);
myfree(xvals);
myfree(yvals);
}
/* Temporary AA HACK */
typedef int frac;
static frac float_to_frac(float x) { return (frac)(0.5+x*16.0); }
static
void
polar_to_plane(float cx, float cy, float angle, float radius, frac *x, frac *y) {
*x = float_to_frac(cx+radius*cos(angle));
*y = float_to_frac(cy+radius*sin(angle));
}
static
void
make_minmax_list(i_mmarray *dot, float x, float y, float radius) {
float angle = 0.0;
float astep = radius>0.1 ? .5/radius : 10;
frac cx, cy, lx, ly, sx, sy;
mm_log((1, "make_minmax_list(dot %p, x %.2f, y %.2f, radius %.2f)\n", dot, x, y, radius));
polar_to_plane(x, y, angle, radius, &sx, &sy);
for(angle = 0.0; angle<361; angle +=astep) {
lx = sx; ly = sy;
polar_to_plane(x, y, angle, radius, &cx, &cy);
sx = cx; sy = cy;
if (fabs(cx-lx) > fabs(cy-ly)) {
int ccx, ccy;
if (lx>cx) {
ccx = lx; lx = cx; cx = ccx;
ccy = ly; ly = cy; cy = ccy;
}
for(ccx=lx; ccx<=cx; ccx++) {
ccy = ly + ((cy-ly)*(ccx-lx))/(cx-lx);
i_mmarray_add(dot, ccx, ccy);
}
} else {
int ccx, ccy;
if (ly>cy) {
ccy = ly; ly = cy; cy = ccy;
ccx = lx; lx = cx; cx = ccx;
}
for(ccy=ly; ccy<=cy; ccy++) {
if (cy-ly) ccx = lx + ((cx-lx)*(ccy-ly))/(cy-ly); else ccx = lx;
i_mmarray_add(dot, ccx, ccy);
}
}
}
}
/* Get the number of subpixels covered */
static
int
i_pixel_coverage(i_mmarray *dot, int x, int y) {
frac minx = x*16;
frac maxx = minx+15;
frac cy;
int cnt = 0;
for(cy=y*16; cy<(y+1)*16; cy++) {
frac tmin = dot->data[cy].min;
frac tmax = dot->data[cy].max;
if (tmax == -1 || tmin > maxx || tmax < minx) continue;
if (tmin < minx) tmin = minx;
if (tmax > maxx) tmax = maxx;
cnt+=1+tmax-tmin;
}
return cnt;
}
/*
=item i_circle_aa(im, x, y, rad, color)
=category Drawing
=synopsis i_circle_aa(im, 50, 50, 45, &color);
Antialias fills a circle centered at (x,y) for radius I<rad> with
color.
=cut
*/
void
i_circle_aa(i_img *im, float x, float y, float rad, const i_color *val) {
i_mmarray dot;
i_color temp;
int ly;
mm_log((1, "i_circle_aa(im %p, x %d, y %d, rad %.2f, val %p)\n", im, x, y, rad, val));
i_mmarray_cr(&dot,16*im->ysize);
make_minmax_list(&dot, x, y, rad);
for(ly = 0; ly<im->ysize; ly++) {
int ix, cy, minx = INT_MAX, maxx = INT_MIN;
/* Find the left/rightmost set subpixels */
for(cy = 0; cy<16; cy++) {
frac tmin = dot.data[ly*16+cy].min;
frac tmax = dot.data[ly*16+cy].max;
if (tmax == -1) continue;
if (minx > tmin) minx = tmin;
if (maxx < tmax) maxx = tmax;
}
if (maxx == INT_MIN) continue; /* no work to be done for this row of pixels */
minx /= 16;
maxx /= 16;
for(ix=minx; ix<=maxx; ix++) {
int cnt = i_pixel_coverage(&dot, ix, ly);
if (cnt>255) cnt = 255;
if (cnt) { /* should never be true */
int ch;
float ratio = (float)cnt/255.0;
i_gpix(im, ix, ly, &temp);
for(ch=0;ch<im->channels; ch++) temp.channel[ch] = (unsigned char)((float)val->channel[ch]*ratio + (float)temp.channel[ch]*(1.0-ratio));
i_ppix(im, ix, ly, &temp);
}
}
}
i_mmarray_dst(&dot);
}
/*
=item i_box(im, x1, y1, x2, y2, color)
=category Drawing
=synopsis i_box(im, 0, 0, im->xsize-1, im->ysize-1, &color).
Outlines the box from (x1,y1) to (x2,y2) inclusive with I<color>.
=cut
*/
void
i_box(i_img *im,int x1,int y1,int x2,int y2,const i_color *val) {
int x,y;
mm_log((1,"i_box(im* 0x%x,x1 %d,y1 %d,x2 %d,y2 %d,val 0x%x)\n",im,x1,y1,x2,y2,val));
for(x=x1;x<x2+1;x++) {
i_ppix(im,x,y1,val);
i_ppix(im,x,y2,val);
}
for(y=y1;y<y2+1;y++) {
i_ppix(im,x1,y,val);
i_ppix(im,x2,y,val);
}
}
/*
=item i_box_filled(im, x1, y1, x2, y2, color)
=category Drawing
=synopsis i_box_filled(im, 0, 0, im->xsize-1, im->ysize-1, &color);
Fills the box from (x1,y1) to (x2,y2) inclusive with color.
=cut
*/
void
i_box_filled(i_img *im,int x1,int y1,int x2,int y2, const i_color *val) {
int x,y;
mm_log((1,"i_box_filled(im* 0x%x,x1 %d,y1 %d,x2 %d,y2 %d,val 0x%x)\n",im,x1,y1,x2,y2,val));
for(x=x1;x<x2+1;x++) for (y=y1;y<y2+1;y++) i_ppix(im,x,y,val);
}
/*
=item i_box_cfill(im, x1, y1, x2, y2, fill)
=category Drawing
=synopsis i_box_cfill(im, 0, 0, im->xsize-1, im->ysize-1, fill);
Fills the box from (x1,y1) to (x2,y2) inclusive with fill.
=cut
*/
void
i_box_cfill(i_img *im,int x1,int y1,int x2,int y2,i_fill_t *fill) {
mm_log((1,"i_box_cfill(im* 0x%x,x1 %d,y1 %d,x2 %d,y2 %d,fill 0x%x)\n",im,x1,y1,x2,y2,fill));
++x2;
if (x1 < 0)
x1 = 0;
if (y1 < 0)
y1 = 0;
if (x2 > im->xsize)
x2 = im->xsize;
if (y2 >= im->ysize)
y2 = im->ysize-1;
if (x1 >= x2 || y1 > y2)
return;
if (im->bits == i_8_bits && fill->fill_with_color) {
i_color *line = mymalloc(sizeof(i_color) * (x2 - x1)); /* checked 5jul05 tonyc */
i_color *work = NULL;
if (fill->combine)
work = mymalloc(sizeof(i_color) * (x2-x1)); /* checked 5jul05 tonyc */
while (y1 <= y2) {
if (fill->combine) {
i_glin(im, x1, x2, y1, line);
(fill->fill_with_color)(fill, x1, y1, x2-x1, im->channels, work);
(fill->combine)(line, work, im->channels, x2-x1);
}
else {
(fill->fill_with_color)(fill, x1, y1, x2-x1, im->channels, line);
}
i_plin(im, x1, x2, y1, line);
++y1;
}
myfree(line);
if (work)
myfree(work);
}
else {
i_fcolor *line = mymalloc(sizeof(i_fcolor) * (x2 - x1)); /* checked 5jul05 tonyc */
i_fcolor *work;
work = mymalloc(sizeof(i_fcolor) * (x2 - x1)); /* checked 5jul05 tonyc */
while (y1 <= y2) {
if (fill->combine) {
i_glinf(im, x1, x2, y1, line);
(fill->fill_with_fcolor)(fill, x1, y1, x2-x1, im->channels, work);
(fill->combinef)(line, work, im->channels, x2-x1);
}
else {
(fill->fill_with_fcolor)(fill, x1, y1, x2-x1, im->channels, line);
}
i_plinf(im, x1, x2, y1, line);
++y1;
}
myfree(line);
if (work)
myfree(work);
}
}
/*
=item i_line(im, x1, y1, x2, y2, val, endp)
=category Drawing
Draw a line to image using bresenhams linedrawing algorithm
im - image to draw to
x1 - starting x coordinate
y1 - starting x coordinate
x2 - starting x coordinate
y2 - starting x coordinate
val - color to write to image
endp - endpoint flag (boolean)
=cut
*/
void
i_line(i_img *im, int x1, int y1, int x2, int y2, const i_color *val, int endp) {
int x, y;
int dx, dy;
int p;
dx = x2 - x1;
dy = y2 - y1;
/* choose variable to iterate on */
if (abs(dx)>abs(dy)) {
int dx2, dy2, cpy;
/* sort by x */
if (x1 > x2) {
int t;
t = x1; x1 = x2; x2 = t;
t = y1; y1 = y2; y2 = t;
}
dx = abs(dx);
dx2 = dx*2;
dy = y2 - y1;
if (dy<0) {
dy = -dy;
cpy = -1;
} else {
cpy = 1;
}
dy2 = dy*2;
p = dy2 - dx;
y = y1;
for(x=x1; x<x2-1; x++) {
if (p<0) {
p += dy2;
} else {
y += cpy;
p += dy2-dx2;
}
i_ppix(im, x+1, y, val);
}
} else {
int dy2, dx2, cpx;
/* sort bx y */
if (y1 > y2) {
int t;
t = x1; x1 = x2; x2 = t;
t = y1; y1 = y2; y2 = t;
}
dy = abs(dy);
dx = x2 - x1;
dy2 = dy*2;
if (dx<0) {
dx = -dx;
cpx = -1;
} else {
cpx = 1;
}
dx2 = dx*2;
p = dx2 - dy;
x = x1;
for(y=y1; y<y2-1; y++) {
if (p<0) {
p += dx2;
} else {
x += cpx;
p += dx2-dy2;
}
i_ppix(im, x, y+1, val);
}
}
if (endp) {
i_ppix(im, x1, y1, val);
i_ppix(im, x2, y2, val);
} else {
if (x1 != x2 || y1 != y2)
i_ppix(im, x1, y1, val);
}
}
void
i_line_dda(i_img *im, int x1, int y1, int x2, int y2, i_color *val) {
float dy;
int x;
for(x=x1; x<=x2; x++) {
dy = y1+ (x-x1)/(float)(x2-x1)*(y2-y1);
i_ppix(im, x, (int)(dy+0.5), val);
}
}
void
i_line_aa3(i_img *im,int x1,int y1,int x2,int y2,i_color *val) {
i_color tval;
float alpha;
float dsec,dfrac;
int temp,dx,dy,isec,ch;
mm_log((1,"i_line_aa(im* 0x%x,x1 %d,y1 %d,x2 %d,y2 %d,val 0x%x)\n",im,x1,y1,x2,y2,val));
dy=y2-y1;
dx=x2-x1;
if (abs(dx)>abs(dy)) { /* alpha < 1 */
if (x2<x1) { temp=x1; x1=x2; x2=temp; temp=y1; y1=y2; y2=temp; }
alpha=(float)(y2-y1)/(float)(x2-x1);
dsec=y1;
while(x1<=x2) {
isec=(int)dsec;
dfrac=dsec-isec;
/* dfrac=1-(1-dfrac)*(1-dfrac); */
/* This is something we can play with to try to get better looking lines */
i_gpix(im,x1,isec,&tval);
for(ch=0;ch<im->channels;ch++) tval.channel[ch]=(unsigned char)(dfrac*(float)tval.channel[ch]+(1-dfrac)*(float)val->channel[ch]);
i_ppix(im,x1,isec,&tval);
i_gpix(im,x1,isec+1,&tval);
for(ch=0;ch<im->channels;ch++) tval.channel[ch]=(unsigned char)((1-dfrac)*(float)tval.channel[ch]+dfrac*(float)val->channel[ch]);
i_ppix(im,x1,isec+1,&tval);
dsec+=alpha;
x1++;
}
} else {
if (y2<y1) { temp=y1; y1=y2; y2=temp; temp=x1; x1=x2; x2=temp; }
alpha=(float)(x2-x1)/(float)(y2-y1);
dsec=x1;
while(y1<=y2) {
isec=(int)dsec;
dfrac=dsec-isec;
/* dfrac=sqrt(dfrac); */
/* This is something we can play with */
i_gpix(im,isec,y1,&tval);
for(ch=0;ch<im->channels;ch++) tval.channel[ch]=(unsigned char)(dfrac*(float)tval.channel[ch]+(1-dfrac)*(float)val->channel[ch]);
i_ppix(im,isec,y1,&tval);
i_gpix(im,isec+1,y1,&tval);
for(ch=0;ch<im->channels;ch++) tval.channel[ch]=(unsigned char)((1-dfrac)*(float)tval.channel[ch]+dfrac*(float)val->channel[ch]);
i_ppix(im,isec+1,y1,&tval);
dsec+=alpha;
y1++;
}
}
}
/*
=item i_line_aa(im, x1, x2, y1, y2, color, endp)
=category Drawing
Antialias draws a line from (x1,y1) to (x2, y2) in color.
The point (x2, y2) is drawn only if endp is set.
=cut
*/
void
i_line_aa(i_img *im, int x1, int y1, int x2, int y2, const i_color *val, int endp) {
int x, y;
int dx, dy;
int p;
dx = x2 - x1;
dy = y2 - y1;
/* choose variable to iterate on */
if (abs(dx)>abs(dy)) {
int dx2, dy2, cpy;
/* sort by x */
if (x1 > x2) {
int t;
t = x1; x1 = x2; x2 = t;
t = y1; y1 = y2; y2 = t;
}
dx = abs(dx);
dx2 = dx*2;
dy = y2 - y1;
if (dy<0) {
dy = -dy;
cpy = -1;
} else {
cpy = 1;
}
dy2 = dy*2;
p = dy2 - dx2; /* this has to be like this for AA */
y = y1;
for(x=x1; x<x2-1; x++) {
int ch;
i_color tval;
float t = (dy) ? -(float)(p)/(float)(dx2) : 1;
float t1, t2;
if (t<0) t = 0;
t1 = 1-t;
t2 = t;
i_gpix(im,x+1,y,&tval);
for(ch=0;ch<im->channels;ch++)
tval.channel[ch]=(unsigned char)(t1*(float)tval.channel[ch]+t2*(float)val->channel[ch]);
i_ppix(im,x+1,y,&tval);
i_gpix(im,x+1,y+cpy,&tval);
for(ch=0;ch<im->channels;ch++)
tval.channel[ch]=(unsigned char)(t2*(float)tval.channel[ch]+t1*(float)val->channel[ch]);
i_ppix(im,x+1,y+cpy,&tval);
if (p<0) {
p += dy2;
} else {
y += cpy;
p += dy2-dx2;
}
}
} else {
int dy2, dx2, cpx;
/* sort bx y */
if (y1 > y2) {
int t;
t = x1; x1 = x2; x2 = t;
t = y1; y1 = y2; y2 = t;
}
dy = abs(dy);
dx = x2 - x1;
dy2 = dy*2;
if (dx<0) {
dx = -dx;
cpx = -1;
} else {
cpx = 1;
}
dx2 = dx*2;
p = dx2 - dy2; /* this has to be like this for AA */
x = x1;
for(y=y1; y<y2-1; y++) {
int ch;
i_color tval;
float t = (dx) ? -(float)(p)/(float)(dy2) : 1;
float t1, t2;
if (t<0) t = 0;
t1 = 1-t;
t2 = t;
i_gpix(im,x,y+1,&tval);
for(ch=0;ch<im->channels;ch++)
tval.channel[ch]=(unsigned char)(t1*(float)tval.channel[ch]+t2*(float)val->channel[ch]);
i_ppix(im,x,y+1,&tval);
i_gpix(im,x+cpx,y+1,&tval);
for(ch=0;ch<im->channels;ch++)
tval.channel[ch]=(unsigned char)(t2*(float)tval.channel[ch]+t1*(float)val->channel[ch]);
i_ppix(im,x+cpx,y+1,&tval);
if (p<0) {
p += dx2;
} else {
x += cpx;
p += dx2-dy2;
}
}
}
if (endp) {
i_ppix(im, x1, y1, val);
i_ppix(im, x2, y2, val);
} else {
if (x1 != x2 || y1 != y2)
i_ppix(im, x1, y1, val);
}
}
static double
perm(int n,int k) {
double r;
int i;
r=1;
for(i=k+1;i<=n;i++) r*=i;
for(i=1;i<=(n-k);i++) r/=i;
return r;
}
/* Note in calculating t^k*(1-t)^(n-k)
we can start by using t^0=1 so this simplifies to
t^0*(1-t)^n - we want to multiply that with t/(1-t) each iteration
to get a new level - this may lead to errors who knows lets test it */
void
i_bezier_multi(i_img *im,int l,const double *x,const double *y, const i_color *val) {
double *bzcoef;
double t,cx,cy;
int k,i;
int lx = 0,ly = 0;
int n=l-1;
double itr,ccoef;
/* this is the same size as the x and y arrays, so shouldn't overflow */
bzcoef=mymalloc(sizeof(double)*l); /* checked 5jul05 tonyc */
for(k=0;k<l;k++) bzcoef[k]=perm(n,k);