Revision 2088cf2f69747cf62d6c7224652ae752b134b33a authored by Software Heritage on 26 June 2019, 00:00:00 UTC, committed by Software Heritage on 10 August 2019, 00:00:00 UTC
0 parent
draw_curve.cpp
// SPDX-License-Identifier: GPL-3.0-or-later
/**
* @file draw_curve.cpp
* @brief Draw a curve in an image
*
* (C) 2011-2014, 2019, Pascal Monasse <pascal.monasse@enpc.fr>
*/
#include "draw_curve.h"
/// max(0,min(abs(v),m-1))
static int clip(float v, int m) {
if(v<0)
return 0;
if(v>=m)
return m-1;
return (int)v;
}
/// Draw line in image
void draw_line(const Point& p, const Point& q, unsigned char v,
unsigned char* im, int w, int h) {
int x0=clip(p.x,w), x1=clip(q.x,w);
int y0=clip(p.y,h), y1=clip(q.y,h);
if(x0==x1 && y0==y1) {
im[y0*w+x0] = v;
return;
}
int sx = (x0<x1)? +1: -1;
int sy = (y0<y1)? +1: -1;
int dx=x1-x0, dy=y1-y0;
int adx=sx*dx, ady=sy*dy;
int x=0,y=0;
if(adx>=ady) {
int z=-adx/2;
while(x!=dx) {
im[(y+y0)*w+(x+x0)] = v;
x += sx;
z += ady;
if(z>0) {
y += sy;
z -= adx;
}
}
} else {
int z=-ady/2;
while(y!=dy) {
im[(y+y0)*w+(x+x0)] = v;
y += sy;
z += adx;
if(z>0) {
x += sx;
z -= ady;
}
}
}
}
/// Draw curve in image
void draw_curve(const std::vector<Point>& curve, unsigned char v,
unsigned char* im, int w, int h) {
if(curve.empty())
return;
Point delta(.5f, .5f);
std::vector<Point>::const_iterator it=curve.begin();
Point o = *it++;
while(it != curve.end()) {
draw_line(o+delta, *it+delta, v, im,w,h);
o = *it++;
}
}
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