void approximateWithTriangles(const Picture& src, Picture& dst, size_t x1,
size_t y1, size_t x2, size_t y2)
{
size_t rgbDst1[3] = {0,0,0}, rgbDst2[3] = {0,0,0};
size_t tr1Pixels = 0, tr2Pixels = 0;
for(size_t x = x1; x < x2; ++x) {
for(size_t y = y1; y < y2; ++y) {
Color color = src.color(x,y);
if(y - y1 >= x - x1) ++tr1Pixels;
else ++tr2Pixels;
for(size_t i = 0; i < 3; ++i) {
if(y - y1 >= x - x1) rgbDst1[i] += color[i];
else rgbDst2[i] += color[i];
}
}
}
for(size_t i = 0; i < 3; ++i) {
if(tr1Pixels > 0) rgbDst1[i] /= tr1Pixels;
if(tr2Pixels > 0) rgbDst2[i] /= tr2Pixels;
}
if(tr1Pixels > 0) {
int v1[] = {x1, y1, x1, y2 - 1, x2 - 1, y2 - 1};
Triangle t1(v1, Color(rgbDst1[0], rgbDst1[1], rgbDst1[2], 255));
dst.paintTriangle(t1);
triangles.push_back(t1);
}
if(tr2Pixels > 0) {
int v2[] = {x1 + 1, y1, x2-1, y1, x2-1, y2 - 2};
Triangle t2(v2, Color(rgbDst2[0], rgbDst2[1], rgbDst2[2], 255));
dst.paintTriangle(t2);
triangles.push_back(t2);
}
}
double Picture::distance(const Picture& pic) const {
assert(m_w == pic.m_w && m_h == pic.m_h);
double dsum = 0;
for(size_t x = 0; x < m_w; ++x) {
for(size_t y = 0; y < m_h; ++y) {
Color c1 = color(x,y), c2 = pic.color(x,y);
double tmp = 0;
for(size_t i = 0; i < 3; ++i) {
double p = c1[i] - (double)c2[i];
tmp += p*p;
}
dsum += sqrt(tmp);
}
}
return dsum;
}