X-Git-Url: https://git.ucc.asn.au/?p=ipdf%2Fcode.git;a=blobdiff_plain;f=src%2Ftests%2Flines.cpp;fp=src%2Ftests%2Flines.cpp;h=b15d2182cd72e697c6e72cc51f376c1aeb16e58d;hp=0000000000000000000000000000000000000000;hb=433bde2ed090928b264203c9f422a5b220857120;hpb=57c3c69cbc7d9b3724874fd83cd001984ac21b6a

diff --git a/src/tests/lines.cpp b/src/tests/lines.cpp
new file mode 100644
index 0000000..b15d218
--- /dev/null
+++ b/src/tests/lines.cpp
@@ -0,0 +1,76 @@
+#include "main.h"
+
+#include "pointstobitmap.h"
+
+using namespace std;
+
+/**
+ * NOTE: I am using vector<pair<T,T> > because it is convenient; don't have to round to pixels, can print to stdout and gnuplot, etc
+ * 		vector<pair<T,T> > should obviously not be used in a practical implementation; directly access the pixel buffer
+ */
+
+template <class T> vector<pair<T, T> > LineDDA(const T & x1, const T & y1, const T & x2, const T & y2)
+{
+	T dx = x2 - x1;
+	T dy = y2 - y1;
+	uint64_t steps = lround(max(abs(dx), abs(dy)));
+	T xInc = T(dx)/T(steps);
+	T yInc = T(dy)/T(steps);
+	T x = x1; T y = y1;
+	vector<pair<T,T> > result(steps);
+	for (uint64_t k = 0; k <= steps; ++k)
+	{
+		result[k] = pair<T,T>(round(x), round(y));
+		x += xInc;
+		y += yInc;
+	}
+	return result;
+}
+/**
+ * Only works for 0 < m < 1
+ */
+template <class T> vector<pair<T, T> > LineBresenham(const T & x1, const T & y1, const T & x2, const T & y2)
+{
+	T dx = abs(x2 - x1);
+	T dy = abs(y2 - y1);
+	T p = 2*dy - dx;
+	T two_dy = 2*dy;
+	T two_dxdy = 2*(dy-dx);
+
+	T x; T y; T xEnd;
+	if (x1 > x2)
+	{
+		x = x2;
+		y = y2;
+		xEnd = x1;
+	}
+	else
+	{
+		x = x1;
+		y = y1;
+		xEnd = x2;
+	}
+	vector<pair<T,T> > result;
+	while (x < xEnd)
+	{
+		x += 1;
+		if (p < 0)
+			p += two_dy;
+		else
+		{
+			y += 1;
+			p += two_dxdy;
+		}
+		result.emplace_back(pair<T,T>(x,y));
+	}
+	return result;
+}
+
+int main(int argc, char ** argv)
+{
+	auto f = LineDDA<float>(0,0,400,200);
+	PointsToBitmap<float>(f, 1, 0,0,0,"lines.bmp");
+	auto i = LineBresenham<int>(0,100,400,300);
+	i.push_back(pair<int,int>(0,0));
+	PointsToBitmap<int>(i, 1, 255,0,0,"lines.bmp", true);
+}