From 4314729ddef28cb619ce97d50f0968ca24c93803 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Wed, 14 Apr 2004 19:54:10 +0000
Subject: Add graph, plot

---
 src/cmd/plot/libplot/vec.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 src/cmd/plot/libplot/vec.c

(limited to 'src/cmd/plot/libplot/vec.c')

diff --git a/src/cmd/plot/libplot/vec.c b/src/cmd/plot/libplot/vec.c
new file mode 100644
index 00000000..89a51786
--- /dev/null
+++ b/src/cmd/plot/libplot/vec.c
@@ -0,0 +1,26 @@
+#include "mplot.h"
+#define	code(x, y)	((x<clipminx?1:x>clipmaxx?2:0)|(y<clipminy?4:y>clipmaxy?8:0))
+void vec(double xx, double yy){
+	int x0, y0, x1, y1, c0, c1, c, tx, ty;
+	double t;
+	t=SCX(e1->copyx); if(fabs(t)>BIGINT) return; x0=t;
+	t=SCY(e1->copyy); if(fabs(t)>BIGINT) return; y0=t;
+	t=SCX(xx); if(fabs(t)>BIGINT) return; x1=t;
+	t=SCY(yy); if(fabs(t)>BIGINT) return; y1=t;
+	e1->copyx=xx;
+	e1->copyy=yy;
+	/* clipping -- what a concept */
+	c0=code(x0, y0);
+	c1=code(x1, y1);
+	while(c0|c1){
+		if(c0&c1) return;
+		c=c0?c0:c1;
+		if(c&1)      ty=y0+(y1-y0)*(clipminx-x0)/(x1-x0), tx=clipminx;
+		else if(c&2) ty=y0+(y1-y0)*(clipmaxx-x0)/(x1-x0), tx=clipmaxx;
+		else if(c&4) tx=x0+(x1-x0)*(clipminy-y0)/(y1-y0), ty=clipminy;
+		else         tx=x0+(x1-x0)*(clipmaxy-y0)/(y1-y0), ty=clipmaxy;
+		if(c==c0) x0=tx, y0=ty, c0=code(x0, y0);
+		else      x1=tx, y1=ty, c1=code(x1, y1);
+	}
+	m_vector(x0, y0, x1, y1, e1->foregr);
+}
-- 
cgit v1.2.3