1 files changed, 67 insertions, 0 deletions
diff --git a/initrd/graph b/initrd/graph
new file mode 100644
index 0000000..a218474
--- /dev/null
+++ b/initrd/graph
@@ -0,0 +1,67 @@
+# graph area
+plotx = 50
+ploty = 50
+plotw = 380
+ploth = 220
+cx = plotx + plotw / 2
+cy = ploty + ploth / 2
+
+# graph range
+xmin = 0 - 10
+xmax = 10
+ymin = 0 - 10
+ymax = 10
+
+xinc = plotw / (xmax - xmin)
+yinc = ploth / (ymax - ymin)
+
+mlines = color(3, 3, 3)
+
+func(makegrid) {
+	rect(plotx, ploty, plotw, ploth, 0)
+
+	x = plotx 
+	while (x <= plotx + plotw) {
+		line(x, ploty, x, ploty + ploth, mlines)
+		x = x + xinc
+	}
+
+	y = ploty
+	while (y <= ploty + ploth) {
+		line(plotx, y, plotx + plotw, y, mlines)
+		y = y + yinc
+	}
+
+	line(cx, ploty, cx, ploty + ploth, 32767)
+	line(plotx, cy, plotx + plotw, cy, 32767)
+}
+
+#
+# BIG LOOP - ask for equ, graph it
+#
+
+makegrid
+clearcmd = "clear"
+while (1) {
+	rect(0, 0, 480, 40, 0)
+	print("f(x) = ")
+	Fx = gets()
+
+	if (Fx == clearcmd) {
+		makegrid
+	} else {
+		# do function
+		x = xmin
+		while (x < xmax) {
+			y = solve(Fx)
+			y = 0 - y
+			if ((y >= ymin) & (y <= ymax)) {
+				pixel(cx + x * xinc, cy + y * yinc, 511)
+			}
+			x = x + 1 / xinc
+		}
+	}
+
+	ppos(0, 0)
+}
+