1 files changed, 62 insertions, 0 deletions
diff --git a/utils/hp2ps/AreaBelow.c b/utils/hp2ps/AreaBelow.c
new file mode 100644
index 0000000000..ec80e1ed48
--- /dev/null
+++ b/utils/hp2ps/AreaBelow.c
@@ -0,0 +1,62 @@
+#include "Main.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "Defines.h"
+#include "Error.h"
+#include "HpFile.h"
+#include "Utilities.h"
+
+/* own stuff */
+#include "AreaBelow.h"
+
+/*
+ *      Return the area enclosed by all of the curves. The algorithm
+ *	used is the same as the trapizoidal rule for integration. 
+ */
+ 
+floatish
+AreaBelow()
+{
+    intish i;
+    intish j;
+    intish bucket;
+    floatish value;
+    struct chunk *ch;
+    floatish area;
+    floatish trap;
+    floatish base;
+    floatish *maxima;
+
+    maxima = (floatish *) xmalloc(nsamples * sizeof(floatish));
+    for (i = 0; i < nsamples; i++) {
+        maxima[i] = 0.0;
+    }   
+
+    for (i = 0; i < nidents; i++) {
+        for (ch = identtable[i]->chk; ch; ch = ch->next) {
+            for (j = 0; j < ch->nd; j++) {
+                bucket = ch->d[j].bucket;
+                value  = ch->d[j].value;
+		if (bucket >= nsamples)
+		    Disaster("bucket out of range");
+                maxima[ bucket ] += value;
+            }   
+        }    
+    }    
+
+    area = 0.0;
+
+    for (i = 1; i < nsamples; i++) {
+	base = samplemap[i] - samplemap[i-1];
+        if (maxima[i] > maxima[i-1]) {
+	    trap = base * maxima[i-1] + ((base * (maxima[i] - maxima[i-1]))/ 2.0);
+	} else {
+	    trap = base * maxima[i]   + ((base * (maxima[i-1] - maxima[i]))/ 2.0);
+        }
+
+	area += trap;
+    }
+
+    free(maxima);
+    return area;
+}