New module to perform decimal floating point arithmetic for charts.

[pspp] / src / output / charts / plot-hist-cairo.c

diff --git a/src/output/charts/plot-hist-cairo.c b/src/output/charts/plot-hist-cairo.c
index 9ce4abb3ed09fec2796c25e4077e9520893116fc..006b39225e274f73e7d0dd2241a203ff7143d25c 100644 (file)
--- a/src/output/charts/plot-hist-cairo.c
+++ b/src/output/charts/plot-hist-cairo.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2009, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2009, 2011, 2014 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -15,9 +15,10 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
 #include <config.h>
-
+#include "math/decimal.h"
 #include "output/charts/plot-hist.h"
 
+#include <float.h>
 #include <gsl/gsl_randist.h>
 
 #include "data/val-type.h"
@@ -38,7 +39,7 @@ histogram_write_legend (cairo_t *cr, const struct xrchart_geometry *geom,
 
   if (n != SYSMIS)
     {
-      char *buf = xasprintf ("N = %.2f", n);
+      char *buf = xasprintf (_("N = %.2f"), n);
       cairo_move_to (cr, geom->legend_left, y);
       xrchart_label (cr, 'l', 'b', geom->font_size, buf);
       y += geom->font_size * 1.5;
@@ -47,7 +48,7 @@ histogram_write_legend (cairo_t *cr, const struct xrchart_geometry *geom,
 
   if (mean != SYSMIS)
     {
-      char *buf = xasprintf ("Mean = %.1f", mean);
+      char *buf = xasprintf (_("Mean = %.1f"), mean);
       cairo_move_to (cr,geom->legend_left, y);
       xrchart_label (cr, 'l', 'b', geom->font_size, buf);
       y += geom->font_size * 1.5;
@@ -56,7 +57,7 @@ histogram_write_legend (cairo_t *cr, const struct xrchart_geometry *geom,
 
   if (stddev != SYSMIS)
     {
-      char *buf = xasprintf ("Std. Dev = %.2f", stddev);
+      char *buf = xasprintf (_("Std. Dev = %.2f"), stddev);
       cairo_move_to (cr, geom->legend_left, y);
       xrchart_label (cr, 'l', 'b', geom->font_size, buf);
       free (buf);
@@ -67,25 +68,30 @@ histogram_write_legend (cairo_t *cr, const struct xrchart_geometry *geom,
 
 static void
 hist_draw_bar (cairo_t *cr, const struct xrchart_geometry *geom,
-               const gsl_histogram *h, int bar)
+               const gsl_histogram *h, int bar, bool label)
 {
   double upper;
   double lower;
   double height;
 
   const size_t bins = gsl_histogram_bins (h);
-  const double x_pos = (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) * bar / (double) bins ;
-  const double width = (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / (double) bins ;
+
+  const double x_pos =
+    (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) *
+    bar / (double) bins ;
+
+  const double width =
+    (geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min) / (double) bins ;
 
   assert ( 0 == gsl_histogram_get_range (h, bar, &lower, &upper));
 
   assert ( upper >= lower);
 
-  height = gsl_histogram_get (h, bar) /
-    (geom->axis[SCALE_ORDINATE].max - geom->axis[SCALE_ORDINATE].min) *
-    (geom->axis[SCALE_ORDINATE].data_max - geom->axis[SCALE_ORDINATE].data_min);
+  height = geom->axis[SCALE_ORDINATE].scale * gsl_histogram_get (h, bar);
 
-  cairo_rectangle (cr, geom->axis[SCALE_ABSCISSA].data_min + x_pos, geom->axis[SCALE_ORDINATE].data_min,
+  cairo_rectangle (cr,
+                  geom->axis[SCALE_ABSCISSA].data_min + x_pos,
+                  geom->axis[SCALE_ORDINATE].data_min,
                    width, height);
   cairo_save (cr);
   cairo_set_source_rgb (cr,
@@ -96,8 +102,21 @@ hist_draw_bar (cairo_t *cr, const struct xrchart_geometry *geom,
   cairo_restore (cr);
   cairo_stroke (cr);
 
-  draw_tick (cr, geom, SCALE_ABSCISSA,
-             x_pos + width / 2.0, "%g", (upper + lower) / 2.0);
+  if (label)
+    {
+      struct decimal decupper;
+      struct decimal declower;
+      struct decimal middle;
+      decimal_from_double (&declower, lower);
+      decimal_from_double (&decupper, upper);
+      middle = declower;
+      decimal_add (&middle, &decupper);
+      decimal_int_divide (&middle, 2);
+      char *str = decimal_to_string (&middle);
+      draw_tick (cr, geom, SCALE_ABSCISSA, bins > 10,
+                x_pos + width / 2.0, "%s", str);
+      free (str);
+    }
 }
 
 void
@@ -121,10 +140,12 @@ xrchart_draw_histogram (const struct chart_item *chart_item, cairo_t *cr,
 
   bins = gsl_histogram_bins (h->gsl_hist);
 
-  xrchart_write_yscale (cr, geom, 0, gsl_histogram_max_val (h->gsl_hist), 5);
+  xrchart_write_yscale (cr, geom, 0, gsl_histogram_max_val (h->gsl_hist));
 
   for (i = 0; i < bins; i++)
-    hist_draw_bar (cr, geom, h->gsl_hist, i);
+    {
+      hist_draw_bar (cr, geom, h->gsl_hist, i, true);
+    }
 
   histogram_write_legend (cr, geom, h->n, h->mean, h->stddev);