* Not ideal, but it is functional.

[scdataviz] / graph.c

diff --git a/graph.c b/graph.c
index 1af3cb8..df419b9 100644 (file)
--- a/graph.c
+++ b/graph.c
@@ -32,6 +32,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <graph.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <math.h>
+
+#ifdef DEBUG
+#define DEBUG_AUTOAXIS
+#endif
 
 G_DEFINE_TYPE(Graph, graph, G_TYPE_OBJECT);
 
@@ -44,6 +49,7 @@ static void graph_init(Graph *graph) {
   graph->symbol = CIRCLE;
   graph->points = g_ptr_array_new();
   graph->lines = NULL;
+  graph->xaxis = graph->yaxis = NULL;
 }
 
 Graph *graph_new(void) {
@@ -82,6 +88,7 @@ int graph_add_point(Graph* graph, double x, double y, const GString *label) {
 }
 
 int graph_add_graph_line(Graph* graph, struct graph_line *l) {
+  if(l == NULL) return 1;
   if(graph->lines == NULL) {
     if((graph->lines = g_ptr_array_new()) == NULL) return 1;
   }
@@ -159,3 +166,69 @@ void graph_bezier_quadratic_to_cubic(double x0, double x3, double *x1, double *x
   *x2 = (x3-2.0*(*x1))/3.0;
   *x1 = (x0-2.0*(*x1))/3.0;
 }
+
+void graph_set_xaxis(Graph *g, struct graph_axis *axis) {
+  if(g->xaxis != NULL) {
+    free(g->xaxis);
+  }
+  g->xaxis=axis;
+}
+void graph_set_yaxis(Graph *g, struct graph_axis *axis) {
+  if(g->yaxis != NULL) {
+    free(g->yaxis);
+  }
+  g->yaxis=axis;
+}
+
+struct graph_axis* autoset_axis(Graph* g, GString* title, double min, double max) {
+  struct graph_axis *axis;
+  double range_mag;
+  double start_mag;
+  double stop_mag;
+  if(g->points->len == 0) {
+    return NULL;
+  }
+  if((axis=(struct graph_axis *)malloc(sizeof(struct graph_axis))) == NULL) {
+    return NULL;
+  }
+  if(g->points->len == 1) {
+    axis->major=1;
+    axis->minor=0;
+    axis->subminor=0;
+    axis->major_start=min;
+    axis->major_step=max;
+  }else{
+    range_mag = logb(max - min);
+    if(min == 0) 
+      start_mag = 0;
+    else
+      start_mag = copysign(pow(10, floor(log10(min))), min);
+    if(max == 0) 
+      stop_mag = 0;
+    else
+      stop_mag = copysign(pow(10, ceil(log10(max))), max);
+    if(stop_mag == start_mag) stop_mag *= 10;
+    axis->major=10;
+    axis->minor=0;
+    axis->subminor=0;
+    axis->major_start=start_mag;
+    axis->major_step=(stop_mag - start_mag)/(axis->major);
+  }
+  axis->title=g_string_new(title->str);
+  #ifdef DEBUG_AUTOAXIS
+  fprintf(stderr, "graph_autoset_xaxis: xmin=%g, log10(xmin)=%g, floor=%g, pow=%g round=%g\n", min, log10(min), floor(log10(min)), pow(10, floor(log10(min))), round(pow(10, floor(log10(min)))));
+  fprintf(stderr, "graph_autoset_xaxis: xmax=%g, log10(xmax)=%g, floor=%g, pow=%g round=%g\n", max, log10(max), floor(log10(max)), pow(10, floor(log10(max))), round(pow(10, floor(log10(max)))));
+  fprintf(stderr, "graph_autoset_xaxis: xmin=%g,max=%g start_mag=%g, stop_mag=%g range_mag=%g\n", min, max, start_mag, stop_mag, range_mag);
+  #endif
+  return axis;
+}
+
+int graph_autoset_xaxis(Graph *g, GString *title) {
+  graph_set_xaxis(g, autoset_axis(g, title, g->minx, g->maxx));
+  return 0;
+}
+
+int graph_autoset_yaxis(Graph *g, GString *title) {
+  graph_set_yaxis(g, autoset_axis(g, title, g->miny, g->maxy));
+  return 0;
+}