X-Git-Url: http://git.scottworley.com/batteryviewer/blobdiff_plain/5a9453723d439ed0e58681d7c0955c9f2e348b4d..dc8fff7805270c015ec9ae8baa2e85494abfffc0:/chart.c

diff --git a/chart.c b/chart.c
index 3efd454..835c63d 100644
--- a/chart.c
+++ b/chart.c
@@ -4,6 +4,7 @@
  */
 
 #include "chart.h"
+#include <float.h>
 #include <gtk/gtk.h>
 
 #define BV_CHART_PRIVATE(obj)                                                  \
@@ -12,18 +13,81 @@
 typedef struct _BVChartPrivate BVChartPrivate;
 
 struct _BVChartPrivate {
-  int temp;
+  GArray *points;
+  float minx, miny, maxx, maxy;
+};
+
+struct BVChartPoint {
+  float x, y;
 };
 
 G_DEFINE_TYPE_WITH_CODE(BVChart, bv_chart, GTK_TYPE_DRAWING_AREA,
                         G_ADD_PRIVATE(BVChart))
 
-static void bv_chart_class_init(BVChartClass *klass __attribute__((unused))) {}
+static gboolean bv_chart_draw(GtkWidget *widget, cairo_t *cr) {
+  BVChart *chart = BV_CHART(widget);
+  BVChartPrivate *priv = bv_chart_get_instance_private(chart);
+
+  cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
+  cairo_paint(cr);
+
+  if (priv->points->len < 2)
+    return TRUE;
+
+  GtkAllocation allocation;
+  gtk_widget_get_allocation(widget, &allocation);
+
+  int margin = 3;
+  float xscale = (allocation.width - 2 * margin) / (priv->maxx - priv->minx);
+  float yscale = (allocation.height - 2 * margin) / (priv->miny - priv->maxy);
+  cairo_set_source_rgb(cr, 0.0, 0.0, 1.0);
+  struct BVChartPoint *start =
+      &g_array_index(priv->points, struct BVChartPoint, 0);
+  cairo_move_to(cr, xscale * (start->x - priv->minx) + margin,
+                yscale * (start->y - priv->maxy) + margin);
+  for (guint i = 1; i < priv->points->len; i++) {
+    struct BVChartPoint *p =
+        &g_array_index(priv->points, struct BVChartPoint, i);
+    cairo_line_to(cr, xscale * (p->x - priv->minx) + margin,
+                  yscale * (p->y - priv->maxy) + margin);
+  }
+  cairo_stroke(cr);
+
+  return TRUE;
+}
+
+static void bv_chart_class_init(BVChartClass *klass) {
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS(klass);
+  widget_class->draw = bv_chart_draw;
+}
 
 static void bv_chart_init(BVChart *chart) {
   gtk_widget_set_has_window(GTK_WIDGET(chart), FALSE);
+  BVChartPrivate *priv = bv_chart_get_instance_private(chart);
+  gboolean zero_terminated = FALSE;
+  gboolean clear_ = FALSE;
+  priv->points =
+      g_array_new(zero_terminated, clear_, sizeof(struct BVChartPoint));
+  priv->minx = FLT_MAX;
+  priv->miny = FLT_MAX;
+  priv->maxx = FLT_MIN;
+  priv->maxy = FLT_MIN;
 }
 
 GtkWidget *bv_chart_new() {
   return GTK_WIDGET(g_object_new(bv_chart_get_type(), NULL));
 }
+
+void bv_chart_add_point(BVChart *chart, float x, float y) {
+  BVChartPrivate *priv = bv_chart_get_instance_private(chart);
+  if (x < priv->minx)
+    priv->minx = x;
+  if (y < priv->miny)
+    priv->miny = y;
+  if (x > priv->maxx)
+    priv->maxx = x;
+  if (y > priv->maxy)
+    priv->maxy = y;
+  struct BVChartPoint p = {.x = x, .y = y};
+  g_array_append_val(priv->points, p);
+}