Keep the charts in State

[batteryviewer] / chart.c

diff --git a/chart.c b/chart.c
index 27057839c0618502c34d3dbb225d54b5077bb779..808a275289830ebf36c179c1063ab704055222ad 100644 (file)
--- a/chart.c
+++ b/chart.c
@@ -24,7 +24,41 @@ struct BVChartPoint {
 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);
+
+  float xscale = allocation.width / (priv->maxx - priv->minx);
+  float yscale = allocation.height / (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),
+                yscale * (start->y - priv->maxy));
+  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),
+                  yscale * (p->y - priv->maxy));
+  }
+  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);