invest: Add chart with stock price history (#680)HEADmaster

* invest: Add chart with stock price history

Adds a chart window that shows stock price history over a configurable
time scale.

* invest: Use array index for x-axis

This gives all data points equal spacing and so gaps between market
closures are not shown.

* invest: Clean up chart pointers on applet removal

Running in-process mode, when the applet was removed from the panel, it
would try to call gtk_widget_get_visible on a destroyed widget, causing
a NULL pointer error. We fix it by properly cleaning up pointers on
applet destroy.

1 files changed, 77 insertions, 0 deletions

diff --git a/invest-applet/invest/invest-applet.h b/invest-applet/invest/invest-applet.h
new file mode 100644
index 00000000..ce610474
--- /dev/null
+++ b/invest-applet/invest/invest-applet.h
@@ -0,0 +1,77 @@
+/*
+ * MATE Invest Applet - Main applet header
+ * Copyright (C) 2025 MATE developers
+ *
+ * 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
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef INVEST_APPLET_H
+#define INVEST_APPLET_H
+
+#include <glib.h>
+#include <gtk/gtk.h>
+#include <mate-panel-applet.h>
+#include <libsoup/soup.h>
+
+G_BEGIN_DECLS
+
+typedef struct _InvestApplet InvestApplet;
+typedef struct _InvestAppletClass InvestAppletClass;
+
+struct _InvestApplet {
+    MatePanelApplet parent;
+
+    GtkWidget *label;
+    GtkWidget *direction_icon; /* icon for stock price going up/down/neutral */
+    GSettings *settings;
+    SoupSession *soup_session;
+
+    guint update_timeout_id;
+    gchar *stock_summary;
+    gdouble change_percent;
+    gint refresh_interval;
+    gint cycle_interval;
+
+    gint pending_requests;
+    gint total_symbols;
+    gchar **stock_symbols;
+    gdouble *stock_prices;
+    gdouble *stock_changes;
+    gboolean *stock_valid;
+
+    /* for cycling through multiple stocks */
+    gint cycle_position;
+    guint cycle_timeout_id;
+
+    /* Chart functionality */
+    struct _InvestChart *chart;
+};
+
+struct _InvestAppletClass {
+    MatePanelAppletClass parent_class;
+};
+
+#define INVEST_TYPE_APPLET (invest_applet_get_type())
+#define INVEST_APPLET(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj), INVEST_TYPE_APPLET, InvestApplet))
+#define INVEST_APPLET_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass), INVEST_TYPE_APPLET, InvestAppletClass))
+#define INVEST_IS_APPLET(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj), INVEST_TYPE_APPLET))
+#define INVEST_IS_APPLET_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass), INVEST_TYPE_APPLET))
+#define INVEST_APPLET_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS((obj), INVEST_TYPE_APPLET, InvestAppletClass))
+
+GType invest_applet_get_type(void);
+
+G_END_DECLS
+
+#endif /* INVEST_APPLET_H */