osc: Implement a way to provide custom algorithm for XY plot

Usage example:
/* define the routine with the algorithm */
static void my_xy_transform(gfloat *x_in, gfloat *y_in, gfloat *x_out, gfloat *y_out,
	unsigned int length, void *user_data)
{
	unsigned int i;
	for (i = 0; i < length; ++i) {
		x_out[i] = some_custom_algorithm(x_in[i]);
		y_out[i] = some_custom_algorithm(y_in[i]);
	}
}

/* Look for an already created plot instance that is configured to display XY data.
Then, configure it to call your routine. Make sure that the plot is stopped the
first time you set the routine. This is to tell the plot to create some internal
buffers first. */
bool plot_is_running = false;
OscPlot *xy_plot = plugin_find_plot_with_domain(XY_PLOT);
if (xy_plot) {
	plot_is_running = osc_plot_running_state(xy_plot);
	if (!plot_is_running) {
		osc_plot_set_xy_transform(xy_plot, my_xy_transform, NULL);
	}
}

Signed-off-by: Dan <[email protected]>

datatypes.h

@@ -150,6 +150,9 @@ struct _constellation_settings {
 	gfloat *x_source;
 	gfloat *y_source;
 	unsigned int num_samples;
+	void (*xy_transform)(gfloat *x_in, gfloat *y_in, gfloat *x_out, gfloat *y_out,
+			unsigned int length, void *user_data); /* optional */
+	void *xy_transform_user_data; /* optional */
 };
 
 struct _cross_correlation_settings {

oscplot.c

@@ -418,6 +418,9 @@ struct _OscPlotPrivate
 
 	void (*quit_callback)(void *user_data);
 	void *qcb_user_data;
+	void (*xy_transform)(gfloat *x_in, gfloat *y_in, gfloat *x_out,
+		gfloat *y_out, unsigned int length, void *user_data);
+	void *xy_transform_user_data;
 };
 
 G_DEFINE_TYPE_WITH_PRIVATE(OscPlot, osc_plot, GTK_TYPE_WIDGET)
@@ -869,6 +872,16 @@ void osc_plot_spect_set_filter_bw(OscPlot *plot, double bw)
 	plot->priv->filter_bw = bw;
 }
 
+void osc_plot_set_xy_transform(OscPlot *plot, void (*xy_transform)(gfloat *x_in,
+		gfloat *y_in, gfloat *x_out, gfloat *y_out, unsigned int length,
+		void *user_data), void *user_data)
+{
+	g_return_if_fail(plot);
+
+	plot->priv->xy_transform = xy_transform;
+	plot->priv->xy_transform_user_data = user_data;
+}
+
 static void osc_plot_dispose(GObject *object)
 {
 	G_OBJECT_CLASS(osc_plot_parent_class)->dispose(object);
@@ -1862,20 +1875,30 @@ bool constellation_transform_function(Transform *tr, gboolean init_transform)
 		/* Initialize axis */
 		tr->x_axis_size = axis_length;
 		tr->y_axis_size = axis_length;
-		tr->x_axis = settings->x_source;
-		tr->y_axis = settings->y_source;
+		if (settings->xy_transform) {
+			Transform_resize_x_axis(tr, axis_length);
+			Transform_resize_y_axis(tr, axis_length);
+		} else {
+			tr->x_axis = settings->x_source;
+			tr->y_axis = settings->y_source;
+		}
 
 		return true;
 	}
 
 	GSList *node;
 
-	if (tr->plot_channels_type == PLOT_MATH_CHANNEL)
+	if (tr->plot_channels_type == PLOT_MATH_CHANNEL) {
 		for (node = tr->plot_channels; node; node = g_slist_next(node)) {
 			PlotMathChn *m = node->data;
 			m->math_expression(m->iio_channels_data,
 				m->data_ref, settings->num_samples);
 		}
+	} else if (settings->xy_transform) {
+		settings->xy_transform(
+			plot_channels_get_nth_data_ref(tr->plot_channels, 0), plot_channels_get_nth_data_ref(tr->plot_channels, 1),
+			tr->x_axis, tr->y_axis, settings->num_samples, settings->xy_transform_user_data);
+	}
 
 	return true;
 }
@@ -2457,6 +2480,8 @@ static void update_transform_settings(OscPlot *plot, Transform *transform)
 		}
 	} else if (plot_type == XY_PLOT){
 		CONSTELLATION_SETTINGS(transform)->num_samples = gtk_spin_button_get_value(GTK_SPIN_BUTTON(priv->sample_count_widget));
+		CONSTELLATION_SETTINGS(transform)->xy_transform = priv->xy_transform;
+		CONSTELLATION_SETTINGS(transform)->xy_transform_user_data = priv->xy_transform_user_data;
 	} else if (plot_type == XCORR_PLOT){
 		int dev_samples = plot_get_sample_count_for_transform(plot, transform);
 		if (dev_samples < 0)
@@ -7427,6 +7452,9 @@ static void create_plot(OscPlot *plot)
 
 	priv->line_thickness = 1;
 
+	priv->xy_transform = NULL;
+	priv->xy_transform_user_data = NULL;
+
 	gtk_window_set_modal(GTK_WINDOW(priv->saveas_dialog), FALSE);
 	gtk_widget_show_all(priv->capture_graph);
 }

oscplot.h

@@ -76,6 +76,8 @@ void          osc_plot_spect_mode       (OscPlot *plot, bool enable);
 void          osc_plot_spect_set_start_f(OscPlot *plot, double freq_mhz);
 void          osc_plot_spect_set_len    (OscPlot *plot, unsigned fft_count);
 void          osc_plot_spect_set_filter_bw(OscPlot *plot, double bw);
+void          osc_plot_set_xy_transform (OscPlot *plot, void (*xy_transform)(gfloat *x_in, gfloat *y_in,
+				gfloat *x_out, gfloat *y_out, unsigned int length, void *user_data), void *user_data);
 
 G_END_DECLS