gtkdatabox-0.9.2.0.patch

diff --git a/gtk/gtkdatabox_lines.c b/gtk/gtkdatabox_lines.c
index 80e19cd..4fe05d9 100644
--- a/gtk/gtkdatabox_lines.c
+++ b/gtk/gtkdatabox_lines.c
@@ -132,6 +132,102 @@ gtk_databox_lines_new (guint len, gfloat * X, gfloat * Y,
    return GTK_DATABOX_GRAPH (lines);
 }
 
+static guint
+gtk_databox_lines_drop_points(GdkPoint * out, const GdkPoint * in,
+		guint len, guint *consumed)
+{
+	guint i;
+	gint min, max, x = in[0].x;
+
+	min = max = in[0].y;
+
+	for (i = 1; i < len && in[i].x == x; i++) {
+		min = MIN(min, in[i].y);
+		max = MAX(max, in[i].y);
+	}
+
+	*consumed = i;
+	out[0] = in[0];
+
+	if (min == max)
+		return 1;
+
+	/* More than two points -> some can be removed */
+	if (i > 2) {
+		out[1].x = x;
+
+		if (in[0].y == min) {
+			out[1].y = max;
+
+			if (in[i - 1].y == max) {
+				return 2;
+			} else {
+				out[2] = in[i - 1];
+				return 3;
+			}
+
+		} else if (in[0].y == max) {
+			out[1].y = min;
+
+			if (in[i - 1].y == min) {
+				return 2;
+			} else {
+				out[2] = in[i - 1];
+				return 3;
+			}
+
+		} else {
+			out[2].x = x;
+
+			if (in[i - 1].y == min) {
+				out[1].y = max;
+				out[2].y = min;
+				return 3;
+			} else if (in[i - 1].y == max) {
+				out[1].y = min;
+				out[2].y = max;
+				return 3;
+			} else if (in[0].y < in[i - 1].y) {
+				out[1].y = min;
+				out[2].y = max;
+				out[3] = in[i - 1];
+				return 4;
+			} else {
+				out[1].y = max;
+				out[2].y = min;
+				out[3] = in[i - 1];
+				return 4;
+			}
+		}
+
+	} else {
+		out[1] = in[1];
+		return 2;
+	}
+}
+
+static guint
+gtk_databox_reduce_number_of_points (GdkPoint *data, guint len)
+{
+	GdkPoint *in = data, *out = data;
+	guint new_len = 0;
+
+	do {
+		guint consumed;
+		guint ret = gtk_databox_lines_drop_points(
+				out, in, len, &consumed);
+		in += consumed;
+		if (len > consumed)
+			len -= consumed;
+		else
+			len = 0;
+		out += ret;
+		new_len += ret;
+	} while (len);
+
+	return new_len;
+}
+
 static void
 gtk_databox_lines_real_draw (GtkDataboxGraph * graph,
 			     GtkDatabox * box)
@@ -147,6 +243,7 @@ gtk_databox_lines_real_draw (GtkDataboxGraph * graph,
    gfloat *Y;
    guint len;
    gint size = 0;
+   gint width;
 
    g_return_if_fail (GTK_DATABOX_IS_LINES (lines));
    g_return_if_fail (GTK_IS_DATABOX (box));
@@ -166,6 +263,22 @@ gtk_databox_lines_real_draw (GtkDataboxGraph * graph,
 
    gtk_databox_values_to_pixels (box, len, X, Y, data);
 
+   /* Clip the points at the left of the drawing area */
+   for (i = 0; i < len && data[i].x < 0; i++);
+   if (i == len)
+	   return;
+
+   data += i;
+   len -= i;
+
+   /* Clip the points at the right of the drawing area */
+   gdk_pixmap_get_size (pixmap, &width, NULL);
+   for (i = 0; i < len && data[i].x < width; i++);
+
+   len = gtk_databox_reduce_number_of_points (data, i);
+   if (len <= 1)
+	   return;
+
    /* More than 2^16 lines will cause X IO error on most XServers
       (Hint from Paul Barton-Davis) */
    for (i = 0; i < len; i += 65536)