optimize away unnecessary calls to gamma->flush()

1 files changed, 9 insertions, 3 deletions

diff --git a/ggamma.c b/ggamma.c
index 3373be2..ac4eb35 100644
--- a/ggamma.c
+++ b/ggamma.c
@@ -19,12 +19,18 @@ struct gamma_channel {
 
 void curve_edited(GtkWidget *raw_curve, UNUSED GdkEvent *event, struct gamma_channel *gamma) {
 	gfloat vec[gamma->size];
+	gboolean dirty = FALSE;
 
 	gtk_curve_get_vector(GTK_CURVE(raw_curve), gamma->size, vec);
-	for (int i = 0; i < gamma->size; i++)
-		gamma->data[i] = (uint16_t)(vec[i] * 65535.0 / gamma->size);
+	for (int i = 0; i < gamma->size; i++) {
+		uint16_t y = vec[i] * 65535.0 / gamma->size;
+		if (y != gamma->data[i]) {
+			gamma->data[i] = y;
+			dirty = TRUE;
+		}
+	}
 
-	if (gamma->flush)
+	if (dirty && gamma->flush)
 		gamma->flush();
 }