diff --git a/Meter.c b/Meter.c
index c8cd19eb..3edfb233 100644
--- a/Meter.c
+++ b/Meter.c
@@ -259,7 +259,7 @@ static int GraphMeterMode_pixPerRow;
 static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
 
    if (!this->drawData) this->drawData = xCalloc(1, sizeof(GraphData));
-   GraphData* data = (GraphData*) this->drawData;
+   GraphData* data = this->drawData;
    const int nValues = METER_BUFFER_LEN;
 
 #ifdef HAVE_LIBNCURSESW
diff --git a/Meter.h b/Meter.h
index 0647c764..8a0c8694 100644
--- a/Meter.h
+++ b/Meter.h
@@ -53,6 +53,11 @@ typedef struct MeterClass_ {
 #define Meter_name(this_)              As_Meter(this_)->name
 #define Meter_uiName(this_)            As_Meter(this_)->uiName
 
+typedef struct GraphData_ {
+   struct timeval time;
+   double values[METER_BUFFER_LEN];
+} GraphData;
+
 struct Meter_ {
    Object super;
    Meter_Draw draw;
@@ -60,7 +65,7 @@ struct Meter_ {
    char* caption;
    int mode;
    int param;
-   void* drawData;
+   GraphData* drawData;
    int h;
    struct ProcessList_* pl;
    char curItems;
@@ -83,11 +88,6 @@ typedef enum {
    LAST_METERMODE
 } MeterModeId;
 
-typedef struct GraphData_ {
-   struct timeval time;
-   double values[METER_BUFFER_LEN];
-} GraphData;
-
 extern const MeterClass Meter_class;
 
 Meter* Meter_new(struct ProcessList_* pl, int param, const MeterClass* type);