Meter: introduce comprisedValues option

Useful for bar mode if latter values of the meter comprise previous
ones.

Meter.c

@@ -219,6 +219,7 @@ static void BarMeterMode_draw(Meter* this, int x, int y, int w) {
  assert(startPos + w <= RichString_sizeVal(bar));
 
  int blockSizes[10];
+ int blockSizeSum = 0;
 
  // First draw in the bar[] buffer...
  int offset = 0;
@@ -230,6 +231,12 @@ static void BarMeterMode_draw(Meter* this, int x, int y, int w) {
  } else {
  blockSizes[i] = 0;
  }
+
+ if (Meter_comprisedValues(this)) {
+ blockSizes[i] = MAXIMUM(blockSizes[i] - blockSizeSum, 0);
+ blockSizeSum += blockSizes[i];
+ }
+
  int nextOffset = offset + blockSizes[i];
  // (Control against invalid values)
  nextOffset = CLAMP(nextOffset, 0, w);
@@ -323,10 +330,14 @@ static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
  for (int i = 0; i < nValues - 1; i++)
  data->values[i] = data->values[i + 1];
 
- double value = 0.0;
- for (uint8_t i = 0; i < this->curItems; i++)
- value += !isnan(this->values[i]) ? this->values[i] : 0;
- data->values[nValues - 1] = value;
+ if (Meter_comprisedValues(this)) {
+ data->values[nValues - 1] = (this->curItems > 0) ? this->values[this->curItems - 1] : 0.0;
+ } else {
+ double value = 0.0;
+ for (uint8_t i = 0; i < this->curItems; i++)
+ value += !isnan(this->values[i]) ? this->values[i] : 0;
+ data->values[nValues - 1] = value;
+ }
  }
 
  int i = nValues - (w * 2), k = 0;

Meter.h

@@ -74,6 +74,7 @@ typedef struct MeterClass_ {
  const char* const description; /* optional meter description in header setup menu */
  const uint8_t maxItems;
  const bool isMultiColumn; /* whether the meter draws multiple sub-columns (defaults to false) */
+ const bool comprisedValues; /* whether latter values comprise previous ones (defaults to false) */
 } MeterClass;
 
 #define As_Meter(this_) ((const MeterClass*)((this_)->super.klass))
@@ -94,6 +95,7 @@ typedef struct MeterClass_ {
 #define Meter_name(this_) As_Meter(this_)->name
 #define Meter_uiName(this_) As_Meter(this_)->uiName
 #define Meter_isMultiColumn(this_) As_Meter(this_)->isMultiColumn
+#define Meter_comprisedValues(this_) As_Meter(this_)->comprisedValues
 
 typedef struct GraphData_ {
  struct timeval time;