[Experimental] Graph meter coloring by items.

This patch colors the graph meter based on the items of the bar meter.
For example, if most of the CPU power is running on low-priority
processes, then blue will be shown on the graph columns. If most of the
CPU is running on kernel things, then the columns will be red, and so
on.

The algorithm in this patch is not final yet. Expect some bugs such as:
that some of the cells are colored gray while ideally they shouldn't.

Meter.c

@@ -25,6 +25,8 @@ in the source distribution for its full text.
 
 #define GRAPH_DELAY (DEFAULT_DELAY/2)
 
+#define GRAPH_HEIGHT 4 /* Unit: rows (lines) */
+
 /*{
 #include "ListItem.h"
 
@@ -104,6 +106,9 @@ typedef enum {
 typedef struct GraphData_ {
    struct timeval time;
    double values[METER_BUFFER_LEN];
+   int colors[METER_BUFFER_LEN][GRAPH_HEIGHT];
+   double *prevItemSums;
+   double *currentItemSums;
 } GraphData;
 
 }*/
@@ -358,16 +363,22 @@ static const char* GraphMeterMode_dotsAscii[] = {
    /*20*/":", /*21*/":", /*22*/":"
 };
 
-#define GRAPH_HEIGHT 4 /* Unit: rows (lines) */
-
 static const char** GraphMeterMode_dots;
 static int GraphMeterMode_pixPerRow;
 
 static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
 
-   if (!this->drawData) this->drawData = calloc(1, sizeof(GraphData));
-    GraphData* data = (GraphData*) this->drawData;
    const int nValues = METER_BUFFER_LEN;
+   if (!this->drawData) {
+      this->drawData = calloc(1, sizeof(GraphData));
+      GraphData* data = (GraphData*) this->drawData;
+      for (int i = 0; i < nValues; i++) {
+         for (int line = 0; line < GRAPH_HEIGHT; line++) {
+            data->colors[i][line] = CRT_colors[BAR_SHADOW];
+         }
+      }
+   }
+   GraphData* data = (GraphData*) this->drawData;
 
 #ifdef HAVE_LIBNCURSESW
    if (CRT_utf8) {
@@ -392,18 +403,51 @@ static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
       struct timeval delay = { .tv_sec = (int)(CRT_delay/10), .tv_usec = (CRT_delay-((int)(CRT_delay/10)*10)) * 100000 };
       timeradd(&now, &delay, &(data->time));
 
-      for (int i = 0; i < nValues - 1; i++)
+      for (int i = 0; i < nValues - 1; i++) {
          data->values[i] = data->values[i+1];
+         memcpy(data->colors[i], data->colors[i+1], sizeof(data->colors[i]));
+      }
    
       char buffer[nValues];
       Meter_setValues(this, buffer, nValues - 1);
-   
-      double value = 0.0;
+
       int items = Meter_getItems(this);
-      for (int i = 0; i < items; i++)
-         value += this->values[i];
-      value /= this->total;
-      data->values[nValues - 1] = value;
+
+      if (!data->prevItemSums) {
+         data->prevItemSums = calloc(items, sizeof(*data->prevItemSums));
+      }
+      if (!data->currentItemSums) {
+         data->currentItemSums = calloc(items, sizeof(*data->currentItemSums));
+      }
+      double *prevItemSums = data->prevItemSums;
+      double *currentItemSums = data->currentItemSums;
+      
+      currentItemSums[0] = this->values[0];
+      for (int i = 0; i < items; i++) {
+         prevItemSums[i] = currentItemSums[i];
+         currentItemSums[i] = ((i > 0) ? currentItemSums[i-1] : 0) + this->values[i];
+      }
+      data->values[nValues - 1] = currentItemSums[items - 1] / this->total;
+
+      // Determine the dominant color of the cell in graph
+      for (int line = 0; line < GRAPH_HEIGHT; line++) {
+         int dominantColor = CRT_colors[BAR_SHADOW];
+         double maxArea = 0.0;
+         for (int i = 0; i < items; i++) {
+             double area;
+             area = MIN(currentItemSums[i], this->total * (GRAPH_HEIGHT - line) / GRAPH_HEIGHT) +
+                    MIN(prevItemSums[i], this->total * (GRAPH_HEIGHT - line) / GRAPH_HEIGHT);
+             if (i > 0) {
+                area -= MAX(currentItemSums[i-1], this->total * (GRAPH_HEIGHT - 1 - line) / GRAPH_HEIGHT) +
+                        MAX(prevItemSums[i-1], this->total * (GRAPH_HEIGHT - 1 - line) / GRAPH_HEIGHT);
+             }
+             if (area > maxArea) {
+                maxArea = area;
+                dominantColor = CRT_colors[Meter_attributes(this)[i]];
+             }
+         }
+         data->colors[nValues - 1][line] = dominantColor;
+      }
    }
    
    for (int i = nValues - (w*2) + 2, k = 0; i < nValues; i+=2, k++) {
@@ -411,14 +455,12 @@ static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
       int v1 = MIN(GraphMeterMode_pixPerRow * GRAPH_HEIGHT, MAX(1, data->values[i] / dot));
       int v2 = MIN(GraphMeterMode_pixPerRow * GRAPH_HEIGHT, MAX(1, data->values[i+1] / dot));
 
-      int colorIdx = GRAPH_1;
       for (int line = 0; line < GRAPH_HEIGHT; line++) {
          int line1 = MIN(GraphMeterMode_pixPerRow, MAX(0, v1 - (GraphMeterMode_pixPerRow * (GRAPH_HEIGHT - 1 - line))));
          int line2 = MIN(GraphMeterMode_pixPerRow, MAX(0, v2 - (GraphMeterMode_pixPerRow * (GRAPH_HEIGHT - 1 - line))));
-
-         attrset(CRT_colors[colorIdx]);
+         
+         attrset(data->colors[i+1][line]);
          mvaddstr(y+line, x+k, GraphMeterMode_dots[line1 * (GraphMeterMode_pixPerRow + 1) + line2]);
-         colorIdx = GRAPH_2;
       }
    }
    attrset(CRT_colors[RESET_COLOR]);

Meter.h

@@ -13,6 +13,8 @@ in the source distribution for its full text.
 
 #define GRAPH_DELAY (DEFAULT_DELAY/2)
 
+#define GRAPH_HEIGHT 4 /* Unit: rows (lines) */
+
 #include "ListItem.h"
 
 #include <sys/time.h>
@@ -91,6 +93,9 @@ typedef enum {
 typedef struct GraphData_ {
    struct timeval time;
    double values[METER_BUFFER_LEN];
+   int colors[METER_BUFFER_LEN][GRAPH_HEIGHT];
+   double *prevItemSums;
+   double *currentItemSums;
 } GraphData;
 
 
@@ -127,8 +132,6 @@ ListItem* Meter_toListItem(Meter* this, bool moving);
 #endif
 
 #define PIXPERROW_ASCII 2
-#define GRAPH_HEIGHT 4 /* Unit: rows (lines) */
-
 
 /* ---------- LEDMeterMode ---------- */