CPUMeter: Improve spacing between sub-meter algorithm

The new algorithm will make the meter bars aligned when groups of CPU
meters with 2, 4 and 8 sub-columns are placed together in one larger
column. It utilizes the fact that the number of sub-columns of CPU
meters are in power of 2 only, and calculates spacing with bit tricks.

Signed-off-by: Kang-Che Sung <[email protected]>

Author: Explorer09

CPUMeter.c

@@ -12,6 +12,7 @@ in the source distribution for its full text.
 #include <assert.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -306,11 +307,14 @@ static void CPUMeterCommonDraw(Meter* this, int x, int y, int w, int ncol) {
    int start, count;
    AllCPUsMeter_getRange(this, &start, &count);
    int colwidth = w / ncol;
-   int diff = w % ncol;
    int nrows = (count + ncol - 1) / ncol;
    for (int i = 0; i < count; i++) {
-      int d = (i / nrows) > diff ? diff : (i / nrows); // dynamic spacer
-      int xpos = x + ((i / nrows) * colwidth) + d;
+      // Spacing between meters based on the remainder of (w % ncol)
+      uint32_t v = (unsigned int)((w % ncol) * 32 / ncol);
+      v = ((v * 0x00210842U) & 0x02082082U) * (unsigned int)(i / nrows);
+      v = (uint32_t)(((v + 0x02108420U) & 0x7DE71840U) * 0x00210842ULL) >> 27;
+      int spacing = (int)v;
+      int xpos = x + ((i / nrows) * colwidth) + spacing;
       int ypos = y + ((i % nrows) * meters[0]->h);
       meters[i]->draw(meters[i], xpos, ypos, colwidth);
    }