drawing dots - ploot - simple plotting tools
 (HTM) git clone git://bitreich.org/ploot git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/ploot
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       ---
 (DIR) commit 8112f382b3e9104289ade9cae2d777ab4d68ea1b
 (DIR) parent 04a8bcf172e92e0f70bc889b5181bc3cbdb8f381
 (HTM) Author: Josuah Demangeon <mail@josuah.net>
       Date:   Fri,  2 Feb 2018 21:05:01 +0100
       
       drawing dots
       
       Diffstat:
         M Makefile                            |       2 +-
         A config.h                            |       2 ++
         M plot                                |       0 
         M plot.c                              |      74 ++++++++++++++++++++++++++-----
       
       4 files changed, 66 insertions(+), 12 deletions(-)
       ---
 (DIR) diff --git a/Makefile b/Makefile
       @@ -1,4 +1,4 @@
        CFLAGS        = -Wall -Wextra -Werror -std=c89 -pedantic
        
       -all: plot.o
       +all: plot.o config.h
                ${CC} -o plot plot.o
 (DIR) diff --git a/config.h b/config.h
       @@ -0,0 +1,2 @@
       +#define MAX_WIDTH        80
       +#define MAX_HEIGHT        20
 (DIR) diff --git a/plot b/plot
       Binary files differ.
 (DIR) diff --git a/plot.c b/plot.c
       @@ -1,18 +1,23 @@
        #include <stdio.h>
       +#include <string.h>
       +
       +#include "config.h"
        
        #define ABS(x)        ((x) < 0 ? -(x) : (x))
       +#define LEN(x)        (sizeof(x) / sizeof(*x))
        
        /*
       - * Set `str' to a human-readable form of `num' with always a width of 8
       - * (including '\0' terminator).
       + * Set `str' to a human-readable form of `num' with always a width of 7 (+ 1
       + * the '\0' terminator).  Buffer overflow is ensured not to happen due to the
       + * max size of a double.
         */
        void
       -humanize(double num, char *str, size_t len)
       +humanize(char *str, double num)
        {
                int        exp;
                char        *label = " kMGTE", fmt[] = "%+.?f%c";
        
       -        for (exp = 0; ABS(num) > 1000; exp += 3)
       +        for (exp = 0; ABS(num) > 1000; exp++)
                        num /= 1000;
        
                fmt[3] = (ABS(num) < 10) ? '3' : (ABS(num) < 100) ? '2' : '1';
       @@ -20,18 +25,65 @@ humanize(double num, char *str, size_t len)
                        fmt[5] = '\0';
                        fmt[3]++;
                }
       -        snprintf(str, len, fmt, num, label[exp / 3]);
       -        if (num > 0)
       +        snprintf(str, 8, fmt, num, label[exp]);
       +        if (num >= 0)
                        str[0] = ' ';
        }
        
       -int
       -main()
       +/*
       + * Print two rows of a plot into a single line using ' ', '.' and ':'.
       + */
       +void
       +line(double *beg, double *end, double top, double bot)
       +{
       +        double        *val;
       +
       +        for (val = beg; val <= end; val++)
       +                putchar((*val < bot) ? ' ' : (*val < top) ? '.' : ':');
       +}
       +
       +/*
       + * Returns the maximal double of values between `beg' and `end'.
       + */
       +double
       +maxdv(double *beg, double *end)
        {
       -        char        str[8];
       +        double        *val, max;
        
       -        humanize(-1 << 18, str, sizeof(str));
       -        printf("%s\n", str);
       +        max = *beg;
       +        for (val = beg; val < end; val++) {
       +                if (*val > max)
       +                        max = *val;
       +        }
       +        return max;
       +}
        
       +/*
       + * Plot values between `beg' and `end' in a plot of height `height'.
       + */
       +void
       +plot(int height, double *beg, double *end)
       +{
       +        double        top, bot, max;
       +        int        h;
       +/*
       +        char        label[8];
       +*/
       +
       +        max = maxdv(beg, end);
       +
       +        for (h = height + height % 2; h > 0; h -= 2) {
       +                top = h * max / height;
       +                bot = (h - 1) * max / height;
       +                line(beg, end, top, bot);
       +                putchar('\n');
       +        }
       +}
       +
       +int
       +main()
       +{
       +        double        val[] = { 0.0, 0.4, 3.4, 2.1, 3.5, 3.0, 1.1, 2.0 } ;
       +        plot(10, val, val + LEN(val));
                return 0;
        }