18
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A bit of background:

When I first learned about Brainf*ck, one of the first things I did was to write a Java application that would take in a string and create a, somewhat, optimized program to print said string.

Recently, I've been playing around with Piet, and I have been playing with doing the same thing. I have realized that Piet is a rather interesting language that adds a bit to this challenge.

So, I wanted to put the challenge out to my friends at SE. Let's see what you can do with this language.

The Challenge

Write a program or function that takes in some non-empty string of ASCII characters. Process the string so that you generate a Piet program that will print the string and terminate.

Output is a piet source image in whatever format is best for you. PNG is preferred, but not mandatory.

Piet functionality can be tested here.

The Piet code must generate the output string itself. No input from users is allowed.

Only Piet-Approved colors may be used, as seen below:

piet colors

As this is a popularity contest, winners will be chosen by votes. Ties will be broken by source code size.

Bonus points will be awarded at my discretion based on the creativity of the output images. These are pictures, after all.

\$\endgroup\$
9
\$\begingroup\$

C, (78 + 26 * strlen) codels

This was surprisingly tricky to optimize, mostly because of the possibility of color collisions in neighbouring lines.

The characters are converted to base 12, so each character is a 2-digit number. Every standard line contains the following: pointer (now right for odd lines, left for even lines), duplicate (the number 12, which is first on the stack), push (1st digit), multiply, push (2nd digit), add, outc, push (1 for odd lines, 3 for even lines), duplicate, whitespace, pointer (now down at the end of the line).

To avoid color collisions in neighbouring lines the state after whitespace filling is remembered, and the generation is rolled back to it if a collision happens. The next try starts there with the next color.

Output for "Hello Piet!":

hello

asciipiet2.c

#include "img.h"

#define WIDTH 26
#define OP(op, h, d) int op() { hue += h; dark += d; hue %= 6; dark %= 3; return setp(); }
#define CCMP(c1, c2) (((c1).r == (c2).r) && ((c1).g == (c2).g) && ((c1).b == (c2).b))
#define OPCNT(op) if(op) continue

Color piet[6][2] =
{
    {{0xff, 0xc0, 0xc0}, {0xff, 0x00, 0x00}, {0xc0, 0x00, 0x00}},
    {{0xff, 0xff, 0xc0}, {0xff, 0xff, 0x00}, {0xc0, 0xc0, 0x00}},
    {{0xc0, 0xff, 0xc0}, {0x00, 0xff, 0x00}, {0x00, 0xc0, 0x00}},
    {{0xc0, 0xff, 0xff}, {0x00, 0xff, 0xff}, {0x00, 0xc0, 0xc0}},
    {{0xc0, 0xc0, 0xff}, {0x00, 0x00, 0xff}, {0x00, 0x00, 0xc0}},
    {{0xff, 0xc0, 0xff}, {0xff, 0x00, 0xff}, {0xc0, 0x00, 0xc0}}
};

Color white = {0xff, 0xff, 0xff};

Image img;
int hue, dark, x, y, dx = 1;

void nextline()
{
    x -= dx;
    dx = -dx;
    y += 1;
}

int setp()
{
    if(y > 0 && CCMP(piet[hue][dark], imgGetP(img, x, y - 1)))
    {
        return 1;
    }
    imgSetP(img, x, y, piet[hue][dark]);
    x += dx;
    return 0;
}

void whiteto(int to)
{
    if(dx == 1)
    {
        while(x < to) imgSetP(img, x++, y, white);
    }
    else
    {
        while(x >= WIDTH - to) imgSetP(img, x--, y, white);
    }
}

OP(fill,    0, 0)
OP(pushraw, 0, 1)
OP(pop,     0, 2)
OP(add,     1, 0)
OP(sub,     1, 1)
OP(mul,     1, 2)
OP(divi,    2, 0)
OP(mod,     2, 1)
OP(not,     2, 2)
OP(gt,      3, 0)
OP(pnt,     3, 1)
OP(sw,      3, 2)
OP(dup,     4, 0)
OP(roll,    4, 1)
OP(in,      4, 2)
OP(inc,     5, 0)
OP(out,     5, 1)
OP(outc,    5, 2)

int push(int num);
int pushn(int num)  { int i; for(i = 0; i < num - 1; ++i) { if(fill()) return 1; } return pushraw(); } 
int push0()         { return (push(1) || not()); }
int push8()         { return (push(2) || dup() || dup() || mul() || mul()); }
int push9()         { return (push(3) || dup() || mul()); }
int push10()        { return (push(9) || push(1) || add()); }
int push11()        { return (push(9) || push(2) || add()); }
int push(int num)
{
    switch(num)
    {
    case 0:  return push0();
    case 8:  return push8();
    case 9:  return push9();
    case 10: return push10();
    case 11: return push11();
    default: return pushn(num);
    }
}

int main(int argc, char* argv[])
{
    char* str;
    int len, i;

    if(argc != 2)
    {
        printf("Usage: %s \"string to print\"\n", argv[0]);
        return -1;
    }

    str = argv[1];
    len = strlen(str);

    imgCreate(img, WIDTH, len + 3);

    fill(); push(4); push(3); mul(); push(1); dup(); whiteto(WIDTH - 2);
    for(i = 0; i < len; ++i)
    {
        int var, sx = x, sy = y, sdx = dx, fin = 0, off = rand();
        for(var = 0; var < 18 && !fin; var++)
        {
            x = sx; y = sy; dx = sdx;
            hue = ((var + off) % 18) / 3; dark = ((var + off) % 18) % 3;

            OPCNT(fill()); OPCNT(pnt());
            nextline(); pnt(); dup();
            OPCNT(push(str[i] / 12)); OPCNT(mul()); OPCNT(push(str[i] % 12)); OPCNT(add()); OPCNT(outc()); OPCNT(push(2 - dx)); if(i != len - 1) { OPCNT(dup()); }
            whiteto(WIDTH - 2);
            fin = 1;
        }
        if (!fin)
        {
           printf("collision unavoidable\n");
           return -1;
        }
    }
    x -= dx;
    {
        int var, sx = x, sy = y, sdx = dx, fin = 0;
        for(var = 0; var < 18 && !fin; var++)
        {
            x = sx; y = sy; dx = sdx;
            hue = var / 3; dark = var % 3;
            OPCNT(fill()); OPCNT(pnt()); OPCNT(fill());
            fin = 1;
        }
        if (!fin)
        {
            printf("collision unavoidable\n");
            return -1;
        }
    }
    x -= 2 * dx;
    y += 1;
    imgSetP(img, x, y, white);
    x -= dx;
    y += 1;
    hue = 0; dark = 1;
    fill(); fill(); fill();

    imgSave(img, "piet.pnm");

    return 0;
}

img.h

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

typedef struct
{
   unsigned char r;
   unsigned char g;
   unsigned char b;
} Color;

typedef struct
{
   Color* data;
   int width;
   int height;
} Image;

#define imgCreate(img, w, h)           {\
                                          int length;\
                                          (img).width = (w);\
                                          (img).height = (h);\
                                          length = (img).width * (img).height * sizeof(Color);\
                                          (img).data = malloc(length);\
                                          memset((img).data, 0, length);\
                                       }

#define imgDestroy(img)                {\
                                          free((img).data);\
                                          (img).width = 0;\
                                          (img).height = 0;\
                                       }

#define imgGetP(img, x, y)             ((img).data[(int)(x) + (int)(y) * (img).width])

#define imgSetP(img, x, y, c)          {\
                                          (img).data[(int)(x) + (int)(y) * (img).width] = c;\
                                       }

#define imgLine(img, x, y, xx, yy, c)  {\
                                          int x0 = (x), y0 = (y), x1 = (xx), y1 = (yy);\
                                          int dx =  abs(x1 - x0), sx = x0 < x1 ? 1 : -1;\
                                          int dy = -abs(y1 - y0), sy = y0 < y1 ? 1 : -1;\
                                          int err = dx + dy, e2;\
                                          \
                                          for(;;)\
                                          {\
                                             imgSetP((img), x0, y0, c);\
                                             if (x0 == x1 && y0 == y1) break;\
                                             e2 = 2 * err;\
                                             if (e2 >= dy) {err += dy; x0 += sx;}\
                                             if (e2 <= dx) {err += dx; y0 += sy;}\
                                          }\
                                       }

#define imgSave(img, fname)            {\
                                          FILE* f = fopen((fname), "wb");\
                                          fprintf(f, "P6\n%d %d\n255\n", (img).width, (img).height);\
                                          fwrite((img).data, sizeof(Color), (img).width * (img).height, f);\
                                          fclose(f);\
                                       }

#define imgLoad(img, fname)            {\
                                          FILE* f = fopen((fname), "rb");\
                                          char buffer[16];\
                                          int index = 0;\
                                          int field = 0;\
                                          int isP5 = 0;\
                                          unsigned char c = ' ';\
                                          while(field < 4)\
                                          {\
                                             do\
                                             {\
                                                if(c == '#') while(c = fgetc(f), c != '\n');\
                                             } while(c = fgetc(f), isspace(c) || c == '#');\
                                             index = 0;\
                                             do\
                                             {\
                                                buffer[index++] = c;\
                                             } while(c = fgetc(f), !isspace(c) && c != '#' && index < 16);\
                                             buffer[index] = 0;\
                                             switch(field)\
                                             {\
                                                case 0:\
                                                   if (strcmp(buffer, "P5") == 0) isP5 = 1;\
                                                   else if (strcmp(buffer, "P6") == 0) isP5 = 0;\
                                                   else fprintf(stderr, "image format \"%s\" unsupported (not P5 or P6)\n", buffer), exit(1);\
                                                   break;\
                                                case 1:\
                                                   (img).width = atoi(buffer);\
                                                   break;\
                                                case 2:\
                                                   (img).height = atoi(buffer);\
                                                   break;\
                                                case 3:\
                                                   index = atoi(buffer);\
                                                   if (index != 255) fprintf(stderr, "image format unsupported (not 255 values per channel)\n"), exit(1);\
                                                   break;\
                                             }\
                                             field++;\
                                          }\
                                          imgCreate((img), (img).width, (img).height);\
                                          if (isP5)\
                                          {\
                                             int length = (img).width * (img).height;\
                                             for(index = 0; index < length; ++index)\
                                             {\
                                                (img).data[index].r = (img).data[index].g = (img).data[index].b = fgetc(f);\
                                             }\
                                          }\
                                          else\
                                          {\
                                             fread((img).data, sizeof(Color), (img).width * (img).height, f);\
                                          }\
                                          fclose(f);\
                                       }
\$\endgroup\$
5
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C, (384 + 256 * strlen) codels, no optimization

No clever hacking in this solution. Every character is represented by a single line with height in pixels = ascii value. Op sequence is then push, outc, push, outc, ...

Output for "Hello Piet!" (and zoom of top part):

piet

asciipiet.c

#include "img.h"

Color piet[6][3] = {
    {{0xff,0xc0,0xc0},{0xff,0x00,0x00},{0xc0,0x00,0x00}},
    {{0xff,0xff,0xc0},{0xff,0xff,0x00},{0xc0,0xc0,0x00}},
    {{0xc0,0xff,0xc0},{0x00,0xff,0x00},{0x00,0xc0,0x00}},
    {{0xc0,0xff,0xff},{0x00,0xff,0xff},{0x00,0xc0,0xc0}},
    {{0xc0,0xc0,0xff},{0x00,0x00,0xff},{0x00,0x00,0xc0}},
    {{0xff,0xc0,0xff},{0xff,0x00,0xff},{0xc0,0x00,0xc0}}
};

Color white = {0xff,0xff,0xff};

int main(int argc, char* argv[])
{
    char* str;
    int len, i, hue, dark;
    Image out;

    if(argc != 2)
    {
        printf("Usage: %s \"string to print\"\n", argv[0]);
        return -1;
    }

    str = argv[1];
    len = strlen(str);

    imgCreate(out, len * 2 + 3, 128);

    hue = 0;
    dark = 1;
    for(i = 0; i < len; i++)
    {
        imgLine(out, i * 2, 0, i * 2, str[i] - 1, piet[hue][dark]);
        dark = (dark + 1) % 3;
        imgSetP(out, i * 2 + 1, 0, piet[hue][dark]);
        dark = (dark + 2) % 3;
        hue = (hue + 5) % 6;
    }
    imgSetP(out, len * 2, 0, piet[hue][dark]);
    imgSetP(out, len * 2 + 1, 0, white);
    imgSetP(out, len * 2 + 2, 0, white);
    imgSetP(out, len * 2 + 2, 1, white);
    imgSetP(out, len * 2 + 2, 2, white);
    imgSetP(out, len * 2 + 2, 3, white);
    imgSetP(out, len * 2 + 1, 3, white);
    imgSetP(out, len * 2, 2, piet[0][4]);
    imgSetP(out, len * 2, 3, piet[0][5]);
    imgSetP(out, len * 2, 4, piet[0][6]);

    imgSave(out, "piet.pnm");

    return 0;
}

img.h

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

typedef struct
{
   unsigned char r;
   unsigned char g;
   unsigned char b;
} Color;

typedef struct
{
   Color* data;
   int width;
   int height;
} Image;

#define imgCreate(img, w, h)           {\
                                          int length;\
                                          (img).width = (w);\
                                          (img).height = (h);\
                                          length = (img).width * (img).height * sizeof(Color);\
                                          (img).data = malloc(length);\
                                          memset((img).data, 0, length);\
                                       }

#define imgDestroy(img)                {\
                                          free((img).data);\
                                          (img).width = 0;\
                                          (img).height = 0;\
                                       }

#define imgGetP(img, x, y)             ((img).data[(int)(x) + (int)(y) * (img).width])

#define imgSetP(img, x, y, c)          {\
                                          (img).data[(int)(x) + (int)(y) * (img).width] = c;\
                                       }

#define imgLine(img, x, y, xx, yy, c)  {\
                                          int x0 = (x), y0 = (y), x1 = (xx), y1 = (yy);\
                                          int dx =  abs(x1 - x0), sx = x0 < x1 ? 1 : -1;\
                                          int dy = -abs(y1 - y0), sy = y0 < y1 ? 1 : -1;\
                                          int err = dx + dy, e2;\
                                          \
                                          for(;;)\
                                          {\
                                             imgSetP((img), x0, y0, c);\
                                             if (x0 == x1 && y0 == y1) break;\
                                             e2 = 2 * err;\
                                             if (e2 >= dy) {err += dy; x0 += sx;}\
                                             if (e2 <= dx) {err += dx; y0 += sy;}\
                                          }\
                                       }

#define imgSave(img, fname)            {\
                                          FILE* f = fopen((fname), "wb");\
                                          fprintf(f, "P6\n%d %d\n255\n", (img).width, (img).height);\
                                          fwrite((img).data, sizeof(Color), (img).width * (img).height, f);\
                                          fclose(f);\
                                       }

#define imgLoad(img, fname)            {\
                                          FILE* f = fopen((fname), "rb");\
                                          char buffer[16];\
                                          int index = 0;\
                                          int field = 0;\
                                          int isP5 = 0;\
                                          unsigned char c = ' ';\
                                          while(field < 4)\
                                          {\
                                             do\
                                             {\
                                                if(c == '#') while(c = fgetc(f), c != '\n');\
                                             } while(c = fgetc(f), isspace(c) || c == '#');\
                                             index = 0;\
                                             do\
                                             {\
                                                buffer[index++] = c;\
                                             } while(c = fgetc(f), !isspace(c) && c != '#' && index < 16);\
                                             buffer[index] = 0;\
                                             switch(field)\
                                             {\
                                                case 0:\
                                                   if (strcmp(buffer, "P5") == 0) isP5 = 1;\
                                                   else if (strcmp(buffer, "P6") == 0) isP5 = 0;\
                                                   else fprintf(stderr, "image format \"%s\" unsupported (not P5 or P6)\n", buffer), exit(1);\
                                                   break;\
                                                case 1:\
                                                   (img).width = atoi(buffer);\
                                                   break;\
                                                case 2:\
                                                   (img).height = atoi(buffer);\
                                                   break;\
                                                case 3:\
                                                   index = atoi(buffer);\
                                                   if (index != 255) fprintf(stderr, "image format unsupported (not 255 values per channel)\n"), exit(1);\
                                                   break;\
                                             }\
                                             field++;\
                                          }\
                                          imgCreate((img), (img).width, (img).height);\
                                          if (isP5)\
                                          {\
                                             int length = (img).width * (img).height;\
                                             for(index = 0; index < length; ++index)\
                                             {\
                                                (img).data[index].r = (img).data[index].g = (img).data[index].b = fgetc(f);\
                                             }\
                                          }\
                                          else\
                                          {\
                                             fread((img).data, sizeof(Color), (img).width * (img).height, f);\
                                          }\
                                          fclose(f);\
                                       }
\$\endgroup\$

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