mirror of https://github.com/GNOME/gimp.git
106 lines
3.1 KiB
C
106 lines
3.1 KiB
C
#include "config.h"
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#include <stdlib.h>
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#include <gtk/gtk.h>
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#include <libgimpmath/gimpmath.h>
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#include <libgimp/gimp.h>
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#include "gimpressionist.h"
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#include "ppmtool.h"
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#include "random.h"
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static int
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pfix (int n)
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{
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if (n < 1) return 1;
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if (n > 255) return 255;
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return n;
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}
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#define PIXEL(y,x,z) p->col[(y) * rowstride + (x) * 3 + z]
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static void
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mkplasma_sub (ppm_t *p, int x1, int x2, int y1, int y2, float turb)
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{
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int rowstride = p->width * 3;
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int r=0;
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int xr, yr, nx, ny;
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xr = abs (x1 - x2);
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yr = abs (y1 - y2);
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if ((xr == 0) && (yr == 0))
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return;
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nx = (x1 + x2)/2;
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ny = (y1 + y2)/2;
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if (!PIXEL (y1,nx,r))
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PIXEL (y1, nx, r) = pfix ((PIXEL (y1, x1, r) + PIXEL (y1, x2, r)) / 2.0 +
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turb * g_rand_double_range (random_generator,
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-xr / 2.0,
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xr / 2.0));
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if (!PIXEL (y2, nx, r))
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PIXEL (y2, nx, r) = pfix ((PIXEL (y2, x1, r) + PIXEL (y2, x2, r)) / 2.0 +
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turb * g_rand_double_range (random_generator,
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-xr / 2.0,
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xr / 2.0));
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if (!PIXEL (ny, x1, r))
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PIXEL (ny, x1, r) = pfix ((PIXEL (y1, x1, r)+PIXEL (y2, x1, r)) / 2.0 +
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turb * g_rand_double_range (random_generator,
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-yr / 2.0,
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yr / 2.0));
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if (!PIXEL (ny, x2, r))
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PIXEL (ny, x2, r) = pfix ((PIXEL (y1, x2, r) + PIXEL (y2, x2, r)) / 2.0 +
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turb * g_rand_double_range (random_generator,
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-yr / 2.0,
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yr / 2.0));
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if (!PIXEL (ny, nx, r))
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PIXEL (ny, nx, r) =
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pfix ((PIXEL (y1, x1, r) + PIXEL (y1, x2, r) +
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PIXEL (y2, x1, r) + PIXEL( y2, x2, r)) / 4.0 +
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turb * g_rand_double_range (random_generator,
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-(xr + yr)/4.0,
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(xr + yr)/4.0));
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if (xr>1)
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{
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mkplasma_sub (p, x1, nx, y1, ny, turb);
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mkplasma_sub (p, nx, x2, y1, ny, turb);
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}
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if (yr>1)
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{
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mkplasma_sub (p, x1, nx, ny, y2, turb);
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mkplasma_sub (p, nx, x2, ny, y2, turb);
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}
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}
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static void
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mkplasma_red (ppm_t *p, float turb)
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{
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int x = 0, y = 0;
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int rowstride = p->width * 3;
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for (x = 0; x < p->width; x++)
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for (y = 0; y < p->height; y++)
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PIXEL (y, x, 0) = 0;
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x--; y--;
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PIXEL (0, 0, 0) = g_rand_int_range (random_generator, 1, 256);
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PIXEL (y, 0, 0) = g_rand_int_range (random_generator, 1, 256);
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PIXEL (0, x, 0) = g_rand_int_range (random_generator, 1, 256);
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PIXEL (y, x, 0) = g_rand_int_range (random_generator, 1, 256);
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mkplasma_sub (p, 0, x, 0, y, turb);
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}
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void
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mkgrayplasma (ppm_t *p, float turb)
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{
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int y, l;
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mkplasma_red (p, turb);
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l = p->width * 3 * p->height;
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for (y = 0; y < l; y += 3)
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p->col[y+1] = p->col[y+2] = p->col[y];
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}
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