Changeset 2790 for libpipi/trunk/pipi/dither/ordered.cTweet

Timestamp:

08/28/08 19:19:30 (5 years ago)

Author:

sam

Message:

• Add pipi_order, to transform any image into an ordered dithering matrix.

File:

• libpipi/trunk/pipi/dither/ordered.c (modified) (2 diffs)

libpipi/trunk/pipi/dither/ordered.c

@@ -19 +19 @@
 #include "config.h"
 #include "common.h"
+
+#include <stdlib.h>
 
 #include "pipi.h"
@@ -57 +59 @@
 }
 
+typedef struct
+{
+    int x, y;
+    double val;
+}
+dot_t;
+
+static int cmpdot(const void *p1, const void *p2)
+{
+    return ((dot_t const *)p1)->val > ((dot_t const *)p2)->val;
+}
+
+pipi_image_t *pipi_order(pipi_image_t *src)
+{
+    double epsilon;
+    pipi_image_t *dst;
+    pipi_pixels_t *dstp, *srcp;
+    float *dstdata, *srcdata;
+    dot_t *circle;
+    int x, y, w, h, n;
+
+    w = src->w;
+    h = src->h;
+    epsilon = 1. / (w * h + 1);
+
+    srcp = pipi_getpixels(src, PIPI_PIXELS_Y_F);
+    srcdata = (float *)srcp->pixels;
+
+    dst = pipi_new(w, h);
+    dstp = pipi_getpixels(dst, PIPI_PIXELS_Y_F);
+    dstdata = (float *)dstp->pixels;
+
+    circle = malloc(w * h * sizeof(dot_t));
+
+    for(y = 0; y < h; y++)
+        for(x = 0; x < w; x++)
+        {
+            circle[y * w + x].x = x;
+            circle[y * w + x].y = y;
+            circle[y * w + x].val = srcdata[y * w + x];
+        }
+    qsort(circle, w * h, sizeof(dot_t), cmpdot);
+
+    for(n = 0; n < w * h; n++)
+    {
+        x = circle[n].x;
+        y = circle[n].y;
+        dstdata[y * w + x] = (float)(n + 1) * epsilon;
+    }
+
+    free(circle);
+
+    return dst;
+}
+