Changeset 2812Tweet

Timestamp:

09/01/08 01:05:55 (5 years ago)

Author:

sam

Message:

• Add a scale parameter to pipi_dither_ordered_ext().
• Reimplement pipi_dither_halftone() using pipi_dither_ordered_ext().

Location:

libpipi/trunk/pipi

Files:

• Makefile.am (modified) (1 diff)
• context.c (modified) (1 diff)
• dither/halftone.c (deleted)
• dither/ordered.c (modified) (2 diffs)
• pipi.h (modified) (1 diff)

libpipi/trunk/pipi/Makefile.am

@@ -77 +77 @@
         dither/ediff.c \
         dither/ordered.c \
-        dither/halftone.c \
         dither/ostromoukhov.c \
         dither/dbs.c \

libpipi/trunk/pipi/context.c

@@ -107 +107 @@
         else if(!strncmp(method, "ordered", 7))
         {
-            double angle = .0;
+            double scale = 1., angle = .0;
+            if(ctx->nimages < 2)
+                return -1;
             method = strchr(method, ':');
             if(method)
-                angle = atof(method + 1);
-            if(ctx->nimages < 2)
-                return -1;
+            {
+                scale = atof(method + 1);
+                method = strchr(method + 1, ':');
+                if(method)
+                    angle = atof(method + 1);
+            }
+            if(scale <= 0.)
+                scale = 1.;
             dst = pipi_dither_ordered_ext(ctx->images[ctx->nimages - 2], src,
-                                          angle);
+                                          scale, angle);
             pipi_free(ctx->images[ctx->nimages - 2]);
             ctx->nimages--;

libpipi/trunk/pipi/dither/ordered.c

@@ -26 +26 @@
 #include "pipi_internals.h"
 
+pipi_image_t *pipi_dither_halftone(pipi_image_t *img, double r, double angle)
+{
+#define PRECISION 4.
+    pipi_image_t *ret, *kernel;
+    int k = (r * PRECISION / sqrt(2.) + .5);
+
+    kernel = pipi_render_halftone(k, k);
+    ret = pipi_dither_ordered_ext(img, kernel, 1. / PRECISION, angle + 45.);
+    pipi_free(kernel);
+
+    return ret;
+}
+
 pipi_image_t *pipi_dither_ordered(pipi_image_t *img, pipi_image_t *kernel)
 {
-    return pipi_dither_ordered_ext(img, kernel, 0.0);
+    return pipi_dither_ordered_ext(img, kernel, 1.0, 0.0);
 }
 
 pipi_image_t *pipi_dither_ordered_ext(pipi_image_t *img, pipi_image_t *kernel,
-                                      double angle)
+                                      double scale, double angle)
 {
     double sint, cost;
@@ -61 +74 @@
             float p, q;
 
-            kx = (int)(cost * x - sint * y + 2 * w * h) % kw;
-            ky = (int)(cost * y + sint * x + 2 * w * h) % kh;
+            kx = (int)((cost * x - sint * y + 2 * w * h) / scale) % kw;
+            ky = (int)((cost * y + sint * x + 2 * w * h) / scale) % kh;
 
             p = dstdata[y * w + x];

libpipi/trunk/pipi/pipi.h

@@ -184 +184 @@
 extern pipi_image_t *pipi_dither_ordered(pipi_image_t *, pipi_image_t *);
 extern pipi_image_t *pipi_dither_ordered_ext(pipi_image_t *, pipi_image_t *,
-                                             double);
+                                             double, double);
 extern pipi_image_t *pipi_dither_halftone(pipi_image_t *, double, double);
 extern pipi_image_t *pipi_dither_random(pipi_image_t *);