* Get rid of the specific error diffusion functions, since our stock kernels

work perfectly well.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@2759 92316355-f0b4-4df1-b90c-862c8a59935f

examples/edd.c

@@ -38,7 +38,7 @@ int main(int argc, char *argv[])
     double sigma = 1.2, precision = 0.001, step = 2.;
     double best = 1., fx = -1., fy = -1., bfx = 0., bfy = 0.;
     double e, e0, e1;
-    pipi_image_t *img, *gauss, *dither, *tmp;
+    pipi_image_t *img, *kernel, *gauss, *dither, *tmp;
     int dx, dy;
 
     if(argc < 2)
@@ -52,7 +52,9 @@ int main(int argc, char *argv[])
     img = pipi_load(argv[1]);
     pipi_getpixels(img, PIPI_PIXELS_Y_F);
     gauss = pipi_gaussian_blur(img, sigma);
-    dither = pipi_dither_floydsteinberg(img, PIPI_SCAN_RASTER);
+    kernel = pipi_load("ediff:fs");
+    dither = pipi_dither_ediff(img, kernel, PIPI_SCAN_RASTER);
+    pipi_free(kernel);
     pipi_free(img);
 
     /* Compute the standard error */

pipi/Makefile.am

@@ -65,9 +65,6 @@ quantize_sources = \
 
 dither_sources = \
 	dither/ediff.c \
-	dither/floydsteinberg.c \
-	dither/jajuni.c \
-	dither/atkinson.c \
 	dither/ordered.c \
 	dither/ostromoukhov.c \
 	dither/dbs.c \

pipi/codec.c

@@ -29,6 +29,7 @@
 pipi_image_t *pipi_load(char const *name)
 {
     if(!strncmp(name, "random:", 7) ||
+       !strncmp(name, "ediff:", 6) ||
        !strncmp(name, "bayer:", 6))
         return pipi_load_stock(name);
 

pipi/context.c

@@ -84,19 +84,7 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
         va_end(ap);
         src = ctx->images[ctx->nimages - 1];
         dst = NULL;
-        if(!strcmp(method, "fs"))
-            dst = pipi_dither_floydsteinberg(src, 0);
-        else if(!strcmp(method, "sfs"))
-            dst = pipi_dither_floydsteinberg(src, 1);
-        else if(!strcmp(method, "jajuni"))
-            dst = pipi_dither_jajuni(src, 0);
-        else if(!strcmp(method, "sjajuni"))
-            dst = pipi_dither_jajuni(src, 1);
-        else if(!strcmp(method, "atkinson"))
-            dst = pipi_dither_atkinson(src, 0);
-        else if(!strcmp(method, "satkinson"))
-            dst = pipi_dither_atkinson(src, 1);
-        else if(!strcmp(method, "ost"))
+        if(!strcmp(method, "ost"))
             dst = pipi_dither_ostromoukhov(src, 0);
         else if(!strcmp(method, "sost"))
             dst = pipi_dither_ostromoukhov(src, 1);
@@ -108,6 +96,14 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
             pipi_free(ctx->images[ctx->nimages - 2]);
             ctx->nimages--;
         }
+        else if(!strcmp(method, "sediff"))
+        {
+            if(ctx->nimages < 2)
+                return -1;
+            dst = pipi_dither_ediff(ctx->images[ctx->nimages - 2], src, 1);
+            pipi_free(ctx->images[ctx->nimages - 2]);
+            ctx->nimages--;
+        }
         else if(!strcmp(method, "ordered"))
         {
             if(ctx->nimages < 2)

pipi/dither/atkinson.c

@@ -1,75 +0,0 @@
-/*
- *  libpipi       Proper image processing implementation library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * atkinson.c: Atkinson dithering functions
- */
-
-#include "config.h"
-#include "common.h"
-
-#include "pipi.h"
-#include "pipi_internals.h"
-
-pipi_image_t *pipi_dither_atkinson(pipi_image_t *img, pipi_scan_t scan)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *dstp;
-    float *dstdata;
-    int x, y, w, h;
-
-    w = img->w;
-    h = img->h;
-
-    dst = pipi_copy(img);
-    dstp = pipi_getpixels(dst, PIPI_PIXELS_Y_F);
-    dstdata = (float *)dstp->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        int reverse = (y & 1) && (scan == PIPI_SCAN_SERPENTINE);
-
-        for(x = 0; x < w; x++)
-        {
-            float p, q, e;
-            int x2 = reverse ? w - 1 - x : x;
-            int s = reverse ? -1 : 1;
-
-            p = dstdata[y * w + x2];
-            q = p < 0.5 ? 0. : 1.;
-            dstdata[y * w + x2] = q;
-
-            e = (p - q) / 8.;
-            if(x < w - 1)
-                dstdata[y * w + x2 + s] += e;
-            if(x < w - 2)
-                dstdata[y * w + x2 + s + s] += e;
-            if(y < h - 1)
-            {
-                if(x > 0)
-                    dstdata[(y + 1) * w + x2 - s] += e;
-                dstdata[(y + 1) * w + x2] += e;
-                if(x < w - 1)
-                    dstdata[(y + 1) * w + x2 + s] += e;
-            }
-            if(y < h - 2)
-            {
-                dstdata[(y + 2) * w + x2] += e;
-            }
-        }
-    }
-
-    return dst;
-}
-

pipi/dither/ediff.c

@@ -24,7 +24,10 @@
 
 /* Perform a generic error diffusion dithering. The first non-zero
  * element in ker is treated as the current pixel. All other non-zero
- * elements are the error diffusion coefficients. */
+ * elements are the error diffusion coefficients.
+ * Making the matrix generic is not terribly slower: the performance
+ * hit is around 4% for Floyd-Steinberg and 13% for JaJuNi, with the
+ * benefit of a lot less code. */
 pipi_image_t *pipi_dither_ediff(pipi_image_t *img, pipi_image_t *ker,
                                 pipi_scan_t scan)
 {

pipi/dither/floydsteinberg.c

@@ -1,71 +0,0 @@
-/*
- *  libpipi       Proper image processing implementation library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * floydsteinberg.c: Floyd-Steinberg dithering functions
- */
-
-#include "config.h"
-#include "common.h"
-
-#include "pipi.h"
-#include "pipi_internals.h"
-
-pipi_image_t *pipi_dither_floydsteinberg(pipi_image_t *img, pipi_scan_t scan)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *dstp;
-    float *dstdata;
-    int x, y, w, h;
-
-    w = img->w;
-    h = img->h;
-
-    dst = pipi_copy(img);
-    dstp = pipi_getpixels(dst, PIPI_PIXELS_Y_F);
-    dstdata = (float *)dstp->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        int reverse = (y & 1) && (scan == PIPI_SCAN_SERPENTINE);
-
-        for(x = 0; x < w; x++)
-        {
-            float p, q, e;
-            int x2 = reverse ? w - 1 - x : x;
-            int s = reverse ? -1 : 1;
-
-            p = dstdata[y * w + x2];
-            q = p < 0.5 ? 0. : 1.;
-            dstdata[y * w + x2] = q;
-
-            /* FIXME: according to our 2008 paper, [7 4 5 0] is a better
-             * error diffusion kernel for serpentine scan than [7 3 5 1]. */
-            e = (p - q) / 16;
-            if(x < w - 1)
-                dstdata[y * w + x2 + s] += e * 7;
-            if(y < h - 1)
-            {
-                if(x > 0)
-                    dstdata[(y + 1) * w + x2 - s] += e * 3;
-                dstdata[(y + 1) * w + x2] += e * 5;
-                if(x < w - 1)
-                    dstdata[(y + 1) * w + x2 + s] += e;
-            }
-        }
-    }
-
-    return dst;
-}
-

pipi/dither/jajuni.c

@@ -1,87 +0,0 @@
-/*
- *  libpipi       Proper image processing implementation library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * jajuni.c: Jarvis-Judice-Ninke dithering functions
- */
-
-#include "config.h"
-#include "common.h"
-
-#include "pipi.h"
-#include "pipi_internals.h"
-
-pipi_image_t *pipi_dither_jajuni(pipi_image_t *img, pipi_scan_t scan)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *dstp;
-    float *dstdata;
-    int x, y, w, h;
-
-    w = img->w;
-    h = img->h;
-
-    dst = pipi_copy(img);
-    dstp = pipi_getpixels(dst, PIPI_PIXELS_Y_F);
-    dstdata = (float *)dstp->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        int reverse = (y & 1) && (scan == PIPI_SCAN_SERPENTINE);
-
-        for(x = 0; x < w; x++)
-        {
-            float p, q, e;
-            int x2 = reverse ? w - 1 - x : x;
-            int s = reverse ? -1 : 1;
-
-            p = dstdata[y * w + x2];
-            q = p < 0.5 ? 0. : 1.;
-            dstdata[y * w + x2] = q;
-
-            e = (p - q) / 48.;
-            if(x < w - 1)
-                dstdata[y * w + x2 + s] += e * 7;
-            if(x < w - 2)
-                dstdata[y * w + x2 + s + s] += e * 5;
-            if(y < h - 1)
-            {
-                if(x > 1)
-                    dstdata[(y + 1) * w + x2 - s - s] += e * 3;
-                if(x > 0)
-                    dstdata[(y + 1) * w + x2 - s] += e * 5;
-                dstdata[(y + 1) * w + x2] += e * 7;
-                if(x < w - 1)
-                    dstdata[(y + 1) * w + x2 + s] += e * 5;
-                if(x < w - 2)
-                    dstdata[(y + 1) * w + x2 + s + s] += e * 3;
-            }
-            if(y < h - 2)
-            {
-                if(x > 1)
-                    dstdata[(y + 2) * w + x2 - s - s] += e;
-                if(x > 0)
-                    dstdata[(y + 2) * w + x2 - s] += e * 3;
-                dstdata[(y + 2) * w + x2] += e * 5;
-                if(x < w - 1)
-                    dstdata[(y + 2) * w + x2 + s] += e * 3;
-                if(x < w - 2)
-                    dstdata[(y + 2) * w + x2 + s + s] += e;
-            }
-        }
-    }
-
-    return dst;
-}
-

pipi/pipi.h

@@ -149,9 +149,6 @@ extern pipi_image_t *pipi_reduce(pipi_image_t *, int, double const *);
 
 extern pipi_image_t *pipi_dither_ediff(pipi_image_t *, pipi_image_t *,
                                        pipi_scan_t);
-extern pipi_image_t *pipi_dither_floydsteinberg(pipi_image_t *, pipi_scan_t);
-extern pipi_image_t *pipi_dither_jajuni(pipi_image_t *, pipi_scan_t);
-extern pipi_image_t *pipi_dither_atkinson(pipi_image_t *, pipi_scan_t);
 extern pipi_image_t *pipi_dither_ordered(pipi_image_t *, pipi_image_t *);
 extern pipi_image_t *pipi_dither_random(pipi_image_t *);
 extern pipi_image_t *pipi_dither_ostromoukhov(pipi_image_t *, pipi_scan_t);

pipi/stock.c

@@ -73,6 +73,51 @@ pipi_image_t *pipi_load_stock(char const *name)
         return ret;
     }
 
+    /* Generate an error diffusion matrix. */
+    if(!strncmp(name, "ediff:", 6))
+    {
+        float const *ker;
+        int w, h;
+
+        if(!strcmp(name + 6, "fs"))
+        {
+            static float const myker[] =
+            {
+                   0.,     1.,  7./16,
+                3./16,  5./16,  1./16
+            };
+            ker = myker; w = 3; h = 2;
+        }
+        else if(!strcmp(name + 6, "jajuni"))
+        {
+            static float const myker[] =
+            {
+                   0.,     0.,     1.,  7./48,  5./48,
+                3./48,  5./48,  7./48,  5./48,  3./48,
+                1./48,  3./48,  5./48,  3./48,  1./48,
+            };
+            ker = myker; w = 5; h = 3;
+        }
+        else if(!strcmp(name + 6, "atkinson"))
+        {
+            static float const myker[] =
+            {
+                  0.,    1.,  1./8,  1./8,
+                1./8,  1./8,  1./8,    0.,
+                  0.,  1./8,    0.,    0.,
+            };
+            ker = myker; w = 4; h = 3;
+        }
+        else
+            return NULL;
+
+        ret = pipi_new(w, h);
+        pix = pipi_getpixels(ret, PIPI_PIXELS_Y_F);
+        memcpy(pix->pixels, ker, w * h * sizeof(float));
+
+        return ret;
+    }
+
     /* Generate a completely random image. */
     if(!strncmp(name, "random:", 7))
     {