From bd54059e606131571869ff336cabd070376c6048 Mon Sep 17 00:00:00 2001
From: sam <sam@92316355-f0b4-4df1-b90c-862c8a59935f>
Date: Sun, 31 Aug 2008 23:05:55 +0000
Subject: [PATCH] * Add a scale parameter to pipi_dither_ordered_ext(). *
Reimplement pipi_dither_halftone() using pipi_dither_ordered_ext().
git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@2812 92316355-f0b4-4df1-b90c-862c8a59935f
---
pipi/Makefile.am | 1 -
pipi/context.c | 17 ++++++---
pipi/dither/halftone.c | 83 ------------------------------------------
pipi/dither/ordered.c | 21 +++++++++--
pipi/pipi.h | 2 +-
5 files changed, 30 insertions(+), 94 deletions(-)
delete mode 100644 pipi/dither/halftone.c
diff --git a/pipi/Makefile.am b/pipi/Makefile.am
index aa77553..27a5d1b 100644
--- a/pipi/Makefile.am
+++ b/pipi/Makefile.am
@@ -76,7 +76,6 @@ quantize_sources = \
dither_sources = \
dither/ediff.c \
dither/ordered.c \
- dither/halftone.c \
dither/ostromoukhov.c \
dither/dbs.c \
dither/random.c
diff --git a/pipi/context.c b/pipi/context.c
index ab8a34c..266c282 100644
--- a/pipi/context.c
+++ b/pipi/context.c
@@ -106,14 +106,21 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
}
else if(!strncmp(method, "ordered", 7))
{
- double angle = .0;
- method = strchr(method, ':');
- if(method)
- angle = atof(method + 1);
+ double scale = 1., angle = .0;
if(ctx->nimages < 2)
return -1;
+ method = strchr(method, ':');
+ if(method)
+ {
+ 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--;
}
diff --git a/pipi/dither/halftone.c b/pipi/dither/halftone.c
deleted file mode 100644
index f50580e..0000000
--- a/pipi/dither/halftone.c
+++ /dev/null
@@ -1,83 +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.
- */
-
-/*
- * halftone.c: screening halftone dithering functions
- */
-
-#include "config.h"
-#include "common.h"
-
-#include <math.h>
-
-#include "pipi.h"
-#include "pipi_internals.h"
-
-pipi_image_t *pipi_dither_halftone(pipi_image_t *img, double r, double angle)
-{
- double sint, cost;
- pipi_image_t *dst;
- pipi_pixels_t *dstp;
- float *dstdata;
- int x, y, w, h;
-
- w = img->w;
- h = img->h;
-
- cost = cos(angle * (M_PI / 180));
- sint = sin(angle * (M_PI / 180));
-
- dst = pipi_copy(img);
- dstp = pipi_getpixels(dst, PIPI_PIXELS_Y_F);
- dstdata = (float *)dstp->pixels;
-
- for(y = 0; y < h; y++)
- {
- for(x = 0; x < w; x++)
- {
- double x2, y2, i, j, dist;
- float p, threshold = .5;
- int invert = 0;
-
- x2 = x + .5;
- y2 = y + .5;
- i = (cost * x2 - sint * y2) / r;
- j = (cost * y2 + sint * x2) / r;
- i = i - (int)i + (i < 0.);
- j = j - (int)j + (j < 0.);
-
- if(j > 0.5)
- {
- i = 1. - i;
- j = 1. - j;
- }
- if(i > 0.5)
- {
- invert = 1;
- i = 1. - i;
- }
-
- dist = (i - .25) * (i - .25) + (j - .25) * (j - .25);
- threshold = dist * 4;
- if(invert)
- threshold = 1. - threshold;
-
- p = dstdata[y * w + x];
- dstdata[y * w + x] = p > threshold ? 1. : 0.;
- }
- }
-
- return dst;
-}
-
diff --git a/pipi/dither/ordered.c b/pipi/dither/ordered.c
index 34a6d2d..f91a722 100644
--- a/pipi/dither/ordered.c
+++ b/pipi/dither/ordered.c
@@ -25,13 +25,26 @@
#include "pipi.h"
#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;
pipi_image_t *dst;
@@ -60,8 +73,8 @@ pipi_image_t *pipi_dither_ordered_ext(pipi_image_t *img, pipi_image_t *kernel,
{
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];
q = p > kerneldata[ky * kw + kx] ? 1. : 0.;
diff --git a/pipi/pipi.h b/pipi/pipi.h
index 6114a2e..35abd57 100644
--- a/pipi/pipi.h
+++ b/pipi/pipi.h
@@ -183,7 +183,7 @@ extern pipi_image_t *pipi_dither_ediff(pipi_image_t *, 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_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 *);
extern pipi_image_t *pipi_dither_ostromoukhov(pipi_image_t *, pipi_scan_t);