Implement pipi_rotate(). Currently nearest-neighbour only, supersample if

you need more precision.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@3546 92316355-f0b4-4df1-b90c-862c8a59935f

pipi/Makefile.am

@@ -70,6 +70,7 @@ filter_sources = \
 	filter/blur.c \
 	filter/convolution.c \
 	filter/color.c \
+	filter/rotate.c \
 	filter/transform.c \
 	filter/median.c \
 	filter/dilate.c \

pipi/context.c

@@ -71,6 +71,7 @@ pipi_command_t const *pipi_get_command_list(void)
         { "rotate90", 0 },
         { "rotate180", 0 },
         { "rotate270", 0 },
+        { "rotate", 1 },
         { "invert", 0 },
         { "threshold", 1 },
         { "dilate", 0 },
@@ -350,7 +351,7 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
         pipi_free(tmp);
     }
     else if(!strcmp(cmd, "brightness") || !strcmp(cmd, "contrast")
-             || !strcmp(cmd, "threshold"))
+             || !strcmp(cmd, "threshold") || !strcmp(cmd, "rotate"))
     {
         pipi_image_t *src, *dst = NULL;
         char const *arg;
@@ -368,6 +369,7 @@ int pipi_command(pipi_context_t *ctx, char const *cmd, ...)
         {
             case 'b': dst = pipi_brightness(src, val); break;
             case 'c': dst = pipi_contrast(src, val); break;
+            case 'r': dst = pipi_rotate(src, val); break;
             case 't': dst = pipi_threshold(src, val); break;
         }
         if(dst == NULL)

pipi/filter/rotate.c

@@ -0,0 +1,100 @@
+/*
+ *  libpipi       Pathetic image processing interface 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.
+ */
+
+/*
+ * wave.c: wave and other warping effects
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#ifndef M_PI
+#   define M_PI 3.14159265358979323846
+#endif
+
+#include "pipi.h"
+#include "pipi_internals.h"
+
+pipi_image_t *pipi_rotate(pipi_image_t *src, double a)
+{
+    pipi_image_t *dst;
+    pipi_pixels_t *srcp, *dstp;
+    float *srcdata, *dstdata;
+    double sina, cosa, cx, cy;
+    int x, y, w, h, i, gray;
+
+    w = src->w;
+    h = src->h;
+
+    gray = (src->last_modified == PIPI_PIXELS_Y_F32);
+
+    srcp = gray ? pipi_get_pixels(src, PIPI_PIXELS_Y_F32)
+                : pipi_get_pixels(src, PIPI_PIXELS_RGBA_F32);
+    srcdata = (float *)srcp->pixels;
+
+    dst = pipi_new(w, h);
+    dstp = gray ? pipi_get_pixels(dst, PIPI_PIXELS_Y_F32)
+                : pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
+    dstdata = (float *)dstp->pixels;
+
+    sina = sin(a * M_PI / 180.0);
+    cosa = cos(a * M_PI / 180.0);
+
+    cx = (double)w / 2.0;
+    cy = (double)h / 2.0;
+
+    for(y = 0; y < h; y++)
+    {
+        for(x = 0; x < w; x++)
+        {
+            double dx, dy;
+            int x2, y2;
+
+            dx = ((double)x - cx) * cosa - ((double)y - cy) * sina;
+            dy = ((double)y - cy) * cosa + ((double)x - cx) * sina;
+
+            x2 = (int)(cx + dx + 0.5);
+            y2 = (int)(cy + dy + 0.5);
+
+            if(gray)
+            {
+                if(x2 < 0 || y2 < 0 || x2 >= w || y2 >= h)
+                    ;
+                else
+                    dstdata[y * w + x] = srcdata[y2 * w + x2];
+            }
+            else
+            {
+                if(x2 < 0 || y2 < 0 || x2 >= w || y2 >= h)
+                {
+                    dstdata[4 * (y * w + x) + 3] = 0.0f;
+                }
+                else
+                {
+                    for(i = 0; i < 4; i++)
+                    {
+                        dstdata[4 * (y * w + x) + i]
+                            = srcdata[4 * (y2 * w + x2) + i];
+                    }
+                }
+            }
+        }
+    }
+
+    return dst;
+}
+

pipi/pipi.h

@@ -192,6 +192,7 @@ __extern pipi_image_t *pipi_invert(pipi_image_t *);
 __extern pipi_image_t *pipi_threshold(pipi_image_t *, double);
 __extern pipi_image_t *pipi_hflip(pipi_image_t *);
 __extern pipi_image_t *pipi_vflip(pipi_image_t *);
+__extern pipi_image_t *pipi_rotate(pipi_image_t *, double);
 __extern pipi_image_t *pipi_rotate90(pipi_image_t *);
 __extern pipi_image_t *pipi_rotate180(pipi_image_t *);
 __extern pipi_image_t *pipi_rotate270(pipi_image_t *);