asdf

1 files changed, 85 insertions, 36 deletions

diff --git a/downscaling.c b/downscaling.c
index 2dadb09..dc16c2e 100644
--- a/downscaling.c
+++ b/downscaling.c
@@ -274,22 +274,95 @@ create_gaussian_kernel (int r, int *n_params)
     return params;
 }
 
+typedef double (* convolution_t) (int size, double x, double y);
+
 static void
-set_gaussian (pixman_image_t *image, int w, int h, double scale)
+set_convolution (pixman_image_t *image, int w, int h,
+		 int size, convolution_t convolution)
 {
     int n_params;
+    pixman_fixed_16_16_t *params;
+    double *dparams;
+    double sum;
+    int i, j;
+
+    n_params = size * size + 2;
+
+    dparams = g_malloc (n_params * sizeof (double));
+    params = g_malloc (n_params * sizeof (pixman_fixed_16_16_t));
+
+    sum = 0.0;
+    for (i = 0; i < size; ++i)
+    {
+	for (j = 0; j < size; ++j)
+	{
+	    int idx = i * size + j + 2;
 
-#define RAD 5
+	    dparams[idx] = convolution (size, i - size / 2, j - size / 2);
 
-    pixman_fixed_16_16_t *params =
-	create_gaussian_kernel (RAD, &n_params);
+	    sum += dparams[idx];
+	}
+    }
 
-    params[0] = (RAD * 2 + 1) << 16;
-    params[1] = (RAD * 2 + 1) << 16;
+    g_print ("sum %f\n", sum);
     
+    for (i = 0; i < size; ++i)
+    {
+	for (j = 0; j < size; ++j)
+	{
+	    int idx = i * size + j + 2;
+	    
+	    params[idx] = _cairo_fixed_16_16_from_double (dparams[idx] / sum);
+
+	    g_print ("%.4f ", dparams[idx] / sum);
+	}
+
+	g_print ("\n");
+    }
+
+    params[0] = size << 16;
+    params[1] = size << 16;
+
     pixman_image_set_filter (image, PIXMAN_FILTER_CONVOLUTION, params, n_params);
+}
 
-    g_free (params);
+static double
+gaussian (int size, double x, double y)
+{
+    double sigma = (size / 2.0) / 2.0;
+    
+    return (1 / (2 * G_PI * sigma * sigma)) * exp (-(x * x + y * y) / (2 * sigma * sigma));
+}
+
+static void
+set_gaussian (pixman_image_t *image, int w, int h, double scale)
+{
+    set_convolution (image, w, h, 5 / scale, gaussian);
+}
+
+static double
+lanczos (int size, double x, double y)
+{
+    double a = size;
+    double d = sqrt (x * x + y * y);
+    double res;
+
+    if (fabs (d) < DBL_EPSILON)
+    {
+	res = 1.0;
+    }
+    else
+    {
+	res = (a * sin (G_PI * d) * sin ((G_PI * d)/ a)) / (G_PI * G_PI * d * d);
+    }
+    
+    return res;
+}
+
+static void
+set_lanczos (pixman_image_t *image, int w, int h, double scale)
+{
+    set_convolution (image, w, h, 5 / scale, lanczos);
 }
 
 static void
@@ -304,10 +377,10 @@ set_nearest (pixman_image_t *image, int w, int h, double scale)
     pixman_image_set_filter (image, PIXMAN_FILTER_NEAREST, NULL, 0);
 }
 
-static void
-set_lanczos (pixman_image_t *image, int w, int h, double scale)
+static double
+box (int size, double x, double y)
 {
-    g_error ("Lanczos filter is not implemented yet");
+    return 1;
 }
 
 static void
@@ -315,35 +388,11 @@ set_box (pixman_image_t *image, int w, int h, double scale)
 {
     if (scale < 1.0)
     {
-	int size = (1.0 / scale + 0.5);
-	int n_params = size * size + 2;
-	pixman_fixed_16_16_t *params = g_malloc (n_params * sizeof (pixman_fixed_16_16_t));
-	int i, j;
-	
-	params[0] = size << 16;
-	params[1] = size << 16;
-
-	g_print ("size of box: %d\n", size);
-	
-	for (i = 0; i < size; ++i)
-	{
-	    for (j = 0; j < size; ++j)
-	    {
-		int idx = i * size + j + 2;
-
-		g_assert (idx < n_params);
-
-		params[idx] = _cairo_fixed_16_16_from_double (1.0 / (size * size));
-	    }
-	}
-	
-	pixman_image_set_filter (image, PIXMAN_FILTER_CONVOLUTION, params, n_params);
-	
-	g_free (params);
+	set_convolution (image, w, h, 1.0 / scale + 0.5, box);
     }
     else
     {
-	pixman_image_set_filter (image, PIXMAN_FILTER_NEAREST, NULL, 0);
+	pixman_image_set_filter (image, PIXMAN_FILTER_BILINEAR, NULL, 0);
     }
 }