static ConvFilter CreateBlurFilter(int radius)
{
ConvFilter filter;
int x, y;
double sum;
filter = new ConvFilter();
filter.size = radius * 2 + 1;
filter.data = new double [filter.size * filter.size];
sum = 0.0;
for (y = 0; y < filter.size; y++)
{
for (x = 0; x < filter.size; x++)
{
sum += filter.data [y * filter.size + x] = Gaussian(x - (filter.size >> 1),
y - (filter.size >> 1),
radius);
}
}
for (y = 0; y < filter.size; y++)
{
for (x = 0; x < filter.size; x++)
{
filter.data [y * filter.size + x] /= sum;
}
}
return(filter);
}
static ConvFilter CreateBlurFilter (int radius)
{
ConvFilter filter;
int x, y;
double sum;
filter = new ConvFilter ();
filter.size = radius * 2 + 1;
filter.data = new double [filter.size * filter.size];
sum = 0.0;
for (y = 0 ; y < filter.size; y++) {
for (x = 0 ; x < filter.size; x++) {
sum += filter.data [y * filter.size + x] = Gaussian (x - (filter.size >> 1),
y - (filter.size >> 1),
radius);
}
}
for (y = 0; y < filter.size; y++) {
for (x = 0; x < filter.size; x++)
filter.data [y * filter.size + x] /= sum;
}
return filter;
}
unsafe static Pixbuf CreateEffect(int src_width, int src_height, ConvFilter filter, int radius, int offset, double opacity)
{
Pixbuf dest;
int x, y, i, j;
int src_x, src_y;
int suma;
int dest_width, dest_height;
int dest_rowstride;
byte * dest_pixels;
dest_width = src_width + 2 * radius + offset;
dest_height = src_height + 2 * radius + offset;
dest = new Pixbuf(Colorspace.Rgb, true, 8, dest_width, dest_height);
dest.Fill(0);
dest_pixels = (byte *)dest.Pixels;
dest_rowstride = dest.Rowstride;
for (y = 0; y < dest_height; y++)
{
for (x = 0; x < dest_width; x++)
{
suma = 0;
src_x = x - radius;
src_y = y - radius;
/* We don't need to compute effect here, since this pixel will be
* discarded when compositing */
if (src_x >= 0 && src_x < src_width && src_y >= 0 && src_y < src_height)
{
continue;
}
for (i = 0; i < filter.size; i++)
{
for (j = 0; j < filter.size; j++)
{
src_y = -(radius + offset) + y - (filter.size >> 1) + i;
src_x = -(radius + offset) + x - (filter.size >> 1) + j;
if (src_y < 0 || src_y >= src_height ||
src_x < 0 || src_x >= src_width)
{
continue;
}
suma += (int)(((byte)0xFF) * filter.data [i * filter.size + j]);
}
}
byte r = (byte)(suma * opacity);
dest_pixels [y * dest_rowstride + x * 4 + 3] = r;
}
}
return(dest);
}
public static Pixbuf AddShadow(int width, int height)
{
if (filter == null)
{
filter = CreateBlurFilter(BLUR_RADIUS);
}
return(CreateEffect(width, height, filter, BLUR_RADIUS, SHADOW_OFFSET, SHADOW_OPACITY));
}
unsafe static Pixbuf CreateEffect (int src_width, int src_height, ConvFilter filter, int radius, int offset, double opacity)
{
Pixbuf dest;
int x, y, i, j;
int src_x, src_y;
int suma;
int dest_width, dest_height;
int dest_rowstride;
byte* dest_pixels;
dest_width = src_width + 2 * radius + offset;
dest_height = src_height + 2 * radius + offset;
dest = new Pixbuf (Colorspace.Rgb, true, 8, dest_width, dest_height);
dest.Fill (0);
dest_pixels = (byte*) dest.Pixels;
dest_rowstride = dest.Rowstride;
for (y = 0; y < dest_height; y++)
{
for (x = 0; x < dest_width; x++)
{
suma = 0;
src_x = x - radius;
src_y = y - radius;
/* We don't need to compute effect here, since this pixel will be
* discarded when compositing */
if (src_x >= 0 && src_x < src_width && src_y >= 0 && src_y < src_height)
continue;
for (i = 0; i < filter.size; i++)
{
for (j = 0; j < filter.size; j++)
{
src_y = -(radius + offset) + y - (filter.size >> 1) + i;
src_x = -(radius + offset) + x - (filter.size >> 1) + j;
if (src_y < 0 || src_y >= src_height ||
src_x < 0 || src_x >= src_width)
continue;
suma += (int) (((byte)0xFF) * filter.data [i * filter.size + j]);
}
}
byte r = (byte) (suma * opacity);
dest_pixels [y * dest_rowstride + x * 4 + 3] = r;
}
}
return dest;
}
public static Pixbuf AddShadow (int width, int height)
{
if (filter == null)
filter = CreateBlurFilter (BLUR_RADIUS);
return CreateEffect (width, height, filter, BLUR_RADIUS, SHADOW_OFFSET, SHADOW_OPACITY);
}
