static void
premultiply_data(png_structp png,
png_row_infop row_info,
png_bytep data)
{
unsigned int i;
png_bytep p;
for (i = 0, p = data; i < row_info->rowbytes; i += 4, p += 4) {
png_byte alpha = p[3];
uint32_t w;
if (alpha == 0) {
w = 0;
} else {
png_byte red = p[0];
png_byte green = p[1];
png_byte blue = p[2];
if (alpha != 0xff) {
red = multiply_alpha(alpha, red);
green = multiply_alpha(alpha, green);
blue = multiply_alpha(alpha, blue);
}
w = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
}
* (uint32_t *) p = w;
}
}
/* Premultiplies data and converts RGBA bytes => native endian. */
static void
premultiply_data( png_structp png,
png_row_infop row_info,
png_bytep data )
{
unsigned int i;
FT_UNUSED( png );
for ( i = 0; i < row_info->rowbytes; i += 4 )
{
unsigned char* base = &data[i];
unsigned int alpha = base[3];
if ( alpha == 0 )
base[0] = base[1] = base[2] = base[3] = 0;
else
{
unsigned int red = base[0];
unsigned int green = base[1];
unsigned int blue = base[2];
if ( alpha != 0xFF )
{
red = multiply_alpha( alpha, red );
green = multiply_alpha( alpha, green );
blue = multiply_alpha( alpha, blue );
}
base[0] = blue;
base[1] = green;
base[2] = red;
base[3] = alpha;
}
}
}
static void
gauss_rle (GimpDrawable *drawable,
gdouble radius,
gint pass,
gboolean show_progress)
{
GimpPixelRgn src_rgn, dest_rgn;
gint width, height;
gint bytes;
gint has_alpha;
guchar *dest, *dp;
guchar *src, *sp;
gint *buf, *bb;
gint pixels;
gint total = 1;
gint x1, y1, x2, y2;
gint i, row, col, b;
gint start, end;
gdouble progress, max_progress;
gint *curve;
gint *sum = NULL;
gint val;
gint length;
gint initial_p, initial_m;
gdouble std_dev;
if (radius <= 0.0)
return;
gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
width = (x2 - x1);
height = (y2 - y1);
if (width < 1 || height < 1)
return;
bytes = drawable->bpp;
has_alpha = gimp_drawable_has_alpha(drawable->drawable_id);
buf = g_new (gint, MAX (width, height) * 2);
/* allocate buffers for source and destination pixels */
src = g_new (guchar, MAX (width, height) * bytes);
dest = g_new (guchar, MAX (width, height) * bytes);
gimp_pixel_rgn_init (&src_rgn,
drawable, 0, 0, drawable->width, drawable->height,
FALSE, FALSE);
gimp_pixel_rgn_init (&dest_rgn,
drawable, 0, 0, drawable->width, drawable->height,
TRUE, TRUE);
progress = 0.0;
max_progress = 2 * width * height;
/* First the vertical pass */
radius = fabs (radius) + 1.0;
std_dev = sqrt (-(radius * radius) / (2 * log (1.0 / 255.0)));
curve = make_curve (std_dev, &length);
sum = g_new (gint, 2 * length + 1);
sum[0] = 0;
for (i = 1; i <= length*2; i++)
sum[i] = curve[i-length-1] + sum[i-1];
sum += length;
total = sum[length] - sum[-length];
for (col = 0; col < width; col++)
{
gimp_pixel_rgn_get_col (&src_rgn, src, col + x1, y1, (y2 - y1));
if (has_alpha)
multiply_alpha (src, height, bytes);
sp = src;
dp = dest;
for (b = 0; b < bytes; b++)
{
initial_p = sp[b];
initial_m = sp[(height-1) * bytes + b];
/* Determine a run-length encoded version of the row */
run_length_encode (sp + b, buf, bytes, height);
for (row = 0; row < height; row++)
{
start = (row < length) ? -row : -length;
end = (height <= (row + length) ?
(height - row - 1) : length);
val = 0;
i = start;
bb = buf + (row + i) * 2;
if (start != -length)
val += initial_p * (sum[start] - sum[-length]);
while (i < end)
{
pixels = bb[0];
i += pixels;
if (i > end)
i = end;
val += bb[1] * (sum[i] - sum[start]);
bb += (pixels * 2);
start = i;
}
if (end != length)
val += initial_m * (sum[length] - sum[end]);
dp[row * bytes + b] = val / total;
}
}
if (has_alpha)
separate_alpha (dest, height, bytes);
gimp_pixel_rgn_set_col (&dest_rgn, dest, col + x1, y1, (y2 - y1));
if (show_progress)
{
progress += height;
if ((col % 32) == 0)
gimp_progress_update (0.5 * (pass + (progress / max_progress)));
}
}
/* prepare for the horizontal pass */
gimp_pixel_rgn_init (&src_rgn,
drawable, 0, 0, drawable->width, drawable->height,
FALSE, TRUE);
/* Now the horizontal pass */
for (row = 0; row < height; row++)
{
gimp_pixel_rgn_get_row (&src_rgn, src, x1, row + y1, (x2 - x1));
if (has_alpha)
multiply_alpha (src, width, bytes);
sp = src;
dp = dest;
for (b = 0; b < bytes; b++)
{
initial_p = sp[b];
initial_m = sp[(width-1) * bytes + b];
/* Determine a run-length encoded version of the row */
run_length_encode (sp + b, buf, bytes, width);
for (col = 0; col < width; col++)
{
start = (col < length) ? -col : -length;
end = (width <= (col + length)) ? (width - col - 1) : length;
val = 0;
i = start;
bb = buf + (col + i) * 2;
if (start != -length)
val += initial_p * (sum[start] - sum[-length]);
while (i < end)
{
pixels = bb[0];
i += pixels;
if (i > end)
i = end;
val += bb[1] * (sum[i] - sum[start]);
bb += (pixels * 2);
start = i;
}
if (end != length)
val += initial_m * (sum[length] - sum[end]);
dp[col * bytes + b] = val / total;
}
}
if (has_alpha)
separate_alpha (dest, width, bytes);
gimp_pixel_rgn_set_row (&dest_rgn, dest, x1, row + y1, (x2 - x1));
if (show_progress)
{
progress += width;
if ((row % 32) == 0)
gimp_progress_update (0.5 * (pass + (progress / max_progress)));
}
}
/* merge the shadow, update the drawable */
gimp_drawable_flush (drawable);
gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
gimp_drawable_update (drawable->drawable_id, x1, y1, (x2 - x1), (y2 - y1));
/* free buffers */
g_free (buf);
g_free (src);
g_free (dest);
}
