static VALUE
rb_gimp_rgb_subtract (VALUE self,
VALUE other)
{
GimpRGB result = rb2GimpRGB(self);
gimp_rgb_subtract(&result, rb2GimpRGBPtr(other));
return GimpRGB2rb(&result);
}
/* do the exchanging */
static void
exchange (GimpDrawable *drawable,
GimpPreview *preview)
{
GimpPixelRgn srcPR, destPR;
guchar min_red, min_green, min_blue;
guchar max_red, max_green, max_blue;
guchar from_red, from_green, from_blue;
guchar to_red, to_green, to_blue;
guchar *src_row, *dest_row;
gint x, y, bpp = drawable->bpp;
gboolean has_alpha;
gint x1, y1, y2;
gint width, height;
GimpRGB min;
GimpRGB max;
if (preview)
{
gimp_preview_get_position (preview, &x1, &y1);
gimp_preview_get_size (preview, &width, &height);
}
else if (! gimp_drawable_mask_intersect (drawable->drawable_id,
&x1, &y1, &width, &height))
{
return;
}
y2 = y1 + height;
has_alpha = gimp_drawable_has_alpha (drawable->drawable_id);
/* allocate memory */
src_row = g_new (guchar, drawable->width * bpp);
gimp_rgb_get_uchar (&xargs.from, &from_red, &from_green, &from_blue);
gimp_rgb_get_uchar (&xargs.to, &to_red, &to_green, &to_blue);
/* get boundary values */
min = xargs.from;
gimp_rgb_subtract (&min, &xargs.threshold);
gimp_rgb_clamp (&min);
gimp_rgb_get_uchar (&min, &min_red, &min_green, &min_blue);
max = xargs.from;
gimp_rgb_add (&max, &xargs.threshold);
gimp_rgb_clamp (&max);
gimp_rgb_get_uchar (&max, &max_red, &max_green, &max_blue);
dest_row = g_new (guchar, drawable->width * bpp);
gimp_pixel_rgn_init (&srcPR, drawable,
x1, y1, width, height, FALSE, FALSE);
gimp_pixel_rgn_init (&destPR, drawable,
x1, y1, width, height, (preview == NULL), TRUE);
for (y = y1; y < y2; y++)
{
gimp_pixel_rgn_get_row (&srcPR, src_row, x1, y, width);
for (x = 0; x < width; x++)
{
guchar pixel_red, pixel_green, pixel_blue;
guchar new_red, new_green, new_blue;
guint idx;
/* get current pixel-values */
pixel_red = src_row[x * bpp];
pixel_green = src_row[x * bpp + 1];
pixel_blue = src_row[x * bpp + 2];
idx = x * bpp;
/* want this pixel? */
if (pixel_red >= min_red &&
pixel_red <= max_red &&
pixel_green >= min_green &&
pixel_green <= max_green &&
pixel_blue >= min_blue &&
pixel_blue <= max_blue)
{
guchar red_delta, green_delta, blue_delta;
red_delta = pixel_red > from_red ?
pixel_red - from_red : from_red - pixel_red;
green_delta = pixel_green > from_green ?
pixel_green - from_green : from_green - pixel_green;
blue_delta = pixel_blue > from_blue ?
pixel_blue - from_blue : from_blue - pixel_blue;
new_red = CLAMP (to_red + red_delta, 0, 255);
new_green = CLAMP (to_green + green_delta, 0, 255);
new_blue = CLAMP (to_blue + blue_delta, 0, 255);
}
else
{
new_red = pixel_red;
new_green = pixel_green;
new_blue = pixel_blue;
}
/* fill buffer */
dest_row[idx + 0] = new_red;
dest_row[idx + 1] = new_green;
dest_row[idx + 2] = new_blue;
/* copy alpha-channel */
if (has_alpha)
dest_row[idx + 3] = src_row[x * bpp + 3];
}
/* store the dest */
gimp_pixel_rgn_set_row (&destPR, dest_row, x1, y, width);
/* and tell the user what we're doing */
if (!preview && (y % 10) == 0)
gimp_progress_update ((gdouble) y / (gdouble) height);
}
g_free (src_row);
g_free (dest_row);
if (preview)
{
gimp_drawable_preview_draw_region (GIMP_DRAWABLE_PREVIEW (preview),
&destPR);
}
else
{
gimp_progress_update (1.0);
/* update the processed region */
gimp_drawable_flush (drawable);
gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
gimp_drawable_update (drawable->drawable_id, x1, y1, width, height);
}
}