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Fixed a bug in assign_pixel_intensity() that happened when 

the target pixel was an RGB pixel with an alpha channel.
This commit is contained in:
Davis King 2011-05-29 17:44:33 -04:00
parent 32e1d0b66c
commit 2f7196db7c
2 changed files with 26 additions and 6 deletions
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20
dlib/pixel.h
View File

@ -255,9 +255,14 @@ namespace dlib
- pixel_traits<P> must be defined
- pixel_traits<T> must be defined
ensures
- #get_pixel_intensity(dest) == get_pixel_intensity(new_intensity)
(or if get_pixel_intensity(new_intensity) can't be represented by
dest then the closest value representable by dest is used)
- This function changes the intensity of the dest pixel. So if the pixel in
question is a grayscale pixel then it simply assigns that pixel with the
value of get_pixel_intensity(new_intensity). However, if the pixel is not
a grayscale pixel then it converts the pixel to the HSI color space and sets
the I channel to the given intensity and then converts this HSI value back to
the original pixel's color space.
- Note that we don't necessarily have #get_pixel_intensity(dest) == get_pixel_intensity(new_intensity)
due to vagaries of how converting to and from HSI works out.
- if (the dest pixel has an alpha channel) then
- #dest.alpha == dest.alpha
!*/
@ -984,12 +989,15 @@ namespace dlib
const T& new_intensity
)
{
unsigned long alpha = dest.alpha;
hsi_pixel p;
assign_pixel(p,dest);
const unsigned long old_alpha = dest.alpha;
dest.alpha = 255;
rgb_pixel temp;
assign_pixel(temp, dest); // put dest into an rgb_pixel to avoid the somewhat complicated assign_pixel(hsi,rgb_alpha).
assign_pixel(p,temp);
assign_pixel(p.i, new_intensity);
assign_pixel(dest,p);
dest.alpha = alpha;
dest.alpha = old_alpha;
}
template <

12
dlib/test/pixel.cpp
View File

@ -467,6 +467,18 @@ namespace
assign_pixel_intensity(p_int, -10000);
assign_pixel_intensity(p_gray, -100);
p_rgba.red = 10;
p_rgba.green = 10;
p_rgba.blue = 10;
p_rgba.alpha = 0;
DLIB_TEST_MSG(get_pixel_intensity(p_rgba) == 10, (int)get_pixel_intensity(p_rgba));
assign_pixel_intensity(p_rgba, 2);
DLIB_TEST_MSG(p_rgba.red == 2, (int)p_rgba.red);
DLIB_TEST_MSG(p_rgba.green == 2, (int)p_rgba.green);
DLIB_TEST_MSG(p_rgba.blue == 2, (int)p_rgba.blue);
DLIB_TEST_MSG(p_rgba.alpha == 0, (int)p_rgba.alpha);
DLIB_TEST_MSG(get_pixel_intensity(p_rgba) == 2, (int)get_pixel_intensity(p_rgba));
DLIB_TEST(p_float == -1000);
DLIB_TEST(get_pixel_intensity(p_float) == -1000);
DLIB_TEST(p_schar == -100);