I thought I'd posted it before, but this time it's partway coloured which I guess is not very exciting.
{"name":"613031","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/4\/2\/42312207b4473362dd0d99ab32f4b487.png","w":325,"h":380,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/4\/2\/42312207b4473362dd0d99ab32f4b487"}
This is an example of the best I could do with PSP7.
What I've done above is add the painted version of the pixie to the black and white image
as another layer and reduced it's opacity.
What my program does is :
#SelectExpand
1/* shade_coloured_picture_process() : takes the colour bitmap and black and white bitmap and
2blends them. */
3int shade_coloured_picture_process
(ALLEGRO_LOCKED_REGION *coloured_bitmap,
ALLEGRO_LOCKED_REGION *check_bitmap_lock_ptr,
ALLEGRO_LOCKED_REGION *clone,
int process_instructions
[NUMBER_OF_INTEGERS_FOR_PROCESSING
])
4{
5 unsigned char *out_ptr,
*ptr2
;
6 int r, g, b
;
7 int nr, ng, nb
;
8 int x, y
;
9 int grey
;
10
11 unsigned int new_colour
;
12
13
14 for(y
= 0; y
< process_instructions
[LOCKED_BITMAP_ONE_HEIGHT_INDEX
]; ++y
)
15 {
16 for(x
= 0; x
< process_instructions
[LOCKED_BITMAP_TWO_WIDTH_INDEX
]; ++x
)
17 {
18 ptr2
= ((unsigned char *) coloured_bitmap->data
) + coloured_bitmap->pitch
* y
+ x
* 4;
19
20 /* Get the r, g, b of the pixel on the colour bitmap. */
21
22 r
= (int) *(ptr2
+ 0);
23 g
= (int) *(ptr2
+ 1);
24 b
= (int) *(ptr2
+ 2);
25
26 out_ptr
= ((unsigned char *) clone->data
) + clone->pitch
* y
+ x
* 4;
27
28 grey
= (int) *(out_ptr
);
29 nr
= (int) ( ((float) grey
/ 255.
0f) * (float) r
);
30 ng
= (int) ( ((float) grey
/ 255.
0f) * (float) g
);
31 nb
= (int) ( ((float) grey
/ 255.
0f) * (float) b
);
32
33
34 if( *((unsigned int *) ptr2
) != MASK_COLOUR_ABGR
)
35 {
36 /* this pixel on the coloured bitmap is not the mask colour so use blended
37 pixel */
38
39 new_colour
= 255 << 24 | (unsigned char) nb
<< 16 | ( unsigned char ) ng
<< 8 | (( unsigned char ) nr
);
40 *((unsigned int *) (out_ptr
)) = new_colour
;
41 }
42 }
43 }
44
45 return PROCESS_RESULT_OKAY
;
46}
Basically I've forgotten exactly what it does but I think approximately it does the equivalent of drawing in the medium used for the black and white image (biro) over the colour painting. Since I draw first with the biro I can't then paint underneath it on the paper so this function achieves that.
There is a big difference between the two images.
BTW, another thing I could do with PSP is rotate an image underneath a superimposed translucent layer. I was trying to rotate a scanned in painting so that the vertical lines on it were exactly vertical on a bitmap (I had trouble scanning it in that way).
I needed a translucent rectangle over it which stretched from top to bottom so I could see 2 straight vertical lines and then I needed to rotate the painting underneath. I could do this in PSP so I decided to add this facility to my program.
Perhaps I'm just being stupid but it pleases me. I'm aware there could be something I don't know which would have saved all the work. It's a small project this art program. I'm doing it also because I want to get better at coding and it's only a small project so I think I can get a first version of it finished.
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, i already see it before. 
