Home » Archimedes archive » Acorn Computing » 1995 01.adf » 9501 » TechForum/Thumbnails/Notes
TechForum/Thumbnails/Notes
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Acorn Computing » 1995 01.adf » 9501 |
| Filename: | TechForum/Thumbnails/Notes |
| Read OK: | ✔ |
| File size: | 1887 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Re TechForum & producing thumbnail sprites from larger source images, using
averaging & error diffusion, a working demo of which is to be found in
directory 'Thumbs'.
There now follows a description of the core function to this process:
The following C function requires the existence of two sprites, of the same
name in different sprite areas. The source sprite must be precisely four
times the height & width of the destination sprite, & contain the image to
be down-sized. The destination sprite's image will be overwritten with the
scaled down source image. The source sprite's image will be corrupted. Both
sprites must be paletteless 8bpp images, with lbit=0 (the first bit used on
each row). x & y are the size of the destination image in pixels.
pal256def is an array of 256 integers, each of the form bbggrr00 - it is a
copy of the default palette for an 8bpp sprite.
Under OS 3 this can be found with ColourTrans_ReadPalette for an 8bpp mode
or sprite, say using the BASIC routine:
SYS "ColourTrans_ReadPalette", 15, -1, 0 TO ,,,Size%
DIM Pal256Def% Size%
SYS "ColourTrans_ReadPalette", 15, -1, Pal256Def%, Size%
SYS "OS_File", 10, "<App$Dir>.pal256def", &FFD, , Pal256Def%, Pal256Def%+Size%
lut is an array of 32768 characters; a look-up-table for converting a 15 bit
rgb colour to the (8 bit) colour number of the nearest available colour in
the default 8bpp palette.
lut can be pre-computed with the BASIC routine:
DIM lut% 32768
SYS "OS_SWINumberFromString",,"ColourTrans_ReturnColourNumberForMode" TO S%
FOR r%=0TO31:FOR g%=0TO31:FOR b%=0TO31
SYS S%,((((b%<<3)+(b%>>2))<<16)+(((g%<<3)+(g%>>2))<<8)+((r%<<3)+(r%>>2)))<<8,15 TO lut%?((b%<<10)+(g%<<5)+r%)
NEXT
NEXT
NEXT
SYS "OS_File", 10, "<App$Dir>.lut", &FFD, , lut%, lut%+32768
END
:
REM To attempt to mimic ChangeFSI, before executing above, ensure rgb weights of 3, 10 & 1 are in use.
REM - via executing *ColourTransLoadings 3 10 1
REM Afterwards, remember to reset the weights to 2 4 1
/* C source code to perform main processing: */
#define SDiscale 4
static BOOL plotprocess(sprite_area **d, sprite_area **s, char *name, int x, int y)
{
sprite_id di, si;
sprite_header *sh, *dh;
char *sp, *dp;
register char *p;
int dalign = (4-(x&3))&3;
int salign = (4-((x*SDiscale)&3))&3;
register int r,g,b; /*desired r,g,b*/
int i, j;
int svoff;
register unsigned int c;
int sr, sg, sb; /*saturated desired r,g,b*/
di.tag=si.tag=sprite_id_name;
di.s.name=si.s.name=name;
if (wimpt_complain(sprite_select_rp(*d, &di, (sprite_ptr *)&di.s.addr))) return FALSE;
if (wimpt_complain(sprite_select_rp(*s, &si, (sprite_ptr *)&si.s.addr))) return FALSE;
di.tag=si.tag=sprite_id_addr;
dh = di.s.addr;
sh = si.s.addr;
dp = (char *)dh + dh->image;
sp = (char *)sh + sh->image;
svoff = 4*(sh->width+1);
salign += (SDiscale-1) * svoff;
for (j=y; j>0; j--, dp+=dalign, sp+=salign) {
for (i=x; i>0; i--, dp++, sp+=SDiscale) {
/*following assumes SDiscale==4*/
p=sp;
c = pal256def[*p++];
r = (c>>8)&255;
g = (c>>16)&255;
b = (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
p += svoff-SDiscale;
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
p += svoff-SDiscale;
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
p += svoff-SDiscale;
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
c = pal256def[*p++];
r += (c>>8)&255;
g += (c>>16)&255;
b += (c>>24);
r /= (SDiscale*SDiscale);
g /= (SDiscale*SDiscale);
b /= (SDiscale*SDiscale);
/*at this point, add in any errors from above, left & above left pixels, with weights 3/8, 3/8, 1/4
ie Floyd-Steinberg*/
if (i!=x) { /*add error to left in*/
p = sp-SDiscale;
r += 3*(*(int *)p)/8;
g += 3*(*(int *)(p+=svoff))/8;
b += 3*(*(int *)(p+=svoff))/8;
}
if (j!=y) { /*add error to above in*/
p = sp-SDiscale*svoff;
r += 3*(*(int *)p)/8;
g += 3*(*(int *)(p+=svoff))/8;
b += 3*(*(int *)(p+=svoff))/8;
if (i!=x) { /*add error to above left in*/
p = sp-SDiscale*(svoff+1);
r += (*(int *)p)/4;
g += (*(int *)(p+=svoff))/4;
b += (*(int *)(p+=svoff))/4;
}
}
/*now have desired colour in r,g,b*/
sr = r>255 ? 255 : (r<0 ? 0 : r);
sg = g>255 ? 255 : (g<0 ? 0 : g);
sb = b>255 ? 255 : (b<0 ? 0 : b);
c = (sr>>3) + ((sg>>3)<<5) + ((sb>>3)<<10);
c = pal256def[ *dp = lut[c] ]; /*set *dp to closest colour number via lut, & c to bbggrr00 value for this colour number*/
/*now have actual destination pixel set up*/
r -= (c>>8)&255;
g -= (c>>16)&255;
b -= (c>>24);
/*r,g,b now hold error (ie desired-actual)*/
/*write this value back into source image (over the pixel data we have just used)*/
/*NB to do this, word alignment is crucial (thus SDiscale must be a multiple of 4)*/
p = sp;
*(int *)p = r;
*(int *)(p+=svoff) = g;
*(int *)(p+=svoff) = b;
}
}
return TRUE;
}
00000000 0a 0a 52 65 20 54 65 63 68 46 6f 72 75 6d 20 26 |..Re TechForum &|
00000010 20 70 72 6f 64 75 63 69 6e 67 20 74 68 75 6d 62 | producing thumb|
00000020 6e 61 69 6c 20 73 70 72 69 74 65 73 20 66 72 6f |nail sprites fro|
00000030 6d 20 6c 61 72 67 65 72 20 73 6f 75 72 63 65 20 |m larger source |
00000040 69 6d 61 67 65 73 2c 20 75 73 69 6e 67 0a 61 76 |images, using.av|
00000050 65 72 61 67 69 6e 67 20 26 20 65 72 72 6f 72 20 |eraging & error |
00000060 64 69 66 66 75 73 69 6f 6e 2c 20 61 20 77 6f 72 |diffusion, a wor|
00000070 6b 69 6e 67 20 64 65 6d 6f 20 6f 66 20 77 68 69 |king demo of whi|
00000080 63 68 20 69 73 20 74 6f 20 62 65 20 66 6f 75 6e |ch is to be foun|
00000090 64 20 69 6e 0a 64 69 72 65 63 74 6f 72 79 20 27 |d in.directory '|
000000a0 54 68 75 6d 62 73 27 2e 0a 0a 0a 54 68 65 72 65 |Thumbs'....There|
000000b0 20 6e 6f 77 20 66 6f 6c 6c 6f 77 73 20 61 20 64 | now follows a d|
000000c0 65 73 63 72 69 70 74 69 6f 6e 20 6f 66 20 74 68 |escription of th|
000000d0 65 20 63 6f 72 65 20 66 75 6e 63 74 69 6f 6e 20 |e core function |
000000e0 74 6f 20 74 68 69 73 20 70 72 6f 63 65 73 73 3a |to this process:|
000000f0 0a 0a 0a 54 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 |...The following|
00000100 20 43 20 66 75 6e 63 74 69 6f 6e 20 72 65 71 75 | C function requ|
00000110 69 72 65 73 20 74 68 65 20 65 78 69 73 74 65 6e |ires the existen|
00000120 63 65 20 6f 66 20 74 77 6f 20 73 70 72 69 74 65 |ce of two sprite|
00000130 73 2c 20 6f 66 20 74 68 65 20 73 61 6d 65 0a 6e |s, of the same.n|
00000140 61 6d 65 20 69 6e 20 64 69 66 66 65 72 65 6e 74 |ame in different|
00000150 20 73 70 72 69 74 65 20 61 72 65 61 73 2e 20 54 | sprite areas. T|
00000160 68 65 20 73 6f 75 72 63 65 20 73 70 72 69 74 65 |he source sprite|
00000170 20 6d 75 73 74 20 62 65 20 70 72 65 63 69 73 65 | must be precise|
00000180 6c 79 20 66 6f 75 72 0a 74 69 6d 65 73 20 74 68 |ly four.times th|
00000190 65 20 68 65 69 67 68 74 20 26 20 77 69 64 74 68 |e height & width|
000001a0 20 6f 66 20 74 68 65 20 64 65 73 74 69 6e 61 74 | of the destinat|
000001b0 69 6f 6e 20 73 70 72 69 74 65 2c 20 26 20 63 6f |ion sprite, & co|
000001c0 6e 74 61 69 6e 20 74 68 65 20 69 6d 61 67 65 20 |ntain the image |
000001d0 74 6f 0a 62 65 20 64 6f 77 6e 2d 73 69 7a 65 64 |to.be down-sized|
000001e0 2e 20 54 68 65 20 64 65 73 74 69 6e 61 74 69 6f |. The destinatio|
000001f0 6e 20 73 70 72 69 74 65 27 73 20 69 6d 61 67 65 |n sprite's image|
00000200 20 77 69 6c 6c 20 62 65 20 6f 76 65 72 77 72 69 | will be overwri|
00000210 74 74 65 6e 20 77 69 74 68 20 74 68 65 0a 73 63 |tten with the.sc|
00000220 61 6c 65 64 20 64 6f 77 6e 20 73 6f 75 72 63 65 |aled down source|
00000230 20 69 6d 61 67 65 2e 20 54 68 65 20 73 6f 75 72 | image. The sour|
00000240 63 65 20 73 70 72 69 74 65 27 73 20 69 6d 61 67 |ce sprite's imag|
00000250 65 20 77 69 6c 6c 20 62 65 20 63 6f 72 72 75 70 |e will be corrup|
00000260 74 65 64 2e 20 42 6f 74 68 0a 73 70 72 69 74 65 |ted. Both.sprite|
00000270 73 20 6d 75 73 74 20 62 65 20 70 61 6c 65 74 74 |s must be palett|
00000280 65 6c 65 73 73 20 38 62 70 70 20 69 6d 61 67 65 |eless 8bpp image|
00000290 73 2c 20 77 69 74 68 20 6c 62 69 74 3d 30 20 28 |s, with lbit=0 (|
000002a0 74 68 65 20 66 69 72 73 74 20 62 69 74 20 75 73 |the first bit us|
000002b0 65 64 20 6f 6e 0a 65 61 63 68 20 72 6f 77 29 2e |ed on.each row).|
000002c0 20 78 20 26 20 79 20 61 72 65 20 74 68 65 20 73 | x & y are the s|
000002d0 69 7a 65 20 6f 66 20 74 68 65 20 64 65 73 74 69 |ize of the desti|
000002e0 6e 61 74 69 6f 6e 20 69 6d 61 67 65 20 69 6e 20 |nation image in |
000002f0 70 69 78 65 6c 73 2e 0a 0a 0a 70 61 6c 32 35 36 |pixels....pal256|
00000300 64 65 66 20 69 73 20 61 6e 20 61 72 72 61 79 20 |def is an array |
00000310 6f 66 20 32 35 36 20 69 6e 74 65 67 65 72 73 2c |of 256 integers,|
00000320 20 65 61 63 68 20 6f 66 20 74 68 65 20 66 6f 72 | each of the for|
00000330 6d 20 62 62 67 67 72 72 30 30 20 2d 20 69 74 20 |m bbggrr00 - it |
00000340 69 73 20 61 0a 63 6f 70 79 20 6f 66 20 74 68 65 |is a.copy of the|
00000350 20 64 65 66 61 75 6c 74 20 70 61 6c 65 74 74 65 | default palette|
00000360 20 66 6f 72 20 61 6e 20 38 62 70 70 20 73 70 72 | for an 8bpp spr|
00000370 69 74 65 2e 0a 55 6e 64 65 72 20 4f 53 20 33 20 |ite..Under OS 3 |
00000380 74 68 69 73 20 63 61 6e 20 62 65 20 66 6f 75 6e |this can be foun|
00000390 64 20 77 69 74 68 20 43 6f 6c 6f 75 72 54 72 61 |d with ColourTra|
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000003c0 6f 72 20 73 70 72 69 74 65 2c 20 73 61 79 20 75 |or sprite, say u|
000003d0 73 69 6e 67 20 74 68 65 20 42 41 53 49 43 20 72 |sing the BASIC r|
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00000420 4d 20 50 61 6c 32 35 36 44 65 66 25 20 53 69 7a |M Pal256Def% Siz|
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000004d0 33 32 37 36 38 20 63 68 61 72 61 63 74 65 72 73 |32768 characters|
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00000530 72 20 6f 66 20 74 68 65 20 6e 65 61 72 65 73 74 |r of the nearest|
00000540 20 61 76 61 69 6c 61 62 6c 65 20 63 6f 6c 6f 75 | available colou|
00000550 72 20 69 6e 0a 74 68 65 20 64 65 66 61 75 6c 74 |r in.the default|
00000560 20 38 62 70 70 20 70 61 6c 65 74 74 65 2e 0a 6c | 8bpp palette..l|
00000570 75 74 20 63 61 6e 20 62 65 20 70 72 65 2d 63 6f |ut can be pre-co|
00000580 6d 70 75 74 65 64 20 77 69 74 68 20 74 68 65 20 |mputed with the |
00000590 42 41 53 49 43 20 72 6f 75 74 69 6e 65 3a 0a 0a |BASIC routine:..|
000005a0 44 49 4d 20 6c 75 74 25 20 33 32 37 36 38 0a 53 |DIM lut% 32768.S|
000005b0 59 53 20 22 4f 53 5f 53 57 49 4e 75 6d 62 65 72 |YS "OS_SWINumber|
000005c0 46 72 6f 6d 53 74 72 69 6e 67 22 2c 2c 22 43 6f |FromString",,"Co|
000005d0 6c 6f 75 72 54 72 61 6e 73 5f 52 65 74 75 72 6e |lourTrans_Return|
000005e0 43 6f 6c 6f 75 72 4e 75 6d 62 65 72 46 6f 72 4d |ColourNumberForM|
000005f0 6f 64 65 22 20 54 4f 20 53 25 0a 46 4f 52 20 72 |ode" TO S%.FOR r|
00000600 25 3d 30 54 4f 33 31 3a 46 4f 52 20 67 25 3d 30 |%=0TO31:FOR g%=0|
00000610 54 4f 33 31 3a 46 4f 52 20 62 25 3d 30 54 4f 33 |TO31:FOR b%=0TO3|
00000620 31 0a 53 59 53 20 53 25 2c 28 28 28 28 62 25 3c |1.SYS S%,((((b%<|
00000630 3c 33 29 2b 28 62 25 3e 3e 32 29 29 3c 3c 31 36 |<3)+(b%>>2))<<16|
00000640 29 2b 28 28 28 67 25 3c 3c 33 29 2b 28 67 25 3e |)+(((g%<<3)+(g%>|
00000650 3e 32 29 29 3c 3c 38 29 2b 28 28 72 25 3c 3c 33 |>2))<<8)+((r%<<3|
00000660 29 2b 28 72 25 3e 3e 32 29 29 29 3c 3c 38 2c 31 |)+(r%>>2)))<<8,1|
00000670 35 20 54 4f 20 6c 75 74 25 3f 28 28 62 25 3c 3c |5 TO lut%?((b%<<|
00000680 31 30 29 2b 28 67 25 3c 3c 35 29 2b 72 25 29 0a |10)+(g%<<5)+r%).|
00000690 4e 45 58 54 0a 4e 45 58 54 0a 4e 45 58 54 0a 53 |NEXT.NEXT.NEXT.S|
000006a0 59 53 20 22 4f 53 5f 46 69 6c 65 22 2c 20 31 30 |YS "OS_File", 10|
000006b0 2c 20 22 3c 41 70 70 24 44 69 72 3e 2e 6c 75 74 |, "<App$Dir>.lut|
000006c0 22 2c 20 26 46 46 44 2c 20 2c 20 6c 75 74 25 2c |", &FFD, , lut%,|
000006d0 20 6c 75 74 25 2b 33 32 37 36 38 0a 45 4e 44 0a | lut%+32768.END.|
000006e0 3a 0a 52 45 4d 20 54 6f 20 61 74 74 65 6d 70 74 |:.REM To attempt|
000006f0 20 74 6f 20 6d 69 6d 69 63 20 43 68 61 6e 67 65 | to mimic Change|
00000700 46 53 49 2c 20 62 65 66 6f 72 65 20 65 78 65 63 |FSI, before exec|
00000710 75 74 69 6e 67 20 61 62 6f 76 65 2c 20 65 6e 73 |uting above, ens|
00000720 75 72 65 20 72 67 62 20 77 65 69 67 68 74 73 20 |ure rgb weights |
00000730 6f 66 20 33 2c 20 31 30 20 26 20 31 20 61 72 65 |of 3, 10 & 1 are|
00000740 20 69 6e 20 75 73 65 2e 0a 52 45 4d 20 2d 20 76 | in use..REM - v|
00000750 69 61 20 65 78 65 63 75 74 69 6e 67 20 2a 43 6f |ia executing *Co|
00000760 6c 6f 75 72 54 72 61 6e 73 4c 6f 61 64 69 6e 67 |lourTransLoading|
00000770 73 20 33 20 31 30 20 31 0a 52 45 4d 20 41 66 74 |s 3 10 1.REM Aft|
00000780 65 72 77 61 72 64 73 2c 20 72 65 6d 65 6d 62 65 |erwards, remembe|
00000790 72 20 74 6f 20 72 65 73 65 74 20 74 68 65 20 77 |r to reset the w|
000007a0 65 69 67 68 74 73 20 74 6f 20 32 20 34 20 31 0a |eights to 2 4 1.|
000007b0 0a 0a 2f 2a 20 43 20 73 6f 75 72 63 65 20 63 6f |../* C source co|
000007c0 64 65 20 74 6f 20 70 65 72 66 6f 72 6d 20 6d 61 |de to perform ma|
000007d0 69 6e 20 70 72 6f 63 65 73 73 69 6e 67 3a 20 2a |in processing: *|
000007e0 2f 0a 0a 23 64 65 66 69 6e 65 20 53 44 69 73 63 |/..#define SDisc|
000007f0 61 6c 65 20 34 0a 73 74 61 74 69 63 20 42 4f 4f |ale 4.static BOO|
00000800 4c 20 70 6c 6f 74 70 72 6f 63 65 73 73 28 73 70 |L plotprocess(sp|
00000810 72 69 74 65 5f 61 72 65 61 20 2a 2a 64 2c 20 73 |rite_area **d, s|
00000820 70 72 69 74 65 5f 61 72 65 61 20 2a 2a 73 2c 20 |prite_area **s, |
00000830 63 68 61 72 20 2a 6e 61 6d 65 2c 20 69 6e 74 20 |char *name, int |
00000840 78 2c 20 69 6e 74 20 79 29 0a 7b 0a 20 20 73 70 |x, int y).{. sp|
00000850 72 69 74 65 5f 69 64 20 64 69 2c 20 73 69 3b 0a |rite_id di, si;.|
00000860 20 20 73 70 72 69 74 65 5f 68 65 61 64 65 72 20 | sprite_header |
00000870 2a 73 68 2c 20 2a 64 68 3b 0a 20 20 63 68 61 72 |*sh, *dh;. char|
00000880 20 2a 73 70 2c 20 2a 64 70 3b 0a 20 20 72 65 67 | *sp, *dp;. reg|
00000890 69 73 74 65 72 20 63 68 61 72 20 2a 70 3b 0a 20 |ister char *p;. |
000008a0 20 69 6e 74 20 64 61 6c 69 67 6e 20 3d 20 28 34 | int dalign = (4|
000008b0 2d 28 78 26 33 29 29 26 33 3b 0a 20 20 69 6e 74 |-(x&3))&3;. int|
000008c0 20 73 61 6c 69 67 6e 20 3d 20 28 34 2d 28 28 78 | salign = (4-((x|
000008d0 2a 53 44 69 73 63 61 6c 65 29 26 33 29 29 26 33 |*SDiscale)&3))&3|
000008e0 3b 0a 20 20 72 65 67 69 73 74 65 72 20 69 6e 74 |;. register int|
000008f0 20 72 2c 67 2c 62 3b 20 20 2f 2a 64 65 73 69 72 | r,g,b; /*desir|
00000900 65 64 20 72 2c 67 2c 62 2a 2f 0a 20 20 69 6e 74 |ed r,g,b*/. int|
00000910 20 69 2c 20 6a 3b 0a 20 20 69 6e 74 20 73 76 6f | i, j;. int svo|
00000920 66 66 3b 0a 20 20 72 65 67 69 73 74 65 72 20 75 |ff;. register u|
00000930 6e 73 69 67 6e 65 64 20 69 6e 74 20 63 3b 0a 20 |nsigned int c;. |
00000940 20 69 6e 74 20 73 72 2c 20 73 67 2c 20 73 62 3b | int sr, sg, sb;|
00000950 20 20 20 20 20 20 2f 2a 73 61 74 75 72 61 74 65 | /*saturate|
00000960 64 20 64 65 73 69 72 65 64 20 72 2c 67 2c 62 2a |d desired r,g,b*|
00000970 2f 0a 0a 20 20 64 69 2e 74 61 67 3d 73 69 2e 74 |/.. di.tag=si.t|
00000980 61 67 3d 73 70 72 69 74 65 5f 69 64 5f 6e 61 6d |ag=sprite_id_nam|
00000990 65 3b 0a 20 20 64 69 2e 73 2e 6e 61 6d 65 3d 73 |e;. di.s.name=s|
000009a0 69 2e 73 2e 6e 61 6d 65 3d 6e 61 6d 65 3b 0a 20 |i.s.name=name;. |
000009b0 20 69 66 20 28 77 69 6d 70 74 5f 63 6f 6d 70 6c | if (wimpt_compl|
000009c0 61 69 6e 28 73 70 72 69 74 65 5f 73 65 6c 65 63 |ain(sprite_selec|
000009d0 74 5f 72 70 28 2a 64 2c 20 26 64 69 2c 20 28 73 |t_rp(*d, &di, (s|
000009e0 70 72 69 74 65 5f 70 74 72 20 2a 29 26 64 69 2e |prite_ptr *)&di.|
000009f0 73 2e 61 64 64 72 29 29 29 20 72 65 74 75 72 6e |s.addr))) return|
00000a00 20 46 41 4c 53 45 3b 0a 20 20 69 66 20 28 77 69 | FALSE;. if (wi|
00000a10 6d 70 74 5f 63 6f 6d 70 6c 61 69 6e 28 73 70 72 |mpt_complain(spr|
00000a20 69 74 65 5f 73 65 6c 65 63 74 5f 72 70 28 2a 73 |ite_select_rp(*s|
00000a30 2c 20 26 73 69 2c 20 28 73 70 72 69 74 65 5f 70 |, &si, (sprite_p|
00000a40 74 72 20 2a 29 26 73 69 2e 73 2e 61 64 64 72 29 |tr *)&si.s.addr)|
00000a50 29 29 20 72 65 74 75 72 6e 20 46 41 4c 53 45 3b |)) return FALSE;|
00000a60 0a 20 20 64 69 2e 74 61 67 3d 73 69 2e 74 61 67 |. di.tag=si.tag|
00000a70 3d 73 70 72 69 74 65 5f 69 64 5f 61 64 64 72 3b |=sprite_id_addr;|
00000a80 0a 20 20 64 68 20 3d 20 64 69 2e 73 2e 61 64 64 |. dh = di.s.add|
00000a90 72 3b 0a 20 20 73 68 20 3d 20 73 69 2e 73 2e 61 |r;. sh = si.s.a|
00000aa0 64 64 72 3b 0a 20 20 64 70 20 3d 20 28 63 68 61 |ddr;. dp = (cha|
00000ab0 72 20 2a 29 64 68 20 2b 20 64 68 2d 3e 69 6d 61 |r *)dh + dh->ima|
00000ac0 67 65 3b 0a 20 20 73 70 20 3d 20 28 63 68 61 72 |ge;. sp = (char|
00000ad0 20 2a 29 73 68 20 2b 20 73 68 2d 3e 69 6d 61 67 | *)sh + sh->imag|
00000ae0 65 3b 0a 20 20 73 76 6f 66 66 20 3d 20 34 2a 28 |e;. svoff = 4*(|
00000af0 73 68 2d 3e 77 69 64 74 68 2b 31 29 3b 0a 20 20 |sh->width+1);. |
00000b00 73 61 6c 69 67 6e 20 2b 3d 20 28 53 44 69 73 63 |salign += (SDisc|
00000b10 61 6c 65 2d 31 29 20 2a 20 73 76 6f 66 66 3b 0a |ale-1) * svoff;.|
00000b20 20 20 66 6f 72 20 28 6a 3d 79 3b 20 6a 3e 30 3b | for (j=y; j>0;|
00000b30 20 6a 2d 2d 2c 20 64 70 2b 3d 64 61 6c 69 67 6e | j--, dp+=dalign|
00000b40 2c 20 73 70 2b 3d 73 61 6c 69 67 6e 29 20 7b 0a |, sp+=salign) {.|
00000b50 20 20 20 20 66 6f 72 20 28 69 3d 78 3b 20 69 3e | for (i=x; i>|
00000b60 30 3b 20 69 2d 2d 2c 20 64 70 2b 2b 2c 20 73 70 |0; i--, dp++, sp|
00000b70 2b 3d 53 44 69 73 63 61 6c 65 29 20 7b 0a 20 20 |+=SDiscale) {. |
00000b80 20 20 20 20 2f 2a 66 6f 6c 6c 6f 77 69 6e 67 20 | /*following |
00000b90 61 73 73 75 6d 65 73 20 53 44 69 73 63 61 6c 65 |assumes SDiscale|
00000ba0 3d 3d 34 2a 2f 0a 20 20 20 20 20 20 70 3d 73 70 |==4*/. p=sp|
00000bb0 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 61 6c 32 |;. c = pal2|
00000bc0 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 |56def[*p++];. |
00000bd0 20 20 20 72 20 3d 20 28 63 3e 3e 38 29 26 32 35 | r = (c>>8)&25|
00000be0 35 3b 0a 20 20 20 20 20 20 67 20 3d 20 28 63 3e |5;. g = (c>|
00000bf0 3e 31 36 29 26 32 35 35 3b 0a 20 20 20 20 20 20 |>16)&255;. |
00000c00 62 20 3d 20 28 63 3e 3e 32 34 29 3b 0a 20 20 20 |b = (c>>24);. |
00000c10 20 20 20 63 20 3d 20 70 61 6c 32 35 36 64 65 66 | c = pal256def|
00000c20 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 20 20 20 72 20 |[*p++];. r |
00000c30 2b 3d 20 28 63 3e 3e 38 29 26 32 35 35 3b 0a 20 |+= (c>>8)&255;. |
00000c40 20 20 20 20 20 67 20 2b 3d 20 28 63 3e 3e 31 36 | g += (c>>16|
00000c50 29 26 32 35 35 3b 0a 20 20 20 20 20 20 62 20 2b |)&255;. b +|
00000c60 3d 20 28 63 3e 3e 32 34 29 3b 0a 20 20 20 20 20 |= (c>>24);. |
00000c70 20 63 20 3d 20 70 61 6c 32 35 36 64 65 66 5b 2a | c = pal256def[*|
00000c80 70 2b 2b 5d 3b 0a 20 20 20 20 20 20 72 20 2b 3d |p++];. r +=|
00000c90 20 28 63 3e 3e 38 29 26 32 35 35 3b 0a 20 20 20 | (c>>8)&255;. |
00000ca0 20 20 20 67 20 2b 3d 20 28 63 3e 3e 31 36 29 26 | g += (c>>16)&|
00000cb0 32 35 35 3b 0a 20 20 20 20 20 20 62 20 2b 3d 20 |255;. b += |
00000cc0 28 63 3e 3e 32 34 29 3b 0a 20 20 20 20 20 20 63 |(c>>24);. c|
00000cd0 20 3d 20 70 61 6c 32 35 36 64 65 66 5b 2a 70 2b | = pal256def[*p+|
00000ce0 2b 5d 3b 0a 20 20 20 20 20 20 72 20 2b 3d 20 28 |+];. r += (|
00000cf0 63 3e 3e 38 29 26 32 35 35 3b 0a 20 20 20 20 20 |c>>8)&255;. |
00000d00 20 67 20 2b 3d 20 28 63 3e 3e 31 36 29 26 32 35 | g += (c>>16)&25|
00000d10 35 3b 0a 20 20 20 20 20 20 62 20 2b 3d 20 28 63 |5;. b += (c|
00000d20 3e 3e 32 34 29 3b 0a 20 20 20 20 20 20 70 20 2b |>>24);. p +|
00000d30 3d 20 73 76 6f 66 66 2d 53 44 69 73 63 61 6c 65 |= svoff-SDiscale|
00000d40 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 61 6c 32 |;. c = pal2|
00000d50 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 |56def[*p++];. |
00000d60 20 20 20 72 20 2b 3d 20 28 63 3e 3e 38 29 26 32 | r += (c>>8)&2|
00000d70 35 35 3b 0a 20 20 20 20 20 20 67 20 2b 3d 20 28 |55;. g += (|
00000d80 63 3e 3e 31 36 29 26 32 35 35 3b 0a 20 20 20 20 |c>>16)&255;. |
00000d90 20 20 62 20 2b 3d 20 28 63 3e 3e 32 34 29 3b 0a | b += (c>>24);.|
00000da0 20 20 20 20 20 20 63 20 3d 20 70 61 6c 32 35 36 | c = pal256|
00000db0 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 20 20 |def[*p++];. |
00000dc0 20 72 20 2b 3d 20 28 63 3e 3e 38 29 26 32 35 35 | r += (c>>8)&255|
00000dd0 3b 0a 20 20 20 20 20 20 67 20 2b 3d 20 28 63 3e |;. g += (c>|
00000de0 3e 31 36 29 26 32 35 35 3b 0a 20 20 20 20 20 20 |>16)&255;. |
00000df0 62 20 2b 3d 20 28 63 3e 3e 32 34 29 3b 0a 20 20 |b += (c>>24);. |
00000e00 20 20 20 20 63 20 3d 20 70 61 6c 32 35 36 64 65 | c = pal256de|
00000e10 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 20 20 20 72 |f[*p++];. r|
00000e20 20 2b 3d 20 28 63 3e 3e 38 29 26 32 35 35 3b 0a | += (c>>8)&255;.|
00000e30 20 20 20 20 20 20 67 20 2b 3d 20 28 63 3e 3e 31 | g += (c>>1|
00000e40 36 29 26 32 35 35 3b 0a 20 20 20 20 20 20 62 20 |6)&255;. b |
00000e50 2b 3d 20 28 63 3e 3e 32 34 29 3b 0a 20 20 20 20 |+= (c>>24);. |
00000e60 20 20 63 20 3d 20 70 61 6c 32 35 36 64 65 66 5b | c = pal256def[|
00000e70 2a 70 2b 2b 5d 3b 0a 20 20 20 20 20 20 72 20 2b |*p++];. r +|
00000e80 3d 20 28 63 3e 3e 38 29 26 32 35 35 3b 0a 20 20 |= (c>>8)&255;. |
00000e90 20 20 20 20 67 20 2b 3d 20 28 63 3e 3e 31 36 29 | g += (c>>16)|
00000ea0 26 32 35 35 3b 0a 20 20 20 20 20 20 62 20 2b 3d |&255;. b +=|
00000eb0 20 28 63 3e 3e 32 34 29 3b 0a 20 20 20 20 20 20 | (c>>24);. |
00000ec0 70 20 2b 3d 20 73 76 6f 66 66 2d 53 44 69 73 63 |p += svoff-SDisc|
00000ed0 61 6c 65 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 |ale;. c = p|
00000ee0 61 6c 32 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a |al256def[*p++];.|
00000ef0 20 20 20 20 20 20 72 20 2b 3d 20 28 63 3e 3e 38 | r += (c>>8|
00000f00 29 26 32 35 35 3b 0a 20 20 20 20 20 20 67 20 2b |)&255;. g +|
00000f10 3d 20 28 63 3e 3e 31 36 29 26 32 35 35 3b 0a 20 |= (c>>16)&255;. |
00000f20 20 20 20 20 20 62 20 2b 3d 20 28 63 3e 3e 32 34 | b += (c>>24|
00000f30 29 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 61 6c |);. c = pal|
00000f40 32 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 |256def[*p++];. |
00000f50 20 20 20 20 72 20 2b 3d 20 28 63 3e 3e 38 29 26 | r += (c>>8)&|
00000f60 32 35 35 3b 0a 20 20 20 20 20 20 67 20 2b 3d 20 |255;. g += |
00000f70 28 63 3e 3e 31 36 29 26 32 35 35 3b 0a 20 20 20 |(c>>16)&255;. |
00000f80 20 20 20 62 20 2b 3d 20 28 63 3e 3e 32 34 29 3b | b += (c>>24);|
00000f90 0a 20 20 20 20 20 20 63 20 3d 20 70 61 6c 32 35 |. c = pal25|
00000fa0 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 20 |6def[*p++];. |
00000fb0 20 20 72 20 2b 3d 20 28 63 3e 3e 38 29 26 32 35 | r += (c>>8)&25|
00000fc0 35 3b 0a 20 20 20 20 20 20 67 20 2b 3d 20 28 63 |5;. g += (c|
00000fd0 3e 3e 31 36 29 26 32 35 35 3b 0a 20 20 20 20 20 |>>16)&255;. |
00000fe0 20 62 20 2b 3d 20 28 63 3e 3e 32 34 29 3b 0a 20 | b += (c>>24);. |
00000ff0 20 20 20 20 20 63 20 3d 20 70 61 6c 32 35 36 64 | c = pal256d|
00001000 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 20 20 20 |ef[*p++];. |
00001010 72 20 2b 3d 20 28 63 3e 3e 38 29 26 32 35 35 3b |r += (c>>8)&255;|
00001020 0a 20 20 20 20 20 20 67 20 2b 3d 20 28 63 3e 3e |. g += (c>>|
00001030 31 36 29 26 32 35 35 3b 0a 20 20 20 20 20 20 62 |16)&255;. b|
00001040 20 2b 3d 20 28 63 3e 3e 32 34 29 3b 0a 20 20 20 | += (c>>24);. |
00001050 20 20 20 70 20 2b 3d 20 73 76 6f 66 66 2d 53 44 | p += svoff-SD|
00001060 69 73 63 61 6c 65 3b 0a 20 20 20 20 20 20 63 20 |iscale;. c |
00001070 3d 20 70 61 6c 32 35 36 64 65 66 5b 2a 70 2b 2b |= pal256def[*p++|
00001080 5d 3b 0a 20 20 20 20 20 20 72 20 2b 3d 20 28 63 |];. r += (c|
00001090 3e 3e 38 29 26 32 35 35 3b 0a 20 20 20 20 20 20 |>>8)&255;. |
000010a0 67 20 2b 3d 20 28 63 3e 3e 31 36 29 26 32 35 35 |g += (c>>16)&255|
000010b0 3b 0a 20 20 20 20 20 20 62 20 2b 3d 20 28 63 3e |;. b += (c>|
000010c0 3e 32 34 29 3b 0a 20 20 20 20 20 20 63 20 3d 20 |>24);. c = |
000010d0 70 61 6c 32 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b |pal256def[*p++];|
000010e0 0a 20 20 20 20 20 20 72 20 2b 3d 20 28 63 3e 3e |. r += (c>>|
000010f0 38 29 26 32 35 35 3b 0a 20 20 20 20 20 20 67 20 |8)&255;. g |
00001100 2b 3d 20 28 63 3e 3e 31 36 29 26 32 35 35 3b 0a |+= (c>>16)&255;.|
00001110 20 20 20 20 20 20 62 20 2b 3d 20 28 63 3e 3e 32 | b += (c>>2|
00001120 34 29 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 61 |4);. c = pa|
00001130 6c 32 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 |l256def[*p++];. |
00001140 20 20 20 20 20 72 20 2b 3d 20 28 63 3e 3e 38 29 | r += (c>>8)|
00001150 26 32 35 35 3b 0a 20 20 20 20 20 20 67 20 2b 3d |&255;. g +=|
00001160 20 28 63 3e 3e 31 36 29 26 32 35 35 3b 0a 20 20 | (c>>16)&255;. |
00001170 20 20 20 20 62 20 2b 3d 20 28 63 3e 3e 32 34 29 | b += (c>>24)|
00001180 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 61 6c 32 |;. c = pal2|
00001190 35 36 64 65 66 5b 2a 70 2b 2b 5d 3b 0a 20 20 20 |56def[*p++];. |
000011a0 20 20 20 72 20 2b 3d 20 28 63 3e 3e 38 29 26 32 | r += (c>>8)&2|
000011b0 35 35 3b 0a 20 20 20 20 20 20 67 20 2b 3d 20 28 |55;. g += (|
000011c0 63 3e 3e 31 36 29 26 32 35 35 3b 0a 20 20 20 20 |c>>16)&255;. |
000011d0 20 20 62 20 2b 3d 20 28 63 3e 3e 32 34 29 3b 0a | b += (c>>24);.|
000011e0 0a 20 20 20 20 20 20 72 20 2f 3d 20 28 53 44 69 |. r /= (SDi|
000011f0 73 63 61 6c 65 2a 53 44 69 73 63 61 6c 65 29 3b |scale*SDiscale);|
00001200 0a 20 20 20 20 20 20 67 20 2f 3d 20 28 53 44 69 |. g /= (SDi|
00001210 73 63 61 6c 65 2a 53 44 69 73 63 61 6c 65 29 3b |scale*SDiscale);|
00001220 0a 20 20 20 20 20 20 62 20 2f 3d 20 28 53 44 69 |. b /= (SDi|
00001230 73 63 61 6c 65 2a 53 44 69 73 63 61 6c 65 29 3b |scale*SDiscale);|
00001240 0a 20 20 20 20 20 20 2f 2a 61 74 20 74 68 69 73 |. /*at this|
00001250 20 70 6f 69 6e 74 2c 20 61 64 64 20 69 6e 20 61 | point, add in a|
00001260 6e 79 20 65 72 72 6f 72 73 20 66 72 6f 6d 20 61 |ny errors from a|
00001270 62 6f 76 65 2c 20 6c 65 66 74 20 26 20 61 62 6f |bove, left & abo|
00001280 76 65 20 6c 65 66 74 20 70 69 78 65 6c 73 2c 20 |ve left pixels, |
00001290 77 69 74 68 20 77 65 69 67 68 74 73 20 33 2f 38 |with weights 3/8|
000012a0 2c 20 33 2f 38 2c 20 31 2f 34 0a 20 20 20 20 20 |, 3/8, 1/4. |
000012b0 20 20 20 69 65 20 46 6c 6f 79 64 2d 53 74 65 69 | ie Floyd-Stei|
000012c0 6e 62 65 72 67 2a 2f 0a 20 20 20 20 20 20 69 66 |nberg*/. if|
000012d0 20 28 69 21 3d 78 29 20 7b 20 20 20 20 20 20 20 | (i!=x) { |
000012e0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
000012f0 2f 2a 61 64 64 20 65 72 72 6f 72 20 74 6f 20 6c |/*add error to l|
00001300 65 66 74 20 69 6e 2a 2f 0a 20 20 20 20 20 20 20 |eft in*/. |
00001310 20 70 20 3d 20 73 70 2d 53 44 69 73 63 61 6c 65 | p = sp-SDiscale|
00001320 3b 0a 20 20 20 20 20 20 20 20 72 20 2b 3d 20 33 |;. r += 3|
00001330 2a 28 2a 28 69 6e 74 20 2a 29 70 29 2f 38 3b 0a |*(*(int *)p)/8;.|
00001340 20 20 20 20 20 20 20 20 67 20 2b 3d 20 33 2a 28 | g += 3*(|
00001350 2a 28 69 6e 74 20 2a 29 28 70 2b 3d 73 76 6f 66 |*(int *)(p+=svof|
00001360 66 29 29 2f 38 3b 0a 20 20 20 20 20 20 20 20 62 |f))/8;. b|
00001370 20 2b 3d 20 33 2a 28 2a 28 69 6e 74 20 2a 29 28 | += 3*(*(int *)(|
00001380 70 2b 3d 73 76 6f 66 66 29 29 2f 38 3b 0a 20 20 |p+=svoff))/8;. |
00001390 20 20 20 20 7d 0a 20 20 20 20 20 20 69 66 20 28 | }. if (|
000013a0 6a 21 3d 79 29 20 7b 20 20 20 20 20 20 20 20 20 |j!=y) { |
000013b0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 2f 2a | /*|
000013c0 61 64 64 20 65 72 72 6f 72 20 74 6f 20 61 62 6f |add error to abo|
000013d0 76 65 20 69 6e 2a 2f 0a 20 20 20 20 20 20 20 20 |ve in*/. |
000013e0 70 20 3d 20 73 70 2d 53 44 69 73 63 61 6c 65 2a |p = sp-SDiscale*|
000013f0 73 76 6f 66 66 3b 0a 20 20 20 20 20 20 20 20 72 |svoff;. r|
00001400 20 2b 3d 20 33 2a 28 2a 28 69 6e 74 20 2a 29 70 | += 3*(*(int *)p|
00001410 29 2f 38 3b 0a 20 20 20 20 20 20 20 20 67 20 2b |)/8;. g +|
00001420 3d 20 33 2a 28 2a 28 69 6e 74 20 2a 29 28 70 2b |= 3*(*(int *)(p+|
00001430 3d 73 76 6f 66 66 29 29 2f 38 3b 0a 20 20 20 20 |=svoff))/8;. |
00001440 20 20 20 20 62 20 2b 3d 20 33 2a 28 2a 28 69 6e | b += 3*(*(in|
00001450 74 20 2a 29 28 70 2b 3d 73 76 6f 66 66 29 29 2f |t *)(p+=svoff))/|
00001460 38 3b 0a 20 20 20 20 20 20 20 20 69 66 20 28 69 |8;. if (i|
00001470 21 3d 78 29 20 7b 20 20 20 20 20 20 20 20 20 20 |!=x) { |
00001480 20 20 20 20 20 20 20 20 20 20 20 2f 2a 61 64 64 | /*add|
00001490 20 65 72 72 6f 72 20 74 6f 20 61 62 6f 76 65 20 | error to above |
000014a0 6c 65 66 74 20 69 6e 2a 2f 0a 20 20 20 20 20 20 |left in*/. |
000014b0 20 20 20 20 70 20 3d 20 73 70 2d 53 44 69 73 63 | p = sp-SDisc|
000014c0 61 6c 65 2a 28 73 76 6f 66 66 2b 31 29 3b 0a 20 |ale*(svoff+1);. |
000014d0 20 20 20 20 20 20 20 20 20 72 20 2b 3d 20 28 2a | r += (*|
000014e0 28 69 6e 74 20 2a 29 70 29 2f 34 3b 0a 20 20 20 |(int *)p)/4;. |
000014f0 20 20 20 20 20 20 20 67 20 2b 3d 20 28 2a 28 69 | g += (*(i|
00001500 6e 74 20 2a 29 28 70 2b 3d 73 76 6f 66 66 29 29 |nt *)(p+=svoff))|
00001510 2f 34 3b 0a 20 20 20 20 20 20 20 20 20 20 62 20 |/4;. b |
00001520 2b 3d 20 28 2a 28 69 6e 74 20 2a 29 28 70 2b 3d |+= (*(int *)(p+=|
00001530 73 76 6f 66 66 29 29 2f 34 3b 0a 20 20 20 20 20 |svoff))/4;. |
00001540 20 20 20 7d 0a 20 20 20 20 20 20 7d 0a 0a 20 20 | }. }.. |
00001550 20 20 20 20 2f 2a 6e 6f 77 20 68 61 76 65 20 64 | /*now have d|
00001560 65 73 69 72 65 64 20 63 6f 6c 6f 75 72 20 69 6e |esired colour in|
00001570 20 72 2c 67 2c 62 2a 2f 0a 20 20 20 20 20 20 73 | r,g,b*/. s|
00001580 72 20 3d 20 72 3e 32 35 35 20 3f 20 32 35 35 20 |r = r>255 ? 255 |
00001590 3a 20 28 72 3c 30 20 3f 20 30 20 3a 20 72 29 3b |: (r<0 ? 0 : r);|
000015a0 0a 20 20 20 20 20 20 73 67 20 3d 20 67 3e 32 35 |. sg = g>25|
000015b0 35 20 3f 20 32 35 35 20 3a 20 28 67 3c 30 20 3f |5 ? 255 : (g<0 ?|
000015c0 20 30 20 3a 20 67 29 3b 0a 20 20 20 20 20 20 73 | 0 : g);. s|
000015d0 62 20 3d 20 62 3e 32 35 35 20 3f 20 32 35 35 20 |b = b>255 ? 255 |
000015e0 3a 20 28 62 3c 30 20 3f 20 30 20 3a 20 62 29 3b |: (b<0 ? 0 : b);|
000015f0 0a 20 20 20 20 20 20 63 20 3d 20 28 73 72 3e 3e |. c = (sr>>|
00001600 33 29 20 2b 20 28 28 73 67 3e 3e 33 29 3c 3c 35 |3) + ((sg>>3)<<5|
00001610 29 20 2b 20 28 28 73 62 3e 3e 33 29 3c 3c 31 30 |) + ((sb>>3)<<10|
00001620 29 3b 0a 20 20 20 20 20 20 63 20 3d 20 70 61 6c |);. c = pal|
00001630 32 35 36 64 65 66 5b 20 2a 64 70 20 3d 20 6c 75 |256def[ *dp = lu|
00001640 74 5b 63 5d 20 5d 3b 20 2f 2a 73 65 74 20 2a 64 |t[c] ]; /*set *d|
00001650 70 20 74 6f 20 63 6c 6f 73 65 73 74 20 63 6f 6c |p to closest col|
00001660 6f 75 72 20 6e 75 6d 62 65 72 20 76 69 61 20 6c |our number via l|
00001670 75 74 2c 20 26 20 63 20 74 6f 20 62 62 67 67 72 |ut, & c to bbggr|
00001680 72 30 30 20 76 61 6c 75 65 20 66 6f 72 20 74 68 |r00 value for th|
00001690 69 73 20 63 6f 6c 6f 75 72 20 6e 75 6d 62 65 72 |is colour number|
000016a0 2a 2f 0a 20 20 20 20 20 20 2f 2a 6e 6f 77 20 68 |*/. /*now h|
000016b0 61 76 65 20 61 63 74 75 61 6c 20 64 65 73 74 69 |ave actual desti|
000016c0 6e 61 74 69 6f 6e 20 70 69 78 65 6c 20 73 65 74 |nation pixel set|
000016d0 20 75 70 2a 2f 0a 0a 20 20 20 20 20 20 72 20 2d | up*/.. r -|
000016e0 3d 20 28 63 3e 3e 38 29 26 32 35 35 3b 0a 20 20 |= (c>>8)&255;. |
000016f0 20 20 20 20 67 20 2d 3d 20 28 63 3e 3e 31 36 29 | g -= (c>>16)|
00001700 26 32 35 35 3b 0a 20 20 20 20 20 20 62 20 2d 3d |&255;. b -=|
00001710 20 28 63 3e 3e 32 34 29 3b 0a 20 20 20 20 20 20 | (c>>24);. |
00001720 2f 2a 72 2c 67 2c 62 20 6e 6f 77 20 68 6f 6c 64 |/*r,g,b now hold|
00001730 20 65 72 72 6f 72 20 28 69 65 20 64 65 73 69 72 | error (ie desir|
00001740 65 64 2d 61 63 74 75 61 6c 29 2a 2f 0a 20 20 20 |ed-actual)*/. |
00001750 20 20 20 2f 2a 77 72 69 74 65 20 74 68 69 73 20 | /*write this |
00001760 76 61 6c 75 65 20 62 61 63 6b 20 69 6e 74 6f 20 |value back into |
00001770 73 6f 75 72 63 65 20 69 6d 61 67 65 20 28 6f 76 |source image (ov|
00001780 65 72 20 74 68 65 20 70 69 78 65 6c 20 64 61 74 |er the pixel dat|
00001790 61 20 77 65 20 68 61 76 65 20 6a 75 73 74 20 75 |a we have just u|
000017a0 73 65 64 29 2a 2f 0a 20 20 20 20 20 20 2f 2a 4e |sed)*/. /*N|
000017b0 42 20 74 6f 20 64 6f 20 74 68 69 73 2c 20 77 6f |B to do this, wo|
000017c0 72 64 20 61 6c 69 67 6e 6d 65 6e 74 20 69 73 20 |rd alignment is |
000017d0 63 72 75 63 69 61 6c 20 28 74 68 75 73 20 53 44 |crucial (thus SD|
000017e0 69 73 63 61 6c 65 20 6d 75 73 74 20 62 65 20 61 |iscale must be a|
000017f0 20 6d 75 6c 74 69 70 6c 65 20 6f 66 20 34 29 2a | multiple of 4)*|
00001800 2f 0a 20 20 20 20 20 20 70 20 3d 20 73 70 3b 0a |/. p = sp;.|
00001810 20 20 20 20 20 20 2a 28 69 6e 74 20 2a 29 70 20 | *(int *)p |
00001820 20 20 20 20 20 20 20 20 20 3d 20 72 3b 0a 20 20 | = r;. |
00001830 20 20 20 20 2a 28 69 6e 74 20 2a 29 28 70 2b 3d | *(int *)(p+=|
00001840 73 76 6f 66 66 29 20 3d 20 67 3b 0a 20 20 20 20 |svoff) = g;. |
00001850 20 20 2a 28 69 6e 74 20 2a 29 28 70 2b 3d 73 76 | *(int *)(p+=sv|
00001860 6f 66 66 29 20 3d 20 62 3b 0a 0a 20 20 20 20 7d |off) = b;.. }|
00001870 0a 20 20 7d 0a 0a 20 20 72 65 74 75 72 6e 20 54 |. }.. return T|
00001880 52 55 45 3b 0a 7d 0a |RUE;.}.|
00001887 
.