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Fix Lua function matchcolor2() inaccuracies caused by integer arithmetics

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git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@2082 416bcca6-2ee7-4201-b75f-2eb2f807beb1
This commit is contained in:
Yves Rizoud
2015-02-15 22:20:47 +00:00
parent 61c8dca353
commit 67d3636512
4 changed files with 61 additions and 57 deletions
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69
src/factory.c
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@@ -860,7 +860,8 @@ int L_MatchColor(lua_State* L)
int L_MatchColor2(lua_State* L)
{
double r, g, b;
int c;
double l_weight = 0.25;
byte best_color = 0;
int nb_args=lua_gettop(L);
if (nb_args < 3 || nb_args > 4)
@@ -870,17 +871,67 @@ int L_MatchColor2(lua_State* L)
LUA_ARG_NUMBER(1, "matchcolor2", r, -DBL_MAX, DBL_MAX);
LUA_ARG_NUMBER(2, "matchcolor2", g, -DBL_MAX, DBL_MAX);
LUA_ARG_NUMBER(3, "matchcolor2", b, -DBL_MAX, DBL_MAX);
if (nb_args == 3)
if (nb_args > 3)
{
c = Best_color_perceptual(clamp_byte(r),clamp_byte(g),clamp_byte(b));
LUA_ARG_NUMBER(4, "matchcolor2", l_weight, 0.0, 1.0);
}
else // nb_args == 4
// Similar to Best_color_perceptual(), but with floating point
{
float weight;
LUA_ARG_NUMBER(4, "matchcolor2", weight, -DBL_MAX, DBL_MAX);
c = Best_color_perceptual_weighted(clamp_byte(r),clamp_byte(g),clamp_byte(b),weight);
}
lua_pushinteger(L, c);
int col;
double best_diff=9e99;
double target_bri;
double bri;
double diff_b, diff_c, diff;
if (r<0.0)
r=0;
else if (r>255.0)
r=255.0;
if (g<0.0)
g=0;
else if (g>255.0)
g=255.0;
if (b<0.0)
b=0;
else if (b>255.0)
b=255.0;
// Similar to Perceptual_lightness();
target_bri = sqrt(0.26*r*0.26*r + 0.55*g*0.55*g + 0.19*b*0.19*b);
for (col=0; col<256; col++)
{
if (Exclude_color[col])
continue;
diff_c = sqrt(
(0.26*(Main_palette[col].R-r))*
(0.26*(Main_palette[col].R-r))+
(0.55*(Main_palette[col].G-g))*
(0.55*(Main_palette[col].G-g))+
(0.19*(Main_palette[col].B-b))*
(0.19*(Main_palette[col].B-b)));
// Exact match
if (diff_c<1.0)
{
lua_pushinteger(L, col);
return 1;
}
bri = sqrt(0.26*0.26*(Main_palette[col].R*Main_palette[col].R) + 0.55*0.55*(Main_palette[col].G*Main_palette[col].G) + 0.19*0.19*(Main_palette[col].B*Main_palette[col].B));
diff_b = fabs(target_bri-bri);
diff=l_weight*(diff_b-diff_c)+diff_c;
if (diff<best_diff)
{
best_diff=diff;
best_color=col;
}
}
}
lua_pushinteger(L, best_color);
return 1;
}