vim中将色彩转换为终端下色彩的算法的选择
2011年8月01日 19:24
看了 依云的文章， 让 Vim 在终端下和 GVIM 一样漂亮：gui2term.py 更新至 3.0 版
决定给自己的vim色彩插件加上终端支持。
colorscheme生成约50个色彩
ColorV的调色板生成约125个色彩
每个色彩需要对比255-16个终端颜色。
最后发现算法 delta_e_cie2000 实在太复杂，vim运行太费时间,要30+s。
而编译成delta.so，用vim的libcall()调用，
gcc -c -fpic -o delta.o delta.c
gcc -shared -lc -o delta.so delta.o
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
/* should declare function if it's not int; */
double degrees();
double radians();
int delta2000(char p_str[100])
{
char ca[80],cb[80];
sscanf(p_str,"%6s:%6s",ca,cb);
hex2lab(ca);
hex2lab(cb);
float L1,a1,b1,L2,a2,b2,delta_E;
sscanf(ca,"%f:%f:%f",&L1,&a1,&b1);
sscanf(cb,"%f:%f:%f",&L2,&a2,&b2);
int Kl = 1;int Kc = 1;int Kh = 1;
float avg_Lp,C1,C2,avg_C1_C2,G,a1p,a2p,C1p,C2p,avg_C1p_C2p;
float h1p,h2p,avg_Hp,T,diff_h2p_h1p,delta_hp,delta_Lp,delta_Cp,delta_Hp;
float S_L,S_C,S_H,delta_ro,R_C,R_T;
avg_Lp = (L1 + L2) / 2.0;
C1 = sqrt(pow(a1, 2) + pow(b1, 2));
C2 = sqrt(pow(a2, 2) + pow(b2, 2));
avg_C1_C2 = (C1 + C2) / 2.0;
G = 0.5 * (1 - sqrt(pow(avg_C1_C2 , 7.0) / (pow(avg_C1_C2, 7.0) + pow(25.0, 7.0))));
a1p = (1.0 + G) * a1;
a2p = (1.0 + G) * a2;
C1p = sqrt(pow(a1p, 2) + pow(b1, 2));
C2p = sqrt(pow(a2p, 2) + pow(b2, 2));
avg_C1p_C2p =(C1p + C2p) / 2.0;
if (degrees(atan2(b1,a1p)) >= 0)
h1p = degrees(atan2(b1,a1p));
else
h1p = degrees(atan2(b1,a1p)) + 360;
if (degrees(atan2(b2,a2p)) >= 0)
h2p = degrees(atan2(b2,a2p));
else
h2p = degrees(atan2(b2,a2p)) + 360;
if (abs(h1p - h2p) > 180)
avg_Hp = (h1p + h2p + 360) / 2.0;
else
avg_Hp = (h1p + h2p) / 2.0;
T = 1 - 0.17 * cos(radians(avg_Hp - 30)) + 0.24 * cos(radians(2 * avg_Hp)) + 0.32 * cos(radians(3 * avg_Hp + 6)) - 0.2 * cos(radians(4 * avg_Hp - 63));
diff_h2p_h1p = h2p - h1p;
if (abs(diff_h2p_h1p) <= 180)
delta_hp = diff_h2p_h1p;
else if ((abs(diff_h2p_h1p) > 180) && (h2p <= h1p))
delta_hp = diff_h2p_h1p + 360;
else
delta_hp = diff_h2p_h1p - 360;
delta_Lp = L2 - L1;
delta_Cp = C2p - C1p;
delta_Hp = 2 * sqrt(C2p * C1p) * sin(radians(delta_hp) / 2.0);
S_L = 1 + ((0.015 * pow(avg_Lp - 50, 2)) / sqrt(20 + pow(avg_Lp - 50, 2.0)));
S_C = 1 + 0.045 * avg_C1p_C2p;
S_H = 1 + 0.015 * avg_C1p_C2p * T;
delta_ro = 30 * exp(-(pow(((avg_Hp - 275) / 25), 2.0)));
R_C = sqrt((pow(avg_C1p_C2p, 7.0)) / (pow(avg_C1p_C2p, 7.0) + pow(25.0, 7.0)));
R_T = -2 * R_C * sin(2 * radians(delta_ro));
delta_E = sqrt(pow(delta_Lp /(S_L * Kl), 2) + pow(delta_Cp /(S_C * Kc), 2) + pow(delta_Hp /(S_H * Kh), 2) + R_T * (delta_Cp /(S_C * Kc)) * (delta_Hp / (S_H * Kh)));
sprintf(p_str,"%f",delta_E);
return p_str;
}
double degrees(double radian)
{
double degree ;
degree = radian * 180 / 3.1415926 ;
return degree;
}
double radians(double degree)
{
double radian ;
radian = degree / 180 * 3.1415926 ;
return radian;
}
int hex2lab(char *hex)
{
int ri,gi,bi;
sscanf(hex,"%2x%2x%2x",&ri,&gi,&bi);
double r,g,b;
r=(double)ri/255.0,g=(double)gi/255.0,b=(double)bi/255.0;
if (r>0.04045) {
r = pow(((r + 0.055) / 1.055) , 2.4);
} else {
r = r / 12.92;
}
if (g>0.04045) {
g = pow(((g + 0.055) / 1.055) , 2.4);
} else{
g = g / 12.92;
}
if (b>0.04045) {
b = pow(((b + 0.055) / 1.055) , 2.4);
} else {
b = b / 12.92;
}
r=r*100,g=g*100,b=b*100;
double X,Y,Z;
X = r * 0.4124 + g * 0.3576 + b * 0.1805;
Y = r * 0.2126 + g * 0.7152 + b * 0.0722;
Z = r * 0.0193 + g * 0.1192 + b * 0.9505;
X = X/95.047;
Y = Y/100.000;
Z = Z/108.883;
if (X > 0.008856)
X = pow(X ,(0.3333333));
else
X = (7.787 * X) + (16 / 116);
if (Y > 0.008856)
Y = pow(Y ,(0.3333333));
else
Y = (7.787 * Y) + (16 / 116);
if (Z > 0.008856)
Z = pow(Z ,(0.3333333));
else
Z = (7.787 * Z) + (16 / 116);
double L,a;
L = (116 * Y) - 16;
a = 500 * (X - Y);
b = 200 * (Y - Z);
sprintf(hex,"%f:%f:%f",L,a,b);
return 0;
}
不得不吐槽一下，vim的libcall不但功能很弱，只能传递一个参数，其速度也非常坑人。
要消耗20+s，只比用vim本身运行略好。
用py_delta_2000()的速度不错，只需要3秒。
之后用 delta_e_cie76 速度差别不大。
然后改成hsv之差的绝对值，不过默认scheme的转换效果不好，而且速度仍要20+s。
最后还是决定用最简单的算法,直接用rgb之差的绝对值。
d=abs(r1-r2)+abs(b1-b2)+abs(g1-g2)
效果还算不错。
py_delta_rgb()只需要1秒左右
best_match = 0
smallest_distance = 10000000
hex1 = vim.eval("hex1")
r1,g1,b1 = int(hex1[0:2],16),int(hex1[2:4],16),int(hex1[4:6],16)
for c in range(16, 256):
hex2 = termcolor[c]
r2,g2,b2 = int(hex2[1:3],16),int(hex2[3:5],16),int(hex2[5:7],16)
d = abs(r1-r2)+abs(g1-g2)+abs(b1-b2)
if d < smallest_distance:
smallest_distance = d
best_match = c
vim.command("let best_match = "+str(best_match))
vi_delta_rgb()需要3秒。
let best_match=0
let smallest_distance = 100000000
let hex1=a:hex
let [r1,g1,b1] = ["0x".hex1[0:1],"0x".hex1[2:3],"0x".hex1[4:5]]
for c in range(16,255)
let hex2=s:fmt_hex(s:tmclr_dict[c])
let [r2,g2,b2] = ["0x".hex2[0:1],"0x".hex2[2:3],"0x".hex2[4:5]]
let d = abs(r1-r2)+abs(g1-g2)+abs(b1-b2)
if d < smallest_distance
let smallest_distance = d
let best_match = c
endif
endfor
return best_match
不过最后一想，还是自己的问题。
毕竟别人的脚本是生成文件，我的目的是动态生成色彩，要求不一样，算法当然不同。
下图为各算法生成色彩与gvim调色板的对比
这个scheme是仿照butterscream.vim的配色生成的。
不过配色生成插件还没完成。