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https://github.com/adammaj1/hsluv-color-gradient
perceptually uniform 1D color gradient ( HSLuv) using C99 implementation of HSLuv (revision 4) www.hsluv.org
https://github.com/adammaj1/hsluv-color-gradient
1d bash c color-gradient color-scheme coloring-algorithm colormaps colorscheme gnuplot gradient graphics-programming hsl hsluv hsv2rgb rgb-color scientific-visualization scientific-visualizations
Last synced: about 1 month ago
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perceptually uniform 1D color gradient ( HSLuv) using C99 implementation of HSLuv (revision 4) www.hsluv.org
- Host: GitHub
- URL: https://github.com/adammaj1/hsluv-color-gradient
- Owner: adammaj1
- License: mit
- Created: 2021-05-01T05:43:40.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2021-05-02T19:51:54.000Z (over 3 years ago)
- Last Synced: 2024-08-04T13:03:15.541Z (5 months ago)
- Topics: 1d, bash, c, color-gradient, color-scheme, coloring-algorithm, colormaps, colorscheme, gnuplot, gradient, graphics-programming, hsl, hsluv, hsv2rgb, rgb-color, scientific-visualization, scientific-visualizations
- Language: C
- Homepage:
- Size: 7.97 MB
- Stars: 4
- Watchers: 2
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
1D discrete and continous perceptually uniform ordered color gradients rendered in [HSL](https://www.hsluv.org/)
# Examples
Gradient types:
* General types
* continous
* discrete
* Joining types ( see also in [1D RGB gradient](https://github.com/adammaj1/1D-RGB-color-gradient/blob/main/README.md#continous-gradient-manipulations))
* no
* steps
* tubes
* diverging
## HSL = [0, 100, l]
### continous
### discrete
## HSL = [60, 100, l]
### continous
### discrete
# Theory
Sequential map with varying lightness, single hue rendered in HSLuv color space. See : [Interactive Creation of Perceptually Uniform Color Maps by M. Lambers ](https://diglib.eg.org/bitstream/handle/10.2312/evs20201048/055-059.pdf)
* h is constant
* s is constant
* l is changing between 0.0 and 100.0 ( full range). It is variable = gradient position
```c
// for each gradient position ( = lightness) compute hsl
for(iX=0; iX 360.0) { h_complementary -= 360.0;}
```
# How program works ?
General steps
* c program creates ppm and txt files
* Image Magic converts ppm to png ( color bars)
* gnuplot converts txt to png files ( 2D RGB color profiles )
* remove txt and ppm files
Steps of the C program:
* for each gradient type and h value create ppm and txt file
* ppm file is created by saving 1D array of rgb values ( virtual 2D array)
* txt file is a simple list of rgb values for gnuplot
Results:
* there are 2 general gradient types ( continous and discrete )
* there are 4 gradient joining types ( no steps tubes diverging)
* there are 7 values of lightnes : 0 60 120 180 240 300 360
* for each gradient there are 2 images: gradient bar and 2D RGB profile
so the program creates [112 png images](./images)
```math
2*4*7*2 = 112
```
```c
// make gradient images for each gradient type
void MakeGradientImages(const double h, const double s){
GradientGeneralType gType;
GradientJoiningType jType;
//
for (gType = 0; gType< gMaxType; ++gType)
for (jType = 0; jType < jMaxType; ++jType)
MakeGradientTypeImages(gType, jType, h, s);
}
// from main : for each h make gradient images
do {
MakeGradientImages(h,s);
h += h_step; // next gradient
} while( h < h_Max );
```
## Gradient Joining Types
```c
double ModifyPosition(const double position, const GradientGeneralType gTypeVar, const GradientJoiningType jTypeVar){
// input position should be in [0,1] range
double p = position; // p = local copy of position
// if position > 1 then we have repetition of colors = periodic function = wave
switch(jTypeVar){
// simple monotone function
case no : { break;} // return input position without modifications
// periodic waves with different joinings
case steps : { p = p * segments; // periodic = change range
p = frac(p);
break;}
case tubes : { p = p * segments; // periodic = change range
int ip = (int)p;
p = p-ip; // fractional part
if (ip % 2) {p = 1.0-p;} // reverse gradient
break;}
case diverging : { p *= 2.0;
if (p>1.0) {p = 2.0 - p;} // reverse gradient
break;}
default:{}
}
if ( gTypeVar == discrete ) { p = double2steps(p); }
return p; // output in [0,1] range = modified position
}
```
## variables
* hsl color
* h Hue. Between 0.0 and 360.0
* s Saturation. Between 0.0 and 100.0
* l Lightness. Between 0.0 and 100.0
* rgb color
* r Red component. Between 0.0 and 1.0
* g Green component. Between 0.0 and 1.0
* b Blue component. Between 0.0 and 1.0
# How to run the code ?
```
make
```
Text output:
```bash
make
printf "make ppm and txt files "
make ppm and txt files gcc g.c hsluv.c -lm -Wall
./a.out
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_continous_no.txt saved.
File 0_100_continous_no.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_continous_steps.txt saved.
File 0_100_continous_steps.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_continous_tubes.txt saved.
File 0_100_continous_tubes.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_continous_diverging.txt saved.
File 0_100_continous_diverging.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_discrete_no.txt saved.
File 0_100_discrete_no.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_discrete_steps.txt saved.
File 0_100_discrete_steps.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_discrete_tubes.txt saved.
File 0_100_discrete_tubes.ppm saved.
first color : hsl = [0, 100, l]
complemntary color : hsl = [180, 100, l]
File 0_100_discrete_diverging.txt saved.
File 0_100_discrete_diverging.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_continous_no.txt saved.
File 60_100_continous_no.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_continous_steps.txt saved.
File 60_100_continous_steps.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_continous_tubes.txt saved.
File 60_100_continous_tubes.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_continous_diverging.txt saved.
File 60_100_continous_diverging.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_discrete_no.txt saved.
File 60_100_discrete_no.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_discrete_steps.txt saved.
File 60_100_discrete_steps.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_discrete_tubes.txt saved.
File 60_100_discrete_tubes.ppm saved.
first color : hsl = [60, 100, l]
complemntary color : hsl = [240, 100, l]
File 60_100_discrete_diverging.txt saved.
File 60_100_discrete_diverging.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_continous_no.txt saved.
File 120_100_continous_no.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_continous_steps.txt saved.
File 120_100_continous_steps.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_continous_tubes.txt saved.
File 120_100_continous_tubes.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_continous_diverging.txt saved.
File 120_100_continous_diverging.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_discrete_no.txt saved.
File 120_100_discrete_no.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_discrete_steps.txt saved.
File 120_100_discrete_steps.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_discrete_tubes.txt saved.
File 120_100_discrete_tubes.ppm saved.
first color : hsl = [120, 100, l]
complemntary color : hsl = [300, 100, l]
File 120_100_discrete_diverging.txt saved.
File 120_100_discrete_diverging.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_continous_no.txt saved.
File 180_100_continous_no.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_continous_steps.txt saved.
File 180_100_continous_steps.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_continous_tubes.txt saved.
File 180_100_continous_tubes.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_continous_diverging.txt saved.
File 180_100_continous_diverging.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_discrete_no.txt saved.
File 180_100_discrete_no.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_discrete_steps.txt saved.
File 180_100_discrete_steps.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_discrete_tubes.txt saved.
File 180_100_discrete_tubes.ppm saved.
first color : hsl = [180, 100, l]
complemntary color : hsl = [360, 100, l]
File 180_100_discrete_diverging.txt saved.
File 180_100_discrete_diverging.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_continous_no.txt saved.
File 240_100_continous_no.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_continous_steps.txt saved.
File 240_100_continous_steps.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_continous_tubes.txt saved.
File 240_100_continous_tubes.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_continous_diverging.txt saved.
File 240_100_continous_diverging.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_discrete_no.txt saved.
File 240_100_discrete_no.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_discrete_steps.txt saved.
File 240_100_discrete_steps.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_discrete_tubes.txt saved.
File 240_100_discrete_tubes.ppm saved.
first color : hsl = [240, 100, l]
complemntary color : hsl = [60, 100, l]
File 240_100_discrete_diverging.txt saved.
File 240_100_discrete_diverging.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_continous_no.txt saved.
File 300_100_continous_no.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_continous_steps.txt saved.
File 300_100_continous_steps.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_continous_tubes.txt saved.
File 300_100_continous_tubes.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_continous_diverging.txt saved.
File 300_100_continous_diverging.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_discrete_no.txt saved.
File 300_100_discrete_no.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_discrete_steps.txt saved.
File 300_100_discrete_steps.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_discrete_tubes.txt saved.
File 300_100_discrete_tubes.ppm saved.
first color : hsl = [300, 100, l]
complemntary color : hsl = [120, 100, l]
File 300_100_discrete_diverging.txt saved.
File 300_100_discrete_diverging.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_continous_no.txt saved.
File 360_100_continous_no.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_continous_steps.txt saved.
File 360_100_continous_steps.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_continous_tubes.txt saved.
File 360_100_continous_tubes.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_continous_diverging.txt saved.
File 360_100_continous_diverging.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_discrete_no.txt saved.
File 360_100_discrete_no.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_discrete_steps.txt saved.
File 360_100_discrete_steps.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_discrete_tubes.txt saved.
File 360_100_discrete_tubes.ppm saved.
first color : hsl = [360, 100, l]
complemntary color : hsl = [180, 100, l]
File 360_100_discrete_diverging.txt saved.
File 360_100_discrete_diverging.ppm saved.
allways free memory (deallocate ) to avoid memory leaks
HSLuv-C: Human-friendly HSL. See www.hsluv.org
h = Hue is in [0.0, 360.0] range
s = Saturation is in [0.0, 100.0] range
l = Lightness is in [0.0, 100.0] range. Here it is variable = gradient position
printf "convert text files to png "
convert text files to png gnuplot plot.gp
printf "convert all ppm files to png using Image Magic convert "
convert all ppm files to png using Image Magic convert chmod +x g.sh
./g.sh
0_100_continous_diverging.ppm
0_100_continous_no.ppm
0_100_continous_steps.ppm
0_100_continous_tubes.ppm
0_100_discrete_diverging.ppm
0_100_discrete_no.ppm
0_100_discrete_steps.ppm
0_100_discrete_tubes.ppm
120_100_continous_diverging.ppm
120_100_continous_no.ppm
120_100_continous_steps.ppm
120_100_continous_tubes.ppm
120_100_discrete_diverging.ppm
120_100_discrete_no.ppm
120_100_discrete_steps.ppm
120_100_discrete_tubes.ppm
180_100_continous_diverging.ppm
180_100_continous_no.ppm
180_100_continous_steps.ppm
180_100_continous_tubes.ppm
180_100_discrete_diverging.ppm
180_100_discrete_no.ppm
180_100_discrete_steps.ppm
180_100_discrete_tubes.ppm
240_100_continous_diverging.ppm
240_100_continous_no.ppm
240_100_continous_steps.ppm
240_100_continous_tubes.ppm
240_100_discrete_diverging.ppm
240_100_discrete_no.ppm
240_100_discrete_steps.ppm
240_100_discrete_tubes.ppm
300_100_continous_diverging.ppm
300_100_continous_no.ppm
300_100_continous_steps.ppm
300_100_continous_tubes.ppm
300_100_discrete_diverging.ppm
300_100_discrete_no.ppm
300_100_discrete_steps.ppm
300_100_discrete_tubes.ppm
360_100_continous_diverging.ppm
360_100_continous_no.ppm
360_100_continous_steps.ppm
360_100_continous_tubes.ppm
360_100_discrete_diverging.ppm
360_100_discrete_no.ppm
360_100_discrete_steps.ppm
360_100_discrete_tubes.ppm
60_100_continous_diverging.ppm
60_100_continous_no.ppm
60_100_continous_steps.ppm
60_100_continous_tubes.ppm
60_100_discrete_diverging.ppm
60_100_discrete_no.ppm
60_100_discrete_steps.ppm
60_100_discrete_tubes.ppm
OK
printf "delete all ppm and txt files "
delete all ppm and txt files rm *.ppm
rm *.txt
```
# Dependencies
* gcc
* hsluv-c: function hsluv2rgb from [HSLuv-C](https://github.com/hsluv/hsluv-c) = C implementation of [HSLuv = Human-friendly HSL](https://www.hsluv.org/)
* make
* gnuplot: onverts txt to png files ( 2D RGB color profiles )
* Image Magic: converts ppm to png ( color bars)
* bash
Tested on:
* GNU Make 4.3
* GNU bash, version 5.0.17(1)
* GNUPLOT Version 5.2 patchlevel 8
* gcc (Ubuntu 10.2.0-13ubuntu1) 10.2.0
* Version: ImageMagick 6.9.10-23 Q16 x86_64 20190101 https://imagemagick.org
# Credits
* function hsluv2rgb from [HSLuv-C](https://github.com/hsluv/hsluv-c) = C implementation of [HSLuv = Human-friendly HSL](https://www.hsluv.org/) by [Alexei Boronine](https://www.boronine.com/)
* [1D-RGB-color-gradient](https://github.com/adammaj1/1D-RGB-color-gradient)
* [ https://www.shellcheck.net/](shellcheck) by Vidar Holen
# Files
# Licence
[Licence](LICENCE)
# Git
```git
echo "# hsluv-color-gradient" >> README.md
git init
git add README.md
git commit -m "first commit"
git branch -M main
git remote add origin [email protected]:adammaj1/hsluv-color-gradient.git
git push -u origin main
```
```
git clone [email protected]:adammaj1/hsluv-color-gradient.git
```
Subdirectory
```git
mkdir images
git add *.png
git mv *.png ./images
git commit -m "move"
git push -u origin main
```
then link the images:
```txt
```
to overwrite
```git
git mv -f
```
[to remove file from remote repo](https://stackoverflow.com/questions/2047465/how-can-i-delete-a-file-from-a-git-repository)
```git
git rm --cached file1.txt
git commit -m "remove"
git push -u origin main
```
local repo: ~/hsluv-c/test/t2