README.md
A theme color extracting library implemented by C.
This library is used in a related company for years.
TODO: Using KD-Tree to find some colors.
聖 白蓮
聖 白蓮（ひじり びゃくれん，Hiziri Byakuren）是系列作品《东方project》中的角色，首次登场于《东方星莲船》。
- 种族：魔法使
- 能力：使用魔法程度的能力（酣畅增强身体能力的）
- 危险度：不明
- 人类友好度：中
- 主要活动场所：命莲寺之类
命莲寺的住持。虽然原本是人类，不过由于常年的修行已经完全超越了人类。现在已经属于人们常说的魔法使了。
虽然已经入了佛门，但是不知道什么原因却被妖怪敬仰着。她从来没有像童话故事中的魔法使那样，念诵着咒语治退妖怪。使用的力量完全是邪恶的，一点都不像是圣人，虽然并没有人目击到她与人类为敌，但其实已彻底成为妖怪的同伴了。
Compile Static Library
This project can be compiled to a static libary (byakuren.a) for using.
After compiling, you may use this library just by including byakuren.h in your project.
Supported Algorithm
APIs
bkr_rgb Structure
typedefstruct bkr_rgb {uint8_t red;uint8_t green;uint8_t blue
} bkr_rgb;RGB pixel structure.
| name | type | description |
|---|---|---|
| red | uint8_t | the RED value (0-255) |
| green | uint8_t | the GREEN value (0-255) |
| blue | uint8_t | the BLUE value (0-255) |
bkr_color_stats Structure
typedefstruct bkr_color_stats {
bkr_rgb color;uint32_t value;uint32_t count;
} bkr_color_stats;Stats of theme color result.
| name | type | description |
|---|---|---|
| color | bkr_rgb | a color pixel to indicate a theme color |
| value | uint32_t | a color pixel's INT32 value to indicates the theme color |
| count | uint32_t | stats of this theme color in the picture |
typedefstruct bkr_palette_array {uint32_t count;
bkr_rgb* colors;
} bkr_palette_array;A crowd of colors to indicate a theme color palette.
| name | type | description |
|---|---|---|
| count | uint32_t | color count in this palette |
| colors | bkr_rgb* | each color in this palette |
bkr_mindiff_parameter Structure
typedefstruct bkr_mindiff_parameter {
bkr_palette_array* palette;int16_t gray_offset;
} bkr_mindiff_parameter;A parameter passes to Min-diff Algorithm.
| name | type | description |
|---|---|---|
| palette | bkr_palette_array* | a palette to calculate the theme color, left for NULL to indicate the default palette |
| gray_offset | int16_t | the offset to judge whether a color is gray, recommand to be 5 |
Octree Algorithm
Build Octree
bkr_octree_node* bkr_build_octree(
bkr_rgb* pixels,uint32_t pixel_count,uint32_t max_colors);| parameter | type | description |
|---|---|---|
| pixels | bkr_rgb* | the RGB pixels of a picture |
| pixel_count | uint32_t | pixel count of the picture |
| max_colors | uint32_t | maximum theme color count this octree will have |
Calculate
intbkr_octree_calculate_color_stats(
bkr_octree_node* node,
bkr_color_stats stats[]);| parameter | type | description |
|---|---|---|
| node | bkr_octree_node* | the octree which bkr_build_octree returned |
| stats | bkr_color_stats | an array to receive each theme color stats |
- Return the count of theme colors.
Release Octree
voidbkr_release_octree(bkr_octree_node* node);| parameter | type | description |
|---|---|---|
| node | bkr_octree_node* | the octree to be released |
Example
bkr_rgb* rgb = GET_PICTURE_RGB(); // implement by yourselfuint32_t color_count = GET_PICTURE_PIXEL_COUNT(); // implement by yourself
bkr_color_stats stats[256];
bkr_octree_node* root = bkr_build_octree(rgb, color_count, 256);int colors = bkr_octree_calculate_color_stats(root, stats);bkr_release_octree(root);Min-diff Algorithm
Calculate
intbkr_mindiff_calculate_color_stats(
bkr_rgb* pixels,uint32_t pixel_count,
bkr_color_stats stats[],
bkr_mindiff_parameter* param);| parameter | type | description |
|---|---|---|
| pixels | bkr_rgb* | the RGB pixels of a picture |
| pixel_count | uint32_t | pixel count of the picture |
| stats | bkr_color_stats | an array to receive each theme color stats |
| param | bkr_mindiff_parameter* | the parameter passes to Min-diff Algorithm for calculating |
- Return the count of theme colors.
Example
bkr_rgb* rgb = GET_PICTURE_RGB(); // implement by yourselfuint32_t color_count = GET_PICTURE_PIXEL_COUNT(); // implement by yourself
bkr_color_stats stats[256];
bkr_mindiff_parameter param;
param.gray_offset = 5;
param.palette = NULL;int colors = bkr_mindiff_calculate_color_stats(rgb, color_count, stats, ¶m);Mix Algorithm
Mix Octree and Min-diff up.
Calculate
intbkr_mix_calculate_color_stats(
bkr_rgb* pixels,uint32_t pixel_count,uint32_t octree_max_colors,
bkr_mindiff_parameter* mindiff_param,
bkr_color_stats stats[]);| parameter | type | description |
|---|---|---|
| pixels | bkr_rgb* | the RGB pixels of a picture |
| pixel_count | uint32_t | pixel count of the picture |
| octree_max_colors | uint32_t | maximum theme color count this octree will have |
| param | bkr_mindiff_parameter* | the parameter passes to Min-diff Algorithm for calculating |
| stats | bkr_color_stats | an array to receive each theme color stats |
- Return the count of theme colors.
Example
bkr_rgb* rgb = GET_PICTURE_RGB(); // implement by yourselfuint32_t color_count = GET_PICTURE_PIXEL_COUNT(); // implement by yourself
bkr_color_stats stats[256];
bkr_mindiff_parameter param;
param.gray_offset = -1;
param.palette = NULL;int colors = bkr_mix_calculate_color_stats(rgb, color_count, 256, ¶m, stats);print_stats(stats, colors);Test Command
After make command, you should generate a binary file named test.rgb. Then run:
$ cdtest&& ./bkr_test ALGORITHMYou may create your own
.rgbfile by referring test/run.js or test/test.c. Or you may have a look at Test Helper.
ALGORITHMis a parameter means algorithm you want to test.support
octree、mindiffandmixso far.
Test Helper
If you want to test quickly (no *.rgb), you may use a simple script.
Install Node.js first and come to test folder. Then run:
NOTICE: You can start test helper directly under OSX. Otherwise, you should compile a test binary executor before testing, that is
$ make ./test/bkr_test.
After installing, run --help.
You will see some introduction. -u means a URL.
For an example:
$ ./run.js -u http://cdn.duitang.com/uploads/item/201205/22/20120522224448_43nFu.thumb.600_0.jpeg -a octreeAfter command above, a browser will be open to display the result.
If you want to test three algorithm at one time, you should make -a be all.
For an example:
$ ./run.js -u http://cdn.duitang.com/uploads/item/201205/22/20120522224448_43nFu.thumb.600_0.jpeg -a allContribution
You're welcome to make Pull Requests.
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