iOS-图片添加滤镜

所用到的知识点为 颜色矩阵，android里面的概念，可以先了解下

//lomo
const float colormatrix_lomo[] = {
    1.7f,  0.1f, 0.1f, 0, -73.1f,
    0,  1.7f, 0.1f, 0, -73.1f,
    0,  0.1f, 1.6f, 0, -73.1f,
    0,  0, 0, 1.0f, 0 };

//黑白
const float colormatrix_heibai[] = {
    0.8f,  1.6f, 0.2f, 0, -163.9f,
    0.8f,  1.6f, 0.2f, 0, -163.9f,
    0.8f,  1.6f, 0.2f, 0, -163.9f,
    0,  0, 0, 1.0f, 0 };
//旧化
const float colormatrix_huajiu[] = {
    0.2f,0.5f, 0.1f, 0, 40.8f,
    0.2f, 0.5f, 0.1f, 0, 40.8f,
    0.2f,0.5f, 0.1f, 0, 40.8f,
    0, 0, 0, 1, 0 };

QQ20170615-163338.gif

GPUImage 为图片添加滤镜

 //中间突出 四周暗，可更换为其他的滤镜
    GPUImageVignetteFilter *passthroughFilter = [[GPUImageVignetteFilter alloc]init];
    
    
    [passthroughFilter useNextFrameForImageCapture];
    
    //获取数据源
    GPUImagePicture *stillImageSource=[[GPUImagePicture alloc]initWithImage:image];

    [stillImageSource addTarget:passthroughFilter];
    
    //开始渲染
    [stillImageSource processImage];
    
    UIImage *finallImage = [passthroughFilter imageFromCurrentFramebuffer];

    UIImageWriteToSavedPhotosAlbum(finallImage, nil, nil, nil);

https://github.com/chjwrr/imageAddFilter