初級(jí)使用（一）

• 給image添加濾鏡，然后顯示到UIImageView上

self.mGPUImageView = [[GPUImageView alloc]init];
self.mGPUImageView.fillMode = kGPUImageFillModeStretch;

GPUImageFilter *filter = [[GPUImageWeakPixelInclusionFilter alloc] init];

UIImage *image = [UIImage imageNamed:@"face"];

self.mGPUImageView.image = [filter imageByFilteringImage:image];

初級(jí)使用（二）

• 從攝像頭獲取數(shù)據(jù)源，并且添加濾鏡，展示在UIImageView上；無錄像

//1. 創(chuàng)建
self.mGPUVideoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset1920x1080 cameraPosition:AVCaptureDevicePositionBack];

self.mGPUImageView = [[GPUImageView alloc]init];
self.mGPUImageView.fillMode = kGPUImageFillModeStretch;

//2.mGPUVideoCamera -> filter -> mGPUImageView
//添加響應(yīng)鏈
GPUImageSepiaFilter* filter = [[GPUImageSepiaFilter alloc] init];
[self.mGPUVideoCamera addTarget:filter];
[filter addTarget:self.mGPUImageView];

//3.啟動(dòng)相機(jī)
[self.mGPUVideoCamera startCameraCapture];

//可有可無
//監(jiān)聽屏幕方向，修改攝像頭的輸出方向
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationDidChange:) name:UIDeviceOrientationDidChangeNotification object:nil];
- (void)deviceOrientationDidChange:(NSNotification *)notification {
    UIInterfaceOrientation orientation = (UIInterfaceOrientation)[UIDevice currentDevice].orientation;
    self.mGPUVideoCamera.outputImageOrientation = orientation;
}

初級(jí)使用（三）

• 錄制視頻并保存

//1.創(chuàng)建
self.videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionFront];
self.videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
self.videoCamera.horizontallyMirrorFrontFacingCamera = YES;
self.filterView = [[GPUImageView alloc] initWithFrame:self.view.frame];
self.filterView.center = self.view.center;
[self.view addSubview:self.filterView];

//2.設(shè)置保存路徑
NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie.m4v"];
unlink([pathToMovie UTF8String]);//刪除路徑下的文件
NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];

//3. 添加響應(yīng)鏈
//videoCamera -> beautifyFilter -> self.filterView
                                -> _movieWriter
_movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(640.0, 480.0)];
    
self.videoCamera.audioEncodingTarget = _movieWriter;

_movieWriter.encodingLiveVideo = YES;

[self.videoCamera startCameraCapture];

GPUImageBeautifyFilter *beautifyFilter = [[GPUImageBeautifyFilter alloc] init];

[self.videoCamera addTarget:beautifyFilter];

[beautifyFilter addTarget:self.filterView];

[beautifyFilter addTarget:_movieWriter];

[_movieWriter startRecording];

初級(jí)使用（四）

• 給GPUImage 添加濾鏡組<轉(zhuǎn)>

// 圖片輸入源
_inputImage = [UIImage imageNamed:@"icon"];
 
// 初始化 picture
_picture    = [[GPUImagePicture alloc] initWithImage:_inputImage smoothlyScaleOutput:YES];
 
// 初始化 imageView
_imageView  = [[GPUImageView alloc] initWithFrame:self.iconImageView.bounds];
[self.iconImageView addSubview:_imageView];
 
// 初始化 filterGroup
_filterGroup = [[GPUImageFilterGroup alloc] init];
[_picture addTarget:_filterGroup];
 
 
// 添加 filter
/**
原理：
1. filterGroup(addFilter) 濾鏡組添加每個(gè)濾鏡
2. 按添加順序（可自行調(diào)整）前一個(gè)filter(addTarget) 添加后一個(gè)filter
3. filterGroup.initialFilters = @[第一個(gè)filter]];
4. filterGroup.terminalFilter = 最后一個(gè)filter;
*/
GPUImageRGBFilter *filter1         = [[GPUImageRGBFilter alloc] init];
GPUImageToonFilter *filter2        = [[GPUImageToonFilter alloc] init];
GPUImageColorInvertFilter *filter3 = [[GPUImageColorInvertFilter alloc] init];
GPUImageSepiaFilter       *filter4 = [[GPUImageSepiaFilter alloc] init];
[self addGPUImageFilter:filter1];
[self addGPUImageFilter:filter2];
[self addGPUImageFilter:filter3];
[self addGPUImageFilter:filter4];
 
// 處理圖片
[_picture processImage];
[_filterGroup useNextFrameForImageCapture];
 

- (void)addGPUImageFilter:(GPUImageOutput<GPUImageInput> *)filter
{
    [_filterGroup addFilter:filter];
 
    GPUImageOutput<GPUImageInput> *newTerminalFilter = filter;
 
    NSInteger count = _filterGroup.filterCount;
 
    if (count == 1)
    {
        _filterGroup.initialFilters = @[newTerminalFilter];
        _filterGroup.terminalFilter = newTerminalFilter;
 
    } else
    {
        GPUImageOutput<GPUImageInput> *terminalFilter    = _filterGroup.terminalFilter;
        NSArray *initialFilters                          = _filterGroup.initialFilters;
 
        [terminalFilter addTarget:newTerminalFilter];
 
        _filterGroup.initialFilters = @[initialFilters[0]];
        _filterGroup.terminalFilter = newTerminalFilter;
    }

上面這幾個(gè)例子其實(shí)表示的很清楚了，GPUImage的常規(guī)使用方式就是source(視頻、圖片源) -> filter（濾鏡） -> final target (處理后視頻、圖片)按照這一套流程來的