GPUImage濾鏡之銳利化，gpuimage濾鏡

GPUImage濾鏡之銳利化，gpuimage濾鏡

　　應用銳利化工具可以快速聚焦模糊邊緣，提高映像中某一部位的清晰度或者焦距程度，使映像特定地區的色彩更加鮮明。 在應用銳利化工具時，若勾選器選項欄中的“對所有圖層取樣”複選框，則可對所有可見圖層中的映像進行銳利化。但一定要適度。銳利化不是萬能的，很容易使東西不真實。

　　在GPUImage中使用GPUImageSharpenFilter類來實現映像的銳利化效果

　　片段著色

 precision highp float;  varying highp vec2 textureCoordinate; varying highp vec2 leftTextureCoordinate; varying highp vec2 rightTextureCoordinate;  varying highp vec2 topTextureCoordinate; varying highp vec2 bottomTextureCoordinate;  varying highp float centerMultiplier; varying highp float edgeMultiplier; uniform sampler2D inputImageTexture;  void main() {     mediump vec3 textureColor = texture2D(inputImageTexture, textureCoordinate).rgb;     mediump vec3 leftTextureColor = texture2D(inputImageTexture, leftTextureCoordinate).rgb;     mediump vec3 rightTextureColor = texture2D(inputImageTexture, rightTextureCoordinate).rgb;     mediump vec3 topTextureColor = texture2D(inputImageTexture, topTextureCoordinate).rgb;     mediump vec3 bottomTextureColor = texture2D(inputImageTexture, bottomTextureCoordinate).rgb;     gl_FragColor = vec4((textureColor * centerMultiplier - (leftTextureColor * edgeMultiplier + rightTextureColor * edgeMultiplier + topTextureColor * edgeMultiplier + bottomTextureColor * edgeMultiplier)), texture2D(inputImageTexture, bottomTextureCoordinate).w); }

 

 　　具體應用

　　

+ (UIImage *)changeValueForSharpenilter:(float)value image:(UIImage *)image{    GPUImageSharpenFilter *filter = [[GPUImageSharpenFilter alloc] init];    filter.sharpness = value;    [filter forceProcessingAtSize:image.size];    GPUImagePicture *pic = [[GPUImagePicture alloc] initWithImage:image];    [pic addTarget:filter];        [pic processImage];    [filter useNextFrameForImageCapture];    return [filter imageFromCurrentFramebuffer];}

 

　　效果