IOS – OpenGL ES 调节图像色度 GPUImageHueFilter

2023-03-21 07:36:58 浏览数 (2)

目录

  • 一.简介

一.简介

GPUImage 共 125 个滤镜, 分为四类

1、Color adjustments : 31 filters , 颜色处理相关 2、Image processing : 40 filters , 图像处理相关. 3、Blending modes : 29 filters , 混合模式相关. 4、Visual effects : 25 filters , 视觉效果相关.

GPUImageAverageColor 属于 GPUImage 颜色处理相关，用来处理图片像素平均色值

通过对图像中每个像素的 RGBA 分量进行平均，处理输入图像并确定场景的平均颜色。使用缩减过程逐渐降低对 GPU 上的源图像的采样，然后在 CPU 上进行简单的平均计算。该过滤器的输出是无意义的，但是您需要将 colorAverageProcessingFinishedBlock 属性设置为一个块，该块具有四个颜色组件和一个帧时间，并与它们做一些事情。

代码语言：javascript复制
/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:GPUImage – 像素平均色值  GPUImageAverageColor
//@Time:2022/03/23 07:30
//@Motto:不积跬步无以至千里，不积小流无以成江海，程序人生的精彩需要坚持不懈地积累！
/******************************************************************************************/

#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageColorAveragingFragmentShaderString = SHADER_STRING
(
 precision highp float;

 uniform sampler2D inputImageTexture;

 varying highp vec2 outputTextureCoordinate;

 varying highp vec2 upperLeftInputTextureCoordinate;
 varying highp vec2 upperRightInputTextureCoordinate;
 varying highp vec2 lowerLeftInputTextureCoordinate;
 varying highp vec2 lowerRightInputTextureCoordinate;

 void main()
 {
     highp vec4 upperLeftColor = texture2D(inputImageTexture, upperLeftInputTextureCoordinate);
     highp vec4 upperRightColor = texture2D(inputImageTexture, upperRightInputTextureCoordinate);
     highp vec4 lowerLeftColor = texture2D(inputImageTexture, lowerLeftInputTextureCoordinate);
     highp vec4 lowerRightColor = texture2D(inputImageTexture, lowerRightInputTextureCoordinate);

     gl_FragColor = 0.25 * (upperLeftColor   upperRightColor   lowerLeftColor   lowerRightColor);
 }
);
#else
NSString *const kGPUImageColorAveragingFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;

 varying vec2 outputTextureCoordinate;

 varying vec2 upperLeftInputTextureCoordinate;
 varying vec2 upperRightInputTextureCoordinate;
 varying vec2 lowerLeftInputTextureCoordinate;
 varying vec2 lowerRightInputTextureCoordinate;

 void main()
 {
     vec4 upperLeftColor = texture2D(inputImageTexture, upperLeftInputTextureCoordinate);
     vec4 upperRightColor = texture2D(inputImageTexture, upperRightInputTextureCoordinate);
     vec4 lowerLeftColor = texture2D(inputImageTexture, lowerLeftInputTextureCoordinate);
     vec4 lowerRightColor = texture2D(inputImageTexture, lowerRightInputTextureCoordinate);

     gl_FragColor = 0.25 * (upperLeftColor   upperRightColor   lowerLeftColor   lowerRightColor);
 }
);
#endif
ios processing es gpu image

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