本案例的目的是理解如何用Metal实现图像包装效果滤镜,用于图像处理色彩丢失和模糊效果;
Demo
实操代码
// 色彩丢失和模糊效果
let filter = C7ColorPacking.init(horizontalTexel: 2.5, verticalTexel: 5)
// 方案1:
let dest = BoxxIO.init(element: originImage, filter: filter)
ImageView.image = try? dest.output()
dest.filters.forEach {
NSLog("%@", "\($0.parameterDescription)")
}
// 方案2:
ImageView.image = try? originImage.make(filter: filter)
// 方案3:
ImageView.image = originImage ->> filter
实现原理
- 过滤器
这款滤镜采用并行计算编码器设计.compute(kernel: "C7ColorPacking")
,参数因子[horizontalTexel, verticalTexel]
对外开放参数
horizontalTexel
: 横向偏移,越大绿色轮廓虚影向右偏移越多;verticalTexel
: 纵向偏移,越大蓝色轮廓虚影向下偏移越多;
/// 色彩丢失/模糊效果
public struct C7ColorPacking: C7FilterProtocol {
/// The larger the transverse offset, the more the green contour shadow offset to the right.
public var horizontalTexel: Float
/// The larger the vertical offset, the more the blue contour shadow offset downward.
public var verticalTexel: Float
public var modifier: Modifier {
return .compute(kernel: "C7ColorPacking")
}
public var factors: [Float] {
return [horizontalTexel, verticalTexel]
}
public init(horizontalTexel: Float = 0, verticalTexel: Float = 0) {
self.horizontalTexel = horizontalTexel
self.verticalTexel = verticalTexel
}
}
- 着色器
纹理坐标和偏移均归一化处理,然后获取到上下左右4个纹理偏移坐标,取出对应的纹理红色值,最后得到像素值;
kernel void C7ColorPacking(texture2d<half, access::write> outputTexture [[texture(0)]],
texture2d<half, access::sample> inputTexture [[texture(1)]],
device float *texelWidthPointer [[buffer(0)]],
device float *texelHeightPointer [[buffer(1)]],
uint2 grid [[thread_position_in_grid]]) {
constexpr sampler quadSampler(mag_filter::linear, min_filter::linear);
const float width = outputTexture.get_width();
const float height = outputTexture.get_height();
const float texelWidth = float(*texelWidthPointer / width);
const float texelHeight = float(*texelHeightPointer / height);
const float2 textureCoordinate = float2(float(grid.x) / width, float(grid.y) / height);
const float2 upperLeftTextureCoordinate = textureCoordinate + float2(-texelWidth, -texelHeight);
const float2 upperRightTextureCoordinate = textureCoordinate + float2(texelWidth, -texelHeight);
const float2 lowerLeftTextureCoordinate = textureCoordinate + float2(-texelWidth, texelHeight);
const float2 lowerRightTextureCoordinate = textureCoordinate + float2(texelWidth, texelHeight);
half upperLeftIntensity = inputTexture.sample(quadSampler, upperLeftTextureCoordinate).r;
half upperRightIntensity = inputTexture.sample(quadSampler, upperRightTextureCoordinate).r;
half lowerLeftIntensity = inputTexture.sample(quadSampler, lowerLeftTextureCoordinate).r;
half lowerRightIntensity = inputTexture.sample(quadSampler, lowerRightTextureCoordinate).r;
const half4 outColor = half4(upperLeftIntensity, upperRightIntensity, lowerLeftIntensity, lowerRightIntensity);
outputTexture.write(outColor, grid);
}
效果图
Harbeth功能清单
- 支持ios系统和macOS系统
- 支持运算符函数式操作
- 支持多种模式数据源 UIImage, CIImage, CGImage, CMSampleBuffer, CVPixelBuffer.
- 支持快速设计滤镜
- 支持合并多种滤镜效果
- 支持输出源的快速扩展
- 支持相机采集特效
- 支持视频添加滤镜特效
- 支持矩阵卷积
- 支持使用系统 MetalPerformanceShaders.
- 支持兼容 CoreImage.
- 滤镜部分大致分为以下几个模块:
最后
- 慢慢再补充其他相关滤镜,喜欢就给我点个星🌟吧。
- 滤镜Demo地址,目前包含
100+
种滤镜,同时也支持CoreImage混合使用。 - 再附上一个开发加速库KJCategoriesDemo地址
- 再附上一个网络基础库RxNetworksDemo地址
- 喜欢的老板们可以点个星🌟,谢谢各位老板!!!
✌️.