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本案例的目的是理解如何用Metal实现行列分屏滤镜，将图片内容画布切分成行列图；
Demo
实操代码：
// 分成两行两列
let filter = C7Storyboard.init(ranks: 2)
// 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: "C7Storyboard")，参数因子[Float(N)]
对外开放参数：
N: 分为N x N个屏幕，也就是N行N列；
/// 分镜滤镜
public struct C7Storyboard: C7FilterProtocol {
/// 分为`N x N`个屏幕
public var N: Int = 2
public var modifier: Modifier {
return .compute(kernel: "C7Storyboard")
}
public var factors: [Float] {
return [Float(N)]
}
public init(ranks: Int = 2) {
self.N = ranks
}
}
- 着色器
对坐标点归一化处理，然后采用fmod函数，取模后的余数再x个数，最后取对应点像素。
kernel void C7Storyboard(texture2d<half, access::write> outputTexture [[texture(0)]],
texture2d<half, access::sample> inputTexture [[texture(1)]],
constant float *few [[buffer(0)]],
uint2 grid [[thread_position_in_grid]]) {
constexpr sampler quadSampler(mag_filter::linear, min_filter::linear);
const float x = float(grid.x) / outputTexture.get_width();
const float y = float(grid.y) / outputTexture.get_height();
const float2 textureCoordinate = float2(x, y);
const int N = int(*few);
const float2 uv = fmod(textureCoordinate, 1.0 / N) * N;
const half4 outColor = inputTexture.sample(quadSampler, uv);
outputTexture.write(outColor, grid);
}
多滤镜联动
- 运算符链式处理
/// 1.转换成BGRA
let filter1 = C7ColorConvert(with: C7ColorConvert.ColorType.bgra)
/// 2.调整颗粒度
var filter2 = C7Granularity()
filter2.grain = 0.8
/// 3.调整白平衡
var filter3 = C7WhiteBalance()
filter3.temperature = 5555
/// 4.调整高光阴影
var filter4 = C7HighlightShadow()
filter4.shadows = 0.4
filter4.highlights = 0.5
/// 5.组合操作，获取结果
filterImageView.image = originImage ->> filter1 ->> filter2 ->> filter3 ->> filter4
- 组合操作
/// 1.转换成RBGA
let filter1 = C7ColorConvert(with: C7ColorConvert.ColorType.rbga)
/// 2.调整颗粒度
var filter2 = C7Granularity()
filter2.grain = 0.8
/// 3.配置灵魂效果
var filter3 = C7SoulOut()
filter3.soul = 0.7
/// 4.组合操作
let group: [C7FilterProtocol] = [filter1, filter2, filter3]
/// 5.获取结果
filterImageView.image = try? originImage.makeGroup(filters: group)
最后
- 关于分镜滤镜介绍与设计到此为止吧。
- 慢慢再补充其他相关滤镜，喜欢就给我点个星🌟吧。
✌️.
