从MTKView创建的UIImage会导致颜色/不透明度差异
从MTKView创建的UIImage会导致颜色/不透明度差异
提问于 2018-03-12 03:29:10
当我将MTKView的内容捕获到UIImage中时，得到的图像看起来有本质上的不同，如下所示：
我用来生成UIImage的代码如下：
let kciOptions = [kCIContextWorkingColorSpace: CGColorSpace(name: CGColorSpace.sRGB)!,
kCIContextOutputPremultiplied: true,
kCIContextUseSoftwareRenderer: false] as [String : Any]
let lastDrawableDisplayed = self.currentDrawable! // needed to hold the last drawable presented to screen
drawingUIView.image = UIImage(ciImage: CIImage(mtlTexture: lastDrawableDisplayed.texture, options: kciOptions)!)由于我没有修改ciImage orientation (.oriented(CGImagePropertyOrientation.downMirrored))，因此生成的图像是颠倒的，如上图所示。我保留镜像方向不变，这样我就可以指出两个图像捕获之间的颜色差异。
无论我如何更改kciOptions参数(例如，甚至将色彩空间更改为灰度)，我都看不到结果UIImage中有任何变化，它看起来比原始的更加暗淡/不饱和。有没有人有什么建议可以让我在UIImage上准确地捕捉到我在MTKView上绘制的内容？任何建议都将不胜感激。
以下是我的MTKView设置，它们可能是相关的：
let renderPipelineDescriptor = MTLRenderPipelineDescriptor()
renderPipelineDescriptor.vertexFunction = vertexProgram
renderPipelineDescriptor.sampleCount = self.sampleCount
renderPipelineDescriptor.colorAttachments[0].pixelFormat = MTLPixelFormat.bgra8Unorm
renderPipelineDescriptor.colorAttachments[0].isBlendingEnabled = true
renderPipelineDescriptor.colorAttachments[0].rgbBlendOperation = .add
renderPipelineDescriptor.colorAttachments[0].alphaBlendOperation = .add
renderPipelineDescriptor.colorAttachments[0].sourceRGBBlendFactor = .sourceAlpha renderPipelineDescriptor.colorAttachments[0].destinationRGBBlendFactor = .oneMinusSourceAlpha renderPipelineDescriptor.colorAttachments[0].sourceAlphaBlendFactor = .sourceAlpha renderPipelineDescriptor.colorAttachments[0].destinationAlphaBlendFactor = .oneMinusSourceAlpha
self.isOpaque = false // makes MTKView bg transparent回答 2
Stack Overflow用户
回答已采纳
发布于 2018-06-14 07:00:51
您的CGColorSpace是.sRGB，但renderPipelineDescriptor的pixelFormat是.bgra8Unorm。尝试将该行更改为：
renderPipelineDescriptor.colorAttachments[0].pixelFormat = MTLPixelFormat.bgra8Unorm_srgbStack Overflow用户
发布于 2018-06-13 19:18:28
let context = CIContext()
let texture = metalView.currentDrawable!.texture
let cImg = CIImage(mtlTexture: texture, options: nil)!
let cgImg = context.createCGImage(cImg, from: cImg.extent)!
let uiImg = UIImage(cgImage: cgImg)页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/49224155
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