Ios 如何为GLKView显示CIImage实现contentMode？

我制作了一个

GLKView

子类来显示

CIImage

，以便更好地显示

CIFilter

链的输出图像

但是，似乎我需要实现

contentMode

逻辑，以便为

drawImage（image:CIImage，inRect:CGRect，fromRect:CGRect）调用
in
drawRect（rect:CGRect）
调用正确的
inRect

任何人都知道如何实现这样的逻辑，以便与iOS 10.3中UIImageView `？
的
contentMode行为保持一致。contentMode的设置似乎不会影响glkView。
它看起来总是一个左下角模式

要使glkView以可查看的格式显示CIImage，这对我很有用

在glkView（view:glkView，drawIn rect:CGRect）中传递的rect需要由视图contentScaleFactor修改

此代码假定您已在GLKViewController的viewDidLoad方法中初始化了EAGLContext（我的glkView名为effectView2）


设置glkView后设置比例因子

myScaleFactor=view.contentScaleFactor

在glkView（view:glkView，drawIn rect:CGRect）中执行此操作

设adjustedRect=CGRect（x:0.0，y:0.0，宽度：rect.width*myScaleFactor，高度：rect.height*myScaleFactor）

然后使用ciContext在adjustedRect中绘制ciImage。将ciImage的范围用作from parm，如下所示：

ciContext!.draw(outputImage, in: adjustedRect , from: (ciSourceImage?.extent)!)

哦，是的。我想您已经找到了调整GLKView比例因子的技术说明。它在GLKView的子类中调用一行。看
在这种方法中，您很可能需要一些调整。我目前正在为不同来源的图像进行问题导向的更改

我花了很长时间才找到这么多，所以我想分享一下这些发现。。
请张贴您发现的任何改进

希望能有帮助
将L-B设置为使contentMode以与UIView类似的方式工作。我上了下面的课

final class ContenModeEnforcer {
    static func rectFor(contentMode: UIViewContentMode, fromRect: CGRect, toRect: CGRect) -> CGRect {
        switch contentMode {
        case .scaleToFill:
            return toRect

        case .scaleAspectFit:
            return aspectFit(fromRect, toRect: toRect)

        case .scaleAspectFill:
            return aspectFill(fromRect, toRect: toRect)

        case .redraw:
            return fromRect

        case .center:
            let origin = CGPoint(
                x: (toRect.size.width - fromRect.size.width) / 2,
                y: (toRect.size.height - fromRect.size.height) / 2)
            return CGRect(origin: origin, size: fromRect.size)

        case .top:
            let origin = CGPoint(
                x: (toRect.size.width - fromRect.size.width) / 2,
                y: 0.0)
            return CGRect(origin: origin, size: fromRect.size)

        case .bottom:
            let origin = CGPoint(
                x: (toRect.size.width - fromRect.size.width) / 2,
                y: toRect.size.height - fromRect.size.height)
            return CGRect(origin: origin, size: fromRect.size)

        case .left:
            let origin = CGPoint(
                x: 0.0,
                y: (toRect.size.height - fromRect.size.height) / 2)
            return CGRect(origin: origin, size: fromRect.size)

        case .right:
            let origin = CGPoint(
                x: toRect.size.width - fromRect.size.width,
                y: (toRect.size.height - fromRect.size.height) / 2)
            return CGRect(origin: origin, size: fromRect.size)


        case .topLeft:
            let origin = CGPoint(
                x: 0.0,
                y: 0.0)
            return CGRect(origin: origin, size: fromRect.size)

        case .topRight:
            let origin = CGPoint(
                x: toRect.size.width - fromRect.size.width,
                y: 0.0)
            return CGRect(origin: origin, size: fromRect.size)

        case .bottomLeft:
            let origin = CGPoint(
                x: 0.0,
                y: toRect.size.height - fromRect.size.height)
            return CGRect(origin: origin, size: fromRect.size)

        case .bottomRight:
            let origin = CGPoint(
                x: toRect.size.width - fromRect.size.width,
                y: toRect.size.height - fromRect.size.height)
            return CGRect(origin: origin, size: fromRect.size)
        }
    }

    static fileprivate func aspectFit(_ fromRect: CGRect, toRect: CGRect) -> CGRect {
        let fromAspectRatio = fromRect.size.width / fromRect.size.height;
        let toAspectRatio = toRect.size.width / toRect.size.height;

        var fitRect = toRect

        if (fromAspectRatio > toAspectRatio) {
            fitRect.size.height = toRect.size.width / fromAspectRatio;
            fitRect.origin.y += (toRect.size.height - fitRect.size.height) * 0.5;
        } else {
            fitRect.size.width = toRect.size.height  * fromAspectRatio;
            fitRect.origin.x += (toRect.size.width - fitRect.size.width) * 0.5;
        }

        return fitRect.integral
    }

    static fileprivate func aspectFill(_ fromRect: CGRect, toRect: CGRect) -> CGRect {
        let fromAspectRatio = fromRect.size.width / fromRect.size.height;
        let toAspectRatio = toRect.size.width / toRect.size.height;

        var fitRect = toRect

        if (fromAspectRatio > toAspectRatio) {
            fitRect.size.width = toRect.size.height  * fromAspectRatio;
            fitRect.origin.x += (toRect.size.width - fitRect.size.width) * 0.5;
        } else {
            fitRect.size.height = toRect.size.width / fromAspectRatio;
            fitRect.origin.y += (toRect.size.height - fitRect.size.height) * 0.5;
        }

        return fitRect.integral
    }
}

在绘图中（u:CGRect）

你弄明白了吗？我找到了这个回购协议：。但对于左、右、下等，其行为与UIImageView不同
final class ContenModeEnforcer {
    static func rectFor(contentMode: UIViewContentMode, fromRect: CGRect, toRect: CGRect) -> CGRect {
        switch contentMode {
        case .scaleToFill:
            return toRect

        case .scaleAspectFit:
            return aspectFit(fromRect, toRect: toRect)

        case .scaleAspectFill:
            return aspectFill(fromRect, toRect: toRect)

        case .redraw:
            return fromRect

        case .center:
            let origin = CGPoint(
                x: (toRect.size.width - fromRect.size.width) / 2,
                y: (toRect.size.height - fromRect.size.height) / 2)
            return CGRect(origin: origin, size: fromRect.size)

        case .top:
            let origin = CGPoint(
                x: (toRect.size.width - fromRect.size.width) / 2,
                y: 0.0)
            return CGRect(origin: origin, size: fromRect.size)

        case .bottom:
            let origin = CGPoint(
                x: (toRect.size.width - fromRect.size.width) / 2,
                y: toRect.size.height - fromRect.size.height)
            return CGRect(origin: origin, size: fromRect.size)

        case .left:
            let origin = CGPoint(
                x: 0.0,
                y: (toRect.size.height - fromRect.size.height) / 2)
            return CGRect(origin: origin, size: fromRect.size)

        case .right:
            let origin = CGPoint(
                x: toRect.size.width - fromRect.size.width,
                y: (toRect.size.height - fromRect.size.height) / 2)
            return CGRect(origin: origin, size: fromRect.size)


        case .topLeft:
            let origin = CGPoint(
                x: 0.0,
                y: 0.0)
            return CGRect(origin: origin, size: fromRect.size)

        case .topRight:
            let origin = CGPoint(
                x: toRect.size.width - fromRect.size.width,
                y: 0.0)
            return CGRect(origin: origin, size: fromRect.size)

        case .bottomLeft:
            let origin = CGPoint(
                x: 0.0,
                y: toRect.size.height - fromRect.size.height)
            return CGRect(origin: origin, size: fromRect.size)

        case .bottomRight:
            let origin = CGPoint(
                x: toRect.size.width - fromRect.size.width,
                y: toRect.size.height - fromRect.size.height)
            return CGRect(origin: origin, size: fromRect.size)
        }
    }

    static fileprivate func aspectFit(_ fromRect: CGRect, toRect: CGRect) -> CGRect {
        let fromAspectRatio = fromRect.size.width / fromRect.size.height;
        let toAspectRatio = toRect.size.width / toRect.size.height;

        var fitRect = toRect

        if (fromAspectRatio > toAspectRatio) {
            fitRect.size.height = toRect.size.width / fromAspectRatio;
            fitRect.origin.y += (toRect.size.height - fitRect.size.height) * 0.5;
        } else {
            fitRect.size.width = toRect.size.height  * fromAspectRatio;
            fitRect.origin.x += (toRect.size.width - fitRect.size.width) * 0.5;
        }

        return fitRect.integral
    }

    static fileprivate func aspectFill(_ fromRect: CGRect, toRect: CGRect) -> CGRect {
        let fromAspectRatio = fromRect.size.width / fromRect.size.height;
        let toAspectRatio = toRect.size.width / toRect.size.height;

        var fitRect = toRect

        if (fromAspectRatio > toAspectRatio) {
            fitRect.size.width = toRect.size.height  * fromAspectRatio;
            fitRect.origin.x += (toRect.size.width - fitRect.size.width) * 0.5;
        } else {
            fitRect.size.height = toRect.size.width / fromAspectRatio;
            fitRect.origin.y += (toRect.size.height - fitRect.size.height) * 0.5;
        }

        return fitRect.integral
    }
}

let inputBounds = image.extent
let drawableBounds = CGRect(x: 0, y: 0, width: self.drawableWidth, height: self.drawableHeight)
let targetBounds = ContenModeEnforcer.rectFor(contentMode: contentMode, fromRect: inputBounds, toRect: drawableBounds)
ciContext.draw(image, in: targetBounds, from: inputBounds)