Image/Text overlay in video swift

Question

I am work with image overlay for watermark effect in video using swift.I am using AVFoundation for this but somehow I am not succeed.

Following is my code

Answer 1

To supplement, here's a function that creates CATextLayers based on an array UITextViews supplied by copying over their rotation, scale and font. Just add these to your container-layer supplied to AVVideoCompositionCoreAnimationTool:

private static func createTextLayer(totalSize: CGSize,
                                        textView: UITextView) -> CATextLayer {
        let textLayer: CACenteredTextLayer = CACenteredTextLayer()
        textLayer.backgroundColor = UIColor.clear
        textLayer.foregroundColor = textView.textColor?.cgColor
        textLayer.masksToBounds = false
        textLayer.isWrapped = true

        let scale: CGFloat = UIScreen.main.scale

        if let font: UIFont = textView.font {
            let upscaledFont: UIFont = font.withSize(font.pointSize * scale)
            let attributedString = NSAttributedString(
                string: textView.text,
                attributes: [NSAttributedString.Key.font: upscaledFont,
                             NSAttributedString.Key.foregroundColor: textView.textColor ?? UIColor.white])
            textLayer.string = attributedString
        }

        // Set text alignment
        let alignment: CATextLayerAlignmentMode
        switch textView.textAlignment {
        case NSTextAlignment.left:
            alignment = CATextLayerAlignmentMode.left
        case NSTextAlignment.center:
            alignment = CATextLayerAlignmentMode.center
        default:
            alignment = CATextLayerAlignmentMode.right
        }
        textLayer.alignmentMode = alignment

        let originalFrame: CGRect = textView.frame

        // Also take scale into consideration
        let targetSize: CGSize = CGSize(width: originalFrame.width * scale,
                                        height: originalFrame.height * scale)

        // The CALayer positioning is inverted on the Y-axes, so apply this
        let origin: CGPoint = CGPoint(x: originalFrame.origin.x * scale,
                                      y: (totalSize.height - (originalFrame.origin.y * scale)) - targetSize.height)

        textLayer.frame = CGRect(x: origin.x,
                                 y: origin.y,
                                 width: targetSize.width,
                                 height: targetSize.height)

        // Determine the scale
        textLayer.anchorPoint = CGPoint(x: 0.5,
                                        y: 0.5)

        var newTransform: CATransform3D = CATransform3DMakeScale(textView.transform.xScale,
                                                                 textView.transform.yScale,
                                                                 0)

        // Convert to degrees, invert the amount and convert back to radians to apply
        newTransform = CATransform3DRotate(newTransform,
                                           textView.transform.radiansFor3DTransform,
                                           0,
                                           0,
                                           1)
        textLayer.transform = newTransform

        return textLayer
}

Combine this with this subclassing of CATextLayer to center the text vertically:

final class CACenteredTextLayer: CATextLayer {
    override func draw(in ctx: CGContext) {
        guard let attributedString = string as? NSAttributedString else { return }

        let height = self.bounds.size.height
        let boundingRect: CGRect = attributedString.boundingRect(
            with: CGSize(width: bounds.width,
                         height: CGFloat.greatestFiniteMagnitude),
            options: NSStringDrawingOptions.usesLineFragmentOrigin,
            context: nil)
        let yDiff: CGFloat = (height - boundingRect.size.height) / 2

        ctx.saveGState()
        ctx.translateBy(x: 0.0, y: yDiff)
        super.draw(in: ctx)
        ctx.restoreGState()
    }
}

private extension CGAffineTransform {
    var xScale: CGFloat {
        return sqrt((a*a) + (c*c))
    }

    var yScale: CGFloat {
        return sqrt((b*b) + (d*d))
    }

    var radiansFor3DTransform: CGFloat {
        let radians: CGFloat = atan2(b, a);
        let degrees: CGFloat = -(radians * 180 / CGFloat.pi)
        let convertedRadians: CGFloat = CGFloat(degrees * (CGFloat.pi / 180))
        return convertedRadians
    }
}