Swift 图片添加水印 logo + title

func getWaterMark(_ originalImage: UIImage?,icon:UIImage?, title: String, andMark markFont: UIFont, andMark markColor: UIColor) -> UIImage? { let HORIZONTAL_SPACE: CGFloat = 130 let VERTICAL_SPACE: CGFloat = 150 var font: UIFont? = markFont if font == nil { font = UIFont.systemFont(ofSize: 23) } var color: UIColor? = markColor if color == nil { color = UIColor.blue } //原始image的宽高 guard let viewWidth = originalImage?.size.width, let viewHeight = originalImage?.size.height else { return nil } //为了防止图片失真，绘制区域宽高和原始图片宽高一样 UIGraphicsBeginImageContext(CGSize(width: viewWidth, height: viewHeight)) //先将原始image绘制上 originalImage?.draw(in: CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight)) //sqrtLength：原始image的对角线length。在水印旋转矩阵中只要矩阵的宽高是原始image的对角线长度，无论旋转多少度都不会有空白。 let sqrtLength = sqrt(viewWidth * viewWidth + viewHeight * viewHeight) let attrStr = NSAttributedString(string: title, attributes: [NSAttributedString.Key.foregroundColor : markColor, NSAttributedString.Key.font: markFont]) //绘制文字的宽高 let strWidth = attrStr.size().width let strHeight = attrStr.size().height //开始旋转上下文矩阵，绘制水印文字 let context = UIGraphicsGetCurrentContext() //将绘制原点（0，0）调整到源image的中心 context?.concatenate(CGAffineTransform(translationX: viewWidth / 2, y: viewHeight / 2)) //以绘制原点为中心旋转 context?.concatenate(CGAffineTransform(rotationAngle: CGFloat(Double.pi / 7.0))) //将绘制原点恢复初始值，保证当前context中心和源image的中心处在一个点(当前context已经旋转，所以绘制出的任何layer都是倾斜的) context?.concatenate(CGAffineTransform(translationX: -viewWidth / 2, y: -viewHeight / 2)) //计算需要绘制的列数和行数 let horCount: Int = Int(sqrtLength / CGFloat(strWidth + HORIZONTAL_SPACE)) + 1 let verCount: Int = Int(sqrtLength / CGFloat(strHeight + VERTICAL_SPACE)) + 1 //此处计算出需要绘制水印文字的起始点，由于水印区域要大于图片区域所以起点在原有基础上移 let orignX: CGFloat = -(sqrtLength - viewWidth) / 2 let orignY: CGFloat = -(sqrtLength - viewHeight) / 2 //在每列绘制时X坐标叠加 var tempOrignX: CGFloat = orignX //在每行绘制时Y坐标叠加 var tempOrignY: CGFloat = orignY let iconW = icon != nil ? strHeight : 0 let iconL = iconW == 0 ? 0 : iconW + 5 for i in 0..<horCount * verCount { if icon != nil { icon?.draw(in: CGRect(x: tempOrignX, y: tempOrignY, width: strHeight, height: strHeight), blendMode: CGBlendMode.hardLight, alpha: 0.9) } title.draw(in: CGRect(x: tempOrignX+iconL, y: tempOrignY, width: strWidth, height: strHeight), withAttributes: [NSAttributedString.Key.foregroundColor : markColor, NSAttributedString.Key.font: markFont]) if i % horCount == 0 && i != 0 { tempOrignX = orignX + ( i%2 == 0 ? (strWidth+HORIZONTAL_SPACE)*0.5 : 0)//是否隔行错开 tempOrignY += strHeight + VERTICAL_SPACE } else { tempOrignX += strWidth + HORIZONTAL_SPACE } } //根据上下文制作成图片 let finalImg: UIImage? = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return finalImg }

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实现效果：