我正在使用 Swift 和Parse.com开发适用于iOS的应用程序
我试图让用户从图像选择器中选择一张图片,然后将所选图像的大小调整为200x200像素,然后再上传到我的后端。
Parse.com有一个用于Instagram复制应用程序的教程,名为“ AnyPic”,其中提供了用于调整图像大小的代码,但这是在Objective- C中。
// Resize the image to be square (what is shown in the preview) UIImage *resizedImage = [anImage resizedImageWithContentMode:UIViewContentModeScaleAspectFit bounds:CGSizeMake(560.0f, 560.0f) interpolationQuality:kCGInterpolationHigh]; // Create a thumbnail and add a corner radius for use in table views UIImage *thumbnailImage = [anImage thumbnailImage:86.0f transparentBorder:0.0f cornerRadius:10.0f interpolationQuality:kCGInterpolationDefault];
如何在Swift中为所选图片创建200x200px版本(然后上传)?
而且,thumbnailImage函数在做什么?
有关更多详细信息,请参阅我的博客文章, 快速且客观地C调整图像大小 。
快速调整图像尺寸的功能如下。
func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage { let size = image.size let widthRatio = targetSize.width / size.width let heightRatio = targetSize.height / size.height // Figure out what our orientation is, and use that to form the rectangle var newSize: CGSize if(widthRatio > heightRatio) { newSize = CGSizeMake(size.width * heightRatio, size.height * heightRatio) } else { newSize = CGSizeMake(size.width * widthRatio, size.height * widthRatio) } // This is the rect that we've calculated out and this is what is actually used below let rect = CGRectMake(0, 0, newSize.width, newSize.height) // Actually do the resizing to the rect using the ImageContext stuff UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0) image.drawInRect(rect) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage }
使用上面的功能并使用200 * 200调整图像大小,如下代码
self.resizeImage(UIImage(named: "yourImageName")!, targetSize: CGSizeMake(200.0, 200.0))
swift3更新
func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage { let size = image.size let widthRatio = targetSize.width / size.width let heightRatio = targetSize.height / size.height // Figure out what our orientation is, and use that to form the rectangle var newSize: CGSize if(widthRatio > heightRatio) { newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio) } else { newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio) } // This is the rect that we've calculated out and this is what is actually used below let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height) // Actually do the resizing to the rect using the ImageContext stuff UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0) image.draw(in: rect) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! }