我刚开始使用swift和cocoa.我正在尝试创建一个执行图像处理的基本应用程序.
我已经获得了图像的所有信息：
let imageRef:CGImageSourceRef = CGImageSourceCreateWithURL(url,nil).takeUnretainedValue() let imageDict:CFDictionaryRef = CGImageSourceCopyPropertiesAtIndex(imageRef,nil).takeUnretainedValue()
该词典包含以下信息：
{
ColorModel = Gray;
DPIHeight = 300;
DPIWidth = 300;
Depth = 1;
Orientation = 1;
PixelHeight = 4167;
PixelWidth = 4167;
"{Exif}" = {
ColorSpace = 65535;
DateTimeDigitized = "2014:07:09 20:25:49";
PixelXDimension = 4167;
PixelYDimension = 4167;
};
"{TIFF}" = {
Compression = 1;
DateTime = "2014:07:09 20:25:49";
Orientation = 1;
PhotometricInterpretation = 0;
ResolutionUnit = 2;
Software = "Adobe Photoshop CS6 (Macintosh)";
XResolution = 300;
YResolution = 300;
};
}
现在我想用以下代码读取DPI的值,并且“__conversion”存在一些问题,我不明白.
let dpiH:NSNumber = CFDictionaryGetValue(imageDict,kCGImagePropertyDPIWidth)
我做错了什么,怎样才能达到字典所需的值？
我发现通过将CFDictionary“转换”为Swift字典来访问属性要容易得多.
原文链接：https://www.f2er.com/swift/320244.htmllet imageSource = CGImageSourceCreateWithURL(imageURL,nil) let imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource,nil) as Dictionary let dpiWidth = imageProperties[kCGImagePropertyDPIWidth] as NSNumber
Swift 2.0的快速更新(原谅所有if let – 我只是快速制作了这段代码)：
import UIKit
import ImageIO
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let imagePath = NSBundle.mainBundle().pathForResource("test",ofType: "jpg") {
let imageURL = NSURL(fileURLWithPath: imagePath)
if let imageSource = CGImageSourceCreateWithURL(imageURL,nil) {
if let imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource,nil) as Dictionary? {
let pixelWidth = imageProperties[kCGImagePropertyPixelWidth] as! Int
print("the image width is: \(pixelWidth)")
}
}
}
}
}
