Methods for reading EXIF information of pictures in C # (i)

Introduction:

EXIF, is an abbreviation of English exchangeable image file (exchangeable images files), originally by Japan Electronics Industry Development Association (JEIDA--japan Electronic Industry Development) Developed, the current version is revised published in June 1998 in version 2.1. The International Organization for Standardization (ISO) is developing a standard for camera file design (DCF-Designing role for Camera file system) that is based on the EXIF2.1 format. Remember, EXIF is an image file format, only the file suffix name or follow the familiar JPG. In fact, EXIF information is a digital camera in the process of capturing a series of information, and then put the information in our well-known JPG file head, that is, EXIF information is embedded in the JPEG image file format of a set of shooting parameters, mainly including the camera aperture, shutter, ISO, Date time and other information related to photographic conditions at the time, camera brand model, color coding, recording sound and Global Positioning System (GPS). Simply put, it's like a instamatics date print function, except that the information recorded in the EXIF information is more detailed and complete. However, JPEG image files with EXIF information are slightly larger than normal JPEG files. In the current market, a new generation of digital cameras have an additional EXIF information function, most digital camera manufacturers will also be with the digital camera when the sale of information to read EXIF software, such as the Nikon series of digital cameras attached to the Nikonview software, AGFA series of cameras are attached Photowize V1.8 version, and Fuji Camera comes with the Exif viewer software is the leader in this area (currently available for free download on many sites.) There are also a number of digital cameras that automatically dump EXIF information into document files, such as NIKON CoolPix 990 and Sony FD series. In addition to hardware manufacturers with digital cameras with the EXIF information to view the software, many professional image software vendors in this respect are not outdone, has launched its own company to look at the latest version of the software to support this near-perfect jpeg-exif image information technology, such as the recently launched ACDSee 4.0 version, On the current popular variety of digital cameras have a good support, in the EXIF image information additional aspect than its 3.0 version also has great progress. Whether it is a hardware manufacturer's software or a professional-looking graphics tool, all of these software are designed to make it easier for digital photographers to save important information about viewing photographic images. We summarize the software that reads EXIF information into four categories: professional exIf information viewing tool (take Fuji's EXIF viewer as an example), a powerful generic view tool with viewing EXIF information (for example, ACDSee), an operating system that supports EXIF information viewing (Microsoft's Windows XP), and an alternative tool to modify EXIF information (EXIF Editer), and what we're talking about here is the use of C # to read EXIF information for a picture on the web.

Second, related class (Getexifmetadata):

Because the code is longer, there are more than 500 lines, I can only take out the key pieces of code to speak, the need for the source of the message to yubo@x263.net, or directly added to MSN on MSN to provide your mailbox.

This class constructs two structure Metadatadetail and Metadata, the former is to store the information of an element in EXIF three kinds of format, play the role of intermediate transformation, one is the hexadecimal index information, one is not used to deal with the information code, one is to display information.　The structure behind that is to store a picture of all EXIF information elements. There are two methods Lookupexifvalue and Getexifmetadata, and the previous method is to handle the corresponding display of a particular element, which reads the relevant information from the picture and fills it into the metadata structure.