10ef31e1fSMike Welles<HTML> 20ef31e1fSMike Welles<HEAD> 30ef31e1fSMike Welles<TITLE> 40ef31e1fSMike WellesIntroduction to the TIFF Documentation 50ef31e1fSMike Welles</TITLE> 60ef31e1fSMike Welles</HEAD> 7*b751b3a5SMike Welles<BODY BGCOLOR=white> 80ef31e1fSMike Welles<H1> 90ef31e1fSMike Welles<IMG SRC=images/strike.gif WIDTH=128 HEIGHT=100 ALIGN=left HSPACE=6> 100ef31e1fSMike WellesIntroduction to the TIFF Documentation 110ef31e1fSMike Welles</H1> 120ef31e1fSMike Welles 130ef31e1fSMike Welles 140ef31e1fSMike Welles<P> 150ef31e1fSMike WellesThe following definitions are used throughout this documentation. 160ef31e1fSMike WellesThey are consistent with the terminology used in the TIFF 6.0 specification. 170ef31e1fSMike Welles 180ef31e1fSMike Welles<DL> 190ef31e1fSMike Welles<DT><I>Sample</I> 200ef31e1fSMike Welles<DD>The unit of information stored in an image; often called a 210ef31e1fSMike Welles channel elsewhere. Sample values are numbers, usually unsigned 220ef31e1fSMike Welles integers, but possibly in some other format if the SampleFormat 230ef31e1fSMike Welles tag is specified in a TIFF 240ef31e1fSMike Welles<DT><I>Pixel</I> 250ef31e1fSMike Welles<DD>A collection of one or more samples that go together. 260ef31e1fSMike Welles<DT><I>Row</I> 270ef31e1fSMike Welles<DD>An Nx1 rectangular collection of pixels. 280ef31e1fSMike Welles<DT><I>Tile</I> 290ef31e1fSMike Welles<DD>An NxM rectangular organization of data (or pixels). 300ef31e1fSMike Welles<DT><I>Strip</I> 310ef31e1fSMike Welles<DD>A tile whose width is the full image width. 320ef31e1fSMike Welles<DT><I>Compression</I> 330ef31e1fSMike Welles<DD>A scheme by which pixel or sample data are stored in 340ef31e1fSMike Welles an encoded form, specifically with the intent of reducing the 350ef31e1fSMike Welles storage cost. 360ef31e1fSMike Welles<DT><I>Codec</I> 370ef31e1fSMike Welles<DD>Software that implements the decoding and encoding algorithms 380ef31e1fSMike Welles of a compression scheme. 390ef31e1fSMike Welles</UL> 400ef31e1fSMike Welles 410ef31e1fSMike Welles<P> 420ef31e1fSMike WellesIn order to better understand how TIFF works (and consequently this 430ef31e1fSMike Wellessoftware) it is important to recognize the distinction between the 440ef31e1fSMike Wellesphysical organization of image data as it is stored in a TIFF and how 450ef31e1fSMike Wellesthe data is interpreted and manipulated as pixels in an image. TIFF 460ef31e1fSMike Wellessupports a wide variety of storage and data compression schemes that 470ef31e1fSMike Wellescan be used to optimize retrieval time and/or minimize storage space. 480ef31e1fSMike WellesThese on-disk formats are independent of the image characteristics; it 490ef31e1fSMike Wellesis the responsibility of the TIFF reader to process the on-disk storage 500ef31e1fSMike Wellesinto an in-memory format suitable for an application. Furthermore, it 510ef31e1fSMike Wellesis the responsibility of the application to properly interpret the 520ef31e1fSMike Wellesvisual characteristics of the image data. TIFF defines a framework for 530ef31e1fSMike Wellesspecifying the on-disk storage format and image characteristics with 540ef31e1fSMike Wellesfew restrictions. This permits significant complexity that can be 550ef31e1fSMike Wellesdaunting. Good applications that handle TIFF work by handling as wide 560ef31e1fSMike Wellesa range of storage formats as possible, while constraining the 570ef31e1fSMike Wellesacceptable image characteristics to those that make sense for the 580ef31e1fSMike Wellesapplication. 590ef31e1fSMike Welles 600ef31e1fSMike Welles 610ef31e1fSMike Welles<P> 620ef31e1fSMike Welles<HR> 630ef31e1fSMike Welles 64*b751b3a5SMike WellesLast updated: $Date: 1999-08-09 18:38:27 $ 650ef31e1fSMike Welles 660ef31e1fSMike Welles</BODY> 670ef31e1fSMike Welles</HTML> 68
