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unit imjmorecfg;
{ This file contains additional configuration options that customize the JPEG software for special applications or support machine-dependent optimizations. Most users will not need to touch this file. }
{ Source: jmorecfg.h; Copyright (C) 1991-1996, Thomas G. Lane. }
interface
{$I imjconfig.inc}
type int = Integer; uInt = Cardinal; short = SmallInt; ushort = Word; long = LongInt;
type voidp = pointer;
type int_ptr = ^int; size_t = int;
{ Define BITS_IN_JSAMPLE as either 8 for 8-bit sample values (the usual setting) 12 for 12-bit sample values Only 8 and 12 are legal data precisions for lossy JPEG according to the JPEG standard, and the IJG code does not support anything else! We do not support run-time selection of data precision, sorry. }
{$ifdef BITS_IN_JSAMPLE_IS_8} { use 8 or 12 }const BITS_IN_JSAMPLE = 8;{$else}const BITS_IN_JSAMPLE = 12;{$endif}
{ Maximum number of components (color channels) allowed in JPEG image. To meet the letter of the JPEG spec, set this to 255. However, darn few applications need more than 4 channels (maybe 5 for CMYK + alpha mask). We recommend 10 as a reasonable compromise; use 4 if you are really short on memory. (Each allowed component costs a hundred or so bytes of storage, whether actually used in an image or not.) }
const MAX_COMPONENTS = 10; { maximum number of image components }
{ Basic data types. You may need to change these if you have a machine with unusual data type sizes; for example, "char" not 8 bits, "short" not 16 bits, or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits, but it had better be at least 16. }
{ Representation of a single sample (pixel element value). We frequently allocate large arrays of these, so it's important to keep them small. But if you have memory to burn and access to char or short arrays is very slow on your hardware, you might want to change these. }
{$ifdef BITS_IN_JSAMPLE_IS_8}{ JSAMPLE should be the smallest type that will hold the values 0..255. You can use a signed char by having GETJSAMPLE mask it with $FF. }
{ CHAR_IS_UNSIGNED }type JSAMPLE = byte; { Pascal unsigned char } GETJSAMPLE = int;
const MAXJSAMPLE = 255; CENTERJSAMPLE = 128;
{$endif}
{$ifndef BITS_IN_JSAMPLE_IS_8}{ JSAMPLE should be the smallest type that will hold the values 0..4095. On nearly all machines "short" will do nicely. }
type JSAMPLE = short; GETJSAMPLE = int;
const MAXJSAMPLE = 4095; CENTERJSAMPLE = 2048;
{$endif} { BITS_IN_JSAMPLE = 12 }
{ Representation of a DCT frequency coefficient. This should be a signed value of at least 16 bits; "short" is usually OK. Again, we allocate large arrays of these, but you can change to int if you have memory to burn and "short" is really slow. }type JCOEF = int; JCOEF_PTR = ^JCOEF;
{ Compressed datastreams are represented as arrays of JOCTET. These must be EXACTLY 8 bits wide, at least once they are written to external storage. Note that when using the stdio data source/destination managers, this is also the data type passed to fread/fwrite. }
type JOCTET = Byte; jTOctet = 0..(MaxInt div SizeOf(JOCTET))-1; JOCTET_FIELD = array[jTOctet] of JOCTET; JOCTET_FIELD_PTR = ^JOCTET_FIELD; JOCTETPTR = ^JOCTET;
GETJOCTET = JOCTET; { A work around }
{ These typedefs are used for various table entries and so forth. They must be at least as wide as specified; but making them too big won't cost a huge amount of memory, so we don't provide special extraction code like we did for JSAMPLE. (In other words, these typedefs live at a different point on the speed/space tradeoff curve.) }
{ UINT8 must hold at least the values 0..255. }
type UINT8 = Byte;
{ UINT16 must hold at least the values 0..65535. }
UINT16 = Word;
{ INT16 must hold at least the values -32768..32767. }
INT16 = SmallInt;
{ INT32 must hold at least signed 32-bit values. }
INT32 = LongInt;type INT32PTR = ^INT32;
{ Datatype used for image dimensions. The JPEG standard only supports images up to 64K*64K due to 16-bit fields in SOF markers. Therefore "unsigned int" is sufficient on all machines. However, if you need to handle larger images and you don't mind deviating from the spec, you can change this datatype. }
type JDIMENSION = uInt;
const JPEG_MAX_DIMENSION = 65500; { a tad under 64K to prevent overflows }
{ Ordering of RGB data in scanlines passed to or from the application. If your application wants to deal with data in the order B,G,R, just change these macros. You can also deal with formats such as R,G,B,X (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing the offsets will also change the order in which colormap data is organized. RESTRICTIONS: 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats. 2. These macros only affect RGB<=>YCbCr color conversion, so they are not useful if you are using JPEG color spaces other than YCbCr or grayscale. 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE is not 3 (they don't understand about dummy color components!). So you can't use color quantization if you change that value. }
{$ifdef RGB_RED_IS_0}const RGB_RED = 0; { Offset of Red in an RGB scanline element } RGB_GREEN = 1; { Offset of Green } RGB_BLUE = 2; { Offset of Blue }{$else}const RGB_RED = 2; { Offset of Red in an RGB scanline element } RGB_GREEN = 1; { Offset of Green } RGB_BLUE = 0; { Offset of Blue }{$endif}
{$ifdef RGB_PIXELSIZE_IS_3}const RGB_PIXELSIZE = 3; { JSAMPLEs per RGB scanline element }{$else}const RGB_PIXELSIZE = ??; { Nomssi: deliberate syntax error. Set this value }{$endif}
{ Definitions for speed-related optimizations. }
{ On some machines (notably 68000 series) "int" is 32 bits, but multiplying two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER as short on such a machine. MULTIPLIER must be at least 16 bits wide. }type MULTIPLIER = int; { type for fastest integer multiply }
{ FAST_FLOAT should be either float or double, whichever is done faster by your compiler. (Note that this type is only used in the floating point DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.) Typically, float is faster in ANSI C compilers, while double is faster in pre-ANSI compilers (because they insist on converting to double anyway). The code below therefore chooses float if we have ANSI-style prototypes. }
type FAST_FLOAT = double; {float}
implementation
end.
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