Category : C Source Code
Archive   : GIF_LIB.ZIP
Filename : GIFRSIZE.C

/*****************************************************************************
* "Gif-Lib" - Yet another gif library. *
* *
* Written by: Gershon Elber IBM PC Ver 0.1, Jul. 1989 *
******************************************************************************
* Program to resize GIF by given factors horizontally and vertically. *
* Options: *
* -s n : resize both x & y direction by factor n. *
* -x n : resize the x direction (horizontally) by factor n. *
* -y n : resize the y direction (vertically) by factor n. *
* -u : set up instead of down (default) by factor n. *
* -d : scale down (default). *
* -h : on line help. *
******************************************************************************
* History: *
* 4 Jul 89 - Version 1.0 by Gershon Elber. *
*****************************************************************************/

#include
#include
#include
#include
#include
#include "gif_lib.h"
#include "getarg.h"

#define PROGRAM_NAME "GifRSize"
#define VERSION "á Version 1.0, "

#define MAX_SCALE 16 /* Maximum scaling factor */

extern unsigned int
_stklen = 16384; /* Increase default stack size */

static char
*VersionStr =
PROGRAM_NAME
" IBMPC "
VERSION
" Gershon Elber, "
__DATE__ ", " __TIME__ "\n"
"(C) Copyright 1989 Gershon Elber, Non commercial use only.\n";
static char
*CtrlStr =
PROGRAM_NAME
" s%-Scale!d x%-XScale!d y%-YScale!d u%- d%- h%- GifFile!*s";
static char *ProgramName;

/* Make some variables global, so we could access them faster: */
static PixelType
BackGroundColor = 0;
static int
XScale = 2,
YScale = 2,
ScaleDown = TRUE;

static void Average(RowType LineIn[], RowType LineOut[], int OutLineLen);
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut);

/******************************************************************************
* Interpret the command line and scan the given GIF file. *
******************************************************************************/
void main(int argc, char **argv)
{
int i, j, Error, NumFiles, ExtCode, ImageNum = 0, Scale, InCount,
ScaleFlag = FALSE, XScaleFlag = FALSE, YScaleFlag = FALSE,
UpFlag = FALSE, DownFlag = FALSE, HelpFlag = FALSE;
GifRecordType RecordType;
char s[80];
ByteType *Extension;
RowType LineIn[MAX_SCALE], LineOut[MAX_SCALE];
char **FileName = NULL;
GifFileType *GifFileIn = NULL, *GifFileOut = NULL;

if (strlen(ProgramName = argv[0]) == 0) /* DOS 3.x only! */
ProgramName = PROGRAM_NAME; /* Do something reasonable for 2.x */

if ((Error = GAGetArgs(argc, argv, CtrlStr, &ScaleFlag, &Scale,
&XScaleFlag, &XScale, &YScaleFlag, &YScale, &UpFlag, &DownFlag,
&HelpFlag, &NumFiles, &FileName)) != FALSE ||
(NumFiles > 1 && !HelpFlag)) {
if (Error) GAPrintErrMsg(Error);
else
if (NumFiles > 1)
MESSAGE("Error in command line parsing - one GIF file please\n");
GAPrintHowTo(CtrlStr);
exit(1);
}

if (HelpFlag) {
fprintf(stderr, VersionStr);
GAPrintHowTo(CtrlStr);
exit(0);
}

/* Decide if we scale up or down: */
if (UpFlag) ScaleDown = FALSE;
if (DownFlag) ScaleDown = TRUE;

/* If specific direction was set, set other direction to 1: */
if (!XScaleFlag && YScaleFlag) XScale = 1;
if (!YScaleFlag && XScaleFlag) YScale = 1;

/* If the specific direction was not set, but global one did use it: */
if (!XScaleFlag && ScaleFlag) XScale = Scale;
if (!YScaleFlag && ScaleFlag) YScale = Scale;
if (XScale > MAX_SCALE) {
sprintf(s, "XScale too big, maximum scale selected instead (%d)\n",
MAX_SCALE);
MESSAGE(s);
XScale = MAX_SCALE;
}
if (YScale > MAX_SCALE) {
sprintf(s, "YScale too big, maximum scale selected instead (%d)\n",
MAX_SCALE);
MESSAGE(s);
YScale = MAX_SCALE;
}

if (NumFiles == 1) {
if ((GifFileIn = DGifOpenFileName(*FileName)) == NULL)
QuitGifError(GifFileIn, GifFileOut);
}
else {
/* Use the stdin instead: */
if ((GifFileIn = DGifOpenFileHandle(0)) == NULL)
QuitGifError(GifFileIn, GifFileOut);
}
BackGroundColor = GifFileIn -> SBackGroundColor;

/* As at this time we know the Screen size of the input gif file, and as */
/* all image(s) in file must be less/equal to it, we can allocate the */
/* scan lines for the input file, and output file. The number of lines */
/* to allocate for each is set by ScaleDown & XScale & YScale: */
if (ScaleDown) {
/* Output is smaller than input so we need only one output scanline: */
LineOut[0] = (RowType) malloc(GifFileIn -> SWidth / XScale *
sizeof(PixelType));
for (i=0; i (RowType) malloc(GifFileIn -> SWidth * sizeof(PixelType));
if (LineIn[YScale - 1] == NULL)
EXIT("Failed to allocate memory required, aborted\n");
}
else {
/* Input is smaller than output so we need only one input scanline: */
LineIn[0] = (RowType) malloc(GifFileIn -> SWidth *
sizeof(PixelType));
for (i=0; i (RowType) malloc(GifFileIn -> SWidth * XScale * sizeof(PixelType));
if (LineOut[YScale - 1] == NULL)
EXIT("Failed to allocate memory required, aborted\n");
}

/* Open stdout for the output file: */
if ((GifFileOut = EGifOpenFileHandle(1)) == NULL)
QuitGifError(GifFileIn, GifFileOut);

/* And dump out its new scaled screen information: */
if (EGifPutScreenDesc(GifFileOut,
ScaleDown ? GifFileIn -> SWidth / XScale :
GifFileIn -> SWidth * XScale,
ScaleDown ? GifFileIn -> SHeight / YScale :
GifFileIn -> SHeight * YScale,
GifFileIn -> SColorResolution, GifFileIn -> SBackGroundColor,
GifFileIn -> SBitsPerPixel, GifFileIn -> SColorMap) == ERROR)
QuitGifError(GifFileIn, GifFileOut);


/* Scan the content of the GIF file and load the image(s) in: */
do {
if (DGifGetRecordType(GifFileIn, &RecordType) == ERROR)
QuitGifError(GifFileIn, GifFileOut);

switch (RecordType) {
case IMAGE_DESC_RECORD_TYPE:
if (DGifGetImageDesc(GifFileIn) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
/* Put the image descriptor to out file: */
if (EGifPutImageDesc(GifFileOut,
ScaleDown ? GifFileIn -> ILeft / XScale :
GifFileIn -> ILeft * XScale,
ScaleDown ? GifFileIn -> ITop / YScale :
GifFileIn -> ITop * YScale,
ScaleDown ? GifFileIn -> IWidth / XScale :
GifFileIn -> IWidth * XScale,
ScaleDown ? GifFileIn -> IHeight / YScale :
GifFileIn -> IHeight * YScale,
GifFileIn -> IInterlace, GifFileIn -> IBitsPerPixel,
GifFileIn -> IColorMap) == ERROR)
QuitGifError(GifFileIn, GifFileOut);

if (GifFileIn -> IInterlace) {
EXIT("Cannt average4 interlaced images - use GifInter first\n");
}
else {
fprintf(stderr, "\n%s: Image %d at (%d, %d) [%dx%d]: ",
ProgramName, ++ImageNum,
GifFileOut -> ILeft, GifFileOut -> ITop,
GifFileOut -> IWidth, GifFileOut -> IHeight);
InCount = 0;
if (ScaleDown) {
/* For each line of output, read YScale input lines, */
/* average them, and dump result out: */
for (i=0; i IHeight; i++) {
fprintf(stderr, "\b\b\b\b%-4d", i);
for (j=0; j if (DGifGetLine(GifFileIn, LineIn[j],
GifFileIn -> IWidth) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
InCount += YScale;
Average(LineIn, LineOut, GifFileOut -> IWidth);
if (EGifPutLine(GifFileOut, LineOut[0],
GifFileOut -> IWidth) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
}
/* If scale is not dividable - discard last lines: */
for (i=InCount; i IHeight; i++)
DGifGetLine(GifFileIn, LineIn[i],
GifFileIn -> IWidth);
}
else {
/* For each line of input, output YScale lines, */
/* by averaging up this line to YScale lines: */
for (i=0; i IHeight; i++) {
fprintf(stderr, "\b\b\b\b%-4d", i * YScale);
if (DGifGetLine(GifFileIn, LineIn[0],
GifFileIn -> IWidth) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
Average(LineIn, LineOut, GifFileOut -> IWidth);
for (j=0; j if (EGifPutLine(GifFileOut, LineOut[j],
GifFileOut -> IWidth) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
}
}
}
break;
case EXTENSION_RECORD_TYPE:
/* Skip any extension blocks in file: */
if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
if (EGifPutExtension(GifFileOut, ExtCode, Extension[0],
Extension) == ERROR)
QuitGifError(GifFileIn, GifFileOut);

/* No support to more than one extension blocks, so discard: */
while (Extension != NULL) {
if (DGifGetExtensionNext(GifFileIn, &Extension) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
}
break;
case TERMINATE_RECORD_TYPE:
break;
default: /* Should be traps by DGifGetRecordType */
break;
}
}
while (RecordType != TERMINATE_RECORD_TYPE);

if (DGifCloseFile(GifFileIn) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
if (EGifCloseFile(GifFileOut) == ERROR)
QuitGifError(GifFileIn, GifFileOut);
}

/******************************************************************************
* Average routine - scale given lines as follows: *
* ScaleDown: for each YScale lines, for each box of size XScale by YScale *
* pick a pixel in it (usually upper left). If that pixel is equal to *
* background color, and there is in that square, none background pixel, pick *
* that instead. Use result pixel as output averaged pixel *
* ScaleUp: each input pixel, is expanded both in X and in Y by the factors *
* XScale & YScale respectively. *
******************************************************************************/
static void Average(RowType LineIn[], RowType LineOut[], int OutLineLen)
{
int i, j, k, o;
PixelType Color;


if (ScaleDown) {
/* For each XScale by YScale pixels in a box, pick the top left one */
/* if not background color, otherwise pick any non background from */
/* other pixels in box if one exists. */
for (i=0, o=0; o if ((Color = LineIn[0][i]) == BackGroundColor) {
/* Scan all pixels to find non background color if exists: */
for (j=i; j for (k=0; k if (LineIn[k][j] != BackGroundColor)
Color = LineIn[k][j];
}
LineOut[0][o] = Color;
}
}
else {
/* Make each input pixel a box of size XScale bu YScale: */
for (i=0, o=0; o for (j=0; j /* And duplicate the other lines from first one: */
for (i=1; i OutLineLen * sizeof(PixelType));
}
}

/******************************************************************************
* Close both input and output file (if open), and exit. *
******************************************************************************/
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut)
{
PrintGifError();
if (GifFileIn != NULL) DGifCloseFile(GifFileIn);
if (GifFileOut != NULL) EGifCloseFile(GifFileOut);
exit(1);
}