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gifrsize.c

/*****************************************************************************
*   "Gif-Lib" - Yet another gif library.                         *
*                                                          *
* Written by:  Gershon Elber                    Ver 0.1, Jul. 1989   *
******************************************************************************
* Program to resize GIF by given factors horizontally and vertically.        *
* Options:                                                 *
* -q : quiet printing mode.                                      *
* -S x y : scale into size as specified by x and y.                    *
* -s r : resize both x & y direction by factor r.                      *
* -x r : resize the x direction (horizontally) by factor r.            *
* -y r : resize the y direction (vertically) by factor r.              *
* -h : on-line help.                                             *
******************************************************************************
* History:                                                 *
* 4 Jul 89 - Version 1.0 by Gershon Elber.                             *
* 22 Dec 89 - Fix minor bag in discarding last line of input (Version 1.1).  *
* 3 Aug 91 - make it scale by an arbitrary size value.                       *
*****************************************************************************/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef __MSDOS__
#include <stdlib.h>
#include <alloc.h>
#endif /* __MSDOS__ */

#ifndef __MSDOS__
#include <stdlib.h>
#endif
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "gif_lib.h"
#include "getarg.h"

#define PROGRAM_NAME    "GifRSize"

#define MAX_SCALE 16.0                /* Maximum scaling factor. */

#ifdef __MSDOS__
extern unsigned int
    _stklen = 16384;                     /* Increase default stack size. */
#endif /* __MSDOS__ */

#ifdef SYSV
static char *VersionStr =
        "Gif toolkit module,\t\tGershon Elber\n\
      (C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr = "GifRSize q%- S%-X|Y!d!d s%-Scale!F x%-XScale!F y%-YScale!F h%- GifFile!*s";
#else
static char
    *VersionStr =
      PROGRAM_NAME
      GIF_LIB_VERSION
      "     Gershon Elber,    "
      __DATE__ ",   " __TIME__ "\n"
      "(C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr =
      PROGRAM_NAME
      " q%- S%-X|Y!d!d s%-Scale!F x%-XScale!F y%-YScale!F h%- GifFile!*s";
#endif /* SYSV */

/* Make some variables global, so we could access them faster: */
static GifPixelType
    BackGroundColor = 0;
static double
    XScale = 0.5,
    YScale = 0.5;
static int
    XSize = 0,
    YSize = 0;

static void ResizeLine(GifRowType LineIn, GifRowType LineOut,
                  int InLineLen, int OutLineLen);
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut);

/******************************************************************************
* Interpret the command line and scan the given GIF file.               *
******************************************************************************/
int main(int argc, char **argv)
{
    int     i, iy, last_iy, l, t, w, h, Error, NumFiles, ExtCode,
      ImageNum = 0,
      SizeFlag = FALSE,
      ScaleFlag = FALSE,
      XScaleFlag = FALSE,
      YScaleFlag = FALSE,
      HelpFlag = FALSE;
    double Scale, y;
    GifRecordType RecordType;
    char s[80];
    GifByteType *Extension;
    GifRowType LineIn, LineOut;
    char **FileName = NULL;
    GifFileType *GifFileIn = NULL, *GifFileOut = NULL;

    if ((Error = GAGetArgs(argc, argv, CtrlStr,
            &GifQuietPrint, &SizeFlag, &XSize, &YSize, &ScaleFlag, &Scale,
            &XScaleFlag, &XScale, &YScaleFlag, &YScale,
            &HelpFlag, &NumFiles, &FileName)) != FALSE ||
            (NumFiles > 1 && !HelpFlag)) {
      if (Error)
          GAPrintErrMsg(Error);
      else if (NumFiles > 1)
          GIF_MESSAGE("Error in command line parsing - one GIF file please.");
      GAPrintHowTo(CtrlStr);
      exit(EXIT_FAILURE);
    }

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

    /* If specific direction was set, set other direction to 1: */
    if (!XScaleFlag && YScaleFlag) XScale = 1.0;
    if (!YScaleFlag && XScaleFlag) YScale = 1.0;

    /* 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 (%f).",
                                                MAX_SCALE);
      GIF_MESSAGE(s);
      XScale = MAX_SCALE;
    }
    if (YScale > MAX_SCALE) {
      sprintf(s, "YScale too big, maximum scale selected instead (%f).",
                                                MAX_SCALE);
      GIF_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;

    /* If size was specified, it is used to derive the scale: */
    if (SizeFlag) {
      XScale = XSize / ((double) GifFileIn->SWidth);
      YScale = YSize / ((double) GifFileIn->SHeight);
    }
    else
    {
      XSize = (int) (GifFileIn->SWidth * XScale + 0.5);
      YSize = (int) (GifFileIn->SHeight * YScale + 0.5);
    }

    /* 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:           */
    LineOut = (GifRowType) malloc(XSize * sizeof(GifPixelType));
    LineIn = (GifRowType) malloc(GifFileIn->SWidth * sizeof(GifPixelType));

    /* 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, XSize, YSize,
      GifFileIn->SColorResolution, GifFileIn->SBackGroundColor,
      GifFileIn->SColorMap) == GIF_ERROR)
      QuitGifError(GifFileIn, GifFileOut);

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

      switch (RecordType) {
          case IMAGE_DESC_RECORD_TYPE:
            if (DGifGetImageDesc(GifFileIn) == GIF_ERROR)
                QuitGifError(GifFileIn, GifFileOut);
            /* Put the image descriptor to out file: */
            l = (int) (GifFileIn->Image.Left * XScale + 0.5);
            w = (int) (GifFileIn->Image.Width * XScale + 0.5);
            t = (int) (GifFileIn->Image.Top * YScale + 0.5);
            h = (int) (GifFileIn->Image.Height * YScale + 0.5);
            if (l < 0) l = 0;
            if (t < 0) t = 0;
            if (l + w > XSize) w = XSize - l;
            if (t + h > YSize) h = YSize - t;

            if (EGifPutImageDesc(GifFileOut, l, t, w, h,
                GifFileIn->Image.Interlace,
                GifFileIn->Image.ColorMap) == GIF_ERROR)
                QuitGifError(GifFileIn, GifFileOut);

            if (GifFileIn->Image.Interlace) {
                GIF_EXIT("Cannt resize interlaced images - use GifInter first.");
            }
            else {
                GifQprintf("\n%s: Image %d at (%d, %d) [%dx%d]:     ",
                  PROGRAM_NAME, ++ImageNum,
                  GifFileOut->Image.Left, GifFileOut->Image.Top,
                  GifFileOut->Image.Width, GifFileOut->Image.Height);

                for (i = GifFileIn->Image.Height, y = 0.0, last_iy = -1;
                   i-- > 0;
                   y += YScale) {
                  if (DGifGetLine(GifFileIn, LineIn,
                              GifFileIn->Image.Width) == GIF_ERROR)
                      QuitGifError(GifFileIn, GifFileOut);

                  iy = (int) y;
                  if (last_iy < iy && last_iy < YSize) {
                      ResizeLine(LineIn, LineOut,
                               GifFileIn->Image.Width, GifFileOut->Image.Width);

                      for (;
                         last_iy < iy && last_iy < GifFileOut->Image.Height - 1;
                         last_iy++) {
                        GifQprintf("\b\b\b\b%-4d", last_iy + 1);
                        if (EGifPutLine(GifFileOut, LineOut,
                                    GifFileOut->Image.Width) ==
                                                    GIF_ERROR)
                            QuitGifError(GifFileIn, GifFileOut);
                      }
                  }
                }

                /* If scale is not dividable - dump last lines: */
                while (++last_iy < GifFileOut->Image.Height) {
                  GifQprintf("\b\b\b\b%-4d", last_iy);
                  if (EGifPutLine(GifFileOut, LineOut,
                              GifFileOut->Image.Width) == GIF_ERROR)
                      QuitGifError(GifFileIn, GifFileOut);
                }
            }
            break;
          case EXTENSION_RECORD_TYPE:
            /* Skip any extension blocks in file: */
            if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == GIF_ERROR)
                QuitGifError(GifFileIn, GifFileOut);
            if (EGifPutExtension(GifFileOut, ExtCode, Extension[0],
                                          Extension) == GIF_ERROR)
                QuitGifError(GifFileIn, GifFileOut);

            /* No support to more than one extension blocks, so discard: */
            while (Extension != NULL) {
                if (DGifGetExtensionNext(GifFileIn, &Extension) == GIF_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) == GIF_ERROR)
      QuitGifError(GifFileIn, GifFileOut);
    if (EGifCloseFile(GifFileOut) == GIF_ERROR)
      QuitGifError(GifFileIn, GifFileOut);

    free(LineOut);
    free(LineIn);

    return 0;
}

/******************************************************************************
* Line resizing routine - scale given lines as follows:                       *
* Scale (by pixel duplication/elimination) from InLineLen to OutLineLen.      *
******************************************************************************/
static void ResizeLine(GifRowType LineIn, GifRowType LineOut,
                  int InLineLen, int OutLineLen)
{
    int i, ix, last_ix;
    double x;

    OutLineLen--;

    for (i = InLineLen, x = 0.0, last_ix = -1;
       i-- > 0;
       x += XScale, LineIn++)
    {
      ix = (int) x;
      for (; last_ix < ix && last_ix < OutLineLen; last_ix++)
          *LineOut++ = *LineIn;
    }

    /* Make sure the line is complete. */
    for (LineIn--; last_ix < OutLineLen; last_ix++)
      *LineOut++ = *LineIn;
}

/******************************************************************************
* 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(EXIT_FAILURE);
}

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