/*****************************************************************************
*   "Gif-Lib" - Yet another gif library.				     *
*									     *
* Written by:  Gershon Elber			IBM PC Ver 0.1,	Jul. 1989    *
******************************************************************************
* Program to clip an image and dump out only portion of it.		     *
* Options:								     *
* -i left top width bottom : clipping information for first image.	     *
* -n n left top width bottom : clipping information for nth image.	     *
* -h : on line help							     *
******************************************************************************
* History:								     *
* 8 Jul 89 - Version 1.0 by Gershon Elber.				     *
*****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <alloc.h>
#include <string.h>
#include "gif_lib.h"
#include "getarg.h"

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

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
	" i%-Xmin|Ymin|Xmax|Ymax!d!d!d!d n%-n|Xmin|Ymin|Xmax|Ymax!d!d!d!d!d h%- GifFile!*s";
static char
    *ProgramName;

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, Error, NumFiles, ExtCode, CodeSize, ImageNum = 0,
	ImageFlag = FALSE, ImageNFlag = FALSE, ImageN, ImageX1, ImageY1,
	ImageX2, ImageY2, ImageWidth, HelpFlag = FALSE;
    GifRecordType RecordType;
    ByteType *Extension, *CodeBlock;
    char **FileName = NULL;
    RowType Line;
    GifFileType *GifFileIn = NULL, *GifFileOut = NULL;

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

    /* Same image dimension vars for both Image & ImageN as only one allowed */
    if ((Error = GAGetArgs(argc, argv, CtrlStr,
		&ImageFlag, &ImageX1, &ImageY1, &ImageX2, &ImageY2,
		&ImageNFlag, &ImageN, &ImageX1, &ImageY1, &ImageX2, &ImageY2,
		&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);
    }

    /* Test to make sure exactly one of ImageFlag & ImageNFlag is set: */
    if ((ImageFlag && ImageNFlag) || (!ImageFlag && !ImageNFlag)) {
	MESSAGE("Exactly one of [-i ...] && [-n ...] please\n");
	GAPrintHowTo(CtrlStr);
	exit(1);
    }
    if (ImageFlag) ImageN = 1;		     /* Its first image we are after */

    /* Make sure the first coordinates of clipping box are smaller: */
    if (ImageX1 > ImageX2) {
	i = ImageX1;
	ImageX1 = ImageX2;
	ImageX2 = i;
    }
    if (ImageY1 > ImageY2) {
	i = ImageX1;
	ImageY1 = ImageY2;
	ImageY2 = i;
    }
    ImageWidth = ImageX2 - ImageX1 + 1;            /* Width of clipped image */

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

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

    /* And dump out exactly same screen information: */
    if (EGifPutScreenDesc(GifFileOut,
	GifFileIn -> SWidth, GifFileIn -> SHeight,
	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);
		if (++ImageNum == ImageN) {
		    /* We can handle only non interlaced images here: */
		    if (GifFileIn -> IInterlace)
			EXIT("Image to clip is interlaced - use GifInter first\n");

		    /* This is the image we should clip - test sizes and     */
		    /* dump out new clipped screen descriptor if o.k.	     */
		    if (GifFileIn -> IWidth <= ImageX2 ||
			GifFileIn -> IHeight <= ImageY2)
			EXIT("Image is smaller than given clip dimensions\n");

		    /* Put the image descriptor to out file: */
		    if (EGifPutImageDesc(GifFileOut,
			GifFileIn -> ILeft, GifFileIn -> ITop,
			ImageWidth, ImageY2 - ImageY1 + 1,
			FALSE, GifFileIn -> IBitsPerPixel,
			GifFileIn -> IColorMap) == ERROR)
			QuitGifError(GifFileIn, GifFileOut);

		    /* o.k. - read the image and clip it: */
		    Line = (RowType) malloc(GifFileIn -> IWidth *
							sizeof(PixelType));
		    fprintf(stderr, "\n%s: Image %d at (%d, %d) [%dx%d]:     ",
			ProgramName, ImageNum,
			GifFileIn -> ILeft, GifFileIn -> ITop,
			GifFileIn -> IWidth, GifFileIn -> IHeight);

		    /* Skip lines below ImageY1: */
		    for (i=0; i<ImageY1; i++) {
			if (DGifGetLine(GifFileIn, Line, GifFileIn -> IWidth)
			    == ERROR)
			    QuitGifError(GifFileIn, GifFileOut);
			fprintf(stderr, "\b\b\b\b%-4d", i);
		    }

		    /* Clip the lines from ImageY1 to ImageY2 (to X1 - X2): */
		    for (i=ImageY1; i<=ImageY2; i++) {
			if (DGifGetLine(GifFileIn, Line, GifFileIn -> IWidth)
			    == ERROR)
			    QuitGifError(GifFileIn, GifFileOut);
			if (EGifPutLine(GifFileOut, &Line[ImageX1],
							ImageWidth) == ERROR)
			    QuitGifError(GifFileIn, GifFileOut);
			fprintf(stderr, "\b\b\b\b%-4d", i);
		    }

		    /* Skip lines above ImageY2: */
		    for (i=ImageY2+1; i<GifFileIn -> IHeight; i++) {
			if (DGifGetLine(GifFileIn, Line, GifFileIn -> IWidth)
			    == ERROR)
			    QuitGifError(GifFileIn, GifFileOut);
			fprintf(stderr, "\b\b\b\b%-4d", i);
		    }

		    free((char *) Line);
		}
		else {
		    /* Copy the image as is (we dont modify this one): */
		    if (EGifPutImageDesc(GifFileOut,
			GifFileIn -> ILeft, GifFileIn -> ITop,
			GifFileIn -> IWidth, GifFileIn -> IHeight,
			GifFileIn -> IInterlace, GifFileIn -> IBitsPerPixel,
			GifFileIn -> IColorMap) == ERROR)
			QuitGifError(GifFileIn, GifFileOut);

		    /* Now read image itself in decoded form as we dont      */
		    /* really care what is there, and this is much faster.   */
		    if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == ERROR
		     || EGifPutCode(GifFileOut, CodeSize, CodeBlock) == ERROR)
			QuitGifError(GifFileIn, GifFileOut);
		    while (CodeBlock != NULL)
			if (DGifGetCodeNext(GifFileIn, &CodeBlock) == ERROR ||
			    EGifPutCodeNext(GifFileOut, CodeBlock) == 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);
}

/******************************************************************************
* 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);
}