/*****************************************************************************
*   "Gif-Lib" - Yet another gif library.				     *
*									     *
* Written by:  Gershon Elber			IBM PC Ver 0.1,	Jul. 1989    *
******************************************************************************
* Program to create histogram of the colors used by the given GIF file.      *
* Dumps out GIF file of constants size GIF_WIDTH by GIF_HEIGHT.		     *
* Options:								     *
* -t : Dump out text instead of GIF - #Colors lines, each with #appearances. *
* -i W H : size of GIF image to generate. Colors of input GIF file are	     *
*      spread homogeneously along Height, which better by dividable by the   *
*      number of colors in input image.					     *
* -n n : select image number to generate histogram to (1 by default).	     *
* -b : strip off background color count.				     *
* -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	"GifHisto"
#define VERSION		"á Version 1.0, "

#define DEFAULT_HISTO_WIDTH	100	       /* Histogram image diemnsions */
#define DEFAULT_HISTO_HEIGHT	256
#define HISTO_BITS_PER_PIXEL	2	 /* Size of bitmap for histogram GIF */

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
	" t%- s%-Width|Height!d!d n%-ImageNumber!d b%- h%- GifFile!*s";
static char
    *ProgramName;
static int
    ImageWidth = DEFAULT_HISTO_WIDTH,
    ImageHeight = DEFAULT_HISTO_HEIGHT,
    ImageN = 1;
static GifColorType
    HistoColorMap[] = {			 /* Constant bit map for histograms: */
	{ 0, 0, 0 },
	{ 255,   0,   0 },
	{   0, 255,   0 },
	{   0,   0, 255 }
    };

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, Size, Error, NumFiles, ExtCode, CodeSize, NumColors, Color,
	Count, ImageNum = 0, TextFlag = FALSE, SizeFlag = FALSE,
	ImageNFlag = FALSE, BackGroundFlag = FALSE, HelpFlag = FALSE;
    long Scaler, Histogram[256];
    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,
		&TextFlag, &SizeFlag, &ImageWidth, &ImageHeight,
		&ImageNFlag, &ImageN, &BackGroundFlag,
		&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);
    }

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

    for (i=0; i<256; i++) Histogram[i] = 0;		  /* Reset counters. */

    /* 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 (GifFileIn -> IColorMap)
		    NumColors = (1 << GifFileIn -> IBitsPerPixel);
		else
		if (GifFileIn -> SColorMap)
		    NumColors = (1 << GifFileIn -> SBitsPerPixel);
		else EXIT("Neither Screen nor Image color map exists\n");

		if ((ImageHeight / NumColors) * NumColors != ImageHeight)
		    EXIT("Image height specified not dividable by #colors\n");

		if (++ImageNum == ImageN) {
		    /* This is the image we should make histogram for:       */
		    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);

		    for (i=0; i<GifFileIn -> IHeight; i++) {
			if (DGifGetLine(GifFileIn, Line, GifFileIn -> IWidth)
			    == ERROR)
			    QuitGifError(GifFileIn, GifFileOut);
			for (j=0; j<GifFileIn -> IWidth; j++)
			    Histogram[Line[j]]++;
			fprintf(stderr, "\b\b\b\b%-4d", i);
		    }

		    free((char *) Line);
		}
		else {
		    /* Skip the image: */
		    /* 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)
			QuitGifError(GifFileIn, GifFileOut);
		    while (CodeBlock != NULL)
			if (DGifGetCodeNext(GifFileIn, &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);

		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);

    /* We we requested to kill back ground count: */
    if (BackGroundFlag) Histogram[GifFileIn -> SBackGroundColor] = 0;

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


    /* We may required to dump out the histogram as text file: */
    if (TextFlag) {
	for (i=0; i<NumColors; i++) printf("%12ld  %3d\n", Histogram[i], i);
    }
    else {
	/* Open stdout for the histogram output file: */
	if ((GifFileOut = EGifOpenFileHandle(1)) == NULL)
	    QuitGifError(GifFileIn, GifFileOut);

	/* Dump out screen descriptor to fit histogram dimensions: */
	if (EGifPutScreenDesc(GifFileOut,
	    ImageWidth, ImageHeight, HISTO_BITS_PER_PIXEL, 0,
	    HISTO_BITS_PER_PIXEL, HistoColorMap) == ERROR)
		QuitGifError(GifFileIn, GifFileOut);

	/* Dump out image descriptor to fit histogram dimensions: */
	if (EGifPutImageDesc(GifFileOut,
	    0, 0, ImageWidth, ImageHeight,
	    FALSE, HISTO_BITS_PER_PIXEL, NULL) == ERROR)
		QuitGifError(GifFileIn, GifFileOut);

	/* Prepare scan line for histogram file, and find scaler to scale    */
	/* histogram to be between 0 and ImageWidth:			     */
	Line = (RowType) malloc(ImageWidth * sizeof(PixelType));
	for (Scaler=0, i=0; i<NumColors; i++) if (Histogram[i] > Scaler)
	    Scaler = Histogram[i];
	Scaler /= ImageWidth;
	if (Scaler == 0) Scaler = 1;   /* In case maximum is less than width */

	/* Dump out the image itself: */
	for (Count=ImageHeight, i=0, Color=1; i<NumColors; i++) {
	    if ((Size = Histogram[i] / Scaler) > ImageWidth) Size = ImageWidth;
	    for (j=0; j<Size; j++)
		Line[j] = Color;
	    for (j=Size; j<ImageWidth; j++)
		Line[j] = GifFileOut -> SBackGroundColor;

	    /* Move to next color: */
	    if (++Color >= (1 << HISTO_BITS_PER_PIXEL)) Color = 1;

	    /* Dump this histogram entry as many times as required: */
	    for (j=0; j<ImageHeight / NumColors; j++) {
		if (EGifPutLine(GifFileOut, Line, ImageWidth) == ERROR)
		    QuitGifError(GifFileIn, GifFileOut);
		fprintf(stderr, "\b\b\b\b%-4d", Count--);
	    }
	}

	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);
}