root/util/gif2rgb.c

DEFINITIONS

1. LoadRGB
2. SaveGif
3. RGB2GIF
4. DumpScreen2RGB
5. GIF2RGB
6. main

/*****************************************************************************

gif2rgb - convert GIF to 24-bit RGB pixel triples or vice-versa

*****************************************************************************/

/***************************************************************************

Toshio Kuratomi had written this in a comment about the rgb2gif code:

  Besides fixing bugs, what's really needed is for someone to work out how to
  calculate a colormap for writing GIFs from rgb sources.  Right now, an rgb
  source that has only two colors (b/w) is being converted into an 8 bit GIF....
  Which is horrendously wasteful without compression.

I (ESR) took this off the main to-do list in 2012 because I don't think
the GIFLIB project actually needs to be in the converters-and-tools business.
Plenty of hackers do that; our jub is to supply stable library capability
with our utilities mainly interesting as test tools.

***************************************************************************/

#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdbool.h>
#include <fcntl.h>

#ifdef _WIN32
#include <io.h>
#endif /* _WIN32 */

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

#define PROGRAM_NAME    "gif2rgb"

static char
    *VersionStr =
        PROGRAM_NAME
        VERSION_COOKIE
        "       Gershon Elber,  "
        __DATE__ ",   " __TIME__ "\n"
        "(C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr =
        PROGRAM_NAME
        " v%- c%-#Colors!d s%-Width|Height!d!d 1%- o%-OutFileName!s h%- GifFile!*s";

static void LoadRGB(char *FileName,
                    int OneFileFlag,
                    GifByteType **RedBuffer,
                    GifByteType **GreenBuffer,
                    GifByteType **BlueBuffer,
                    int Width, int Height);
static void SaveGif(GifByteType *OutputBuffer,
                    int Width, int Height, 
                    int ExpColorMapSize, ColorMapObject *OutputColorMap);

/******************************************************************************
 Load RGB file into internal frame buffer.
******************************************************************************/
static void LoadRGB(char *FileName,
                    int OneFileFlag,
                    GifByteType **RedBuffer,
                    GifByteType **GreenBuffer,
                    GifByteType **BlueBuffer,
                    int Width, int Height)
{
    int i;
    unsigned long Size;
    GifByteType *RedP, *GreenP, *BlueP;
    FILE *rgbfp[3];

    Size = ((long) Width) * Height * sizeof(GifByteType);

    if ((*RedBuffer = (GifByteType *) malloc((unsigned int) Size)) == NULL ||
        (*GreenBuffer = (GifByteType *) malloc((unsigned int) Size)) == NULL ||
        (*BlueBuffer = (GifByteType *) malloc((unsigned int) Size)) == NULL)
        GIF_EXIT("Failed to allocate memory required, aborted.");

    RedP = *RedBuffer;
    GreenP = *GreenBuffer;
    BlueP = *BlueBuffer;

    if (FileName != NULL) {
        if (OneFileFlag) {
            if ((rgbfp[0] = fopen(FileName, "rb")) == NULL)
                GIF_EXIT("Can't open input file name.");
        }
        else {
            static char *Postfixes[] = { ".R", ".G", ".B" };
            char OneFileName[80];

            for (i = 0; i < 3; i++) {
                strncpy(OneFileName, FileName, sizeof(OneFileName)-1);
                /* cppcheck-suppress uninitstring */
                strncat(OneFileName, Postfixes[i], 
                        sizeof(OneFileName) - 1 - strlen(OneFileName));

                if ((rgbfp[i] = fopen(OneFileName, "rb")) == NULL)
                    GIF_EXIT("Can't open input file name.");
            }
        }
    }
    else {
        OneFileFlag = true;

#ifdef _WIN32
        _setmode(0, O_BINARY);
#endif /* _WIN32 */

        rgbfp[0] = stdin;
    }

    GifQprintf("\n%s: RGB image:     ", PROGRAM_NAME);

    if (OneFileFlag) {
        GifByteType *Buffer, *BufferP;

        if ((Buffer = (GifByteType *) malloc(Width * 3)) == NULL)
            GIF_EXIT("Failed to allocate memory required, aborted.");

        for (i = 0; i < Height; i++) {
            int j;
            GifQprintf("\b\b\b\b%-4d", i);
            if (fread(Buffer, Width * 3, 1, rgbfp[0]) != 1)
                GIF_EXIT("Input file(s) terminated prematurly.");
            for (j = 0, BufferP = Buffer; j < Width; j++) {
                *RedP++ = *BufferP++;
                *GreenP++ = *BufferP++;
                *BlueP++ = *BufferP++;
            }
        }

        free((char *) Buffer);
        fclose(rgbfp[0]);
    }
    else {
        for (i = 0; i < Height; i++) {
            GifQprintf("\b\b\b\b%-4d", i);
            if (fread(RedP, Width, 1, rgbfp[0]) != 1 ||
                fread(GreenP, Width, 1, rgbfp[1]) != 1 ||
                fread(BlueP, Width, 1, rgbfp[2]) != 1)
                GIF_EXIT("Input file(s) terminated prematurly.");
            RedP += Width;
            GreenP += Width;
            BlueP += Width;
        }

        fclose(rgbfp[0]);
        // cppcheck-suppress useClosedFile
        fclose(rgbfp[1]);
        // cppcheck-suppress useClosedFile
        fclose(rgbfp[2]);
    }
}

/******************************************************************************
 Save the GIF resulting image.
******************************************************************************/
static void SaveGif(GifByteType *OutputBuffer,
                    int Width, int Height,
                    int ExpColorMapSize, ColorMapObject *OutputColorMap)
{
    int i, Error;
    GifFileType *GifFile;
    GifByteType *Ptr = OutputBuffer;

    /* Open stdout for the output file: */
    if ((GifFile = EGifOpenFileHandle(1, &Error)) == NULL) {
        PrintGifError(Error);
        exit(EXIT_FAILURE);
    }

    if (EGifPutScreenDesc(GifFile,
                          Width, Height, ExpColorMapSize, 0,
                          OutputColorMap) == GIF_ERROR ||
        EGifPutImageDesc(GifFile,
                         0, 0, Width, Height, false, NULL) ==
                                                                     GIF_ERROR)
        PrintGifError(Error);
        if (GifFile != NULL) {
            EGifCloseFile(GifFile, NULL);
        }
        exit(EXIT_FAILURE);

    GifQprintf("\n%s: Image 1 at (%d, %d) [%dx%d]:     ",
               PROGRAM_NAME, GifFile->Image.Left, GifFile->Image.Top,
               GifFile->Image.Width, GifFile->Image.Height);

    for (i = 0; i < Height; i++) {
        if (EGifPutLine(GifFile, Ptr, Width) == GIF_ERROR)
        {
            if (GifFile != NULL) {
                EGifCloseFile(GifFile, NULL);
            }
            exit(EXIT_FAILURE);
        }
        GifQprintf("\b\b\b\b%-4d", Height - i - 1);

        Ptr += Width;
    }

    if (EGifCloseFile(GifFile, &Error) == GIF_ERROR)
        PrintGifError(Error);
        if (GifFile != NULL) {
            EGifCloseFile(GifFile, NULL);
        }
        exit(EXIT_FAILURE);
}

/******************************************************************************
 Close output file (if open), and exit.
******************************************************************************/
static void RGB2GIF(bool OneFileFlag, int NumFiles, char *FileName,
                    int ExpNumOfColors, int Width, int Height)
{
    int ColorMapSize;

    GifByteType *RedBuffer = NULL, *GreenBuffer = NULL, *BlueBuffer = NULL,
        *OutputBuffer = NULL;
    ColorMapObject *OutputColorMap = NULL;

    ColorMapSize = 1 << ExpNumOfColors;

    if (NumFiles == 1) {
        LoadRGB(FileName, OneFileFlag,
                &RedBuffer, &GreenBuffer, &BlueBuffer, Width, Height);
    }
    else {
        LoadRGB(NULL, OneFileFlag,
                &RedBuffer, &GreenBuffer, &BlueBuffer, Width, Height);
    }

    if ((OutputColorMap = GifMakeMapObject(ColorMapSize, NULL)) == NULL ||
        (OutputBuffer = (GifByteType *) malloc(Width * Height *
                                            sizeof(GifByteType))) == NULL)
        GIF_EXIT("Failed to allocate memory required, aborted.");

    if (GifQuantizeBuffer(Width, Height, &ColorMapSize,
                       RedBuffer, GreenBuffer, BlueBuffer,
                       OutputBuffer, OutputColorMap->Colors) == GIF_ERROR)
        exit(EXIT_FAILURE);
    free((char *) RedBuffer);
    free((char *) GreenBuffer);
    free((char *) BlueBuffer);

    SaveGif(OutputBuffer, Width, Height, ExpNumOfColors, OutputColorMap);
}

/******************************************************************************
 The real screen dumping routine.
******************************************************************************/
static void DumpScreen2RGB(char *FileName, int OneFileFlag,
                           ColorMapObject *ColorMap,
                           GifRowType *ScreenBuffer,
                           int ScreenWidth, int ScreenHeight)
{
    int i, j;
    GifRowType GifRow;
    GifColorType *ColorMapEntry;
    FILE *rgbfp[3];

    if (FileName != NULL) {
        if (OneFileFlag) {
            if ((rgbfp[0] = fopen(FileName, "wb")) == NULL)
            GIF_EXIT("Can't open input file name.");
        } else {
            static char *Postfixes[] = { ".R", ".G", ".B" };
            char OneFileName[80];

            for (i = 0; i < 3; i++) {
                strncpy(OneFileName, FileName, sizeof(OneFileName)-1);
                /* cppcheck-suppress uninitstring */
                strncat(OneFileName, Postfixes[i], 
                        sizeof(OneFileName) - 1 - strlen(OneFileName));
    
                if ((rgbfp[i] = fopen(OneFileName, "wb")) == NULL) {
                    GIF_EXIT("Can't open input file name.");
                }
            }
        }
    } else {
        OneFileFlag = true;

#ifdef _WIN32
        _setmode(1, O_BINARY);
#endif /* _WIN32 */
        
        rgbfp[0] = stdout;
    }

    if (OneFileFlag) {
        unsigned char *Buffer, *BufferP;

        if ((Buffer = (unsigned char *) malloc(ScreenWidth * 3)) == NULL)
            GIF_EXIT("Failed to allocate memory required, aborted.");
        for (i = 0; i < ScreenHeight; i++) {
            GifRow = ScreenBuffer[i];
            GifQprintf("\b\b\b\b%-4d", ScreenHeight - i);
            for (j = 0, BufferP = Buffer; j < ScreenWidth; j++) {
                ColorMapEntry = &ColorMap->Colors[GifRow[j]];
                *BufferP++ = ColorMapEntry->Red;
                *BufferP++ = ColorMapEntry->Green;
                *BufferP++ = ColorMapEntry->Blue;
            }
            if (fwrite(Buffer, ScreenWidth * 3, 1, rgbfp[0]) != 1)
                GIF_EXIT("Write to file(s) failed.");
        }

        free((char *) Buffer);
        fclose(rgbfp[0]);
    } else {
        unsigned char *Buffers[3];

        if ((Buffers[0] = (unsigned char *) malloc(ScreenWidth)) == NULL ||
            (Buffers[1] = (unsigned char *) malloc(ScreenWidth)) == NULL ||
            (Buffers[2] = (unsigned char *) malloc(ScreenWidth)) == NULL)
            GIF_EXIT("Failed to allocate memory required, aborted.");

        for (i = 0; i < ScreenHeight; i++) {
            GifRow = ScreenBuffer[i];
            GifQprintf("\b\b\b\b%-4d", ScreenHeight - i);
            for (j = 0; j < ScreenWidth; j++) {
                ColorMapEntry = &ColorMap->Colors[GifRow[j]];
                Buffers[0][j] = ColorMapEntry->Red;
                Buffers[1][j] = ColorMapEntry->Green;
                Buffers[2][j] = ColorMapEntry->Blue;
            }
            if (fwrite(Buffers[0], ScreenWidth, 1, rgbfp[0]) != 1 ||
                fwrite(Buffers[1], ScreenWidth, 1, rgbfp[1]) != 1 ||
                fwrite(Buffers[2], ScreenWidth, 1, rgbfp[2]) != 1)
                GIF_EXIT("Write to file(s) failed.");
        }

        free((char *) Buffers[0]);
        free((char *) Buffers[1]);
        free((char *) Buffers[2]);
        fclose(rgbfp[0]);
        // cppcheck-suppress useClosedFile
        fclose(rgbfp[1]);
        // cppcheck-suppress useClosedFile
        fclose(rgbfp[2]);
    }
}

static void GIF2RGB(int NumFiles, char *FileName, 
                    bool OneFileFlag, 
                    char *OutFileName)
{
    int i, j, Size, Row, Col, Width, Height, ExtCode, Count;
    GifRecordType RecordType;
    GifByteType *Extension;
    GifRowType *ScreenBuffer;
    GifFileType *GifFile;
    int
        InterlacedOffset[] = { 0, 4, 2, 1 }, /* The way Interlaced image should. */
        InterlacedJumps[] = { 8, 8, 4, 2 };    /* be read - offsets and jumps... */
    int ImageNum = 0;
    ColorMapObject *ColorMap;
    int Error;

    if (NumFiles == 1) {
        int Error;
        if ((GifFile = DGifOpenFileName(FileName, &Error)) == NULL) {
            PrintGifError(Error);
            exit(EXIT_FAILURE);
        }
    }
    else {
        int Error;
        /* Use stdin instead: */
        if ((GifFile = DGifOpenFileHandle(0, &Error)) == NULL) {
            PrintGifError(Error);
            exit(EXIT_FAILURE);
        }
    }

    /* 
     * Allocate the screen as vector of column of rows. Note this
     * screen is device independent - it's the screen defined by the
     * GIF file parameters.
     */
    if ((ScreenBuffer = (GifRowType *)
        malloc(GifFile->SHeight * sizeof(GifRowType))) == NULL)
            GIF_EXIT("Failed to allocate memory required, aborted.");

    Size = GifFile->SWidth * sizeof(GifPixelType);/* Size in bytes one row.*/
    if ((ScreenBuffer[0] = (GifRowType) malloc(Size)) == NULL) /* First row. */
        GIF_EXIT("Failed to allocate memory required, aborted.");

    for (i = 0; i < GifFile->SWidth; i++)  /* Set its color to BackGround. */
        ScreenBuffer[0][i] = GifFile->SBackGroundColor;
    for (i = 1; i < GifFile->SHeight; i++) {
        /* Allocate the other rows, and set their color to background too: */
        if ((ScreenBuffer[i] = (GifRowType) malloc(Size)) == NULL)
            GIF_EXIT("Failed to allocate memory required, aborted.");

        memcpy(ScreenBuffer[i], ScreenBuffer[0], Size);
    }

    /* Scan the content of the GIF file and load the image(s) in: */
    do {
        if (DGifGetRecordType(GifFile, &RecordType) == GIF_ERROR) {
            PrintGifError(GifFile->Error);
            exit(EXIT_FAILURE);
        }
        switch (RecordType) {
            case IMAGE_DESC_RECORD_TYPE:
                if (DGifGetImageDesc(GifFile) == GIF_ERROR) {
                    PrintGifError(GifFile->Error);
                    exit(EXIT_FAILURE);
                }
                Row = GifFile->Image.Top; /* Image Position relative to Screen. */
                Col = GifFile->Image.Left;
                Width = GifFile->Image.Width;
                Height = GifFile->Image.Height;
                GifQprintf("\n%s: Image %d at (%d, %d) [%dx%d]:     ",
                    PROGRAM_NAME, ++ImageNum, Col, Row, Width, Height);
                if (GifFile->Image.Left + GifFile->Image.Width > GifFile->SWidth ||
                   GifFile->Image.Top + GifFile->Image.Height > GifFile->SHeight) {
                    fprintf(stderr, "Image %d is not confined to screen dimension, aborted.\n",ImageNum);
                    exit(EXIT_FAILURE);
                }
                if (GifFile->Image.Interlace) {
                    /* Need to perform 4 passes on the images: */
                    for (Count = i = 0; i < 4; i++)
                        for (j = Row + InterlacedOffset[i]; j < Row + Height;
                                                 j += InterlacedJumps[i]) {
                            GifQprintf("\b\b\b\b%-4d", Count++);
                            if (DGifGetLine(GifFile, &ScreenBuffer[j][Col],
                                Width) == GIF_ERROR) {
                                PrintGifError(GifFile->Error);
                                exit(EXIT_FAILURE);
                            }
                        }
                }
                else {
                    for (i = 0; i < Height; i++) {
                        GifQprintf("\b\b\b\b%-4d", i);
                        if (DGifGetLine(GifFile, &ScreenBuffer[Row++][Col],
                                Width) == GIF_ERROR) {
                            PrintGifError(GifFile->Error);
                            exit(EXIT_FAILURE);
                        }
                    }
                }
                break;
            case EXTENSION_RECORD_TYPE:
                /* Skip any extension blocks in file: */
                if (DGifGetExtension(GifFile, &ExtCode, &Extension) == GIF_ERROR) {
                    PrintGifError(GifFile->Error);
                    exit(EXIT_FAILURE);
                }
                while (Extension != NULL) {
                    if (DGifGetExtensionNext(GifFile, &Extension) == GIF_ERROR) {
                        PrintGifError(GifFile->Error);
                        exit(EXIT_FAILURE);
                    }
                }
                break;
            case TERMINATE_RECORD_TYPE:
                break;
            default:                /* Should be trapped by DGifGetRecordType. */
                break;
        }
    } while (RecordType != TERMINATE_RECORD_TYPE);

    /* Lets dump it - set the global variables required and do it: */
    ColorMap = (GifFile->Image.ColorMap
                ? GifFile->Image.ColorMap
                : GifFile->SColorMap);
    if (ColorMap == NULL) {
        fprintf(stderr, "Gif Image does not have a colormap\n");
        exit(EXIT_FAILURE);
    }

    DumpScreen2RGB(OutFileName, OneFileFlag,
                   ColorMap,
                   ScreenBuffer, 
                   GifFile->SWidth, GifFile->SHeight);

    (void)free(ScreenBuffer);

    if (DGifCloseFile(GifFile, &Error) == GIF_ERROR) {
        PrintGifError(Error);
        exit(EXIT_FAILURE);
    }

}

/******************************************************************************
* Interpret the command line and scan the given GIF file.
******************************************************************************/
int main(int argc, char **argv)
{
    bool Error, OutFileFlag = false, ColorFlag = false, SizeFlag = false;
    int NumFiles, Width = 0, Height = 0, ExpNumOfColors = 8;
    char *OutFileName,
        **FileName = NULL;
    static bool
        OneFileFlag = false,
        HelpFlag = false;

    if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifNoisyPrint,
                &ColorFlag, &ExpNumOfColors, &SizeFlag, &Width, &Height, 
                &OneFileFlag, &OutFileFlag, &OutFileName,
                &HelpFlag, &NumFiles, &FileName)) != false ||
                (NumFiles > 1 && !HelpFlag)) {
        if (Error)
            GAPrintErrMsg(Error);
        else if (NumFiles > 1)
            GIF_MESSAGE("Error in command line parsing - one input file please.");
        GAPrintHowTo(CtrlStr);
        exit(EXIT_FAILURE);
    }

    if (HelpFlag) {
        (void)fprintf(stderr, VersionStr, GIFLIB_MAJOR, GIFLIB_MINOR);
        GAPrintHowTo(CtrlStr);
        exit(EXIT_SUCCESS);
    }
    if (!OutFileFlag) OutFileName = NULL;

    if (SizeFlag && Width > 0 && Height > 0)
        RGB2GIF(OneFileFlag, NumFiles, *FileName, 
                ExpNumOfColors, Width, Height);
    else
        GIF2RGB(NumFiles, *FileName, OneFileFlag, OutFileName);

    return 0;
}

/* end */