egif_lib.c

1. 8623L平台

        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }
    GifFile->Image.Left = Left;
    GifFile->Image.Top = Top;
    GifFile->Image.Width = Width;
    GifFile->Image.Height = Height;
    GifFile->Image.Interlace = Interlace;
    if (ColorMap) {
        GifFile->Image.ColorMap = MakeMapObject(ColorMap->ColorCount,
                                                ColorMap->Colors);
        if (GifFile->Image.ColorMap == NULL) {
            _GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
            return GIF_ERROR;
        }
    } else {
        GifFile->Image.ColorMap = NULL;
    }

    /* Put the image descriptor into the file: */
    Buf[0] = ',';    /* Image seperator character. */
#ifndef DEBUG_NO_PREFIX
    WRITE(GifFile, Buf, 1);
#endif /* DEBUG_NO_PREFIX */
    EGifPutWord(Left, GifFile);
    EGifPutWord(Top, GifFile);
    EGifPutWord(Width, GifFile);
    EGifPutWord(Height, GifFile);
    Buf[0] = (ColorMap ? 0x80 : 0x00) |
       (Interlace ? 0x40 : 0x00) |
       (ColorMap ? ColorMap->BitsPerPixel - 1 : 0);
#ifndef DEBUG_NO_PREFIX
    WRITE(GifFile, Buf, 1);
#endif /* DEBUG_NO_PREFIX */

    /* If we have Global color map - dump it also: */
#ifndef DEBUG_NO_PREFIX
    if (ColorMap != NULL)
        for (i = 0; i < ColorMap->ColorCount; i++) {
            /* Put the ColorMap out also: */
            Buf[0] = ColorMap->Colors[i].Red;
            Buf[1] = ColorMap->Colors[i].Green;
            Buf[2] = ColorMap->Colors[i].Blue;
            if (WRITE(GifFile, Buf, 3) != 3) {
                _GifError = E_GIF_ERR_WRITE_FAILED;
                return GIF_ERROR;
            }
        }
#endif /* DEBUG_NO_PREFIX */
    if (GifFile->SColorMap == NULL && GifFile->Image.ColorMap == NULL) {
        _GifError = E_GIF_ERR_NO_COLOR_MAP;
        return GIF_ERROR;
    }

    /* Mark this file as has screen descriptor: */
    Private->FileState |= FILE_STATE_IMAGE;
    Private->PixelCount = (long)Width *(long)Height;

    EGifSetupCompress(GifFile);    /* Reset compress algorithm parameters. */

    return GIF_OK;
}

/******************************************************************************
 * Put one full scanned line (Line) of length LineLen into GIF file.
 *****************************************************************************/
int
EGifPutLine(GifFileType * GifFile,
            GifPixelType * Line,
            int LineLen) {

    int i;
    GifPixelType Mask;
    GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    if (!LineLen)
        LineLen = GifFile->Image.Width;
    if (Private->PixelCount < (unsigned)LineLen) {
        _GifError = E_GIF_ERR_DATA_TOO_BIG;
        return GIF_ERROR;
    }
    Private->PixelCount -= LineLen;

    /* Make sure the codes are not out of bit range, as we might generate
     * wrong code (because of overflow when we combine them) in this case: */
    Mask = CodeMask[Private->BitsPerPixel];
    for (i = 0; i < LineLen; i++)
        Line[i] &= Mask;

    return EGifCompressLine(GifFile, Line, LineLen);
}

/******************************************************************************
 * Put one pixel (Pixel) into GIF file.
 *****************************************************************************/
int
EGifPutPixel(GifFileType * GifFile,
             GifPixelType Pixel) {

    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    if (Private->PixelCount == 0) {
        _GifError = E_GIF_ERR_DATA_TOO_BIG;
        return GIF_ERROR;
    }
    --Private->PixelCount;

    /* Make sure the code is not out of bit range, as we might generate
     * wrong code (because of overflow when we combine them) in this case: */
    Pixel &= CodeMask[Private->BitsPerPixel];

    return EGifCompressLine(GifFile, &Pixel, 1);
}

/******************************************************************************
 * Put a comment into GIF file using the GIF89 comment extension block.
 *****************************************************************************/
int
EGifPutComment(GifFileType * GifFile,
               const char *Comment) {
  
    unsigned int length = strlen(Comment);
    char *buf;

    length = strlen(Comment);
    if (length <= 255) {
        return EGifPutExtension(GifFile, COMMENT_EXT_FUNC_CODE,
                                length, Comment);
    } else {
        buf = (char *)Comment;
        if (EGifPutExtensionFirst(GifFile, COMMENT_EXT_FUNC_CODE, 255, buf)
                == GIF_ERROR) {
            return GIF_ERROR;
        }
        length -= 255;
        buf = buf + 255;

        /* Break the comment into 255 byte sub blocks */
        while (length > 255) {
            if (EGifPutExtensionNext(GifFile, 0, 255, buf) == GIF_ERROR) {
                return GIF_ERROR;
            }
            buf = buf + 255;
            length -= 255;
        }
        /* Output any partial block and the clear code. */
        if (length > 0) {
            if (EGifPutExtensionLast(GifFile, 0, length, buf) == GIF_ERROR) {
                return GIF_ERROR;
            }
        } else {
            if (EGifPutExtensionLast(GifFile, 0, 0, NULL) == GIF_ERROR) {
                return GIF_ERROR;
            }
        }
    }
    return GIF_OK;
}

/******************************************************************************
 * Put a first extension block (see GIF manual) into gif file.  Here more
 * extensions can be dumped using EGifPutExtensionNext until
 * EGifPutExtensionLast is invoked.
 *****************************************************************************/
int
EGifPutExtensionFirst(GifFileType * GifFile,
                      int ExtCode,
                      int ExtLen,
                      const VoidPtr Extension) {

    GifByteType Buf[3];
    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    if (ExtCode == 0) {
        WRITE(GifFile, (GifByteType *)&ExtLen, 1);
    } else {
        Buf[0] = '!';
        Buf[1] = ExtCode;
        Buf[2] = ExtLen;
        WRITE(GifFile, Buf, 3);
    }

    WRITE(GifFile, Extension, ExtLen);

    return GIF_OK;
}

/******************************************************************************
 * Put a middle extension block (see GIF manual) into gif file.
 *****************************************************************************/
int
EGifPutExtensionNext(GifFileType * GifFile,
                     int ExtCode,
                     int ExtLen,
                     const VoidPtr Extension) {

    GifByteType Buf;
    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    Buf = ExtLen;
    WRITE(GifFile, &Buf, 1);
    WRITE(GifFile, Extension, ExtLen);

    return GIF_OK;
}

/******************************************************************************
 * Put a last extension block (see GIF manual) into gif file.
 *****************************************************************************/
int
EGifPutExtensionLast(GifFileType * GifFile,
                     int ExtCode,
                     int ExtLen,
                     const VoidPtr Extension) {

    GifByteType Buf;
    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    /* If we are given an extension sub-block output it now. */
    if (ExtLen > 0) {
        Buf = ExtLen;
        WRITE(GifFile, &Buf, 1);
        WRITE(GifFile, Extension, ExtLen);
    }

    /* Write the block terminator */
    Buf = 0;
    WRITE(GifFile, &Buf, 1);

    return GIF_OK;
}

/******************************************************************************
 * Put an extension block (see GIF manual) into gif file.
 * Warning: This function is only useful for Extension blocks that have at
 * most one subblock.  Extensions with more than one subblock need to use the
 * EGifPutExtension{First,Next,Last} functions instead.
 *****************************************************************************/
int
EGifPutExtension(GifFileType * GifFile,
                 int ExtCode,
                 int ExtLen,
                 const VoidPtr Extension) {

    GifByteType Buf[3];
    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    if (ExtCode == 0)
        WRITE(GifFile, (GifByteType *)&ExtLen, 1);
    else {
        Buf[0] = '!';       /* Extension Introducer 0x21 */
        Buf[1] = ExtCode;   /* Extension Label */
        Buf[2] = ExtLen;    /* Extension length */
        WRITE(GifFile, Buf, 3);
    }
    WRITE(GifFile, Extension, ExtLen);
    Buf[0] = 0;
    WRITE(GifFile, Buf, 1);

    return GIF_OK;
}

/******************************************************************************
 * Put the image code in compressed form. This routine can be called if the
 * information needed to be piped out as is. Obviously this is much faster
 * than decoding and encoding again. This routine should be followed by calls
 * to EGifPutCodeNext, until NULL block is given.
 * The block should NOT be freed by the user (not dynamically allocated).
 *****************************************************************************/
int
EGifPutCode(GifFileType * GifFile,
            int CodeSize,
            const GifByteType * CodeBlock) {

    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (!IS_WRITEABLE(Private)) {
        /* This file was NOT open for writing: */
        _GifError = E_GIF_ERR_NOT_WRITEABLE;
        return GIF_ERROR;
    }

    /* No need to dump code size as Compression set up does any for us: */
    /* 
     * Buf = CodeSize;
     * if (WRITE(GifFile, &Buf, 1) != 1) {
     *      _GifError = E_GIF_ERR_WRITE_FAILED;
     *      return GIF_ERROR;
     * }
     */

    return EGifPutCodeNext(GifFile, CodeBlock);
}

/******************************************************************************
 * Continue to put the image code in compressed form. This routine should be
 * called with blocks of code as read via DGifGetCode/DGifGetCodeNext. If
 * given buffer pointer is NULL, empty block is written to mark end of code.
 *****************************************************************************/
int
EGifPutCodeNext(GifFileType * GifFile,
                const GifByteType * CodeBlock) {

    GifByteType Buf;
    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;

    if (CodeBlock != NULL) {
        if (WRITE(GifFile, CodeBlock, CodeBlock[0] + 1)
               != (unsigned)(CodeBlock[0] + 1)) {
            _GifError = E_GIF_ERR_WRITE_FAILED;
            return GIF_ERROR;
        }
    } else {
        Buf = 0;
        if (WRITE(GifFile, &Buf, 1) != 1) {
            _GifError = E_GIF_ERR_WRITE_FAILED;
            return GIF_ERROR;
        }
        Private->PixelCount = 0;    /* And local info. indicate image read. */
    }