/*

    File:       EI_GraphicsExport.c

    Description: QuickTime graphics exporter component

    Author:     QuickTime Engineering, dts

    Copyright:  © Copyright 2003 Apple Computer, Inc. All rights reserved.

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

                ("Apple") in consideration of your agreement to the following terms, and your

                use, installation, modification or redistribution of this Apple software

                constitutes acceptance of these terms.  If you do not agree with these terms,

                please do not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following terms, and subject

                to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs

                copyrights in this original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or without

                modifications, in source and/or binary forms; provided that if you redistribute

                the Apple Software in its entirety and without modifications, you must retain

                this notice and the following text and disclaimers in all such redistributions of

                the Apple Software.  Neither the name, trademarks, service marks or logos of

                Apple Computer, Inc. may be used to endorse or promote products derived from the

                Apple Software without specific prior written permission from Apple.  Except as

                expressly stated in this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any patent rights that

                may be infringed by your derivative works or by other works in which the Apple

                Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

                COMBINATION WITH YOUR PRODUCTS.

                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

                CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

                GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

                ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION

                OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT

                (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN

                ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    Change History (most recent first):

       <1>      04/20/03    dts         first file

*/

/* Graphics exporter components provide a standard interface for exporting graphics to image

   files in a variety of formats. QuickTime selects a graphic exporter component based on the

   desired output format. A graphic image can be exported to a handle, a file, or a data reference.

   Graphics exporter components have component type 'grex' and, by convention, component subtype

   matching the Mac OS file type for the image file format. For example, the graphics exporter for

   PNG files has component subtype 'PNGf'.

   QuickTime provides a base graphics export component which provides abstractions that greatly

   simplify the work of format-specific graphics exporter components, while offering applications

   a rich interface. 

   Format-specific graphics exporters, are relatively simple components. When a format-specific exporter

   is opened, it opens and targets an instance of the base graphics exporter.  Subsequently, it delegates

   most of its calls to the base exporter instance. See the following URL for an illustrated example:

        < http://developer.apple.com/techpubs/quicktime/qtdevdocs/REF/refExporter.15.htm >

   The base exporter communicates with data handler components to write image file data. If necessary, it

   calls the Image Compression Manager to perform compression operations.

   There are three modes that format-specific exporters can operate in:

        Transcode - Data is transferred from one image file to another without decompressing and recompressing. 

                   (The data may be modified along the way, if appropriate.)

        Using a Compressor - The graphics exporter provides an atom container identifying which compressor to use,

                             and any settings to be passed to that compressor.

        Standalone Export - The graphics exporter component does all the work itself, without using an image compressor.

    When an application calls GraphicsExportDoExport, the base exporter asks the following questions:

        Can QuickTime transcode? 

        It calls the format-specific exporter's GraphicsExportCanTranscode function. If the answer is yes,

        it calls the exporter's GraphicsExportDoTranscode function. 

    Otherwise, 

        Can QuickTime use a compressor? 

        It calls the format-specific exporter's GraphicsExportCanUseCompressor function. If the answer is yes,

        it calls the Image Compression Manager to compress using the compressor and parameters specified in the

        atom container. This is done in the base exporter's GraphicsExportDoUseCompressor function. (Usually the

        format-specific exporter does not need to override this function and should simply delegate it. If the

        format-specific exporter's format is a container format [such as a PICT or QuickTime Image], it can override

        and delegate this in order to encapsulate the compressed data in the container format.) 

    Otherwise, 

        QuickTime must perform a standalone export.

        If neither transcoding nor compressing is appropriate, it calls the format-specific exporter's

        GraphicsExportDoStandaloneExport function.

    Graphics Exporter Components Reference:

        < http://developer.apple.com/techpubs/quicktime/qtdevdocs/REF/refExporter.1.htm >

*/

#if TARGET_OS_WIN32

    #include "EIComponentWindowsPrefix.h"

#endif

#if __MACH__

    #include <Carbon/Carbon.h>

    #include <QuickTime/QuickTime.h>

#else

    #include <ConditionalMacros.h>

    #include <ImageCompression.h>

    #include <QDOffscreen.h>

    #include <Endian.h>

    #include <StdDef.h> // for offsetof

#endif

#include "EI_Image.h"

#include "EI_GraphicsExportVersion.h"

#pragma mark- Data Structures

// Data structures

#if PRAGMA_STRUCT_ALIGN

    #pragma options align=packed

#elif PRAGMA_STRUCT_PACKPUSH

    #pragma pack(push, 1)

#elif PRAGMA_STRUCT_PACK

    #pragma pack(1)

#endif

typedef struct {

    UInt8   red;

    UInt8   green;

    UInt8   blue;

} PackedColor;

typedef struct {

    UInt8   opcode;

    UInt8   pixelData[1];

} RLE8Packet;

typedef struct {

    UInt8   opcode;

    UInt16  pixelData[1];

} RLE16Packet;

typedef struct {

    UInt8   opcode;

    UInt32  pixelData[1];

} RLE32Packet;

#if PRAGMA_STRUCT_ALIGN

    #pragma options align=reset

#elif PRAGMA_STRUCT_PACKPUSH

    #pragma pack(pop)

#elif PRAGMA_STRUCT_PACK

    #pragma pack()

#endif

typedef struct {

    ComponentInstance self;

    ComponentInstance parent;

    ComponentInstance delegateComponent;

} EI_GraphicsExportGlobalsRecord, *EI_GraphicsExportGlobals;

#pragma mark- Internal Prototypes

// Prototypes

static ComponentResult WriteImageFrameHeader(GraphicsExportComponent ci, CTabHandle cTabHdl, short width, short height, short depth, Size compressBufferSize);

static ComponentResult WriteColorTable(GraphicsExportComponent ci , CTabHandle cTabHdl);

static OSErr CompressRLE(Ptr baseAddr, long rowBytes, short depth, short width, short height, Ptr compressBuffer, Size *compressBufferSizePtr);

static void  CompressRLE8(UInt8 *srcPtr, Size srcSize, Ptr compressBuffer, Size *compressBufferSizePtr);

static void  CompressRLE16(UInt16 *srcPtr, Size srcSize, Ptr compressBuffer, Size *compressBufferSizePtr);

static void  CompressRLE32(UInt32 *srcPtr, Size srcSize, Ptr compressBuffer, Size *compressBufferSizePtr);

#pragma mark- Component Dispatch

// Setup required for ComponentDispatchHelper.c

#define CALLCOMPONENT_BASENAME()    EI_GraphicsExport

#define CALLCOMPONENT_GLOBALS()     EI_GraphicsExportGlobals storage

#define GRAPHICSEXPORT_BASENAME()   CALLCOMPONENT_BASENAME()

#define GRAPHICSEXPORT_GLOBALS()    CALLCOMPONENT_GLOBALS()

#define COMPONENT_BASENAME()        CALLCOMPONENT_BASENAME()

#define COMPONENT_GLOBALS()         CALLCOMPONENT_GLOBALS()

#define COMPONENT_DISPATCH_FILE     "EI_GraphicsExportDispatch.h"

#define COMPONENT_UPP_SELECT_ROOT() GraphicsExport                  // root for Type's UPP_PREFIX and SELECT_PREFIX 

#define GET_DELEGATE_COMPONENT()    (storage->delegateComponent)    // how to find who we delegate to

#if __MACH__

    #include <CoreServices/Components.k.h>

    #include <QuickTime/ImageCompression.k.h>

    #include <QuickTime/ComponentDispatchHelper.c>

#else

    #include <Components.k.h>

    #include <ImageCompression.k.h>

    #include <ComponentDispatchHelper.c>

#endif

#pragma mark -

//============================================================================

//

//  Standard component calls

//

// Component Open Request - Required

pascal ComponentResult EI_GraphicsExportOpen(EI_GraphicsExportGlobals store, ComponentInstance self)

{

    ComponentResult err = noErr;

    store = (EI_GraphicsExportGlobals)NewPtrClear(sizeof(EI_GraphicsExportGlobalsRecord));

    if (err = MemError()) goto bail;

    SetComponentInstanceStorage(self, (Handle)store);

    store->self = self;

    store->parent = self;

    err = OpenADefaultComponent(GraphicsExporterComponentType, kBaseGraphicsExporterSubType, &store->delegateComponent);

    if (err) goto bail;

    err = ComponentSetTarget(store->delegateComponent, self);

    if (err) goto bail;

bail:

    return err;

}

// Component Close Request - Required

pascal ComponentResult EI_GraphicsExportClose(EI_GraphicsExportGlobals store, ComponentInstance self)

{

#pragma unused(self)

    if (store) {

        if (store->delegateComponent)

            CloseComponent(store->delegateComponent);

        DisposePtr((Ptr)store);

    }

    return noErr;

}

// Component Version Request - Required

pascal ComponentResult EI_GraphicsExportVersion(EI_GraphicsExportGlobals store)

{

#pragma unused(store)

    return kEI_GraphicsExportVersion;

}

// Component Target Request

//      Allows another component to "target" you i.e., you call another component whenever

// you would call yourself (as a result of your component being used by another component)

pascal ComponentResult EI_GraphicsExportTarget(EI_GraphicsExportGlobals store, ComponentInstance target)

{

    store->parent = target;

    return noErr;

}

#pragma mark -

//============================================================================

//

//  Export routines

//

// GraphicsExportDoStandaloneExport

//      Performs a standalone graphics export operation. If both GraphicsExportCanTranscode

// and GraphicsExportCanUseCompressor reply FALSE, the base graphics exporter makes this call

// of the format-specific exporter to perform the export. This function is used for internal

// communication between the base and format-specific graphics exporter. Applications will not

// usually need to call it directly.

pascal ComponentResult EI_GraphicsExportDoStandaloneExport(EI_GraphicsExportGlobals store)

{

    ImageHeader            imgHeader;

    ImageDescriptionHandle desc = NULL;

    GWorldPtr              gw = NULL;

    PixMapHandle           hPixMap = NULL;

    Ptr                    baseAddr, compressBuffer;

    long                   rowBytes;

    CTabHandle             cTabHdl;

    Rect                   bounds;

    short                  width, height, depth;

    Size                   compressBufferSize;

    ComponentResult err;

    // Get the image description describing the input image for this

    // graphics export operation -- Remember, you are responsible for

    // disposing of the returned image description handle

    err = GraphicsExportGetInputImageDescription(store->parent, &desc);

    if (err) goto bail;

    // Get the dimensions of the input image for this graphics export operation

    err = GraphicsExportGetInputImageDimensions(store->parent, &bounds);

    if (err) goto bail;

    // Setup the Electric Image header...

    imgHeader.imageVersion = EndianU16_NtoB(5);

    imgHeader.imageFrames = EndianU32_NtoB(1); // always a single frame

    // ...and write it

    err = GraphicsExportWriteOutputData(store->parent, &imgHeader, sizeof(ImageHeader));

    if (err) goto bail;

    depth = ((**desc).depth == 24) ? k32ARGBPixelFormat : (**desc).depth;

    // Create a GWorld to draw the input image into

    err = QTNewGWorld(&gw, depth, &bounds, NULL, NULL, kICMTempThenAppMemory);

    if (err) goto bail;

    hPixMap = GetGWorldPixMap(gw);

    LockPixels(hPixMap);

    // Draw the input image -- NULL for srcRect indicates no source extraction

    err = GraphicsExportDrawInputImage(store->parent, gw, NULL, NULL, &bounds);

    if (err) goto bail;

    baseAddr = GetPixBaseAddr(hPixMap);

    rowBytes = QTGetPixMapHandleRowBytes(hPixMap);

    cTabHdl = (**hPixMap).pmTable;

    MacOffsetRect(&bounds, -bounds.left, -bounds.top);

    width = bounds.right;

    height = bounds.bottom;

    // Allocate memory enough to store maximum compressed data

    compressBuffer = NewPtrClear(width * height * depth * 2);

    err = MemError();

    if (err) goto bail;

    // Compress the pixels from the GWorld so we get our RLE compressed image data

    err = CompressRLE(baseAddr, rowBytes, depth, width, height, compressBuffer, &compressBufferSize);

    if (err) goto bail;

    // Write the image frame header

    err = WriteImageFrameHeader(store->parent, cTabHdl, width, height, depth, compressBufferSize);

    if (err) goto bail;

    // Write the colorTable

    err = WriteColorTable(store->parent, cTabHdl);

    if (err) goto bail;

    // Write the image data

    err = GraphicsExportWriteOutputData(store->parent, compressBuffer, compressBufferSize);

bail:

    if (compressBuffer) DisposePtr(compressBuffer);

    if (desc) DisposeHandle((Handle)desc);

    if (gw) DisposeGWorld(gw);

    return err;

}

//============================================================================

//

//  Format-specific information

//

// GraphicsExportGetDefaultFileTypeAndCreator

//      Returns the suggested file type and creator for a graphics export operation.

// This function, along with GraphicsExportGetDefaultFileNameExtension and GraphicsExportGetMIMETypeList,

// returns information about the image format supported by a format-specific graphics exporter. Format-specific

// exporters must implement all three of these calls. 

pascal ComponentResult EI_GraphicsExportGetDefaultFileTypeAndCreator(EI_GraphicsExportGlobals store, OSType *fileType, OSType *fileCreator)

{

#pragma unused(store)

    if (!fileType && !fileCreator) return paramErr;

    if (fileType)

        *fileType = FOUR_CHAR_CODE('EIDI');

    if (fileCreator)

        #if TARGET_API_MAC_OSX

            *fileCreator = FOUR_CHAR_CODE('TVOD');

        #else 

            *fileCreator = FOUR_CHAR_CODE('ogle');

        #endif

    return noErr;

}

// GraphicsExportGetDefaultFileNameExtension

//      Returns the suggested file name extension for a graphics export operation. 

// File name extensions are returned as upper-case big-endian four-character codes. For example, the extension .png

// would be returned as 'PNG ' (0x504E4720 ). This function, along with GraphicsExportGetDefaultFileTypeAndCreator

// and GraphicsExportGetMIMETypeList, returns information about the image format supported by a format-specific graphics

// exporter. Format-specific exporters must implement all three of these calls.

pascal ComponentResult EI_GraphicsExportGetDefaultFileNameExtension(EI_GraphicsExportGlobals store, OSType *fileNameExtension)

{

#pragma unused(store)

    if (!fileNameExtension) return paramErr;

    *fileNameExtension = FOUR_CHAR_CODE('EIM ');

    return noErr;

}

// GraphicsExportGetMIMETypeList

//      Returns MIME types and other information about the graphics format in a graphics export operation. 

// This function creates and returns a QuickTime atom container that contains the format's name, as a string

// in an atom of type 'desc' (kMimeInfoDescriptionTag ), and optionally the MIME type as a string in an atom

// of type 'mime' (kMimeInfoMimeTypeTag ). This function, along with GraphicsExportGetDefaultFileTypeAndCreator

// and GraphicsExportGetDefaultFileNameExtension, returns information about the image format supported by a

// format-specific graphics exporter. Format-specific exporters must implement all three of these calls.

pascal ComponentResult EI_GraphicsExportGetMIMETypeList(EI_GraphicsExportGlobals store, void *qtAtomContainerPtr)

{

    return GetComponentResource((Component)store->self, FOUR_CHAR_CODE('mime'), 2048, (Handle *)qtAtomContainerPtr);

}

#pragma mark -

//============================================================================

//

//  Format-specific Routines

//

// WriteImageFrameHeader

//      The routine writes the image frame header out to the file, see 'EI_Image.h'.

static ComponentResult WriteImageFrameHeader(GraphicsExportComponent ci, CTabHandle cTabHdl, short width, short height, short depth, Size compressBufferSize)

{

    ImageFrame      imgFrame;

    // Setup the frame header

    imgFrame.frameTime = 0;

    imgFrame.frameRect.top = 0;                     

    imgFrame.frameRect.left = 0;                    

    imgFrame.frameRect.bottom = EndianU16_NtoB(height);                     

    imgFrame.frameRect.right = EndianU16_NtoB(width);                   

    imgFrame.frameBitDepth = (depth == 32 ? 24 : depth);

    imgFrame.frameType = (depth > 8 ? 0 : 1);

    imgFrame.framePackRect = imgFrame.frameRect;

    imgFrame.framePacking = 1;

    imgFrame.frameAlpha = (depth == 32 ? 8 : 0);

    imgFrame.frameSize = EndianU32_NtoB(compressBufferSize);

    imgFrame.framePalettes = EndianU16_NtoB((**cTabHdl).ctSize + 1);

    imgFrame.frameBackground = EndianU16_NtoB((**cTabHdl).ctSize);

    return GraphicsExportWriteOutputData(ci, &imgFrame, sizeof(ImageFrame));

}

// WriteColorTable

//      This rountine writes out the color table and get called after the image frame header is written.

static ComponentResult WriteColorTable(GraphicsExportComponent ci, CTabHandle cTabHdl)

{

    PackedColor colors[256];

    ColorSpec   *ctTable = (**cTabHdl).ctTable;

    UInt16      i, numOfColorEntries = (**cTabHdl).ctSize + 1;  // ctSize is number of entries in array of ColorSpec records minus 1

    for (i = 0; i < numOfColorEntries; i++) {

        colors[i].red = (UInt8)(ctTable[i].rgb.red >> 8);

        colors[i].green = (UInt8)(ctTable[i].rgb.green >> 8);

        colors[i].blue = (UInt8)(ctTable[i].rgb.blue >> 8);

    }

    return GraphicsExportWriteOutputData(ci, (Ptr)colors, sizeof(PackedColor) * numOfColorEntries);

}

#pragma mark -

// CompressRLE

//      Main compress routine, this function will call the appropriate RLE compression

// method depending on the pixel depth of the source image.

static OSErr CompressRLE(Ptr baseAddr, long rowBytes, short depth, short width, short height, Ptr compressBuffer, Size *compressBufferSizePtr)

{

    Handle hdl;

    Ptr    tempPtr;

    short  i;

    Size   widthByteSize = (depth * width + 7) >> 3;

    OSErr  err;

    // Make a temp buffer for the source

    hdl = NewHandleClear(height * widthByteSize);

    err = MemError();

    if (err) goto bail;

    HLock(hdl);

    tempPtr = *hdl;

    // Get rid of row bytes padding

    for (i = 0; i < height; i++) {

        BlockMoveData(baseAddr, tempPtr, widthByteSize);

        tempPtr += widthByteSize;

        baseAddr += rowBytes;

    }

    // Compress

    switch (depth) {

    case 1:

        CompressRLE8((UInt8 *)*hdl, height * widthByteSize, compressBuffer, compressBufferSizePtr);

        break;

    case 8:

        CompressRLE8((UInt8 *)*hdl, height * widthByteSize, compressBuffer, compressBufferSizePtr);

        break;

    case 16:

        CompressRLE16((UInt16 *)*hdl, height * (widthByteSize >> 1), compressBuffer, compressBufferSizePtr);

        break;

    case 32:

        CompressRLE32((UInt32 *)*hdl, height * (widthByteSize >> 2), compressBuffer, compressBufferSizePtr);

        break;

    }

bail:

    if (hdl)

        DisposeHandle(hdl);

    return err;

}

// CompressRLE8

static void CompressRLE8(UInt8 *srcPtr, Size srcSize, Ptr compressBuffer, Size *compressBufferSizePtr)

{

    UInt8      prevPixel, currentPixel;

    UInt8      sameCharCount;

    UInt8      diffCharCount;

    RLE8Packet *packetPtr;

    // Initialize some stuff

    sameCharCount = 1;

    diffCharCount = 0;

    packetPtr = (RLE8Packet *)compressBuffer;

    prevPixel = *srcPtr++;

    while (srcSize >= 2 ) {

        currentPixel = *srcPtr++;

        if (prevPixel == currentPixel) {

            // If diffCharCount > 0, we are holding pixels which should be read literally

            if (diffCharCount > 0) {

                packetPtr->opcode = 127 + diffCharCount;

                packetPtr = (RLE8Packet *)((Ptr)packetPtr + offsetof(RLE8Packet, pixelData[diffCharCount]));

                diffCharCount = 0;

            }

            if (sameCharCount < 128) {

                sameCharCount++;

            } else {

                packetPtr->opcode = sameCharCount - 1;

                packetPtr->pixelData[0] = prevPixel;

                packetPtr = (RLE8Packet *)((Ptr)packetPtr + offsetof(RLE8Packet, pixelData[1]));

                sameCharCount = 1;

            }

        } else {

            // If sameCharCount > 1, we are holding pixels which should be read repeatedly

            if (sameCharCount > 1) {

                packetPtr->opcode = sameCharCount - 1;

                packetPtr->pixelData[0] = prevPixel;

                packetPtr = (RLE8Packet *)((Ptr)packetPtr + offsetof(RLE8Packet, pixelData[1]));

                sameCharCount = 1;

            } else {

                packetPtr->pixelData[diffCharCount++] = prevPixel;

                if (diffCharCount == 128) {

                    packetPtr->opcode = 127 + diffCharCount;

                    packetPtr = (RLE8Packet *)((Ptr)packetPtr + offsetof(RLE8Packet, pixelData[diffCharCount]));

                    diffCharCount = 0;

                }

            }

            prevPixel = currentPixel;

        }

        srcSize--;

    }

    // If sameCharCount > 1, we are holding pixels which should be read repeatedly

    // If not so, we are holding pixels which should be read literally

    if (sameCharCount > 1) {

        packetPtr->opcode = sameCharCount - 1;

        packetPtr->pixelData[0] = prevPixel;

        packetPtr = (RLE8Packet *)((Ptr)packetPtr + offsetof(RLE8Packet, pixelData[1]));

    } else {

        packetPtr->pixelData[diffCharCount++] = prevPixel;

        packetPtr->opcode = 127 + diffCharCount;

        packetPtr = (RLE8Packet *)((Ptr)packetPtr + offsetof(RLE8Packet, pixelData[diffCharCount]));

    }

    *compressBufferSizePtr = (Ptr)packetPtr - compressBuffer;

}

// CompressRLE16

static void CompressRLE16(UInt16 *srcPtr, Size srcSize, Ptr compressBuffer, Size *compressBufferSizePtr)

{

    UInt16      prevPixel, currentPixel;

    UInt8       sameCharCount;

    UInt8       diffCharCount;

    RLE16Packet *packetPtr;

    // Initialize some stuff

    sameCharCount = 1;

    diffCharCount = 0;

    packetPtr = (RLE16Packet *)compressBuffer;

    prevPixel = *srcPtr++;

    while (srcSize >= 2) {

        currentPixel = *srcPtr++;

        if (prevPixel == currentPixel) {

            // If diffCharCount > 0, we are holding pixels which should be read literally

            if (diffCharCount > 0) {

                packetPtr->opcode = 127 + diffCharCount;

                packetPtr = (RLE16Packet *)((Ptr)packetPtr + offsetof(RLE16Packet, pixelData[diffCharCount]));

                diffCharCount = 0;

            }

            if (sameCharCount < 128) {

                sameCharCount++;

            } else {

                packetPtr->opcode = sameCharCount - 1;

                packetPtr->pixelData[0] = prevPixel;

                packetPtr = (RLE16Packet *)((Ptr)packetPtr + offsetof(RLE16Packet, pixelData[1]));

                sameCharCount = 1;

            }

        } else {

            // If sameCharCount > 1, we are holding pixels which should be read repeatedly

            if (sameCharCount > 1)

            {

                packetPtr->opcode = sameCharCount - 1;

                packetPtr->pixelData[0] = prevPixel;

                packetPtr = (RLE16Packet *)((Ptr)packetPtr + offsetof(RLE16Packet, pixelData[1]));

                sameCharCount = 1;

            } else {

                packetPtr->pixelData[diffCharCount++] = prevPixel;

                if (diffCharCount == 128)

                {

                    packetPtr->opcode = 127 + diffCharCount;

                    packetPtr = (RLE16Packet *)((Ptr)packetPtr + offsetof(RLE16Packet, pixelData[diffCharCount]));

                    diffCharCount = 0;

                }

            }

            prevPixel = currentPixel;

        }

        srcSize--;

    }

    // If sameCharCount > 1, we are holding pixels which should be read repeatedly

    // If not so, we are holding pixels which should be read literally

    if (sameCharCount > 1) {

        packetPtr->opcode = sameCharCount - 1;

        packetPtr->pixelData[0] = prevPixel;

        packetPtr = (RLE16Packet *)((Ptr)packetPtr + offsetof(RLE16Packet, pixelData[1]));

    } else {

        packetPtr->pixelData[diffCharCount++] = prevPixel;

        packetPtr->opcode = 127 + diffCharCount;

        packetPtr = (RLE16Packet *)((Ptr)packetPtr + offsetof(RLE16Packet, pixelData[diffCharCount]));

    }

    *compressBufferSizePtr = (Ptr)packetPtr - compressBuffer;

}

// CompressRLE32

static void CompressRLE32(UInt32 *srcPtr, Size srcSize, Ptr compressBuffer, Size *compressBufferSizePtr)

{

    UInt32      prevPixel, currentPixel;

    UInt8       sameCharCount;

    UInt8       diffCharCount;

    RLE32Packet *packetPtr;

    // Initialize some stuff

    sameCharCount = 1;

    diffCharCount = 0;

    packetPtr = (RLE32Packet *)compressBuffer;

    prevPixel = *srcPtr++;

    while (srcSize >= 2) {

        currentPixel = *srcPtr++;

        if (prevPixel == currentPixel) {

            // If diffCharCount > 0, we are holding pixels which should be read literally

            if (diffCharCount > 0) {

                packetPtr->opcode = 127 + diffCharCount;

                packetPtr = (RLE32Packet *)((Ptr)packetPtr + offsetof(RLE32Packet, pixelData[diffCharCount]));

                diffCharCount = 0;

            }

            if (sameCharCount < 128) {

                sameCharCount++;

            } else {

                packetPtr->opcode = sameCharCount - 1;

                packetPtr->pixelData[0] = prevPixel;

                packetPtr = (RLE32Packet *)((Ptr)packetPtr + offsetof(RLE32Packet, pixelData[1]));

                sameCharCount = 1;

            }

        } else {

            // If sameCharCount > 1, we are holding pixels which should be read repeatedly

            if (sameCharCount > 1) {

                packetPtr->opcode = sameCharCount - 1;

                packetPtr->pixelData[0] = prevPixel;

                packetPtr = (RLE32Packet *)((Ptr)packetPtr + offsetof(RLE32Packet, pixelData[1]));

                sameCharCount = 1;

            } else {

                packetPtr->pixelData[diffCharCount++] = prevPixel;

                if (diffCharCount == 128) {

                    packetPtr->opcode = 127 + diffCharCount;

                    packetPtr = (RLE32Packet *)((Ptr)packetPtr + offsetof(RLE32Packet, pixelData[diffCharCount]));

                    diffCharCount = 0;

                }

            }

            prevPixel = currentPixel;

        }

        srcSize--;

    }

    // If sameCharCount > 1, we are holding pixels which should be read repeatedly

    // If not so, we are holding pixels which should be read literally

    if (sameCharCount > 1) {

        packetPtr->opcode = sameCharCount - 1;

        packetPtr->pixelData[0] = prevPixel;

        packetPtr = (RLE32Packet *)((Ptr)packetPtr + offsetof(RLE32Packet, pixelData[1]));

    } else {

        packetPtr->pixelData[diffCharCount++] = prevPixel;

        packetPtr->opcode = 127 + diffCharCount;

        packetPtr = (RLE32Packet *)((Ptr)packetPtr + offsetof(RLE32Packet, pixelData[diffCharCount]));

    }

    *compressBufferSizePtr = (Ptr)packetPtr - compressBuffer;

}

#pragma mark-

// When building the *Application Version Only* make our component available for use by applications (or other clients).

// Once the Component Manager has registered a component, applications can find and open the component using standard

// Component Manager routines.

#if !STAND_ALONE && !TARGET_OS_WIN32

void EI_GraphicsExporterRegister(void);

void EI_GraphicsExporterRegister(void)

{

    ComponentDescription foo;   

    #if !TARGET_API_MAC_CARBON

        ComponentRoutineUPP componentEntryPoint = NewComponentRoutineProc(EI_GraphicsExportComponentDispatch);

    #else

        ComponentRoutineUPP componentEntryPoint = NewComponentRoutineUPP((ComponentRoutineProcPtr)EI_GraphicsExportComponentDispatch);

    #endif

    foo.componentType = GraphicsExporterComponentType;

    foo.componentSubType = FOUR_CHAR_CODE('EIDI');

    foo.componentManufacturer = kAppleManufacturer;

    foo.componentFlags = 0;

    foo.componentFlagsMask = 0;

    RegisterComponent(&foo, componentEntryPoint, registerComponentGlobal, NULL, NULL, NULL);

}

#endif // !STAND_ALONE && !TARGET_OS_WIN32