pngloader.cpp

一款大砖块的游戏

/*
* ============================================================================
*  Name     : CPngLoader from PngLoader.cpp
*  Part of  : Mopoid
*  Created  : 16.01.2004 by Andreas Jakl / Mopius - http://www.mopius.com/
*  Description:
*     Takes care of loading png/jpg images.
*  Version  : 1.02
*  Copyright: 
*     'Mopoid' is free software; you can redistribute
*     it and/or modify it under the terms of the GNU General Public License
*     as published by the Free Software Foundation; either version 2 of
*     the License, or (at your option) any later version.
* 
*     'Mopoid' is distributed in the hope that it
*     will be useful, but WITHOUT ANY WARRANTY; without even the implied
*     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*     See the GNU General Public License for more details.
* 
*     You should have received a copy of the GNU General Public License
*     along with 'Mopoid'; if not, write to the Free Software
*     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
* ============================================================================
*/

#include "PngLoader.h"

// Read the image file with maximum color depth and then convert them
// down to something lower if the user wants it that way.
// If we'd read directly in the low color depth, the system would dither
// the image. This results in ugly images most of the times. The conversion 
// we do later doesn't dither.
static const TDisplayMode KSourceColourDepth = EColor16M;

CPngLoader::CPngLoader(const TDesC *aFilename)
:
    iErrorCode(KErrNone)
{
    // make a local copy of the filename
    iFilename = aFilename->Alloc();
    iBitmap = NULL;
}

CPngLoader::~CPngLoader()
{
    // deallocate all data
    delete iBitmap;
    delete iFilename;
    delete iConverter;
}

void CPngLoader::LoadAndSplitImageL(const TDesC& aFilename, CFbsBitmap** aTargetBmps, TInt aNumPics, TDisplayMode aDisplayMode)
{
	CFbsBitmap* bigBmp = LoadImageL(aFilename, aDisplayMode);
	CleanupStack::PushL(bigBmp);

	TInt bmpWidth = (bigBmp->SizeInPixels()).iWidth / aNumPics;
	TSize newBmpSize(bmpWidth, (bigBmp->SizeInPixels()).iHeight);

	// Split the bitmap up into the individual frames
	for (TInt i = 0; i < aNumPics; i++)
	{
		aTargetBmps[i] = NBitmapMethods::CreateBitmapL(newBmpSize, aDisplayMode);
		
		CFbsBitmapDevice*		bitmapDevice	= NBitmapMethods::CreateBitmapDeviceLC(*aTargetBmps[i]);
		CFbsBitGc*				bitmapGc		= NULL;
		User::LeaveIfError( bitmapDevice->CreateContext(bitmapGc) );
		CleanupStack::PushL(bitmapGc);
		bitmapGc->BitBlt( TPoint(0, 0), bigBmp, TRect(TPoint(i * bmpWidth, 0), newBmpSize) );
		CleanupStack::PopAndDestroy(2); // device and gc
	}
	CleanupStack::PopAndDestroy(bigBmp);
}

CFbsBitmap* CPngLoader::LoadImageL(const TDesC& aFilename, const TDisplayMode aDisplayMode)
{
    TFileName fullName(aFilename);
    CompleteWithAppPath(fullName);
#ifdef __WINS__
    fullName[0] = 'C';
#endif

    // construct new loader instance
    CPngLoader *loader = new (ELeave) CPngLoader(&fullName);
    CleanupStack::PushL(loader);

    // perform operations for reading and converting the image
    loader->ReadImageL();

	// Convert the color depth of the image to something more memory-saving
	// Get the size of the original bitmap
	const TSize bitmapSize = loader->iBitmap->SizeInPixels();
	CFbsBitmap* newBitmap = NBitmapMethods::CreateBitmapLC(bitmapSize, aDisplayMode);

	CFbsBitmapDevice* newBitmapDevice = NBitmapMethods::CreateBitmapDeviceLC(*newBitmap);
	CFbsBitGc* newBitmapGc;
	User::LeaveIfError( newBitmapDevice->CreateContext(newBitmapGc) );
	newBitmapGc->BitBlt(TPoint(0,0), loader->iBitmap);
	delete newBitmapGc;
	CleanupStack::PopAndDestroy(newBitmapDevice); // Bitmap device

    // deallocate the instance
    CleanupStack::Pop(newBitmap);
    CleanupStack::PopAndDestroy(loader);

    // return the created texture
    return newBitmap;
}



// performs the actual reading and conversion of the image
void CPngLoader::ReadImageL()
{   
    iConverter = CMdaImageFileToBitmapUtility::NewL(*this);
    iConverter->OpenL(*iFilename);

    // Continue here when the opening process is finished
    CActiveScheduler::Start();

    if (iErrorCode)
        User::Leave(iErrorCode);

    TFrameInfo info;
    iConverter->FrameInfo(0, info);

    // create a bitmap to write into
    iBitmap = new (ELeave) CFbsBitmap();
    User::LeaveIfError(iBitmap->Create(info.iOverallSizeInPixels, KSourceColourDepth));
    
    // convert the gif into a bitmap
    iConverter->ConvertL(*iBitmap);

    // Continue when converting is finished
    CActiveScheduler::Start();
    
    if (iErrorCode)
        User::Leave(iErrorCode);
}



//This function is called when the gif file has been opened or an error has occured in the process
void CPngLoader::MiuoOpenComplete(TInt aError)
{
    iErrorCode = aError;
    CActiveScheduler::Stop();

}

// called when ConvertL() finishes
void CPngLoader::MiuoConvertComplete(TInt aError)
{
    iErrorCode = aError;
    CActiveScheduler::Stop();
}


//This function is called when the bitmap (output) file has been created
void CPngLoader::MiuoCreateComplete(TInt /*aError*/)
{
    // Unused
    /*iErrorCode = aError;
    CActiveScheduler::Stop();*/
}