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Unflip wxImage loading

I have the code here working perfectly, except all the feeble 2 images are flipped in the y direction. The wxImageLoader file has this loop which I believe is the culprit:

    for(int y=0; y<newHeight; y++)
    {
        for(int x=0; x<newWidth; x++)
        {

            if( x<(*imageWidth) && y<(*imageHeight) ){
                imageData[(x+y*newWidth)*bytesPerPixel+0]=
                bitmapData[( x+(rev_val-y)*(*imageWidth))*old_bytesPerPixel + 0];

                imageData[(x+y*newWidth)*bytesPerPixel+1]=
                    bitmapData[( x+(rev_val-y)*(*imageWidth))*old_bytesPerPixel + 1];

                imageData[(x+y*newWidth)*bytesPerPixel+2]=
                    bitmapData[( x+(rev_val-y)*(*imageWidth))*old_bytesPerPixel + 2];

                if(bytesPerPixel==4) imageData[(x+y*newWidth)*bytesPerPixel+3]=
                    alphaData[ x+(rev_val-y)*(*imageWidth) ];

            }
            else
            {

                imageData[(x+y*newWidth)*bytesPerPixel+0] = 0;
                imageData[(x+y*newWidth)*bytesPerPixel+1] = 0;
                imageData[(x+y*newWidth)*bytesPerPixel+2] = 0;
                if(bytesPerPixel==4) imageData[(x+y*newWidth)*bytesPerPixel+3] = 0;
            }

        }//next
    }//next

But I can't figure out how not to flip the images.

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2 answers


Correct loop:



for(int y=0; y<newHeight; y++)
    {
        for(int x=0; x<newWidth; x++)
        {

            if( x<(*imageWidth) && y<(*imageHeight) ){
                imageData[(x+y*newWidth)*bytesPerPixel+0]=
                bitmapData[( x+y*(*imageWidth))*old_bytesPerPixel + 0];

                imageData[(x+y*newWidth)*bytesPerPixel+1]=
                    bitmapData[( x+y*(*imageWidth))*old_bytesPerPixel + 1];

                imageData[(x+y*newWidth)*bytesPerPixel+2]=
                    bitmapData[( x+y*(*imageWidth))*old_bytesPerPixel + 2];

                if(bytesPerPixel==4) imageData[(x+y*newWidth)*bytesPerPixel+3]=
                    alphaData[ x+y*(*imageWidth) ];

            }
            else
            {

                imageData[(x+y*newWidth)*bytesPerPixel+0] = 0;
                imageData[(x+y*newWidth)*bytesPerPixel+1] = 0;
                imageData[(x+y*newWidth)*bytesPerPixel+2] = 0;
                if(bytesPerPixel==4) imageData[(x+y*newWidth)*bytesPerPixel+3] = 0;
            }

        }//next
    }//next
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In your loop, you use (rev_val - y)

to index the pixels of your "old" image. This will flip the image. Try to find an alternative. From your code you posted it is difficult to know what the rev_val function is.



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