How to convert Windows Bitmap into Actionscript Bitmap in C++ - c++

Question

to circumvent some (a lot) of problems with the Actionscript Camera API on Windows 8 Systems,
I decided to create a native extension to deal with the camera.
Right now, the camera part and all the glue to communicate with the AIR Runtime is actually working, so clicking on a button in AIR will open a new Windows window that will return a System::Drawing::Bitmap.
My task would be now to
a) Create a FREBitmapData object and
b) Fill in the BitmapData from the Windows Bitmap.
Should be easy, I thought, many days ago... As I'm not really familiar with C++ I didn't get this to work at all.
Here's what I tried so far:
bmp = form1->bitmap; // bmp is a handle to the System::Drawing::Bitmap returned from the external window
// Lock the bitmap's bits.
Rectangle rect = Rectangle(0, 0, bmp->Width, bmp->Height);
System::Drawing::Imaging::BitmapData^ bmpData = bmp->LockBits(rect, System::Drawing::Imaging::ImageLockMode::ReadWrite, bmp->PixelFormat);
// Get the address of the first line.
IntPtr ptr = bmpData->Scan0;
// Declare an array to hold the bytes of the bitmap.
// This code is specific to a bitmap with 24 bits per pixels.
int inputLength = Math::Abs(bmpData->Stride) * bmp->Height;
array<Byte>^ input = gcnew array<Byte>(inputLength);
// Copy the RGB values into the array.
System::Runtime::InteropServices::Marshal::Copy(ptr, input, 0, inputLength);
// Unlock the bits.
bmp->UnlockBits(bmpData);
// Create a FREByteArray to hold the data.
// Don't know, if this is necessary
FREObject* outputObject;
FREByteArray* outputBytes = new FREByteArray;
outputBytes->length = inputLength;
outputBytes->bytes = (uint8_t *) &input;
FREAcquireByteArray(outputObject, outputBytes);
// now copy it over
memcpy(outputBytes->bytes, &input, inputLength);
FREReleaseByteArray(outputObject);
// we create a new instance of BitmapData here,
// as we cannot simply pass it over in the args,
// because we don't know it's correct size at extension creation
FREObject* width;
FRENewObjectFromUint32(bmp->Width, width);
FREObject* height;
FRENewObjectFromUint32(bmp->Height, height);
FREObject* transparent;
FRENewObjectFromBool(uint32_t(0), transparent);
FREObject* fillColor;
FRENewObjectFromUint32(uint32_t(0xFFFFFF), fillColor);
FREObject obs[4] = { width, height, transparent, fillColor };
// we create some Actionscript Intsances here, we want to send back
FREObject* asBmpObj;
FRENewObject("BitmapData", 4, obs, asBmpObj, NULL);
// Now we have our AS bitmap data, copy bytes over
FREBitmapData* asData;
FREAcquireBitmapData(asBmpObj, asData);
// Now what? asData->bits32 won't accept array<Bytes> or any other value I've tried.
return asBmpObj;
The basic idea was:
a) find out the size and bit-depth of the original Win Bitmap (size is determinded by cam resolution picked in the Camera window)
b) write it's bytes to an array. Convert to 32 bits as necessary. (Still missing any idea.)
c) create AS Bitmap of the same size. Bit-depth must always be 32.
d) copy over array to AS Bitmap.
But I just can't achieve this.
Any advice? Thank you!

Answer 1

I don't think the following straight copy will work.
// Copy the RGB values into the array.
System::Runtime::InteropServices::Marshal::Copy(ptr, input, 0, inputLength);
You have to convert pixel by pixel. I don't know how to convert it to FREBitmapData. Here are the examples you can following on msdn

Answer 2

I finally figured it out:
the code below doesn't deal with the 24to32 bit conversion though, but it actually works in my application quite well, so I thought, i might share it:
FREObject launch(FREContext ctx, void* funcData, uint32_t argc, FREObject argv[])
{
System::Drawing::Bitmap^ windowsBitmap;
SKILLCamControl::CamControlForm^ form1;
form1 = gcnew SKILLCamControl::CamControlForm();
DialogResult dr;
// Show testDialog as a modal dialog and determine if DialogResult = OK.
dr = form1->ShowDialog();
if (dr == DialogResult::OK) {
windowsBitmap = form1->bitmap;
int bmpW = windowsBitmap->Width;
int bmpH = windowsBitmap->Height;
// we create a new instance of BitmapData here,
// as we cannot simply pass it over in the args,
// because we don't know it's correct size at extension creation
FREObject width;
FRENewObjectFromUint32( uint32_t(bmpW), &width);
FREObject height;
FRENewObjectFromUint32( uint32_t(bmpH), &height);
FREObject transparent;
FRENewObjectFromBool( uint32_t(0), &transparent);
FREObject fillColor;
FRENewObjectFromUint32( uint32_t(0xFF0000), &fillColor);
FREObject obs[4] = { width, height, transparent, fillColor };
FREObject freBitmap;
FRENewObject((uint8_t *)"flash.display.BitmapData", 4, obs, &freBitmap , NULL);
FREBitmapData2 freBitmapData;
FREAcquireBitmapData2(freBitmap, &freBitmapData);
// is inverted?
if (&freBitmapData.isInvertedY != (uint32_t*)(0) ) windowsBitmap->RotateFlip(RotateFlipType::RotateNoneFlipY);
int pixelSize = 4;
//Rect rect( 0, 0, freBitmap.width, freBitmap.height );
System::Drawing::Rectangle rect(0, 0, bmpW, bmpH);
BitmapData^ windowsBitmapData = windowsBitmap->LockBits(rect, ImageLockMode::ReadOnly, PixelFormat::Format32bppArgb);
for (int y = 0; y < bmpH ; y++)
{
//get pixels from each bitmap
byte* oRow = (byte*)windowsBitmapData->Scan0.ToInt32() + (y * windowsBitmapData->Stride);
byte* nRow = (byte*)freBitmapData.bits32 + (y * freBitmapData.lineStride32 * 4);
for (int x = 0; x < bmpW ; x++)
{
// set pixels
nRow[x * pixelSize] = oRow[x * pixelSize]; //B
nRow[x * pixelSize + 1] = oRow[x * pixelSize + 1]; //G
nRow[x * pixelSize + 2] = oRow[x * pixelSize + 2]; //R
}
}
// Free resources
FREReleaseBitmapData(freBitmap);
FREInvalidateBitmapDataRect(freBitmap, 0, 0, bmpW, bmpH);
windowsBitmap->UnlockBits(windowsBitmapData);
delete windowsBitmapData;
delete windowsBitmap;
return freBitmap;
}
else if (dr == DialogResult::Cancel)
{
return NULL;
}
return NULL;
}

Answer 3

I dont use C++ myself so this is not a full answer but just something to consider...
Bitmap data is universal raw pixel data. It should be passable within different software. Unless you are actually creating .BMP files with header etc??
...that will return a System::Drawing::Bitmap does this mean you have a bitmap's data held by C++ (as raw uncompressed RGBA pixels)? If so then just either put that inside a byteArray and send to AS3 or a if you can get that bitmap copied to the Windows clipboard then use AS3 to read from clipboard into a new AS3 Bitmap.
these might help you:
AS3: Copy image from clipboard
AS3: Serialize Bitmaps : Scroll down to the section ByteArray to BitmapData (for this to work you must first store the C++ bitmap bytes as a file call it what you want, example tempIMG.dat or myPIc.bin or whatever since file extension does not really matter just that you need a loadable URL).