wxImage and wxMemoryBuffer Topic is solved

[bcteh]

Hi,

Is that posible to save/convert wxImage to wxMemoryBuffer ?

Regards
Teh

[upCASE]

Hi!
That depends on what info you want to store in the buffer.

The most easy case I can think of would be to store the RGB data of the image. You could simply do something like:

Code: Select all

unsigned int byteCount = image.GetWidth()*image.Height()*3;
wxMemoryBuffer buffer( byteCount );
buffer.AppendData(image.GetData(),bytecount);

[bcteh]

Hi,

After convert to wxMemoryBuffer , How can i convert/restore (RGB data) back
to wxImage ?

Now, I am able to write wxMemoryBuffer back to wxImage, If i read from file by below code.

wxFile FileIn(filename);
int nDataLength = FileIn.Length();
wxMemoryBuffer BufferIn;
int nBytesRead = FileIn.Read(BufferIn.GetWriteBuf(nDataLength), nDataLength);

wxMemoryInputStream mis(BufferIn.GetData(), BufferIn.GetBufSize());
if (!GetImage().LoadFile(mis) ) {
wxLogError(wxT("Can't load BMP image from stream"));
}

But I try to load the wxMemoryBuffer by the code your provided. It return "Can't load BMP image from stream".

Regards
Teh

[upCASE]

Hi!
Honestly, I don't get what you want or expect to happen.

Your initial question was how to store the wxImage in a wxMemoryBuffer. Although this only stores the RGB data, I gave you a solution. Now you want to know how you can load that data??

LoadFile() won't work on this. It is simple RGB data that is stored, not data in a specific image format the LoadFile() or the wxImage handlers could parse...

So, please, explain what you want to do and what seems to be the problem.

[GeraldG]

You use wxImage::GetData to store, then you should use wxImage::SetData to recreate the image.

But see docs, use malloc for creation of buffer and dont delete it (its owned by wxImage after SetData).

[lester]

Hi,

After convert to wxMemoryBuffer , How can i convert/restore (RGB data) back
to wxImage ?

Now, I am able to write wxMemoryBuffer back to wxImage, If i read from file by below code.

wxFile FileIn(filename);
int nDataLength = FileIn.Length();
wxMemoryBuffer BufferIn;
int nBytesRead = FileIn.Read(BufferIn.GetWriteBuf(nDataLength), nDataLength);

wxMemoryInputStream mis(BufferIn.GetData(), BufferIn.GetBufSize());
if (!GetImage().LoadFile(mis) ) {
wxLogError(wxT("Can't load BMP image from stream"));
}

But I try to load the wxMemoryBuffer by the code your provided. It return "Can't load BMP image from stream".

Regards
Teh

You must use constructor not LoadFile - wxImage(mis)

[lester]

Hi,

Is that posible to save/convert wxImage to wxMemoryBuffer ?

Regards
Teh

for save image You must use wxImage::SaveFile(wxOutputStream& stream, int type) and wxMemoryOutputStream, from wxMemoryOutputStream You can read data and store into wxMemoryBuffer

[JimFairway]

Hi,

If all you want to do is load an image, modify the pixel data, then save it, I'm not sure why you don't just do the following:

Code: Select all

 wxImage image;
wxString aFileToLoad(_T("myinfile.bmp"));
wxString aFileToSave(_T("myoutfile.bmp"));

image.LoadFile(aFileToLoad);
unsigned char *pixelData = image.GetData();

// modify the pixel data as you please...

image.SaveFile(aFileToSave);

Jim

PS. Using the code tags makes your post much easier to read and follow.