Re: Gdk::Pixbuf create_from_inline

[Carl Nygard <cjnygard fast net>]

On Wed, 2004-11-24 at 12:14, Andy Ma wrote:
> Hello,
> 
> Does anybody have any reference to an example of how to use Gdk::Pixbuf
> create_from_inline or
> Gdk::Pixmap create_from_data or create_from_xpm
> 
> I'd like to test it and run a program with inline image data.
> 
> If anybody has any examples, it's greatly appreciated.
> 

Code initializes Pixbuf from raster image [0-255] via lookup table
(containing real colors) and mask table for setting alpha channel.  Also
does rotations in 90deg increments.

void RasterObject::_InitializeImage()
{
    Debug dbg(_dbg, "_InitializeImage");
    StopWatch timer("Build Pixbuf");

    int sz = _data->Size();
    guint8* buf = new guint8[4*sz];
    guint8* dst = buf;

    const unsigned long* lut = _lut.GetLut();
    const vector<int>& maskPix = _lut.Mask();
    vector<char> mask(256, 255);
    for(vector<int>::const_iterator it = maskPix.begin();
        it != maskPix.end(); ++it){
        mask[*it] = 0;
    }

    int startIdx, endIdx, rowDelta, colDelta;
    int width, height;
    dbg[1] << "Angle: " << _angle << endl;
    if(roundf(_angle) == 0.0){
        for(const unsigned char* src = _data->Buffer(); 
            src != _data->Buffer()+sz; ++src){
            *dst++ = (lut[*src] >> 16) & 0xff;
            *dst++ = (lut[*src] >> 8)  & 0xff;
            *dst++ = (lut[*src])       & 0xff;
            *dst++ = mask[*src];
        }
        width = _data->Width();
        height = _data->Height();
    }else {
        if(roundf(_angle) == 270.0) { // 90deg counter-clockwise
            startIdx = _data->Width()-1;
            endIdx = -1;
            rowDelta = -1;
            colDelta = _data->Width();
            height = _data->Width();
            width = _data->Height();
        }
        if(roundf(_angle) == 180.0) { // upside down
            startIdx = ( _data->Width() * _data->Height() ) - 1;
            endIdx = -1;
            rowDelta = -_data->Width();
            colDelta = -1;
            width = _data->Width();
            height = _data->Height();
        }
        if(roundf(_angle) == 90.0) { // upside down
            startIdx = _data->Width() * (_data->Height()-1);
            endIdx = _data->Width() * _data->Height();
            rowDelta = 1;
            colDelta = -_data->Width();
            height = _data->Width();
            width = _data->Height();
        }

        for(int s = startIdx; s != endIdx; s += rowDelta){
            for(int idx = s, count = 0; count < width; ++count, idx+=colDelta){
                int val = _data->Buffer()[idx];
                *dst++ = (lut[val] >> 16) & 0xff;
                *dst++ = (lut[val] >> 8)  & 0xff;
                *dst++ = (lut[val])       & 0xff;
                *dst++ = mask[val];
            }
        }
    }        
            
    using SigC::slot;
    using SigC::bind;
    _pix = Gdk::Pixbuf::create_from_data(buf, 
                                         Gdk::COLORSPACE_RGB,
                                         true, 8, 
                                         width, height, width*4,
                                         slot(&LoaderDataDtor)
                                         );
}