QDBus and org.freedesktop.Notifications.Notify

[TheOneRing]

Hi I'm currently developing a small tcp based notification server using the "org.freedesktop.Notifications.Notify" dbus binding and everything works fine on my Kubuntu, I even got the callbacks working with qdbus(I don't want to use libnotify because there are too many gtk depenecys).
The current problem is that I don't know how to sent the a notification image over qdbus.

on http://www.galago-project.org/specs/.../0.9/x207.html
the image is defined as

The icon_data field should be a raw image data structure of signature (iiibiiay) which describes the width, height, rowstride, has alpha, bits per sample, channels and image data respectively.

and here is an except from dbus-monitor of a working notification

array [
      dict entry(
         string "icon_data"
         variant             struct {
               int32 50
               int32 50
               int32 200
               boolean true
               int32 8
               int32 4
               array [
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32       
		  .......
            ]
            }
      )
   ]

array [
      dict entry(
         string "icon_data"
         variant             struct {
               int32 50
               int32 50
               int32 200
               boolean true
               int32 8
               int32 4
               array [
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32       
		  .......
            ]
            }
      )
   ]

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The image defined above should be part of a QVariantMap.

Problematic is how to get bits per sample and channels and finally how to sent these data over dbus.


Regards

TheOneRing

[wysota]

Bits per sample is most probably 8 or 24 - this is just the depth of your image (the only thing to check out is that if the number should describe one pixel (24b for RGB) or one channel(8b for RGB)). Channels will be one for gray images, 3 for colour images and 4 for colour images with alpha channel. You can deduce all the values based on QImage::format().

[TheOneRing]

Great but how to send the data over dbus?
Currently I'm getting this

string "icon_data"
   int32 133
   int32 135
   int32 532
   boolean true
   int32 8
   int32 4
   array [
      byte 137
      byte 80
      byte 78
      byte 71
     .....
  ]

string "icon_data"
   int32 133
   int32 135
   int32 532
   boolean true
   int32 8
   int32 4
   array [
      byte 137
      byte 80
      byte 78
      byte 71
     .....
  ]

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how to get the right form?

[wysota]

I don't understand your question. What exactly do you have trouble with? From your post it seems an image 32bit deep (4 channels (RGBA) 8 bits each) with size of 133x135 is carried.

[TheOneRing]

The problem is not the data (thanks for help) the current problem is which datatype I have to use that QDBus sends it in the correct form.
Currently I use a QVariantList and insert all the vaues, in the working notification it looks like I have to send a struct over QDBus but I don't know how.

Here is what I get

string "icon_data"
   int32 133
   int32 135
   int32 532
   boolean true
   int32 8
   int32 4
   array [
      byte 137
      byte 80
      byte 78
      byte 71
     .....
  ]

string "icon_data"
   int32 133
   int32 135
   int32 532
   boolean true
   int32 8
   int32 4
   array [
      byte 137
      byte 80
      byte 78
      byte 71
     .....
  ]

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and this is what I need:

array [
      dict entry(
         string "icon_data"
         variant             struct {
               int32 50
               int32 50
               int32 200
               boolean true
               int32 8
               int32 4
               array [
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32       
          .......
            ]
            }
      )
   ]

array [
      dict entry(
         string "icon_data"
         variant             struct {
               int32 50
               int32 50
               int32 200
               boolean true
               int32 8
               int32 4
               array [
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32                                                                                                                                                 
                  byte 57                                                                                                                                                 
                  byte 93                                                                                                                                                 
                  byte 255                                                                                                                                                
                  byte 32       
          .......
            ]
            }
      )
   ]

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[TheOneRing]

Ok now I get that far

array [
      dict entry(
         string "icon_data"
         variant             array [
               variant                   int32 133
               variant                   int32 135
               variant                   int32 532
               variant                   boolean true
               variant                   int32 8
               variant                   int32 4
               variant                   array [
                     byte 137
                     byte 80
                     byte 78
                     byte 71
                     byte 13
                     byte 10
               .......

array [
      dict entry(
         string "icon_data"
         variant             array [
               variant                   int32 133
               variant                   int32 135
               variant                   int32 532
               variant                   boolean true
               variant                   int32 8
               variant                   int32 4
               variant                   array [
                     byte 137
                     byte 80
                     byte 78
                     byte 71
                     byte 13
                     byte 10
               .......

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at least the beginning seams to be right
but I have no idea how to get the entry struct.

My current code is

QVariantMap Notify::getImage(QString* path){
    QImage img(*path);
    QVariantMap out;
 
    if(img.isNull())return out;
    int width=img.width();
    int height=img.height();
    int rowstride=img.bytesPerLine();
    bool hasAlpha=img.hasAlphaChannel();
    int channels;
    if(img.isGrayscale())
        channels=1;
    else{
        channels =3;
        if(hasAlpha)
            channels=4;
    }
    int bitsPerSample=img.depth()/channels;
    QByteArray image;
    QBuffer buffer(&image,NULL );
    buffer.open( QBuffer::WriteOnly);
    img.save( &buffer, "PNG" );
    QVariantList o2;
    o2<<width<<height<<rowstride<<hasAlpha<<bitsPerSample<<channels<<image;
    out.insert("icon_data",o2);
    return out;
 
}

QVariantMap Notify::getImage(QString* path){
    QImage img(*path);
    QVariantMap out;

    if(img.isNull())return out;
    int width=img.width();
    int height=img.height();
    int rowstride=img.bytesPerLine();
    bool hasAlpha=img.hasAlphaChannel();
    int channels;
    if(img.isGrayscale())
        channels=1;
    else{
        channels =3;
        if(hasAlpha)
            channels=4;
    }
    int bitsPerSample=img.depth()/channels;
    QByteArray image;
    QBuffer buffer(&image,NULL );
    buffer.open( QBuffer::WriteOnly);
    img.save( &buffer, "PNG" );
    QVariantList o2;
    o2<<width<<height<<rowstride<<hasAlpha<<bitsPerSample<<channels<<image;
    out.insert("icon_data",o2);
    return out;

}

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but instead of QVariantList for the body i have to use something different, but what?

[TheOneRing]

Hi I finally got it to send a image but the image is not displayed correct, so I think there is a bug in my mtheode so here is the code

void  Notify::getImage(QVariantMap *hints,QString* path){
    QImage img(*path);
    if(img.isNull())return;
    int id=qDBusRegisterMetaType<iiibiiay>();
    iiibiiay i;
    i.width=img.width();
    i.height=img.height();
    i.rowstride=img.bytesPerLine();
    i.hasAlpha=img.hasAlphaChannel();
    if(img.isGrayscale())
        i.channels=1;
    else{
        i.channels =3;
        if(i.hasAlpha)
            i.channels=4;
    }
    i.bitsPerSample=img.depth()/i.channels;
    QBuffer buffer(&i.image,NULL );
    buffer.open( QBuffer::WriteOnly);
    img.save( &buffer, "PNG" );
    hints->insert("icon_data",QVariant(id,&i));
}
 
QDBusArgument &operator<<(QDBusArgument &a, const iiibiiay &i) {
    a.beginStructure();
    a << i.width<<i.height<<i.rowstride<<i.hasAlpha<<i.bitsPerSample<<i.channels<<i.image;
    a.endStructure();
    return a;
}
 
const QDBusArgument & operator >>(const QDBusArgument &a,  iiibiiay &i) {
    a.beginStructure();
    a >> i.width>> i.height>> i.rowstride>> i.hasAlpha>> i.bitsPerSample>> i.channels>> i.image;
    a.endStructure();
    return a;
}

void  Notify::getImage(QVariantMap *hints,QString* path){
    QImage img(*path);
    if(img.isNull())return;
    int id=qDBusRegisterMetaType<iiibiiay>();
    iiibiiay i;
    i.width=img.width();
    i.height=img.height();
    i.rowstride=img.bytesPerLine();
    i.hasAlpha=img.hasAlphaChannel();
    if(img.isGrayscale())
        i.channels=1;
    else{
        i.channels =3;
        if(i.hasAlpha)
            i.channels=4;
    }
    i.bitsPerSample=img.depth()/i.channels;
    QBuffer buffer(&i.image,NULL );
    buffer.open( QBuffer::WriteOnly);
    img.save( &buffer, "PNG" );
    hints->insert("icon_data",QVariant(id,&i));
}

QDBusArgument &operator<<(QDBusArgument &a, const iiibiiay &i) {
    a.beginStructure();
    a << i.width<<i.height<<i.rowstride<<i.hasAlpha<<i.bitsPerSample<<i.channels<<i.image;
    a.endStructure();
    return a;
}

const QDBusArgument & operator >>(const QDBusArgument &a,  iiibiiay &i) {
    a.beginStructure();
    a >> i.width>> i.height>> i.rowstride>> i.hasAlpha>> i.bitsPerSample>> i.channels>> i.image;
    a.endStructure();
    return a;
}

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The image in the upper left corner and the big rectangel should be the same

[wysota]

Try only sending img.bits() as the image data. If you were to send PNG image will all headers and stuff, all the information about the image wouldn't be necessary because they could be taken from PNG headers.

[TheOneRing]

I'v got even one step closer to my ultimate goal

for(int ii=0;ii<img.numBytes();++ii)
        i.image.append(img.pixel(ii%i.width,ii/i.width));

for(int ii=0;ii<img.numBytes();++ii)
        i.image.append(img.pixel(ii%i.width,ii/i.width));

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does anybody know how to get a pixbuff out of a QImage without using gdk?

[wysota]

pixbuff is a GDK concept. It's equivalent in Qt is either QImage::bits() or QImage itself. Based on your code I think you should really try QImage::bits()

[TheOneRing]

Big thanks but I get the wrong color.

iiibiiay::iiibiiay(QImage* img){
    width=img->width();
    height=img->height();
    rowstride=img->bytesPerLine();
    hasAlpha=img->hasAlphaChannel();
    channels =img->isGrayscale()?1:hasAlpha?4:3;
    bitsPerSample=img->depth()/channels;
    image.append((char*)img->bits(),img->numBytes());
}

iiibiiay::iiibiiay(QImage* img){
    width=img->width();
    height=img->height();
    rowstride=img->bytesPerLine();
    hasAlpha=img->hasAlphaChannel();
    channels =img->isGrayscale()?1:hasAlpha?4:3;
    bitsPerSample=img->depth()/channels;
    image.append((char*)img->bits(),img->numBytes());
}

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[wysota]

You probably have to swap the order of channels. I would assume - from RGB to BGR, or something like that.

[TheOneRing]

And again big thanks QImage::rgbSwapped() solved the problem
so finally every problem is solved, wysota you are my hero!