[Qt-interest] difference between QGraphicsSimpleTextItem and drawText when printing text on printer

[changwon lee]

  Hello

I have tried two different method when I draw text.

1. draw using QGraphicsSimpleTextItem
2. derive QGraphicsItem and inside paint function, painter->drawText

I have used same font pointsize.
when I render scene via graphicsview (screen output), there are no 
difference between two methods.
but when I render scene to printer, 2nd method has bigger font size.

I have to think about the meaning of pointsize in different context.

I want to check some knowledge.

1. the pointsize of font used in QGrahicsTextItem or 
QGraphicsSimpleTextItem is scene unit.
     the definition of 1pointsize is 1/72inch doesn't apply in this 
case. Scene can draw text consistently irrespective of device.
2. in qpainter context
    if I draw text using pointsize 72, is the length of font size always 
1 inch regardless of device if there is no scale transformation. right?
   what is the relation between this pointsize and logical unit in 
window coordinate?
   because I have seen some example adjust text location according to 
width and height of text.
   I don't what is the unit of returned QRect of boundingRect function 
in QFontMetrics.
3. why I have to consider dpi of device above 2nd method.
   To make results same I have adjust fontsize of 2nd method by screen 
dpi/printer dpi.
   I want to know how QGraphicsScene acheives device independence in 
handling font.

regards