[Development] Revisiting high-DPI configuration options

[Uwe Rathmann]

On Wed, 20 Jul 2016 10:44:16 -0700, Thiago Macieira wrote:

>> Why SVG support of QIcon can not cache rendered result? So re-rendering
>> will be as fast as for PNGs. Or you are saying about app startup time?
> 
> Startup.

When using SVGs you have to load/parse it into QSvgRenderer and later it 
needs to be replayed via QPainter in the size you need.

While the second step can't be avoided at runtime, it is possible to 
convert SVGs into something, that can be loaded significantly faster, at 
compile time.

I'm using an implementation based on this class: http://
qwt.sourceforge.net/class_qwt_graphic.html. This is a record/replay 
device for QPainter commands - like QPicture, but suitable for vector 
graphics. I added load/save methods ( not yet in SVN ) and then the 
compiler itself is 20 lines of code only.

When using such a concept with Qt Quick, better don't use standard Image 
classes as they are designed for raster graphics. Better write your own 
type of control for it - at least this is what I did.

Uwe