[Qt-interest] QGraphicsSvgItem scalling image question

[frares at gmail.com]

If you need to scale individual items, apply the transformation to it.

If your whole scene should be zoomed, apply the transformation to the  
QGraphicsView.

Francisco


Em 23/08/2011 09:27, franki <franki at franki.eu.org> escreveu:
> Dnia wtorek, 23 sierpnia 2011 o 13:30:53 Pritam Ghanghas napisał(a):

> > On Tue, 2011-08-23 at 15:32 +0530, franki wrote:

> > > Dnia poniedziałek, 22 sierpnia 2011 o 14:56:06 franki napisał(a):

> > > > Hi,

> > > >

> > > > I have some items on QGraphicsView that represents icons. Icons are

> > > > clickable and can change look (eg switch on/off) I need these icons

> > > > to come in different resolutions without lose of quality, so I  
> tunerd

> > > > to QGraphicsSvgItem, supposedly this is Scalable Vector Graphics.  
> But

> > > > I can find no way to change icon resolution. I've googled and all  
> I've

> > > > got is that I could change some parameters in svg file before  
> loading,

> > > > simply by parsing it. But with complex icon's that nearly  
> impossible,

> > > > or at least highly cumbersome.

> > > >

> > > > I do have however setScale() function that somes from QGraphicsItem,

> > > > but

> > > >

> > > > this is just applying transormation matrix onto item, and the item  
> does

> > > > not have to be svg item,

> > > >

> > > > So my question is: Do I get this right? Only possible scalling is by

> > > >

> > > > setScale function or parsing svg text file? Because if so, what

> > > > advantages gives me using svg format? Does this downscale better  
> that

> > > > png format giving better item quality?

> > >

> > > Please anyone..

> > > I know it may be stupid question, but is it possible that function  
> scale,

> > > or setScale inherited from QGraphicsItem by QGraphicsSvgItem, takes

> > > advantage of SVG file and render it without loss of quality in  
> different

> > > size? SVG Cards example is doing this that way, setting scale for  
> every

> > > item form one svg file.

> >

> > setScale() should result in properly scaled svg Item (lossless). It

> > should be very easy to check.

> > create the item,

> > set the scale to be very huge may be 20x and then look for artifacts.

> > If scale is being applied after rasterization, you will get very visible

> > ugly looking pixel blocks.



> Thanks it's seems to be OK, as far as I can tell there is no ugly looking

> pixels, at least under qt simulator..., but usually items look beter on N8

> than on simulator ;)



> Thanks

> Marek



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