[Interest] What image format and size should I use in my QML app?

[Артур Истомин]

On Sun, Sep 25, 2016 at 10:33:00PM +0100, Gianluca wrote:
> 
> > Il giorno 25 set 2016, alle ore 22:24, Артур Истомин <art.istom at yandex.ru> ha scritto:
> > 
> > On Sun, Sep 25, 2016 at 09:54:59PM +0100, Gianluca wrote:
> >> I use SVG format.
> >> No matter what resolution and pixel density, they always look great because they can be resized at any scale without any loss.
> >> They are a bit slower than other formats, but with the power of the average device user won’t notice it.
> >> On the other hand you save a lot of space for your app.
> > 
> > I'm thinking in the same direction. But there are several sizes: 18dp, 24dp, 36dp and 48dp. So what should I use to cover
> > as many devices as possible?
> 
> You don’t have to think about that. That’s the wonderful aspect of SVG.
> Because they are a vectorial representation … they are essentially mathematical curves and the image is generated directly at runtime on the device.
> In fact, SVG are dimensionless. It doesn’t exists an SVG of 600x600 pixel … or 6x6 cm … or whatever because doesn’t make sense in the SVG format.
> 
> You just need to use sourceSize property of Image to scale it properly to the correct size of your device.
> For example in my code, if I want to display an image of 2x2 cm, I calculate at runtime a constant representing the number of pixel into 1 millimeter (reading the physical screen information) and then I do the following:
> 
> Image {
>    source: "my.svg"
>    width: 20*mm
>    height: 20*mm
>    sourceSize.width: 2*20*mm
>    sourceSize.height: 2*20*mm
>    smooth: true
> }
> 
> In that case Qt will generate (and cache) and image of 4x4 cm from the SVG format and it will display at 2x2 cm size using Image.
> In my experience, I found that you get better quality results if you set the sourceSize to double of the size on which you need to display the image.

Thank You very much!
> 
> 
> > 
> >> 
> >> Ciao,
> >> Gianluca.
> >> 
> >> 
> >>> Il giorno 25 set 2016, alle ore 21:21, Артур Истомин <art.istom at yandex.ru> ha scritto:
> >>> 
> >>> I want to use images for icons from google's icons set. 
> >>> For example https://design.google.com/icons/#ic_search
> >>> 
> >>> So I have options: 18dp, 24dp, 36dp, 48dp PNGs or SVGs. Moreover
> >>> if I choose PNG format, there are 5 different images for different
> >>> screens: hdpi, mdpi, xhdpi, xxhdpi, xxxhdpi.
> >>> 
> >>> My software targets Android and Windows (desktop) devices with different
> >>> screens and resolution and will have Material and Universal UI respectively. 
> >>> The app is writen with Qt Quick.
> >>> 
> >>> What should I use? 
> >>> 
> >>> Thank you!
> >>> _______________________________________________
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> >>> Interest at qt-project.org
> >>> http://lists.qt-project.org/mailman/listinfo/interest
> >> 
> >> 
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>