This is the expceted result. smooth: true uses bilinear filtering which is what
is supported in hardware. When scaling down, this starts to degrade. The effect
is drastic for high-contrast content like the edges of a font. Once go get
below 0.5x scale factor the sampling starts to ignore pixels and aliasing
become very visible.
The preferred solution is to prepare raster content (images in your case) close
to the size you intend to show them. If you must scale them down, then use
mipmapping. With the image element, you can get this by doing:
Image {
layer.enabled: true
layer.smooth: true
layer.mipmap: true
...
}
However, by enabling the layer you get an extra texture copy of your rather
large image, so it might be preferable to implement a custom QQuickItem which
returns a QSGSimpleTextureNode with a QSGTexture with mipmapping.
cheers,
Gunnar
On 22 Jan 2014, at 04:03, Joshua Kolden <[email protected]> wrote:
> I’m getting boxed in with rendering bugs on two fronts. Originally I tried
> to work with fonts for the following animation, but have both render quality
> and font ‘subfamily’ selection bugs to deal with there. So I took the effort
> to switch a lot of stuff around and use images instead, however I’m getting
> aliasing artifacts now. I’m rather stuck at the moment for rendering a good
> quality large font design.
>
> This video shows the aliasing I’m talking about. There are 3 images here one
> is 2048x512 and two are 512x512 for the Camera4 and C4 text logos. The movie
> is captured pixel for pixel, and the images at their largest (in this
> example) are smaller then the source resolution.
>
> http://c4.dev.s3.amazonaws.com/QMLImageRenderQuality.mov
>
> Here is an example of one of the Image invocations:
>
> Image {
> id: c4CameraImage
> fillMode: Image.PreserveAspectFit
> source: “path/to/c4camera.png"
> anchors.left: parent.left
> anchors.top: parent.top
> anchors.bottom: parent.bottom
> smooth : true
> opacity: 0.0
> }
>
> The animation is created with a number animation on the width and height of
> the parent rectangles.
>
> I’ve asked on IRC, and in the [interest] list, but one said it should just
> work and the other didn’t reply.
>
> Is this a known issue, a bug, or and I’m I doing it wrong?
>
> Thanks,
> j
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