QQuickImageProvider equivalent in slint?

[bog-dan-ro]

Hi,

What's the best way to provide images to slint Image ui element?
Is there any QQuickImageProvider equivalent in slint?
Slint should cache the image texture by some id/path and reuse it when needed.

[tronical]

Images are specified with the source property. You can either supply that give the literal @image-url("string literal path to image here") or you can programmatically create slint::Image objects in Rust and C++ and assign them to the source property. The type of the source property is image, which maps to slint::Image.

The documentation linked above has examples how to create slint::Image objects from pixel buffers. Those are shared by reference count. Both, in Rust and C++, slint::Image can also be created from a path to an image file on disk, using load_from_path().

If you repeatedly call slint::Image::load_from_path() with the same path, it will only load the image from disk the first time. Subsequent calls will re-use the previously loaded image from a cache. The cache has a capacity of roughly 5MB at the time of writing, the size of each item in the cache is weighed by the weight of the image in bytes (where possible).

Once a slint::Image is assigned to the source property of an Image element, the renderer takes care of allocating and populating a texture for it (unless it's the software renderer). That texture is cached by the same keying mechanism as the regular image cache, so the texture will not be re-populated on every frame.

[bog-dan-ro]

Thanks!

[bog-dan-ro]

If I'm creating 100 slint::Image from the same SharedPixelBuffer will they share the same texture?

[tronical]

No, such images will not share the same texture. It might be possible to fix this, I'm not sure.

[bog-dan-ro]

Well, without sharing the same texture it will waste a lot of resources ;-)
Maybe turn this discussion into a task?

[tronical]

Sure.