Expose slide physical levels from generator

[Dainerx]

Having the real physical levels of slides exposed by generator is very useful. I've had this in my fork long time, first contribution among many to come.

Thank you for such an amazing driver.

[github-actions]

openslide-rs Benchmark

Details

Benchmark suite	Current: 2c22ec6	Previous: 41edcc8	Ratio
deepzoom_read_image_256	1153734 ns/iter (± 5769)	1154966 ns/iter (± 11381)	1.00
deepzoom_read_image_256_arc	1153235 ns/iter (± 7010)	1157794 ns/iter (± 8269)	1.00
deepzoom_read_image_256_recreate_dz	1155773 ns/iter (± 6466)	1156887 ns/iter (± 16701)	1.00
deepzoom_read_image_512	4603568 ns/iter (± 74845)	4605548 ns/iter (± 81183)	1.00
deepzoom_read_image_512_arc	4561190 ns/iter (± 80355)	4602386 ns/iter (± 91881)	0.99
deepzoom_read_image_512_recreate_dz	4574949 ns/iter (± 78430)	4618409 ns/iter (± 100998)	0.99
openslide_read_image_256	1120246 ns/iter (± 7520)	1125333 ns/iter (± 11235)	1.00
openslide_read_image_512	4585907 ns/iter (± 109550)	4643420 ns/iter (± 108503)	0.99
openslide_read_region_256	1067651 ns/iter (± 11418)	1071402 ns/iter (± 10519)	1.00
openslide_read_region_512	4389313 ns/iter (± 20960)	4411229 ns/iter (± 54003)	1.00

This comment was automatically generated by workflow using github-action-benchmark.

[AzHicham]

Having the real physical levels of slides exposed by generator is very useful. I've had this in my fork long time, first contribution among many to come.

Thank you for such an amazing driver.

I do not understand clearly what you need here ? the zoom level of real pyramid levels ? dimensions ? Because they can be obtained directly using those functions

openslide-rs/src/wrapper.rs

Line 108 in dd41458

pub fn get_all_level_dimensions(&self) -> Result<Vec<Size>> {

and

openslide-rs/src/wrapper.rs

Line 129 in dd41458

pub fn get_all_level_downsample(&self) -> Result<Vec<f64>> {