What parameters metrics dimensions give each Composable item

Question

What parameters metrics dimensions give each Composable item it s Clickable area on screen Can the shape or area be customised Thanks

Kebbin · Answer

When rotating X or Y axis of an item the click sensing area for each item is increased massively and is shifted based on its relative position on the screen It s like as if there is a substantial invisible Z component that rears up and moves

romainguy · Answer

X Y rotations are 3D rotations

Kebbin · Answer

Yes so why does the clickable area shift

romainguy · Answer

And unless the default projection has changed compared to Views it will indeed massively increase the touch target but it should be the same as what s visible if you paint the bounds

romainguy · Answer

Maybe your rotation pivot is not the item s center

Kebbin · Answer

I have a small number of items placed across the Surface spread across the screen to test these things They work when Rotating Z but not X or Y The rotation point for everything is the centre of the screen Actually I think when the tilted objects are panned to the centre they are more evenly responsive but still a massive touch target If I rotate back in X the target grows in Y

Kebbin · Answer

Even tho the drawn item shrinks in Y as it should

Kebbin · Answer

If I can find what affects the clickable target I can prob adjust it When adjusting the view projection using matrices the targets just remain in their original position hence trying this way now

Kebbin · Answer

I tried finding a way to draw a custom outline for an object based on different perceived view angles but only found basic Shape options I can draw custom shapes on the canvas but the clickable target remains square for a Box Maybe I need to try placing a different type of clickable object that s more customisable Like a button perhaps

Kebbin · Answer

Another thought I had was not to even rotate the X axis but just simulate it like everything else Might be easier to control the shapes if they remain flat

Kebbin · Answer

If I can control the clickable targets or have them match the shapes

Kebbin · Answer

More experimenting Thanks very much for your time and help again

romainguy · Answer

< Nader Jawad> couls confirm but rotations should be properly handled with touch events Either it sounds like a bug or I don t quite understand your description A video and or a reproducible example would be extremely helpful

Kebbin · Answer

Hopefully this shows clearly enough what s happening The rotations work but the objects targets don t act as expected

Kebbin · Answer

They work fine until they are rotated in X or Y These are just clickable Boxes on a Surface with a grid background Image

Kebbin · Answer

I tried adding a ` clip GenericShape ` random path shape but the selection targets didn t change even just in flat 2D presentation They still clicked using the underlying Box shape size

romainguy · Answer

Hit tests are only based on boxes optionally transformed via rotations scales shear etc but that s about it

romainguy · Answer

Seems like there s a bug in the handling of those events when a transform matrix is applied

romainguy · Answer

Could you please file a bug

Nader Jawad · Answer

I know that we take into account matrix transformations for touch events on the most recently graphicsLayer that is being transformed Just to verify can you try running the same code on Android so we can verify if it is a transformation issue on desktop vs Android vs compose in general cc < George Mount> who also worked on touch transformations for matrix transformed layers

George Mount · Answer

It should work and I m sure we have some tests but I think the tests are all with easy 90 degree turns Our tests may not have sufficient coverage for this and it is worth double checking

Kebbin · Answer

Hello all Thanks so much for your time on this This is a hobby project for the railway modelling hobby in general and I m not set up to do Android testing yet sorry to promote the team I have perspective transforms working by drawing into the Canvas of the Surface using `drawWithContent drawContent ` but that just transforms the visual leaving the base objects in their original position Thanks very very much to < Igor Demin> for lighting the path to that I m now trying some different perspective maths to adjust the actual base object position on screen and actually just rotate the Surface itself to try and retain the link between object base and visual As soon as the X axis is tilted back the targets go haywire I ll get back on it again tonight ~8hrs I m in Aus Thanks Colin Grabham NSW

Kebbin · Answer

Hello all I prob won t be much help but can you please show me where to start looking for the code that handles the touch targets and the rotation adjustments I m curious how it works I ve just updated my program to Compose 1 0 0

Kebbin · Answer

< Nader Jawad> < George Mount> Can you point me to the code that handles the click targets Thanks