Getting the pixel data of a sprite after scale, filter etc

[tbird]

I know how to get the raw pixel data of the original texture of an image sprite, but is there a way to get the pixel data of the sprite just before it is composited with all of the other elements, but after it has been altered by scaling, filters, etc?

renderer.extract.pixels(mysprite) seems to just return the original texture no matter what transformations have been performed on the sprite.

[ivan.popelyshev]

put it to container, extract pixels from container. 

In any case, I always recommend to look how that `pixels` work - its actually several difficult operations, and any of them can misfire. gettngs bounds of object + render to texture + readPixels

[tbird]

Are you saying pixels is unreliable? If so, is there an alternative?

[ivan.popelyshev]

Unreliable = "we (community) found so many bugs in it, there can be more"

The only thing you can do is to be aware of how its done and do parts manually if something goes wrong.

[tbird]

I'm writing this as a favor for a public school teacher.

I have an image of a geographical map with a bunch of "hot" areas that I want to be able to individually detect clicks on.

My plan is to use different bitmap masks to represent each different area so they can scale to fit the browser window bounds along with the image. Then I was going to use pixels() to detect the alpha values of the mask pixel the mouse cursor is over.

Is there a smarter way to do arbitrary click-area detection that doesn't use pixels()?

Thank you for your help! 

[ivan.popelyshev]

> Then I was going to use pixels() to detect the alpha values of the mask pixel the mouse cursor is over.

https://github.com/pixijs/pixi.js/wiki/v5-Hacks#pixel-perfect-interaction

 

[tbird]

You are a god.

Will that work if even if the stage scales after a change in the browser window dimensions?

Edited June 25, 2020 by tbird

[ivan.popelyshev]

yes, i should, all resizes are handled with coordinates transformation (toLocal/toGlobal stuff)

in case something fails, check if interactionManager actually has correct coords of mouse, "renderer.plugins.interaction.somethingsomething" , you can override positioning function if you need : https://github.com/pixijs/pixi.js/wiki/v4-Gotchas#css-transforms-on-canvas

Edited June 27, 2020 by ivan.popelyshev