What is going on with masks of display groups and images in them?

#1

My screen is 320x480. My mask file, mask.png is 320x480 with some white, black and slightly opaque black parts. When I set a mask on a display group, the mask is way off. Even though it says it’s maskX and maskY is 0 and 0, I can only see the whole part of my masked display group when I move the mask to 160,240 (the center of my screen)

And how come I can’t set the alpha of images inside my display group, but I can set the alpha to other display objects?

\_W = display.contentWidth  
\_H = display.contentHeight  
  
local dg = display.newGroup()  
local mask = graphics.newMask('mask.png')  
dg:setMask(mask)  
print (dg.maskX,dg.maskY) -- maskX and maskY are 0 and 0 but...  
dg.maskX = 160 -- i have to set this  
dg.maskY = 240 -- and this to the center of the screen  
 -- otherwise i only see the top left corner of the mask  
 -- as if the default maskX and maskY are -160 and -240  
 -- even though printing them shows 0 and 0!  
  
local rect = display.newRect(dg,0,0,\_W,\_H)  
rect.alpha = .5 -- the rect I draw can have its alpha adjusted  
  
local box = display.newImage(dg,'box.png',20,20)  
box.alpha = .5 -- the image I draw can NOT have its alpha adjusted???

box.png
mask.png
[import]uid: 213270 topic_id: 36144 reply_id: 336144[/import]

#2

Off the top of my head I would think if the x/y is 0,0 then the mask must be setup with a center reference point. I am not familair with using masks much except with my table views.

As for the alpha, that could be a bug that was around for quite some time with masks. I know it was fixed with alpha and table views in a recent daily build. However I don’t know if that fixed masked all the way around.

Your posting account says test driver so you may not have a paid account. If you are using public build .971 then it still has alpha/mask issues. [import]uid: 56820 topic_id: 36144 reply_id: 143552[/import]

#3

Thanks for the info! The reference point was my assumption too, but I didn’t see that behavior when I put mask on other display objects or a way to change the reference points for the mask.

You are correct, I have not committed yet to the full version of Corona and am using build .971. I am still testing the waters, making sure that developing a full app (game actually) is totally doable with Corona.

So I guess I can only hope that this issue won’t arise in the latest build? [import]uid: 213270 topic_id: 36144 reply_id: 143555[/import]

#4

Hi @mike.rp99,
Please see the following API pages on masks, if you haven’t already. Applying a mask to a display group versus a display object requires a re-positioning (for a group) because the group’s inherent top-left reference point.

http://docs.coronalabs.com/api/library/graphics/newMask.html
http://docs.coronalabs.com/api/type/DisplayObject/setMask.html

Also, your mask should have a black border around it of 4 pixels or so. This is documented above. Finally, as of Daily Build 1025, alpha now works on masked images.

Hope this helps,
Brent [import]uid: 200026 topic_id: 36144 reply_id: 143621[/import]

#5

Gotcha. That’s good news that the alphas for masked objects are fixed. And thanks for the info and links to documentation on using masks, Brent! [import]uid: 213270 topic_id: 36144 reply_id: 143677[/import]

#6

Off the top of my head I would think if the x/y is 0,0 then the mask must be setup with a center reference point. I am not familair with using masks much except with my table views.

As for the alpha, that could be a bug that was around for quite some time with masks. I know it was fixed with alpha and table views in a recent daily build. However I don’t know if that fixed masked all the way around.

Your posting account says test driver so you may not have a paid account. If you are using public build .971 then it still has alpha/mask issues. [import]uid: 56820 topic_id: 36144 reply_id: 143552[/import]

#7

Thanks for the info! The reference point was my assumption too, but I didn’t see that behavior when I put mask on other display objects or a way to change the reference points for the mask.

You are correct, I have not committed yet to the full version of Corona and am using build .971. I am still testing the waters, making sure that developing a full app (game actually) is totally doable with Corona.

So I guess I can only hope that this issue won’t arise in the latest build? [import]uid: 213270 topic_id: 36144 reply_id: 143555[/import]

#8

Hi @mike.rp99,
Please see the following API pages on masks, if you haven’t already. Applying a mask to a display group versus a display object requires a re-positioning (for a group) because the group’s inherent top-left reference point.

http://docs.coronalabs.com/api/library/graphics/newMask.html
http://docs.coronalabs.com/api/type/DisplayObject/setMask.html

Also, your mask should have a black border around it of 4 pixels or so. This is documented above. Finally, as of Daily Build 1025, alpha now works on masked images.

Hope this helps,
Brent [import]uid: 200026 topic_id: 36144 reply_id: 143621[/import]

#9

Gotcha. That’s good news that the alphas for masked objects are fixed. And thanks for the info and links to documentation on using masks, Brent! [import]uid: 213270 topic_id: 36144 reply_id: 143677[/import]

#10

Off the top of my head I would think if the x/y is 0,0 then the mask must be setup with a center reference point. I am not familair with using masks much except with my table views.

As for the alpha, that could be a bug that was around for quite some time with masks. I know it was fixed with alpha and table views in a recent daily build. However I don’t know if that fixed masked all the way around.

Your posting account says test driver so you may not have a paid account. If you are using public build .971 then it still has alpha/mask issues. [import]uid: 56820 topic_id: 36144 reply_id: 143552[/import]

#11

Thanks for the info! The reference point was my assumption too, but I didn’t see that behavior when I put mask on other display objects or a way to change the reference points for the mask.

You are correct, I have not committed yet to the full version of Corona and am using build .971. I am still testing the waters, making sure that developing a full app (game actually) is totally doable with Corona.

So I guess I can only hope that this issue won’t arise in the latest build? [import]uid: 213270 topic_id: 36144 reply_id: 143555[/import]

#12

Hi @mike.rp99,
Please see the following API pages on masks, if you haven’t already. Applying a mask to a display group versus a display object requires a re-positioning (for a group) because the group’s inherent top-left reference point.

http://docs.coronalabs.com/api/library/graphics/newMask.html
http://docs.coronalabs.com/api/type/DisplayObject/setMask.html

Also, your mask should have a black border around it of 4 pixels or so. This is documented above. Finally, as of Daily Build 1025, alpha now works on masked images.

Hope this helps,
Brent [import]uid: 200026 topic_id: 36144 reply_id: 143621[/import]

#13

Gotcha. That’s good news that the alphas for masked objects are fixed. And thanks for the info and links to documentation on using masks, Brent! [import]uid: 213270 topic_id: 36144 reply_id: 143677[/import]

#14

Off the top of my head I would think if the x/y is 0,0 then the mask must be setup with a center reference point. I am not familair with using masks much except with my table views.

As for the alpha, that could be a bug that was around for quite some time with masks. I know it was fixed with alpha and table views in a recent daily build. However I don’t know if that fixed masked all the way around.

Your posting account says test driver so you may not have a paid account. If you are using public build .971 then it still has alpha/mask issues. [import]uid: 56820 topic_id: 36144 reply_id: 143552[/import]

#15

Thanks for the info! The reference point was my assumption too, but I didn’t see that behavior when I put mask on other display objects or a way to change the reference points for the mask.

You are correct, I have not committed yet to the full version of Corona and am using build .971. I am still testing the waters, making sure that developing a full app (game actually) is totally doable with Corona.

So I guess I can only hope that this issue won’t arise in the latest build? [import]uid: 213270 topic_id: 36144 reply_id: 143555[/import]

#16

Hi @mike.rp99,
Please see the following API pages on masks, if you haven’t already. Applying a mask to a display group versus a display object requires a re-positioning (for a group) because the group’s inherent top-left reference point.

http://docs.coronalabs.com/api/library/graphics/newMask.html
http://docs.coronalabs.com/api/type/DisplayObject/setMask.html

Also, your mask should have a black border around it of 4 pixels or so. This is documented above. Finally, as of Daily Build 1025, alpha now works on masked images.

Hope this helps,
Brent [import]uid: 200026 topic_id: 36144 reply_id: 143621[/import]

#17

Gotcha. That’s good news that the alphas for masked objects are fixed. And thanks for the info and links to documentation on using masks, Brent! [import]uid: 213270 topic_id: 36144 reply_id: 143677[/import]