Thrash pixels on some Android phone

Rickyngk

I'm using Galaxy Gio: http://www.gsmarena.com/samsung_galaxy_gio_s5660-3741.php
And the following attachment shows exactly that is displayed on phone. There're a lot of black dots

Have you ever got the same issue before, please give me a hint !

Thanks,

moopf

That looks a lot like dithering to me. Does it look the same in the Gideros desktop player? If it does, then it's likely to be the bit depth you have saved the images in originally. If it doesn't, do you know what the bit depth of the Gio is?

Rickyngk

This issue is not happened on desktop player (and some other device)

The folowing is GIO's detail:

TFT capacitive touchscreen, 16M colors
Device VGA infomation:
+ Vender: Qualcomm
+ Renderer: Adreno 200
+ Version: OpelGLES 2.0

+ Pixel formats (rgba - z - stencil)
5650 - 0 - 0
5650 - 16 - 0
5650 - 24 - 8
8880 - 0 - 0
8880 - 16 - 0
8888 - 0 - 0
8888 - 16 - 0
8888 - 24 - 8
0008 - 0 - 0
0008 - 16 - 0

moopf

OK, what format are you saving the images in? My only other guess would be that however you're saving them, this is being downgraded for display by the Gio. I don't know the phone at all, so it's purely a guess.

Rickyngk

I find-out that many phones which support only 16M color, 256K color have got this issue.
I used 24/32bit png file. So, should I reduce to 16 bits (and how ?) ?

moopf

What image package are you using?

Rickyngk

image package ? What do you mean ?

moopf

I mean what application are you using to create the images in the first place.

Rickyngk

I use both ps and paint.net

moopf

You should be able to change it to save a 16-bit PNG in PS, try that. Not sure about paint.net

Rickyngk

Thank @moopf. I'll try when back to my office in next week

Rickyngk

Finally, I've found the reason behind. I can't give exactly my code, but it works in the same way with following code:

function GetWatermark(alpha, rgb, x, y, w, h) local obj = Shape.new() obj:setLineStyle(0, rgb) obj:setFillStyle(Shape.SOLID, rgb, alpha) obj:beginPath() obj:moveTo(x, y) obj:lineTo(x, y + h) obj:lineTo(x + w, y + h) obj:lineTo(x + w, y) obj:lineTo(x, y) obj:closePath() obj:endPath() obj:setVisible(alpha > 0) return obj end   spr = Sprite.new() sprChild = {Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new(), Sprite.new()}   for _,v in pairs(sprChild) do v:addChild(GetWatermark(0, 0xFFFFFF, 0, 0, 320, 240)) spr:addChild(v) end   local texture = Texture.new("logo.png") local bitmap = Bitmap.new(texture)   sprChild[1]:addChild(bitmap)   stage:addChild(spr)

This bug is come from

v:addChild(GetWatermark(0, 0xFFFFFF, 0, 0, 320, 240))

@atilim: would you please explain why?

I fixed by checking if alpha is zero, I set visible to false.

(Note: this bug happen on Android device, which support 16M color or 256K color)