Transparent PNG Layers problem

Solar2D Android
#1

I have an ebook application where a page is built from two image layers. The above layer is basically a transparent png but has some texts on it. Some of those texts have a white background. The underlying background layer is filled with white color (for the area to show the texts).

On Android device build, once they overlapped, a grey color outline (about one pixel wide) appeared between the white and parent pixels. However, on iPhone and iPad I didn’t got this problem.

2 images are PNG format?I also tried Jpeg format for underlying image but the problem is still there.

Is there a smart way to solve this problem?
[import]uid: 38415 topic_id: 18749 reply_id: 318749[/import]

#2

maybye it’s a problem with thwe 16bit rendering on Android, are you using a daily build? If i remember, 32bits mode is supported since 3-4 daily versions. [import]uid: 44010 topic_id: 18749 reply_id: 72160[/import]

#3

I have a similar issue on certain GPUs on Android, namely the Adreno 200 that incorrectly renders transparency. This started about the time of 63x builds IIRC. It seems that the transparency mode is set to subtract instead of add. The result looks like the transparency is fading towards transparent black instead of transparent white. On a Tegra2 everything displays fine. [import]uid: 61899 topic_id: 18749 reply_id: 72184[/import]

#4

Thanks CluelessIdeas. So the problem is not easy to solve in the lua script level … We may need to edit image files to deal with those ugly lines.

BTW, The device I used is a HTC 510e mobile phone. [import]uid: 38415 topic_id: 18749 reply_id: 72189[/import]

#5

brought this up with engineering…

c.
[import]uid: 24 topic_id: 18749 reply_id: 72238[/import]

#6

Huang,

The release version of the Corona SDK (build #591) rendered everything in 16-bit color, which is the default for all Android apps. We added 32-bit color support in the newest daily builds. Try building with the newest daily build and see how it comes out. Also, make sure to run your app on a high-end Android device. Corona will automatically reduce the color quality to 16-bit color on low-end Android devices if they don’t have enough memory to hold the image in uncompressed form (which is what OpenGL requires).
[import]uid: 32256 topic_id: 18749 reply_id: 72289[/import]

#7

Thanks Carlos and Joshua. I tried the latest build (703) but the problem is still there. I will continues to try more saving options for the png file … [import]uid: 38415 topic_id: 18749 reply_id: 72686[/import]

#8

Hello Huang,

This issue is now fixed in the newest daily builds.

We noticed that this issue only happened on our Kindle Fire and Nook Tablet devices, but not on any of our other Android devices we tested with. Looked like an OpenGL driver bug on those 2 devices that caused all text and polygons to blend with black, thus making them appear darker than normal. It also caused PNGs with semi-transparent backgrounds to come out darker than normal too, which was a premultiplied alpha issue that occurs on those devices only. All of these problems should be gone now. I know this is an old post, but if you confirm that it is fixed on your end then that would be great. Thanks! [import]uid: 32256 topic_id: 18749 reply_id: 105960[/import]

#9

Hello, Joshua.

Yes, as you post, the prolem looks disappeared. Thanks for your effort and thanks for the description. [import]uid: 38415 topic_id: 18749 reply_id: 106031[/import]

#10

Like I said before, this was also happening in a LG Optimus Black P970 with Android 2.2 so it wasn’t just on Kindle Fire and Nook. Unfortunately I don’t have access to that phone anymore, so I can’t confirm if this is fixed or not, but I remember trying one of the 76x builds a while back and IIRC it was mostly fixed. [import]uid: 61899 topic_id: 18749 reply_id: 106046[/import]

#11

The changes we made should affect all Android devices, not just Kindle Fire and Nook Tablet… although those specific devices were the ones that generated the most noise for us which is why mention them specifically. I suspect that buggy OpenGL driver is used in other Android devices as well. [import]uid: 32256 topic_id: 18749 reply_id: 106134[/import]