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?

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.

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.

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.

brought this up with engineering...

c.

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).

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 ...