App uses incorrect screen resolution

[Guest]

I wonder whether anybody has stumbled over this..

When I generate an android app with RH10 and display it on a device with 480x800 screen resolution, then the HTML pages act as if they run on 320x480 instead.

This results in the following problems:

* Images in topics that would actually fit easily on a 480x800 display (e.g. images with a width of 350) are scaled larger and require horizontal scrolling.

* Media queries do not funktion properly. MQs that switch depending on width (e.g. changing formatting at a screen width below 340) apply the smaller size formatting even though the screen width is larger.

We have confirmed this behaviour on two different devices (Android 2.2.2 and 2.3.4). I have also tried adding a supports-screens tag to the manifest to enable xlargeScreens but this did not help. Any ideas?

Robert

[Peter Grainge]

Whatever layout you get, even if the wrong one to what you intended, the layout itself should fit to screen. At least, that is my experience.

Media queries seem to be appyling based on window size rather then screen size. Try it with a desktop layout and resize the window. Text colour for example will change as you resize. Also the query seems to be taking into account window size only and ignoring the link with the profile. In other words font changing to red at 600 pixels for say Android will change in Desktop layout.

Have you checked the optimization settings for each profile to see that resizing is on in all of them?

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@petergrainge

[Guest]

It seems that the images with problems all had image maps. Evidently this

prevented them from rescaling to fit the display width. So I guess I'll

have to get rid of the maps.

The oddity concerning media queries still exists. When I create an MQ that

e.g. turns the writing red below a width of 340px then this is applied

even though the screen width is 480px (and the app fills the entire

width). It works correctly in HTML5 output with my desktop browser, just

the app behaves strange.

[Guest]

Solved! I had to add the following to the viewport tag in the Topic.slp page:

target-densityDpi=device-dpi

This forces the device to omit any scaling and display images 1:1.

[Peter Grainge]

Had you tried doing that via the optimisation settings? 

[Guest]

Yes, but as it turned out the entire issue is more related to mobile display principles that I was not aware of.

Here is a good article I found - even though it addresses IOS applications the described basics apply commonly. The solution to my problem was posted as comment #28 at the end:

http://www.quirksmode.org/blog/archives/2010/04/a_pixel_is_not.html

P.S. I would not recommend to use this unless a 1:1 pixel control is really required. Normally the devices do a good job at rescaling HTML content to make it more readable.