in my app I have a preview screen. On one device (LG, with Android 2.2, 320×480 screen) and another one (HTC, with Android 2.3, 480×800 screen) everything is OK. In both cases the list of supported preview sizes include one that fits the screen size exactly, I choose it and the image is perfect.
The problem comes with yet another device, having a screen similar to the first one (Samsung, Android 2.3, 320×480 screen). Regardless of the fact that I select a preview size that fits the screen size, as in previous cases, the image doe not preserve its aspect ratio; circles appear oval; the image is squeezed along the short axis of the screen. It seems the hardware itself, in order to obtain a 320×480 preview, squeezes the image (the camera has a form factor 4:3, while the screen has a form factor 3:2).
So I have altered the layout params of the view where the preview appears, in order to fit the form factor of the camera (size: 360×480. This PARTIALLY solves the problem; actually, to solve it completely I had to set 380×480 (!!!).
The fact is that I can’t possibly find any API that tells me about this different behavior, so that I can automatically compensate for it. Not even the Camera.Parameters.getHorizontalViewAngle and Camera.Parameters.getHorizontalViewAngle seem to be helpful; they give the same values on all of the three devices!
Can anyone help me?
in my app I have a preview screen. On one device (LG, with Android
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After deeper investigation, that included writing ad-hoc code to check how the preview is actually shown on the screen, this is what I found out.
On one device (LG E-720), the preview image is cropped in order to obtain a 3:2 form factor, then it is resized to fit on the screen. Aspect ratio is preserved:
On the second device (Samsung ACE), the preview image appears to be cropped in a different way, resulting in a 5:4 image (!?), that is then resized to fit on screen. Due to the different form factors, the image on screen appears squeezed.:
I have checked whether a software update was available for the second device, but this wansn’t the case. So in order to get a more or less correct image on screen, I have defined the target view as being 384 pixels tall; this actually causes a cropping that restores the correct aspect ratio. It doesn’t compensate, though, a small horizontal shift due to the fact that the original cropping is horizontally asymmetric.