Converting Pixel values to mm - Android

Question

Because of specific needs, in my android layout, I have used "mm" to provide size. In TextView also, I have provided sizes in "mm". When I do textView.getTextSize(), the size returned is always in pixel values. I want to convert that pixel value in "mm". For example, if I have set font size as "2mm", then on any device, when I do getTextSize(), I would like to get "2mm".

Should I use any specific method for that? I could find answers to convert "mm" to "pixel" but could not find anything about converting vice-versa.

score 11 · Accepted Answer · edited May 29 '14 at 08:50

11

we use TypedValue.java

float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_MM, 1, 
                getResources().getDisplayMetrics());

  public static float applyDimension(int unit, float value,
                                       DisplayMetrics metrics)
    {
        switch (unit) {
        case COMPLEX_UNIT_PX:
            return value;
        case COMPLEX_UNIT_DIP:
            return value * metrics.density;
        case COMPLEX_UNIT_SP:
            return value * metrics.scaledDensity;
        case COMPLEX_UNIT_PT:
            return value * metrics.xdpi * (1.0f/72);
        case COMPLEX_UNIT_IN:
            return value * metrics.xdpi;
        case COMPLEX_UNIT_MM:
            return value * metrics.xdpi * (1.0f/25.4f);
        }
        return 0;
    }

So you can try

Pix = mm * metrics.xdpi * (1.0f/25.4f);

MM = pix / metrics.xdpi * 25.4f;

edited May 29 '14 at 08:50

Oliv

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answered Jan 28 '13 at 20:04

Nimish Choudhary

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Thanks Nimish, your answer seems correct to me. I have edited it a bit - added brackets - float mm = pix /(dm.xdpi * (1.0f/25.4f)); – Raj Patel Jan 28 '13 at 20:28
hmm... strange but breaks are still absent. – Eugene Dudnyk Dec 26 '13 at 09:04
I edited it too: MM = pix / metrics.xdpi * 25.4f; Maybe they will accept my edit... – Oliv May 29 '14 at 08:50
the formula is correct as originally written.
please ignore the edits – federico verchez Jun 14 '21 at 19:21

score 8 · Answer 2 · answered Jan 22 '15 at 11:07

I'd say a more robust method (which evolves with whatever new insight is applied in the Android framework) is this:

public static float pxToMm(final float px, final Context context)
{
    final DisplayMetrics dm = context.getResources().getDisplayMetrics();
    return px / TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_MM, 1, dm);
}

score 0 · Answer 3 · edited May 23 '17 at 12:31

0

Try looking with this link. You are looking for screen pixel density.

getting the screen density programmatically in android?

From here you can use inches to mm conversions (1 inch == 25.4 mm) to get your answer.

edited May 23 '17 at 12:31

Community

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answered Jan 28 '13 at 19:52

trumpetlicks

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score 0 · Answer 4 · answered Jan 28 '13 at 19:56

0

Here is another option from google: http://developer.android.com/reference/android/util/DisplayMetrics.html

You'll need to scale this number to mm so use 25.4mm = 1 inch.

answered Jan 28 '13 at 19:56

paulczak

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6

score -2 · Answer 5 · answered Jan 28 '13 at 20:00

-2

float mm = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, 1, 
            getResources().getDisplayMetrics());

applyDimesion parameters

answered Jan 28 '13 at 20:00

Vikalp Patel

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This will return pixel value as is. – Eugene Dudnyk Dec 26 '13 at 09:01

Converting Pixel values to mm - Android

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