Which unit of measurement does the Paint.setTextSize(float) use?

问题

I want to draw text with an specific height(in pixels) on a view using Canvas. Can you simply use Paint.setTextSize(float) with the number of pixels or is this using dp or sp?

回答1:

It uses pixels, but you can convert it to dp using this code:

double getDPFromPixels(double pixels) {
    DisplayMetrics metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    switch(metrics.densityDpi){
     case DisplayMetrics.DENSITY_LOW:
                pixels = pixels * 0.75;
                break;
     case DisplayMetrics.DENSITY_MEDIUM:
                 //pixels = pixels * 1;
                 break;
     case DisplayMetrics.DENSITY_HIGH:
                 pixels = pixels * 1.5;
                 break;
    }
    return pixels;
}

回答2:

The easiest way to get a px value for such methods is to simply define the appropriate dp or sp value in the dimens.xml file and retrieve it like this:

int sizeInPx = context.getResources().getDimensionPixelSize(R.dimen.sizeInSp);

You actually have 3 methods available to use depending on your needs:

getDimension() Returns a float in pixels.
getDimensionPixelSize() Returns an int in pixels. This is the same as getDimension(), except the returned value is ROUNDED to the nearest integer value and it ensures that a non-zero input value results in a non zero output value (eg 0.1 is returned as 1, not 0).
getDimensionPixelOffset() Returns an int in pixels. This is the same as getDimension(), except the returned value is TRUNCATED (ie. rounded down). The result may be zero.

回答3:

These methods include DisplayMetrics that can be added into future Android SDK.

Pixels to dip:

public static float getDipFromPixels(float px) {
        return TypedValue.applyDimension(
                TypedValue.COMPLEX_UNIT_PX,
                px,
                Resources.getSystem().getDisplayMetrics()
        );
}

Dip to pixels:

public static float getPixelsFromDip(float dip) {
        return TypedValue.applyDimension(
                TypedValue.COMPLEX_UNIT_DIP, 
                dip,
                Resources.getSystem().getDisplayMetrics()
        );
}

来源：https://stackoverflow.com/questions/11720093/which-unit-of-measurement-does-the-paint-settextsizefloat-use

标签

android

units-of-measurement