Measuring text width to be drawn on Canvas ( Android )

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轮回少年
轮回少年 2020-12-12 16:18

Is there a method which returns the width ( in pixels ) of a text to be drawn on an Android canvas using the drawText() method according to the Paint used to draw it?

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  • 2020-12-12 16:22

    Supplemental answer

    There is a slight difference between the width returned by Paint.measureText and Paint.getTextBounds. measureText returns a width that includes the glyph's advanceX value padding the beginning and end of the string. The Rect width returned by getTextBounds does not have this padding because the bounds is the Rect that tightly wraps the text.

    source

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  • 2020-12-12 16:26

    I used the methods measureText() and getTextPath()+computeBounds() and build up an Excel with all text attributes for fixed size font that can be found under https://github.com/ArminJo/android-blue-display/blob/master/TextWidth.xlsx . There you will find also simple formulas for other text attributes like ascend etc.

    The app as well as the function drawFontTest() for generating the raw values used in the excel are also available in this repo.

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  • 2020-12-12 16:29

    Have you looked at android.graphics.Paint.measureText(String txt)?

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  • 2020-12-12 16:32

    Well I have done in different way:

    String finalVal ="Hiren Patel";
    
    Paint paint = new Paint();
    paint.setTextSize(40);
    Typeface typeface = Typeface.createFromAsset(getAssets(), "Helvetica.ttf");
    paint.setTypeface(typeface);
    paint.setColor(Color.BLACK);
    paint.setStyle(Paint.Style.FILL);
    
    Rect result = new Rect();
    paint.getTextBounds(finalVal, 0, finalVal.length(), result);
    
    Log.i("Text dimensions", "Width: "+result.width()+"-Height: "+result.height());
    

    Hope this will help you.

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  • 2020-12-12 16:35

    There's actually three different ways of measuring text.

    GetTextBounds:

    val paint = Paint()
    paint.typeface = ResourcesCompat.getFont(context, R.font.kaushanscript)
    paint.textSize = 500f
    paint.color = Color.argb(255, 3, 221, 252)
    val contents = "g"
    val rect = Rect()
    paint.getTextBounds(contents, 0, 1, rect)
    val width = rect.width()
    

    MeasureTextWidth:

    val paint = Paint()
    paint.typeface = ResourcesCompat.getFont(context, R.font.kaushanscript)
    paint.textSize = 500f
    paint.color = Color.argb(255, 3, 221, 252)
    val contents = "g"
    val width = paint.measureText(contents, 0, 1)
    

    And getTextWidths:

    val paint = Paint()
    paint.typeface = ResourcesCompat.getFont(context, R.font.kaushanscript)
    paint.textSize = 500f
    paint.color = Color.argb(255, 3, 221, 252)
    val contents = "g"
    val rect = Rect()
    val arry = FloatArray(contents.length)
    paint.getTextBounds(contents, 0, contents.length, rect)
    paint.getTextWidths(contents, 0, contents.length, arry)
    val width = ary.sum()
    

    Note that getTextWidths could be useful if you are trying to determine when to wrap text to the next line.

    The measureTextWidth and getTextWidth are equal and have the advanced width that measure that others have posted about. Some consider this space excessive. However, this is very subjective and dependent on the font.

    For example the width from measure text bounds may actually look too small:

    measure text bounds looks small

    However when adding an additional text the bounds for one letter looks normal: measure text bounds looks normal for strings

    Images taken from Android Developers Guide to Custom Canvas Drawing

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  • 2020-12-12 16:41
    Paint paint = new Paint();
    Rect bounds = new Rect();
    
    int text_height = 0;
    int text_width = 0;
    
    paint.setTypeface(Typeface.DEFAULT);// your preference here
    paint.setTextSize(25);// have this the same as your text size
    
    String text = "Some random text";
    
    paint.getTextBounds(text, 0, text.length(), bounds);
    
    text_height =  bounds.height();
    text_width =  bounds.width();
    
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