如何使用Paint.getTextBounds（）快速获取TextView的宽度和高度？

Question

There is a method in Paint class: Paint.getTextBounds() which returns Rect occupied by some text. But according to this answer it returns something different then width/height of TextView.

Q1: Is there a way to get width and height of TextView using Rect returned by Paint.getTextBounds() ?

Note, I do need to know width/height precisely. I will be happy to know upper bound of the rect with possible error about 2-3%, but it MUST be not greater (and should work for any phone not depending on screen resolution and pixel density) then TextView bounds

Q2: Is there any other QUICK method of determining width and height of some text with specified textSize?

I know, width can be determined by Paint.measureText() , but this doesn't return height. Height can be determined by creating new StaticLayout with text and then calling StaticLayout.getHeight() , but this is too slow. I need something more quicker.

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The background for all of this is making AutoFitTextView which will automaticaly fit text inside its bounds by up- or down-scaling text size, and it should do this quickly, as there will be many of such AutoFitTextView s changed dynamically very quickly.

Answer 1

Found a simple and not slow method of determining text width/height drawn with specific Paint that doesn't use StaticLayout .

public int getTextWidth(String text, Paint paint) {
    Rect bounds = new Rect();
    paint.getTextBounds(text, 0, text.length(), bounds);
    int width = bounds.left + bounds.width();
    return width;
}

public int getTextHeight(String text, Paint paint) {
    Rect bounds = new Rect();
    paint.getTextBounds(text, 0, text.length(), bounds);
    int height = bounds.bottom + bounds.height();
    return height;
}

The short simple description of trick: Paint.getTextBounds(String text, int start, int end, Rect bounds) returns Rect which doesn't starts at (0,0) . That is, to get actual width of text that will be set by calling Canvas.drawText(String text, float x, float y, Paint paint) with the same Paint object from getTextBounds() you should add the left position of Rect .

Notice this bounds.left - this the key of the problem.

In this way you will receive the same width of text, that you would receive using Canvas.drawText() .

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Much more detailed explanation is given in this answer.

Answer 2

With java I used class FontMetrics.

Font f= new Font("Arial", Font.BOLD, 16);
FontMetrics metric = getFontMetrics(f);


metric.stringWidth("the text I want to measure");