FontMetrics-----Draw Text, get text height

When Canvas draws text, the coordinates of the position are calculated using the FontMetrics object.

1  Public Static classFontMetrics {2     /**3 * The maximum distance above the baseline for the tallest glyph in4 * The font at a given text size.5      */6      Public floattop;7     /**8 * The recommended distance above the baseline for singled spaced text.9      */Ten      Public floatascent; One     /** A * The recommended distance below the baseline for singled spaced text. -      */ -      Public floatdescent; the     /** - * The maximum distance below the baseline for the lowest glyph in - * The font at a given text size. -      */ +      Public floatBottom; -     /** + * The recommended additional space to add between lines of text. A      */ at      Public floatleading; -}

Its various baselines can be consulted as follows:

1 /**draw various lines of a FontMetrics object*/2 Mpaint.reset ();3 Mpaint.setcolor (color.white);4Mpaint.settextsize (80);5 //FontMetrics Object6FontMetrics FontMetrics =mpaint.getfontmetrics ();7String Text = "ABCDEFG";8 //calculate each of the coordinates9 floatTextWidth =mpaint.measuretext (text);Ten floatBaseX = 30; One floatBasey = 700; A floatTopy = Basey +Fontmetrics.top; - floatAscenty = Basey +fontmetrics.ascent; - floatDescenty = Basey +fontmetrics.descent; the floatbottomy = Basey +Fontmetrics.bottom; - //Draw Text - canvas.drawtext (text, BaseX, Basey, mpaint); - //Baseline Depiction + Mpaint.setcolor (color.red); -Canvas.drawline (BaseX, Basey, BaseX +textWidth, Basey, mpaint); +Mpaint.settextsize (20); ACanvas.drawtext ("base", BaseX +textWidth, Basey, mpaint); at //base Painting -Canvas.drawcircle (BaseX, Basey, 5, mpaint); - //topline Depiction - Mpaint.setcolor (color.ltgray); -Canvas.drawline (BaseX, topy, BaseX +textWidth, Topy, mpaint); -Canvas.drawtext ("Top", BaseX +textWidth, Topy, mpaint); in //Ascentline Depiction - Mpaint.setcolor (color.green); toCanvas.drawline (BaseX, Ascenty, BaseX +textWidth, Ascenty, mpaint); +Canvas.drawtext ("Ascent", BaseX + textWidth, Ascenty + 10, mpaint); - //Descentline Depiction the Mpaint.setcolor (color.yellow); *Canvas.drawline (BaseX, Descenty, BaseX +textWidth, Descenty, mpaint); $Canvas.drawtext ("Descent", BaseX +textWidth, Descenty, mpaint);Panax Notoginseng //Buttomline Depiction - Mpaint.setcolor (Color.magenta); theCanvas.drawline (BaseX, bottomy, BaseX +textWidth, bottomy, mpaint); +Canvas.drawtext ("Buttom", BaseX + textWidth, bottomy + ten, mpaint);

Believe that through the above procedures, can be a good understanding of topline,buttomline,baseline,ascentline,descentline.

In addition: There are two methods of the paint class

1 /**2 * Return The distance above (negative) the baseline (ascent) based on the3 * Current typeface and text size.4  *5  * @returnThe distance above (negative) the baseline (ascent) based on the6 * Current typeface and text size.7  */8  Public native floatascent ();9 Ten /** One * Return the distance below (positive) the baseline (descent) based on the A * Current typeface and text size. -  * -  * @returnThe distance below (positive) the baseline (descent) based on the * The current typeface and text size. -  */ -  Public native floatDescent ();

Ascent (): The distance above the baseline (height above baseline)

Descent (): The distance below the baseline (height below baseline)

So ascent () + descent () can be regarded as the height of the text.

So far, how to get the height and width of the text has been announced:

Get Height:mPaint.ascent () + mpaint.descent ()

Get Width:mPaint.measureText (text)

FontMetrics-----Draw Text, get text height