Android绘制文字时垂直居中 _绘制文字

上下观古今，起伏千万途。这篇文章主要讲述Android绘制文字时垂直居中相关的知识，希望能为你提供帮助。

canvas.drawText(String text, float x, float y, Paint paint);

【Android绘制文字时垂直居中】是android中绘制文本的方法，其中的x代表文字绘制时在X轴的起始点，而y是在Y轴绘制时，文字的 baseline，不是文字的中心点也不是文字的底部。
下面代码根据绘制的Y轴中心点centerY，算出了baseline，top，bottom，ascent和descent

@Override protected void onDraw(Canvas canvas) {int top = mPaint.getFontMetricsInt().top; int bottom = mPaint.getFontMetricsInt().bottom; int ascent = mPaint.getFontMetricsInt().ascent; int descent = mPaint.getFontMetricsInt().descent; int baselineY =centerY + (bottom-top)/2 - bottom; top = baselineY + top; bottom = baselineY + bottom; ascent = baselineY + ascent; descent = baselineY + descent; mPaint.setColor(Color.GREEN); canvas.drawText(text, 100, baselineY, mPaint); canvas.drawLine(0, centerY, getMeasuredWidth(), centerY, mPaint); mPaint.setStrokeWidth(2); mPaint.setColor(Color.BLACK); canvas.drawLine(0, top, getMeasuredWidth(), top, mPaint); mPaint.setColor(Color.YELLOW); canvas.drawLine(0, ascent, getMeasuredWidth(), ascent, mPaint); mPaint.setColor(Color.RED); canvas.drawLine(0, baselineY, getMeasuredWidth(), baselineY, mPaint); mPaint.setColor(Color.YELLOW); canvas.drawLine(0, descent, getMeasuredWidth(), descent, mPaint); mPaint.setColor(Color.BLACK); canvas.drawLine(0, bottom, getMeasuredWidth(), bottom, mPaint); }