android fontMetrics 使用說明

FontMetrics對象 它以四個基本座標爲基準，分別爲：

・FontMetrics.top ・FontMetrics.ascent ・FontMetrics.descent ・FontMetrics.bottom

實例JAVA代碼以下： Paint textPaint = new Paint( Paint.ANTI_ALIAS_FLAG); textPaint.setTextSize( 35); textPaint.setColor( Color.WHITE);

// FontMetrics對象 FontMetrics fontMetrics = textPaint.getFontMetrics(); String text = "abcdefghijklmnopqrstu";

// 計算每個座標 float baseX = 0; float baseY = 100; float topY = baseY + fontMetrics.top; float ascentY = baseY + fontMetrics.ascent; float descentY = baseY + fontMetrics.descent; float bottomY = baseY + fontMetrics.bottom;

// 繪製文本 canvas.drawText( text, baseX, baseY, textPaint);

// BaseLine描畫 Paint baseLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG); baseLinePaint.setColor( Color.RED); canvas.drawLine(0, baseY, getWidth(), baseY, baseLinePaint);

// Base描畫 canvas.drawCircle( baseX, baseY, 5, baseLinePaint);

// TopLine描畫 Paint topLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG); topLinePaint.setColor( Color.LTGRAY); canvas.drawLine(0, topY, getWidth(), topY, topLinePaint);

// AscentLine描畫 Paint ascentLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG); ascentLinePaint.setColor( Color.GREEN); canvas.drawLine(0, ascentY, getWidth(), ascentY, ascentLinePaint);

// DescentLine描畫 Paint descentLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG); descentLinePaint.setColor( Color.YELLOW); canvas.drawLine(0, descentY, getWidth(), descentY, descentLinePaint);

// ButtomLine描畫 Paint bottomLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG); bottomLinePaint.setColor( Color.MAGENTA); canvas.drawLine(0, bottomY, getWidth(), bottomY, bottomLinePaint);