Android 绘制之文字测量

drawText() 绘制文字

绘制进度条:paint.strokeCap = Paint.CAP.RONUD 线条两边样式 

设置文字字体:paint.typeFace = Resources.Compat.getFont(context,font)

设置加粗  paint.isFakeBoldText

设置居中: paint.setTextAlign = Paint.Align.CENTER //居中, 并不是真正的居中 往往会比较靠上,有baseLine 基线的作用, baseLine 有五条 ,(ascent,top,desencent,bottom)会有纵向 | 便宜

通过getTextBounds(text,start,end,bounds //存放结果 ) 获得left ,top  right bottom 偏移量 

静态文字设置示例:

paint.getTextBounds("AAAA",0,"AAAA".length,bounds)
canvas.drawText("AAAA",width / 2f,height / 2f - ((bounds.top + bounds.bottom) / 2),paint)

计算偏移量 设置居中,

动态设置:

paint.getFontMetrics(fontMetrices)
canvas.drawText("abcpst",width / 2f,height / 2f - ((fontMetrices.ascent + fontMetrices.descent) / 2),paint)

文字靠左显示:

paint.textAlign = Paint.Align.LEFT
canvas.drawText("ababab",0f, - fontMetrices.top,paint)

靠左上角

paint.textAlign = Paint.Align.LEFT
paint.getTextBounds("ababab",0,"ababab".length,bounds)
canvas.drawText("ababab",0f, - bounds.top.toFloat(),paint) //静态

文字左右各占空间 字体越大 占用空越大 示例:

        paint.textSize = 150.dp
        paint.textAlign = Paint.Align.LEFT
        paint.getTextBounds("ababab",0,"ababab".length,bounds)
        canvas.drawText("ababab",0f, - bounds.top.toFloat(),paint) 


        paint.textSize = 15.dp
        paint.getTextBounds("ababab",0,"ababab".length,bounds)
        canvas.drawText("ababab",0f, - bounds.top.toFloat(),paint) 

字体越大 文字间间距越大,因为有baseLine的左右以及textBound设置

解决:

        paint.textSize = 150.dp
        paint.textAlign = Paint.Align.LEFT
        paint.getTextBounds("ababab",0,"ababab".length,bounds)
        canvas.drawText("ababab",- bounds.left.toFloat(), - bounds.top.toFloat(),paint) 

     
        paint.textSize = 15.dp
        paint.getTextBounds("ababab",0,"ababab".length,bounds)
        canvas.drawText("ababab",-bounds.left.toFloat(), - bounds.top.toFloat(),paint) 

其实仔细看还是有一点点间距,这是文字的字体所占用的缝隙

StaticLayout 使用

StaticLayout(text,textPaint,width ,align,span 间距,行距)

val staticLayout = StaticLayout.Builder.obtain(text, 0, text.length, textPaint, width)
textPaint.textSize = 16.dp
staticLayout.build().draw(canvas)

 

paint.fontSpacing 行间距

单个图文混合排序示例

canvas.drawBitmap(bitmap, width - IMAGE_SIZE, IMAGEPADDING, paint)
        paint.getFontMetrics(fontMetrice)


        val mesureWidth = floatArrayOf(0f)
        var start = 0
        var count: Int
        var offSet = -fontMetrice.top
        var maxWidth: Float
        while (start < text.length) {

            if (offSet + fontMetrice.bottom < IMAGEPADDING || offSet + fontMetrice.top > IMAGE_SIZE + IMAGEPADDING) {
                maxWidth = width.toFloat()
            } else {
                maxWidth = width.toFloat() - IMAGE_SIZE
            }

            count = paint.breakText(
                text,
                start,
                text.length,
                true,
                maxWidth,
                mesureWidth
            )

            canvas.drawText(text, start, start + count, 0f, offSet, paint)
            start += count
            offSet += paint.fontSpacing

        }