TextMeasure

TextMeasure

import android.graphics.Paint
import android.util.TypedValue
import android.widget.TextView

/**
 * Use it for [android.widget.EditText], because on it autoSize doesn't work
 */
class TextMeasure(
    private val textView: TextView,
    private val maxSize: Float = 24.dp.toFloat(),
    private val minSize: Float = 2.dp.toFloat(),
    private val step: Float = 2.dp.toFloat(),
) {

    private val paint = Paint().also {
        it.typeface = textView.typeface
        it.letterSpacing = textView.letterSpacing
    }

    fun adjustTextSizeToMaxWidth(maxWidth: Int) {
        var size = textView.textSize
        var measuredWidth = measureTextWidthPx(size)

        if (measuredWidth > maxWidth) {
            while (true) {
                size -= step
                size = size.coerceAtLeast(minSize)
                measuredWidth = measureTextWidthPx(size)
                if (measuredWidth <= maxWidth || size <= minSize) {
                    textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, size)
                    return
                }
            }
        }

        if (measuredWidth < maxWidth) {
            var sizePrev = size
            while (true) {
                size += step
                size = size.coerceAtMost(maxSize)
                measuredWidth = measureTextWidthPx(size)
                if (measuredWidth > maxWidth) {
                    textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, sizePrev)
                    return
                }
                if (size == maxSize) {
                    textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, size)
                    return
                }
                sizePrev = size
            }
        }
    }

    private fun measureTextWidthPx(textSize: Float): Float {
        paint.textSize = textSize
        var string = textView.text?.toString() ?: ""
        if (string.isEmpty()) {
            string = textView.hint?.toString() ?: ""
        }
        return paint.measureText(string)
    }
}