| package androidx.ui.text.platform.style |
| |
| import android.text.TextPaint |
| import android.text.style.MetricAffectingSpan |
| import androidx.annotation.Px |
| import androidx.ui.text.platform.InternalPlatformTextApi |
| |
| /** |
| * Span that sets the letter spacing as [letterSpacing], in the unit of pixel. |
| * |
| * @suppress |
| */ |
| @InternalPlatformTextApi |
| class LetterSpacingSpanPx(@Px val letterSpacing: Float) : MetricAffectingSpan() { |
| private fun TextPaint.updatePaint() { |
| // In framework, 1em letterSpacing equals to textSize * textScaleX pixels. |
| val emWidth = textSize * textScaleX |
| // Do nothing if emWidth is 0.0f. |
| if (emWidth != 0.0f) { |
| letterSpacing = this@LetterSpacingSpanPx.letterSpacing / emWidth |
| } |
| } |
| |
| override fun updateDrawState(textPaint: TextPaint) { |
| textPaint.updatePaint() |
| } |
| |
| override fun updateMeasureState(textPaint: TextPaint) { |
| textPaint.updatePaint() |
| } |
| } |