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| import android.graphics.*
import android.graphics.Paint.ANTI_ALIAS_FLAG
import android.graphics.Paint.DITHER_FLAG
import androidx.annotation.ColorInt
fun addWatermark(
bitmap: Bitmap,
watermarkText: String,
options: WatermarkOptions = WatermarkOptions()
): Bitmap {
val result = bitmap.copy(bitmap.config, true)
val canvas = Canvas(result)
val paint = Paint(ANTI_ALIAS_FLAG or DITHER_FLAG)
paint.textAlign = when (options.corner) {
Corner.TOP_LEFT,
Corner.BOTTOM_LEFT -> Paint.Align.LEFT
Corner.TOP_RIGHT,
Corner.BOTTOM_RIGHT -> Paint.Align.RIGHT
}
val textSize = result.width * options.textSizeToWidthRatio
paint.textSize = textSize
paint.color = options.textColor
if (options.shadowColor != null) {
paint.setShadowLayer(textSize / 2, 0f, 0f, options.shadowColor)
}
if (options.typeface != null) {
paint.typeface = options.typeface
}
val padding = result.width * options.paddingToWidthRatio
val coordinates =
calculateCoordinates(watermarkText, paint, options, canvas.width, canvas.height, padding)
canvas.drawText(watermarkText, coordinates.x, coordinates.y, paint)
return result
}
private fun calculateCoordinates(
watermarkText: String,
paint: Paint,
options: WatermarkOptions,
width: Int,
height: Int,
padding: Float
): PointF {
val x = when (options.corner) {
Corner.TOP_LEFT,
Corner.BOTTOM_LEFT -> {
padding
}
Corner.TOP_RIGHT,
Corner.BOTTOM_RIGHT -> {
width - padding
}
}
val y = when (options.corner) {
Corner.BOTTOM_LEFT,
Corner.BOTTOM_RIGHT -> {
height - padding
}
Corner.TOP_LEFT,
Corner.TOP_RIGHT -> {
val bounds = Rect()
paint.getTextBounds(watermarkText, 0, watermarkText.length, bounds)
val textHeight = bounds.height()
textHeight + padding
}
}
return PointF(x, y)
}
enum class Corner {
TOP_LEFT,
TOP_RIGHT,
BOTTOM_LEFT,
BOTTOM_RIGHT,
}
data class WatermarkOptions(
val corner: Corner = Corner.BOTTOM_RIGHT,
val textSizeToWidthRatio: Float = 0.04f,
val paddingToWidthRatio: Float = 0.03f,
@ColorInt val textColor: Int = Color.WHITE,
@ColorInt val shadowColor: Int? = Color.BLACK,
val typeface: Typeface? = null
)
|
