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@marcusmotill
Created March 12, 2016 18:36
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Image compression for Android in Kotlin
class BitmapUtils {
companion object
}
fun BitmapUtils.Companion.getCompressedImage(pathName: String, scalingLogic: ImageView.ScaleType): String {
val options = BitmapFactory.Options()
options.inJustDecodeBounds = true
BitmapFactory.decodeFile(pathName, options)
options.inJustDecodeBounds = false
val dstWidth: Double = ((options.outWidth.toDouble() / (options.outWidth.toDouble() * options.outHeight.toDouble())) * 1000) * options.outWidth.toDouble()
val dstHeight: Double = ((options.outHeight.toDouble() / (options.outWidth.toDouble() * options.outHeight.toDouble())) * 1000) * options.outHeight.toDouble()
options.inSampleSize = calculateSampleSize(options.outWidth, options.outHeight, dstWidth.toInt(), dstHeight.toInt(), scalingLogic)
val unscaledBitmap = BitmapFactory.decodeFile(pathName, options)
return createScaledBitmap(unscaledBitmap, dstWidth.toInt(), dstHeight.toInt(), scalingLogic)
}
private fun createScaledBitmap(unscaledBitmap: Bitmap, dstWidth: Int, dstHeight: Int, scalingLogic: ImageView.ScaleType): String {
val srcRect = calculateSrcRect(unscaledBitmap.width, unscaledBitmap.height, dstWidth, dstHeight, scalingLogic)
val dstRect = calculateDstRect(unscaledBitmap.width, unscaledBitmap.height, dstWidth, dstHeight, scalingLogic)
val scaledBitmap = Bitmap.createBitmap(dstRect.width(), dstRect.height(), Bitmap.Config.ARGB_8888)
val canvas = Canvas(scaledBitmap)
canvas.drawBitmap(unscaledBitmap, srcRect, dstRect, Paint(Paint.FILTER_BITMAP_FLAG))
return writeToFile(scaledBitmap)
}
private fun writeToFile(scaledBitmap: Bitmap): String {
val f: File = File(Environment.getExternalStorageDirectory(), "${DateTime().millisOfDay()}.png");
f.createNewFile();
//Convert bitmap to byte array
val bos: ByteArrayOutputStream = ByteArrayOutputStream();
scaledBitmap.compress(Bitmap.CompressFormat.PNG, 0 /*ignored for PNG*/, bos);
//write the bytes in file
val fos: FileOutputStream = FileOutputStream(f)
fos.write(bos.toByteArray());
fos.flush();
fos.close();
return f.absolutePath
}
private fun calculateSampleSize(srcWidth: Int, srcHeight: Int, dstWidth: Int, dstHeight: Int, scalingLogic: ImageView.ScaleType): Int {
if (scalingLogic == ImageView.ScaleType.FIT_CENTER) {
val srcAspect = srcWidth.toFloat() / srcHeight.toFloat()
val dstAspect = dstWidth.toFloat() / dstHeight.toFloat()
if (srcAspect > dstAspect) {
return srcWidth / dstWidth
} else {
return srcHeight / dstHeight
}
} else {
val srcAspect = srcWidth.toFloat() / srcHeight.toFloat()
val dstAspect = dstWidth.toFloat() / dstHeight.toFloat()
if (srcAspect > dstAspect) {
return srcHeight / dstHeight
} else {
return srcWidth / dstWidth
}
}
}
private fun calculateSrcRect(srcWidth: Int, srcHeight: Int, dstWidth: Int, dstHeight: Int, scalingLogic: ImageView.ScaleType): Rect {
if (scalingLogic == ImageView.ScaleType.CENTER_CROP) {
val srcAspect = srcWidth.toFloat() / srcHeight.toFloat()
val dstAspect = dstWidth.toFloat() / dstHeight.toFloat()
if (srcAspect > dstAspect) {
val srcRectWidth = (srcHeight * dstAspect).toInt()
val srcRectLeft = (srcWidth - srcRectWidth) / 2
return Rect(srcRectLeft, 0, srcRectLeft + srcRectWidth, srcHeight)
} else {
val srcRectHeight = (srcWidth / dstAspect).toInt()
val scrRectTop = (srcHeight - srcRectHeight).toInt() / 2
return Rect(0, scrRectTop, srcWidth, scrRectTop + srcRectHeight)
}
} else {
return Rect(0, 0, srcWidth, srcHeight)
}
}
private fun calculateDstRect(srcWidth: Int, srcHeight: Int, dstWidth: Int, dstHeight: Int, scalingLogic: ImageView.ScaleType): Rect {
if (scalingLogic == ImageView.ScaleType.FIT_CENTER) {
val srcAspect = srcWidth.toFloat() / srcHeight.toFloat()
val dstAspect = dstWidth.toFloat() / dstHeight.toFloat()
if (srcAspect > dstAspect) {
return Rect(0, 0, dstWidth, (dstWidth / srcAspect).toInt())
} else {
return Rect(0, 0, (dstHeight * srcAspect).toInt(), dstHeight)
}
} else {
return Rect(0, 0, dstWidth, dstHeight)
}
}
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