feat: add Stackblur BlurTransformation utility
Made-with: Cursor
This commit is contained in:
cottongin
@@ -0,0 +1,134 @@
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package xyz.cottongin.radio247.ui.util
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import android.graphics.Bitmap
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import coil3.size.Size
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import coil3.transform.Transformation
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import kotlinx.coroutines.Dispatchers
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import kotlinx.coroutines.withContext
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import kotlin.math.abs
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import kotlin.math.roundToInt
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class BlurTransformation(
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private val radius: Int = 25,
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private val scale: Float = 0.1f
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) : Transformation() {
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override val cacheKey: String = "${javaClass.name}-$radius-$scale"
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override suspend fun transform(input: Bitmap, size: Size): Bitmap =
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input.stackBlur(scale, radius) ?: input
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override fun equals(other: Any?): Boolean {
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if (this === other) return true
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return other is BlurTransformation && radius == other.radius && scale == other.scale
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}
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override fun hashCode(): Int = 31 * radius.hashCode() + scale.hashCode()
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}
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private suspend fun Bitmap.stackBlur(scale: Float, radius: Int): Bitmap? =
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withContext(Dispatchers.IO) {
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var sentBitmap = this@stackBlur
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val width = (sentBitmap.width * scale).roundToInt()
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val height = (sentBitmap.height * scale).roundToInt()
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sentBitmap = Bitmap.createScaledBitmap(sentBitmap, width, height, false)
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val bitmap = sentBitmap.copy(sentBitmap.config ?: Bitmap.Config.ARGB_8888, true)
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if (radius < 1) return@withContext null
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val w = bitmap.width
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val h = bitmap.height
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val pix = IntArray(w * h)
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bitmap.getPixels(pix, 0, w, 0, 0, w, h)
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val wm = w - 1
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val hm = h - 1
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val wh = w * h
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val div = radius + radius + 1
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val r = IntArray(wh)
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val g = IntArray(wh)
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val b = IntArray(wh)
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var rsum: Int; var gsum: Int; var bsum: Int
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var x: Int; var y: Int; var i: Int; var p: Int; var yp: Int; var yi: Int
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val vmin = IntArray(w.coerceAtLeast(h))
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var divsum = div + 1 shr 1
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divsum *= divsum
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val dv = IntArray(256 * divsum) { it / divsum }
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yi = 0; var yw = 0
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val stack = Array(div) { IntArray(3) }
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var stackpointer: Int; var stackstart: Int; var sir: IntArray; var rbs: Int
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val r1 = radius + 1
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var routsum: Int; var goutsum: Int; var boutsum: Int
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var rinsum: Int; var ginsum: Int; var binsum: Int
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y = 0
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while (y < h) {
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bsum = 0; gsum = 0; rsum = 0; boutsum = 0; goutsum = 0; routsum = 0
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binsum = 0; ginsum = 0; rinsum = 0
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i = -radius
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while (i <= radius) {
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p = pix[yi + wm.coerceAtMost(i.coerceAtLeast(0))]
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sir = stack[i + radius]
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sir[0] = p and 0xff0000 shr 16; sir[1] = p and 0x00ff00 shr 8; sir[2] = p and 0x0000ff
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rbs = r1 - abs(i)
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rsum += sir[0] * rbs; gsum += sir[1] * rbs; bsum += sir[2] * rbs
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if (i > 0) { rinsum += sir[0]; ginsum += sir[1]; binsum += sir[2] }
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else { routsum += sir[0]; goutsum += sir[1]; boutsum += sir[2] }
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i++
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}
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stackpointer = radius; x = 0
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while (x < w) {
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r[yi] = dv[rsum]; g[yi] = dv[gsum]; b[yi] = dv[bsum]
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rsum -= routsum; gsum -= goutsum; bsum -= boutsum
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stackstart = stackpointer - radius + div
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sir = stack[stackstart % div]
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routsum -= sir[0]; goutsum -= sir[1]; boutsum -= sir[2]
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if (y == 0) vmin[x] = (x + radius + 1).coerceAtMost(wm)
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p = pix[yw + vmin[x]]
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sir[0] = p and 0xff0000 shr 16; sir[1] = p and 0x00ff00 shr 8; sir[2] = p and 0x0000ff
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rinsum += sir[0]; ginsum += sir[1]; binsum += sir[2]
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rsum += rinsum; gsum += ginsum; bsum += binsum
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stackpointer = (stackpointer + 1) % div
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sir = stack[stackpointer % div]
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routsum += sir[0]; goutsum += sir[1]; boutsum += sir[2]
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rinsum -= sir[0]; ginsum -= sir[1]; binsum -= sir[2]
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yi++; x++
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}
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yw += w; y++
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}
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x = 0
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while (x < w) {
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bsum = 0; gsum = 0; rsum = 0; boutsum = 0; goutsum = 0; routsum = 0
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binsum = 0; ginsum = 0; rinsum = 0
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yp = -radius * w; i = -radius
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while (i <= radius) {
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yi = 0.coerceAtLeast(yp) + x
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sir = stack[i + radius]
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sir[0] = r[yi]; sir[1] = g[yi]; sir[2] = b[yi]
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rbs = r1 - abs(i)
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rsum += r[yi] * rbs; gsum += g[yi] * rbs; bsum += b[yi] * rbs
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if (i > 0) { rinsum += sir[0]; ginsum += sir[1]; binsum += sir[2] }
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else { routsum += sir[0]; goutsum += sir[1]; boutsum += sir[2] }
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if (i < hm) yp += w
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i++
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}
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yi = x; stackpointer = radius; y = 0
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while (y < h) {
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pix[yi] = -0x1000000 and pix[yi] or (dv[rsum] shl 16) or (dv[gsum] shl 8) or dv[bsum]
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rsum -= routsum; gsum -= goutsum; bsum -= boutsum
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stackstart = stackpointer - radius + div
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sir = stack[stackstart % div]
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routsum -= sir[0]; goutsum -= sir[1]; boutsum -= sir[2]
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if (x == 0) vmin[y] = (y + r1).coerceAtMost(hm) * w
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p = x + vmin[y]
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sir[0] = r[p]; sir[1] = g[p]; sir[2] = b[p]
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rinsum += sir[0]; ginsum += sir[1]; binsum += sir[2]
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rsum += rinsum; gsum += ginsum; bsum += binsum
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stackpointer = (stackpointer + 1) % div
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sir = stack[stackpointer]
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routsum += sir[0]; goutsum += sir[1]; boutsum += sir[2]
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rinsum -= sir[0]; ginsum -= sir[1]; binsum -= sir[2]
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yi += w; y++
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}
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x++
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}
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bitmap.setPixels(pix, 0, w, 0, 0, w, h)
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sentBitmap.recycle()
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bitmap
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}
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