add inner shadow sample

Author: SmartToolFactory

Diff for: Tutorial1-1Basics/src/main/java/com/smarttoolfactory/tutorial1_1basics/chapter6_graphics/Tutorial6_36InnerShadow.kt

@@ -0,0 +1,143 @@
+package com.smarttoolfactory.tutorial1_1basics.chapter6_graphics
+
+import android.graphics.BlurMaskFilter
+import android.graphics.PorterDuff
+import android.graphics.PorterDuffXfermode
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.Slider
+import androidx.compose.material.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.composed
+import androidx.compose.ui.draw.drawWithContent
+import androidx.compose.ui.geometry.toRect
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.Paint
+import androidx.compose.ui.graphics.Shape
+import androidx.compose.ui.graphics.drawOutline
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+
+
+@Preview
+@Composable
+fun InnerShadowSample() {
+
+    Column(
+        modifier = Modifier.fillMaxSize()
+            .background(Color(0xff00796B))
+            .padding(16.dp)
+    ) {
+
+        var blurRadiusWhite by remember {
+            mutableFloatStateOf(5f)
+        }
+
+        var blurRadiusBlack by remember {
+            mutableFloatStateOf(4f)
+        }
+
+        Text("Blur white: $blurRadiusWhite")
+
+
+        Slider(
+            value = blurRadiusWhite,
+            onValueChange = {
+                blurRadiusWhite = it
+            },
+            valueRange = 1f..20f
+        )
+
+        Text("Blur black: $blurRadiusBlack")
+        Slider(
+            value = blurRadiusBlack,
+            onValueChange = {
+                blurRadiusBlack = it
+            },
+            valueRange = 1f..20f
+        )
+
+
+        Row(
+            modifier = Modifier
+                .innerShadow(
+                    shape = RoundedCornerShape(16.dp),
+                    color = Color.White.copy(.8f),
+                    x = (-2).dp,
+                    y = (-2).dp,
+                    blurRadius = blurRadiusWhite.dp
+                )
+                .innerShadow(
+                    shape = RoundedCornerShape(16.dp),
+                    color = Color.Black,
+                    x = 2.dp,
+                    y = 2.dp,
+                    blurRadius = (blurRadiusBlack).dp
+                )
+                .background(Color(0xff009688), RoundedCornerShape(16.dp))
+                .padding(16.dp)
+        ) {
+            Text(
+                text = "Hello World",
+                fontSize = 30.sp,
+
+                )
+        }
+    }
+}
+
+fun Modifier.innerShadow(
+    shape: Shape,
+    color: Color = Color.Black,
+    x: Dp = 2.dp,
+    y: Dp = 2.dp,
+    blurRadius: Dp = 4.dp,
+) = composed {
+    val paint = remember {
+        Paint()
+    }
+
+    println("Paint: $paint")
+
+    drawWithContent {
+        drawContent()
+
+        val outline = shape.createOutline(size, layoutDirection, this)
+
+        paint.color = color
+
+        with(drawContext.canvas) {
+            saveLayer(size.toRect(), paint)
+
+            drawOutline(outline, paint)
+
+            val frameworkPaint = paint.asFrameworkPaint()
+
+            frameworkPaint.apply {
+                xfermode = PorterDuffXfermode(PorterDuff.Mode.DST_OUT)
+                maskFilter =
+                    BlurMaskFilter(blurRadius.toPx(), BlurMaskFilter.Blur.NORMAL)
+            }
+
+            paint.color = Color.Black
+
+            translate(x.toPx(), y.toPx())
+            drawOutline(outline, paint)
+
+            frameworkPaint.xfermode = null
+            frameworkPaint.maskFilter = null
+            restore()
+        }
+    }
+}