Add forward & backward

app/src/main/java/eu/wewox/pagecurl/MainActivity.kt

@@ -3,24 +3,83 @@ package eu.wewox.pagecurl
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.material.MaterialTheme
-import androidx.compose.material.Surface
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.Text
-import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.tooling.preview.Preview
-import eu.wewox.pagecurl.page.Page
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import eu.wewox.pagecurl.config.PageCurlConfig
+import eu.wewox.pagecurl.page.PageCurl
 import eu.wewox.pagecurl.ui.theme.PageCurlTheme
+import eu.wewox.pagecurl.utils.Data
 
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContent {
             PageCurlTheme {
-                // A surface container using the 'background' color from the theme
-                Surface(modifier = Modifier.fillMaxSize(), color = MaterialTheme.colors.background) {
-                    Page()
+                var current by remember { mutableStateOf(0) }
+                val count = 6
+                PageCurl(
+                    current = current,
+                    count = count,
+                    onCurrentChange = {
+                        current = it
+                    },
+                    config = PageCurlConfig(),
+                ) { index ->
+                    Box(
+                        modifier = Modifier
+                            .fillMaxSize()
+                            .background(Color.White)
+                    ) {
+                        when (index) {
+                            0 -> {
+                                Image(
+                                    painter = painterResource(R.drawable.img_sleep),
+                                    contentDescription = null,
+                                    contentScale = ContentScale.Crop,
+                                )
+                            }
+                            count - 1 -> {
+                                Text(
+                                    text = "The End",
+                                    fontSize = 34.sp,
+                                    textAlign = TextAlign.Center,
+                                    modifier = Modifier.align(Alignment.Center)
+                                )
+                            }
+                            else -> {
+                                Text(
+                                    text = if (index % 2 == 1) Data.Lorem1 else Data.Lorem2,
+                                    fontSize = 22.sp,
+                                    modifier = Modifier.padding(16.dp)
+                                )
+                            }
+                        }
+                        Text(
+                            text = index.toString(),
+                            color = Color.White,
+                            modifier = Modifier
+                                .align(Alignment.BottomEnd)
+                                .background(Color.Black, RoundedCornerShape(topStartPercent = 100))
+                                .padding(16.dp)
+                        )
+                    }
                 }
             }
         }

app/src/main/java/eu/wewox/pagecurl/config/CurlConfig.kt

@@ -0,0 +1,46 @@
+package eu.wewox.pagecurl.config
+
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Rect
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.DpOffset
+import androidx.compose.ui.unit.dp
+
+data class PageCurlConfig(
+    val curl: CurlConfig = CurlConfig(),
+    val interaction: InteractionConfig = InteractionConfig()
+)
+
+data class InteractionConfig(
+    val forward: CurlDirection.Forward = CurlDirection.Forward(
+        Rect(Offset(0.5f, 0.0f), Offset(1.0f, 1.0f)),
+        Rect(Offset(0.0f, 0.0f), Offset(0.5f, 1.0f)),
+    ),
+    val backward: CurlDirection.Backward = CurlDirection.Backward(forward.end, forward.start),
+)
+
+sealed interface CurlDirection {
+    val start: Rect
+    val end: Rect
+
+    data class Forward(override val start: Rect, override val end: Rect) : CurlDirection
+    data class Backward(override val start: Rect, override val end: Rect) : CurlDirection
+}
+
+data class CurlConfig(
+    val backPage: BackPageConfig = BackPageConfig(),
+    val shadow: ShadowConfig = ShadowConfig(),
+)
+
+data class BackPageConfig(
+    val color: Color = Color.White,
+    val contentAlpha: Float = 0.1f,
+)
+
+data class ShadowConfig(
+    val color: Color = Color.Black,
+    val alpha: Float = 0.2f,
+    val radius: Dp = 15.dp,
+    val offset: DpOffset = DpOffset((-5).dp, 0.dp),
+)

app/src/main/java/eu/wewox/pagecurl/page/CurlDraw.kt

@@ -7,7 +7,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.CacheDrawScope
 import androidx.compose.ui.draw.drawWithCache
 import androidx.compose.ui.geometry.Offset
-import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.geometry.toRect
 import androidx.compose.ui.graphics.Paint
 import androidx.compose.ui.graphics.Path
 import androidx.compose.ui.graphics.asAndroidPath
@@ -18,43 +18,29 @@ import androidx.compose.ui.graphics.drawscope.rotateRad
 import androidx.compose.ui.graphics.drawscope.withTransform
 import androidx.compose.ui.graphics.nativeCanvas
 import androidx.compose.ui.graphics.toArgb
-import androidx.compose.ui.unit.Dp
-import androidx.compose.ui.unit.DpOffset
 import androidx.compose.ui.unit.dp
+import eu.wewox.pagecurl.config.CurlConfig
 import eu.wewox.pagecurl.utils.Polygon
 import eu.wewox.pagecurl.utils.lineLineIntersection
 import eu.wewox.pagecurl.utils.rotate
 import java.lang.Float.max
 import kotlin.math.atan2
 
-data class CurlConfig(
-    val backPage: BackPageConfig = BackPageConfig(),
-    val shadow: ShadowConfig = ShadowConfig()
-) {
-    data class BackPageConfig(
-        val color: Color = Color.White,
-        val contentAlpha: Float = 0.1f,
-    )
-
-    data class ShadowConfig(
-        val color: Color = Color.Black,
-        val alpha: Float = 0.2f,
-        val radius: Dp = 15.dp,
-        val offset: DpOffset = DpOffset((-5).dp, 0.dp),
-    )
-}
-
 fun Modifier.drawCurl(
     config: CurlConfig = CurlConfig(),
-    posA: Offset?,
-    posB: Offset?,
+    posA: Offset,
+    posB: Offset,
 ): Modifier = drawWithCache {
     fun drawOnlyContent() =
         onDrawWithContent {
             drawContent()
         }
 
-    if (posA == null || posB == null) {
+    if (posA == size.toRect().topLeft && posB == size.toRect().bottomLeft) {
+        return@drawWithCache onDrawWithContent { }
+    }
+
+    if (posA == size.toRect().topRight && posB == size.toRect().bottomRight) {
         return@drawWithCache drawOnlyContent()
     }
 

app/src/main/java/eu/wewox/pagecurl/page/CurlGesture.kt

@@ -1,29 +1,62 @@
 package eu.wewox.pagecurl.page
 
 import androidx.compose.foundation.gestures.awaitFirstDown
+import androidx.compose.foundation.gestures.drag
 import androidx.compose.foundation.gestures.forEachGesture
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Rect
+import androidx.compose.ui.input.pointer.consumeAllChanges
 import androidx.compose.ui.input.pointer.pointerInput
-import androidx.compose.ui.input.pointer.positionChangeConsumed
+import androidx.compose.ui.unit.IntSize
+import eu.wewox.pagecurl.config.CurlDirection
+import eu.wewox.pagecurl.utils.rotate
+import kotlin.math.PI
 
 fun Modifier.curlGesture(
+    enabled: Boolean,
+    direction: CurlDirection,
+    onStart: () -> Unit,
     onCurl: (Offset, Offset) -> Unit,
+    onEnd: () -> Unit,
     onCancel: () -> Unit,
-): Modifier = pointerInput(true) {
+): Modifier = pointerInput(enabled) {
+    if (!enabled) {
+        return@pointerInput
+    }
+
+    val startRect by lazy { direction.start.multiply(size) }
+    val endRect by lazy { direction.end.multiply(size) }
     forEachGesture {
         awaitPointerEventScope {
-            awaitFirstDown(requireUnconsumed = false)
-            do {
-                val event = awaitPointerEvent()
-                val canceled = event.changes.any { it.positionChangeConsumed() }
-                val posA = event.changes.getOrNull(0)?.position
-                val posB = event.changes.getOrNull(1)?.position
-                if (posA != null && posB != null) {
-                    onCurl(posA, posB)
-                }
-            } while (!canceled && event.changes.any { it.pressed })
-            onCancel()
+            val down = awaitFirstDown(requireUnconsumed = false)
+            if (!startRect.contains(down.position)) {
+                return@awaitPointerEventScope
+            }
+
+            val dragStart = down.position.copy(x = size.width.toFloat())
+
+            onStart()
+
+            var dragCurrent = dragStart
+            drag(down.id) { change ->
+                dragCurrent = change.position
+                change.consumeAllChanges()
+                val vector = (dragStart - dragCurrent).rotate(PI.toFloat() / 2)
+                onCurl(dragCurrent - vector, dragCurrent + vector)
+            }
+
+            if (endRect.contains(dragCurrent)) {
+                onEnd()
+            } else {
+                onCancel()
+            }
         }
     }
 }
+
+private fun Rect.multiply(size: IntSize): Rect =
+    Rect(
+        topLeft = Offset(size.width * left, size.height * top),
+        bottomRight = Offset(size.width * right, size.height * bottom),
+    )

app/src/main/java/eu/wewox/pagecurl/page/Page.kt

@@ -1,64 +0,0 @@
-package eu.wewox.pagecurl.page
-
-import androidx.compose.foundation.background
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
-import androidx.compose.material.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.geometry.Offset
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
-import eu.wewox.pagecurl.utils.Data
-
-@Composable
-fun Page() {
-    Text(
-        text = Data.Lorem2,
-        fontSize = 22.sp,
-        modifier = Modifier
-            .fillMaxSize()
-            .background(Color.White)
-            .padding(16.dp)
-    )
-
-    var posA by remember { mutableStateOf<Offset?>(null) }
-    var posB by remember { mutableStateOf<Offset?>(null) }
-
-    Box(
-        Modifier
-            .curlGesture(
-                onCurl = { a, b ->
-                    posA = a
-                    posB = b
-                },
-                onCancel = {
-                    posA = null
-                    posB = null
-                }
-            )
-            .drawCurl(CurlConfig(), posA, posB)
-    ) {
-        Text(
-            text = Data.Lorem1,
-            fontSize = 22.sp,
-            modifier = Modifier
-                .fillMaxSize()
-                .background(Color.White)
-                .padding(16.dp)
-        )
-        //        Image(
-        //            painter = painterResource(R.drawable.img_sleep),
-        //            contentDescription = null,
-        //            contentScale = ContentScale.Crop,
-        //            modifier = Modifier
-        //                .fillMaxSize()
-        //        )
-    }
-}

app/src/main/java/eu/wewox/pagecurl/page/PageCurl.kt

@@ -0,0 +1,133 @@
+package eu.wewox.pagecurl.page
+
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.AnimationVector4D
+import androidx.compose.animation.core.TwoWayConverter
+import androidx.compose.animation.core.VisibilityThreshold
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import eu.wewox.pagecurl.config.CurlDirection
+import eu.wewox.pagecurl.config.PageCurlConfig
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+
+@Composable
+fun PageCurl(
+    current: Int,
+    count: Int,
+    modifier: Modifier = Modifier,
+    onCurrentChange: (Int) -> Unit,
+    config: PageCurlConfig = PageCurlConfig(),
+    content: @Composable (Int) -> Unit
+) {
+    val scope = rememberCoroutineScope()
+    val updatedCurrent by rememberUpdatedState(current)
+
+    BoxWithConstraints(modifier) {
+        val maxWidthPx = constraints.maxWidth.toFloat()
+        val maxHeightPx = constraints.maxHeight.toFloat()
+        val left = Curl(Offset(0f, 0f), Offset(0f, maxHeightPx))
+        val right = Curl(Offset(maxWidthPx, 0f), Offset(maxWidthPx, maxHeightPx))
+
+        val forward = remember { Animatable(right, Curl.VectorConverter, Curl.VisibilityThreshold) }
+        val backward = remember { Animatable(left, Curl.VectorConverter, Curl.VisibilityThreshold) }
+
+        Box(
+            Modifier
+                .curlGesture(
+                    enabled = updatedCurrent < count - 1,
+                    scope = scope,
+                    direction = config.interaction.forward,
+                    start = right,
+                    end = left,
+                    animatable = forward,
+                    onChange = { onCurrentChange(updatedCurrent + 1) }
+                )
+                .curlGesture(
+                    enabled = updatedCurrent > 0,
+                    scope = scope,
+                    direction = config.interaction.backward,
+                    start = left,
+                    end = right,
+                    animatable = backward,
+                    onChange = { onCurrentChange(updatedCurrent - 1) }
+                )
+        ) {
+            if (updatedCurrent + 1 < count) {
+                content(updatedCurrent + 1)
+            }
+
+            if (updatedCurrent < count) {
+                Box(Modifier.drawCurl(config.curl, forward.value.a, forward.value.b)) {
+                    content(updatedCurrent)
+                }
+            }
+
+            if (updatedCurrent > 0) {
+                Box(Modifier.drawCurl(config.curl, backward.value.a, backward.value.b)) {
+                    content(updatedCurrent - 1)
+                }
+            }
+        }
+    }
+}
+
+private fun Modifier.curlGesture(
+    enabled: Boolean,
+    scope: CoroutineScope,
+    direction: CurlDirection,
+    start: Curl,
+    end: Curl,
+    animatable: Animatable<Curl, AnimationVector4D>,
+    onChange: () -> Unit,
+): Modifier =
+    curlGesture(
+        enabled = enabled,
+        direction = direction,
+        onStart = {
+            scope.launch {
+                animatable.snapTo(start)
+            }
+        },
+        onCurl = { a, b ->
+            scope.launch {
+                animatable.animateTo(Curl(a, b))
+            }
+        },
+        onEnd = {
+            scope.launch {
+                try {
+                    animatable.animateTo(end)
+                } finally {
+                    onChange()
+                    animatable.snapTo(start)
+                }
+            }
+        },
+        onCancel = {
+            scope.launch {
+                animatable.animateTo(start)
+            }
+        },
+    )
+
+
+private data class Curl(val a: Offset, val b: Offset) {
+    companion object {
+        val VectorConverter: TwoWayConverter<Curl, AnimationVector4D> =
+            TwoWayConverter(
+                convertToVector = { AnimationVector4D(it.a.x, it.a.y, it.b.x, it.b.y) },
+                convertFromVector = { Curl(Offset(it.v1, it.v2), Offset(it.v3, it.v4)) }
+            )
+
+        val VisibilityThreshold: Curl =
+            Curl(Offset.VisibilityThreshold, Offset.VisibilityThreshold)
+    }
+}

build.gradle

@@ -1,12 +1,12 @@
 buildscript {
     ext {
-        compose_version = '1.0.1'
+        compose_version = '1.2.0-alpha07'
     }
 }// Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
     id 'com.android.application' version '7.1.1' apply false
     id 'com.android.library' version '7.1.1' apply false
-    id 'org.jetbrains.kotlin.android' version '1.5.21' apply false
+    id 'org.jetbrains.kotlin.android' version '1.6.10' apply false
 }
 
 task clean(type: Delete) {