PageCurlDemo.kt

gistfile1.txt

@Composable
fun BookPageFlip() {
    var offsetX by remember { mutableStateOf(0f) }
    var currentPage by remember { mutableStateOf(0) }

    val animatedOffset = animateFloatAsState(
        targetValue = offsetX,
        animationSpec = spring(
            dampingRatio = 0.8f,
            stiffness = Spring.StiffnessLow
        )
    )

    Box(
        modifier = Modifier
            .fillMaxSize()
            .pointerInput(Unit) {
                detectDragGestures(
                    onDragEnd = {
                        // 드래그가 끝났을 때 페이지 전환 여부 결정
                        val threshold = size.width * 0.4f
                        if (abs(offsetX) > threshold) {
                            if (offsetX > 0 && currentPage > 0) {
                                currentPage--
                            } else if (offsetX < 0) {
                                currentPage++
                            }
                        }
                        offsetX = 0f
                    },
                    onDrag = { change, dragAmount ->
                        change.consume()
                        offsetX += dragAmount.x
                    }
                )
            }
    ) {
        // 현재 페이지
        Box(
            modifier = Modifier
                .fillMaxSize()
                .graphicsLayer {
                    val pageRotation = (offsetX / size.width) * 180f
                    rotationY = pageRotation
                    cameraDistance = 12f * density
                }
        ) {
            BookPage(currentPage)
        }

        // 다음/이전 페이지 (뒷면)
        Box(
            modifier = Modifier
                .fillMaxSize()
                .graphicsLayer {
                    val pageRotation = ((offsetX / size.width) * 180f) + 180f
                    rotationY = pageRotation
                    cameraDistance = 12f * density
                }
        ) {
            if (offsetX > 0 && currentPage > 0) {
                BookPage(currentPage - 1)
            } else if (offsetX < 0) {
                BookPage(currentPage + 1)
            }
        }
    }
}

@Composable
fun BookPage(pageNumber: Int) {
    Box(
        modifier = Modifier
            .fillMaxSize()
            .background(Color.White)
            .shadow(8.dp)
    ) {
        // 페이지 내용
        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(16.dp)
        ) {
            Text(
                text = "Page ${pageNumber + 1}",
                style = MaterialTheme.typography.bodyLarge,
                modifier = Modifier.padding(bottom = 16.dp)
            )

            Text(
                text = "Lorem ipsum dolor sit amet...",
                style = MaterialTheme.typography.bodyMedium
            )
        }
    }
}

// 페이지 그림자 효과
@Composable
fun PageShadow(progress: Float) {
    Box(
        modifier = Modifier
            .fillMaxHeight()
            .width(8.dp)
            .background(
                brush = Brush.horizontalGradient(
                    colors = listOf(
                        Color.Black.copy(alpha = 0.2f * (1 - progress)),
                        Color.Transparent
                    )
                )
            )
    )
}

// 사용 예시
@Preview(showBackground = true)
@Composable
fun BookReader() {
    Surface(
        modifier = Modifier.fillMaxSize().systemBarsPadding(),
        color = Color.White
    ) {
        BookPageFlip()
    }
}