haerzig.core.views.Scollbar.kt Maven / Gradle / Ivy

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package haerzig.core.views

import androidx.compose.animation.core.AnimationSpec
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.ScrollState
import androidx.compose.foundation.gestures.FlingBehavior
import androidx.compose.foundation.gestures.Orientation
import androidx.compose.foundation.horizontalScroll
import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.foundation.layout.calculateEndPadding
import androidx.compose.foundation.layout.calculateStartPadding
import androidx.compose.foundation.verticalScroll
import androidx.compose.runtime.getValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.draw.drawWithContent
import androidx.compose.ui.geometry.CornerRadius
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.LayoutDirection
import androidx.compose.ui.unit.dp
import kotlin.math.max

fun Modifier.scrollbar(
    state: ScrollState,
    direction: Orientation,
    indicatorThickness: Dp = 8.dp,
    indicatorColor: Color = Color.LightGray,
    showAlways: Boolean = false,
    alpha: Float = if (showAlways || state.isScrollInProgress) 0.8f else 0f,
    alphaAnimationSpec: AnimationSpec = tween(
        delayMillis = if (showAlways || state.isScrollInProgress) 0 else 1500,
        durationMillis = if (showAlways || state.isScrollInProgress) 150 else 500
    ),
    padding: PaddingValues = PaddingValues(all = 0.dp)
): Modifier = composed {
    val scrollbarAlpha by animateFloatAsState(
        targetValue = alpha,
        animationSpec = alphaAnimationSpec, label = "scrollbar"
    )

    drawWithContent {
        drawContent()

        val showScrollBar = (state.isScrollInProgress || scrollbarAlpha > 0.0f)

        // Draw scrollbar only if currently scrolling or if scroll animation is ongoing or when showAlways.
        if ((showAlways || showScrollBar) && state.maxValue != 0) {
            val (topPadding, bottomPadding, startPadding, endPadding) = listOf(
                padding.calculateTopPadding().toPx(), padding.calculateBottomPadding().toPx(),
                padding.calculateStartPadding(layoutDirection).toPx(),
                padding.calculateEndPadding(layoutDirection).toPx()
            )
            val contentOffset = state.value
            val viewPortLength = if (direction == Orientation.Vertical) size.height else size.width
            val viewPortCrossAxisLength = if (direction == Orientation.Vertical) size.width else size.height
            val contentLength = max(viewPortLength + state.maxValue, 0.001f)  // To prevent divide by zero error
            val indicatorLength = ((viewPortLength / contentLength) * viewPortLength) - (if (direction == Orientation.Vertical) topPadding + bottomPadding else startPadding + endPadding)
            val indicatorThicknessPx = indicatorThickness.toPx()
            val scrollOffsetViewPort = viewPortLength * contentOffset / contentLength
            val scrollbarSizeWithoutInsets = if (direction == Orientation.Vertical) Size(indicatorThicknessPx, indicatorLength) else Size(indicatorLength, indicatorThicknessPx)
            val scrollbarPositionWithoutInsets = if (direction == Orientation.Vertical)
                Offset(
                    x = if (layoutDirection == LayoutDirection.Ltr)
                        viewPortCrossAxisLength - indicatorThicknessPx - endPadding
                    else startPadding,
                    y = scrollOffsetViewPort + topPadding
                )
            else
                Offset(
                    x = if (layoutDirection == LayoutDirection.Ltr)
                        scrollOffsetViewPort + startPadding
                    else viewPortLength - scrollOffsetViewPort - indicatorLength - endPadding,
                    y = viewPortCrossAxisLength - indicatorThicknessPx - bottomPadding
                )

            drawRoundRect(
                color = indicatorColor,
                cornerRadius = CornerRadius(x = indicatorThicknessPx / 2, y = indicatorThicknessPx / 2),
                topLeft = scrollbarPositionWithoutInsets,
                size = scrollbarSizeWithoutInsets,
                alpha = scrollbarAlpha
            )
        }
    }
}

data class ScrollBarConfig(
    val indicatorThickness: Dp = 8.dp,
    val indicatorColor: Color = Color.LightGray,
    val alpha: Float? = null,
    val alphaAnimationSpec: AnimationSpec? = null,
    val padding: PaddingValues = PaddingValues(all = 0.dp),
    val showAlways: Boolean = false
)

fun Modifier.verticalScrollWithScrollbar(
    state: ScrollState,
    enabled: Boolean = true,
    flingBehavior: FlingBehavior? = null,
    reverseScrolling: Boolean = false,
    scrollbarConfig: ScrollBarConfig = ScrollBarConfig()
) = this
    .scrollbar(
        state,
        Orientation.Vertical,
        indicatorThickness = scrollbarConfig.indicatorThickness,
        indicatorColor = scrollbarConfig.indicatorColor,
        alpha = scrollbarConfig.alpha ?: if (scrollbarConfig.showAlways || state.isScrollInProgress) 0.8f else 0f,
        alphaAnimationSpec = scrollbarConfig.alphaAnimationSpec ?: tween(
            delayMillis = if (scrollbarConfig.showAlways || state.isScrollInProgress) 0 else 1500,
            durationMillis = if (scrollbarConfig.showAlways || state.isScrollInProgress) 150 else 500
        ),
        padding = scrollbarConfig.padding,
        showAlways = scrollbarConfig.showAlways

)
    .verticalScroll(state, enabled, flingBehavior, reverseScrolling)


fun Modifier.horizontalScrollWithScrollbar(
    state: ScrollState,
    enabled: Boolean = true,
    flingBehavior: FlingBehavior? = null,
    reverseScrolling: Boolean = false,
    scrollbarConfig: ScrollBarConfig = ScrollBarConfig()
) = this
    .scrollbar(
        state, Orientation.Horizontal,
        indicatorThickness = scrollbarConfig.indicatorThickness,
        indicatorColor = scrollbarConfig.indicatorColor,
        alpha = scrollbarConfig.alpha ?: if (state.isScrollInProgress) 0.8f else 0f,
        alphaAnimationSpec = scrollbarConfig.alphaAnimationSpec ?: tween(
            delayMillis = if (state.isScrollInProgress) 0 else 1500,
            durationMillis = if (state.isScrollInProgress) 150 else 500
        ),
        padding = scrollbarConfig.padding,
        showAlways = scrollbarConfig.showAlways
    )
    .horizontalScroll(state, enabled, flingBehavior, reverseScrolling)