/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.wear.compose.foundation
import androidx.compose.runtime.Composable
import androidx.compose.runtime.Stable
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.drawscope.DrawScope
import androidx.compose.ui.layout.Measurable
import androidx.compose.ui.layout.MeasureScope
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp
/**
* Apply additional space along each edge of the content in [Dp].
* See the [ArcPaddingValues] factories for convenient ways to
* build [ArcPaddingValues].
*/
@Stable
public interface ArcPaddingValues {
/**
* Padding in the outward direction from the center of the [CurvedLayout]
*/
fun calculateOuterPadding(): Dp
/**
* Padding in the inwards direction towards the center of the [CurvedLayout]
*/
fun calculateInnerPadding(): Dp
/**
* Padding added at the start of the component.
*/
fun calculateStartPadding(): Dp
/**
* Padding added at the end of the component.
*/
fun calculateEndPadding(): Dp
}
/**
* Apply additional space along each edge of the content in [Dp]. Note that the start and end
* edges will be determined by the direction (clockwise or counterclockwise)
*
* @param outer Padding in the outward direction from the center of the
* [CurvedLayout]
* @param inner Padding in the inwards direction towards the center of the [CurvedLayout]
* @param start Padding added at the start of the component.
* @param end Padding added at the end of the component.
*/
public fun ArcPaddingValues(
outer: Dp = 0.dp,
inner: Dp = 0.dp,
start: Dp = 0.dp,
end: Dp = 0.dp
): ArcPaddingValues =
ArcPaddingValuesImpl(outer, inner, start, end)
/**
* Apply [all] dp of additional space along each edge of the content.
*/
public fun ArcPaddingValues(all: Dp): ArcPaddingValues = ArcPaddingValuesImpl(all, all, all, all)
/**
* Apply [radial] dp of additional space on the edges towards and away from the center, and
* [angular] dp before and after the component.
*/
public fun ArcPaddingValues(radial: Dp = 0.dp, angular: Dp = 0.dp): ArcPaddingValues =
ArcPaddingValuesImpl(radial, radial, angular, angular)
@Stable
internal class ArcPaddingValuesImpl(val outer: Dp, val inner: Dp, val start: Dp, val end: Dp) :
ArcPaddingValues {
override fun equals(other: Any?): Boolean {
return other is ArcPaddingValuesImpl &&
outer == other.outer &&
inner == other.inner &&
start == other.start &&
end == other.end
}
override fun hashCode() = ((outer.hashCode() * 31 + inner.hashCode()) * 31 + start.hashCode()) *
31 + end.hashCode()
override fun toString(): String {
return "ArcPaddingValuesImpl(outer=$outer, inner=$inner, start=$start, end=$end)"
}
override fun calculateOuterPadding() = outer
override fun calculateInnerPadding() = inner
override fun calculateStartPadding() = start
override fun calculateEndPadding() = end
}
/**
* [basicCurvedText] is a component allowing developers to easily write curved text following
* the curvature a circle (usually at the edge of a circular screen).
* [basicCurvedText] can be only created within the [CurvedLayout] since it's not a not a
* composable.
*
* @sample androidx.wear.compose.foundation.samples.CurvedAndNormalText
*
* @param text The text to display
* @param modifier The [CurvedModifier] to apply to this curved text.
* @param clockwise The direction the text follows (default is true). Usually text at the top of the
* screen goes clockwise, and text at the bottom goes counterclockwise.
* @param contentArcPadding Allows to specify additional space along each "edge" of the content in
* [Dp] see [ArcPaddingValues]
* @param style A @Composable factory to provide the style to use. This composable SHOULDN'T
* generate any compose nodes.
*/
public fun CurvedScope.basicCurvedText(
text: String,
modifier: CurvedModifier = CurvedModifier,
clockwise: Boolean = true,
contentArcPadding: ArcPaddingValues = ArcPaddingValues(0.dp),
style: @Composable () -> CurvedTextStyle = { CurvedTextStyle() }
) = add(CurvedTextChild(text, clockwise, contentArcPadding, style), modifier)
/**
* [basicCurvedText] is a component allowing developers to easily write curved text following
* the curvature a circle (usually at the edge of a circular screen).
* [basicCurvedText] can be only created within the [CurvedLayout] since it's not a not a
* composable.
*
* @sample androidx.wear.compose.foundation.samples.CurvedAndNormalText
*
* @param text The text to display
* @param modifier The [CurvedModifier] to apply to this curved text.
* @param style A style to use.
* @param clockwise The direction the text follows (default is true). Usually text at the top of the
* screen goes clockwise, and text at the bottom goes counterclockwise.
* @param contentArcPadding Allows to specify additional space along each "edge" of the content in
* [Dp] see [ArcPaddingValues]
*/
public fun CurvedScope.basicCurvedText(
text: String,
style: CurvedTextStyle,
modifier: CurvedModifier = CurvedModifier,
clockwise: Boolean = true,
// TODO: reimplement as modifiers
contentArcPadding: ArcPaddingValues = ArcPaddingValues(0.dp)
) = basicCurvedText(text, modifier, clockwise, contentArcPadding) { style }
internal class CurvedTextChild(
val text: String,
val clockwise: Boolean = true,
val contentArcPadding: ArcPaddingValues = ArcPaddingValues(0.dp),
val style: @Composable () -> CurvedTextStyle = { CurvedTextStyle() }
) : CurvedChild() {
private val delegate: CurvedTextDelegate = CurvedTextDelegate()
private lateinit var actualStyle: CurvedTextStyle
override fun MeasureScope.initializeMeasure(
measurables: List<Measurable>,
index: Int
): Int {
// TODO: move padding into a CurvedModifier
val arcPaddingPx = ArcPaddingPx(
contentArcPadding.calculateOuterPadding().toPx(),
contentArcPadding.calculateInnerPadding().toPx(),
contentArcPadding.calculateStartPadding().toPx(),
contentArcPadding.calculateEndPadding().toPx()
)
delegate.updateIfNeeded(text, clockwise, actualStyle.fontSize.toPx(), arcPaddingPx)
return index // No measurables where mapped.
}
@Composable
override fun SubComposition() {
actualStyle = DefaultCurvedTextStyles + style()
}
override fun doEstimateThickness(maxRadius: Float): Float = delegate.textHeight
override fun doRadialPosition(
parentOuterRadius: Float,
parentThickness: Float
): PartialLayoutInfo {
val measureRadius = parentOuterRadius - delegate.baseLinePosition
return PartialLayoutInfo(
delegate.textWidth / measureRadius,
parentOuterRadius,
delegate.textHeight,
measureRadius
)
}
override fun DrawScope.draw() {
with(delegate) {
doDraw(layoutInfo!!, actualStyle.color, actualStyle.background)
}
}
}
internal data class ArcPaddingPx(
val outer: Float,
val inner: Float,
val before: Float,
val after: Float
)
internal expect class CurvedTextDelegate() {
var textWidth: Float
var textHeight: Float
var baseLinePosition: Float
fun updateIfNeeded(
text: String,
clockwise: Boolean,
fontSizePx: Float,
arcPaddingPx: ArcPaddingPx
)
fun DrawScope.doDraw(layoutInfo: CurvedLayoutInfo, color: Color, background: Color)
}