/*
* Copyright 2020 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.compose.foundation.layout
import androidx.compose.runtime.Stable
import androidx.compose.ui.Modifier
import androidx.compose.ui.layout.LayoutModifier
import androidx.compose.ui.layout.Measurable
import androidx.compose.ui.layout.MeasureResult
import androidx.compose.ui.layout.MeasureScope
import androidx.compose.ui.platform.InspectorInfo
import androidx.compose.ui.platform.InspectorValueInfo
import androidx.compose.ui.platform.debugInspectorInfo
import androidx.compose.ui.unit.Constraints
import androidx.compose.ui.unit.Density
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.IntOffset
import androidx.compose.ui.unit.dp
/**
* Offset the content by ([x] dp, [y] dp). The offsets can be positive as well as non-positive.
* Applying an offset only changes the position of the content, without interfering with
* its size measurement.
*
* This modifier will automatically adjust the horizontal offset according to the layout direction:
* when the layout direction is LTR, positive [x] offsets will move the content to the right and
* when the layout direction is RTL, positive [x] offsets will move the content to the left.
* For a modifier that offsets without considering layout direction, see [absoluteOffset].
*
* @see absoluteOffset
*
* Example usage:
* @sample androidx.compose.foundation.layout.samples.OffsetModifier
*/
@Stable
fun Modifier.offset(x: Dp = 0.dp, y: Dp = 0.dp) = this.then(
OffsetModifier(
x = x,
y = y,
rtlAware = true,
inspectorInfo = debugInspectorInfo {
name = "offset"
properties["x"] = x
properties["y"] = y
}
)
)
/**
* Offset the content by ([x] dp, [y] dp). The offsets can be positive as well as non-positive.
* Applying an offset only changes the position of the content, without interfering with
* its size measurement.
*
* This modifier will not consider layout direction when calculating the position of the content:
* a positive [x] offset will always move the content to the right.
* For a modifier that considers the layout direction when applying the offset, see [offset].
*
* @see offset
*
* Example usage:
* @sample androidx.compose.foundation.layout.samples.AbsoluteOffsetModifier
*/
@Stable
fun Modifier.absoluteOffset(x: Dp = 0.dp, y: Dp = 0.dp) = this.then(
OffsetModifier(
x = x,
y = y,
rtlAware = false,
inspectorInfo = debugInspectorInfo {
name = "absoluteOffset"
properties["x"] = x
properties["y"] = y
}
)
)
/**
* Offset the content by [offset] px. The offsets can be positive as well as non-positive.
* Applying an offset only changes the position of the content, without interfering with
* its size measurement.
*
* This modifier is designed to be used for offsets that change, possibly due to user interactions.
* It avoids recomposition when the offset is changing, and also adds a graphics layer that
* prevents unnecessary redrawing of the context when the offset is changing.
*
* This modifier will automatically adjust the horizontal offset according to the layout direction:
* when the LD is LTR, positive horizontal offsets will move the content to the right and
* when the LD is RTL, positive horizontal offsets will move the content to the left.
* For a modifier that offsets without considering layout direction, see [absoluteOffset].
*
* @see [absoluteOffset]
*
* Example usage:
* @sample androidx.compose.foundation.layout.samples.OffsetPxModifier
*/
fun Modifier.offset(offset: Density.() -> IntOffset) = this.then(
OffsetPxModifier(
offset = offset,
rtlAware = true,
inspectorInfo = debugInspectorInfo {
name = "offset"
properties["offset"] = offset
}
)
)
/**
* Offset the content by [offset] px. The offsets can be positive as well as non-positive.
* Applying an offset only changes the position of the content, without interfering with
* its size measurement.
*
* This modifier is designed to be used for offsets that change, possibly due to user interactions.
* It avoids recomposition when the offset is changing, and also adds a graphics layer that
* prevents unnecessary redrawing of the context when the offset is changing.
*
* This modifier will not consider layout direction when calculating the position of the content:
* a positive horizontal offset will always move the content to the right.
* For a modifier that considers layout direction when applying the offset, see [offset].
*
* @see offset
*
* Example usage:
* @sample androidx.compose.foundation.layout.samples.AbsoluteOffsetPxModifier
*/
fun Modifier.absoluteOffset(
offset: Density.() -> IntOffset
) = this.then(
OffsetPxModifier(
offset = offset,
rtlAware = false,
inspectorInfo = debugInspectorInfo {
name = "absoluteOffset"
properties["offset"] = offset
}
)
)
private class OffsetModifier(
val x: Dp,
val y: Dp,
val rtlAware: Boolean,
inspectorInfo: InspectorInfo.() -> Unit
) : LayoutModifier, InspectorValueInfo(inspectorInfo) {
override fun MeasureScope.measure(
measurable: Measurable,
constraints: Constraints
): MeasureResult {
val placeable = measurable.measure(constraints)
return layout(placeable.width, placeable.height) {
if (rtlAware) {
placeable.placeRelative(x.roundToPx(), y.roundToPx())
} else {
placeable.place(x.roundToPx(), y.roundToPx())
}
}
}
override fun equals(other: Any?): Boolean {
if (this === other) return true
val otherModifier = other as? OffsetModifier ?: return false
return x == otherModifier.x &&
y == otherModifier.y &&
rtlAware == otherModifier.rtlAware
}
override fun hashCode(): Int {
var result = x.hashCode()
result = 31 * result + y.hashCode()
result = 31 * result + rtlAware.hashCode()
return result
}
override fun toString(): String = "OffsetModifier(x=$x, y=$y, rtlAware=$rtlAware)"
}
private class OffsetPxModifier(
val offset: Density.() -> IntOffset,
val rtlAware: Boolean,
inspectorInfo: InspectorInfo.() -> Unit
) : LayoutModifier, InspectorValueInfo(inspectorInfo) {
override fun MeasureScope.measure(
measurable: Measurable,
constraints: Constraints
): MeasureResult {
val placeable = measurable.measure(constraints)
return layout(placeable.width, placeable.height) {
val offsetValue = offset()
if (rtlAware) {
placeable.placeRelativeWithLayer(offsetValue.x, offsetValue.y)
} else {
placeable.placeWithLayer(offsetValue.x, offsetValue.y)
}
}
}
override fun equals(other: Any?): Boolean {
if (this === other) return true
val otherModifier = other as? OffsetPxModifier ?: return false
return offset == otherModifier.offset &&
rtlAware == otherModifier.rtlAware
}
override fun hashCode(): Int {
var result = offset.hashCode()
result = 31 * result + rtlAware.hashCode()
return result
}
override fun toString(): String = "OffsetPxModifier(offset=$offset, rtlAware=$rtlAware)"
}