commonMain.com.github.panpf.zoomimage.compose.internal.MyImage.kt Maven / Gradle / Ivy
/*
* Copyright (C) 2023 panpf
*
* 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 com.github.panpf.zoomimage.compose.internal
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clipToBounds
import androidx.compose.ui.draw.paint
import androidx.compose.ui.graphics.ColorFilter
import androidx.compose.ui.graphics.DefaultAlpha
import androidx.compose.ui.graphics.painter.Painter
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.layout.Layout
import androidx.compose.ui.semantics.Role
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.role
import androidx.compose.ui.semantics.semantics
/**
* Creates a composable that lays out and draws a given [Painter]. This will attempt to size
* the composable according to the [Painter]'s intrinsic size. However, an optional [Modifier]
* parameter can be provided to adjust sizing or draw additional content (ex. background)
*
* **NOTE** a Painter might not have an intrinsic size, so if no LayoutModifier is provided
* as part of the Modifier chain this might size the [MyImage] composable to a width and height
* of zero and will not draw any content. This can happen for Painter implementations that
* always attempt to fill the bounds like [ColorPainter]
*
* @sample androidx.compose.foundation.samples.BitmapPainterSample
*
* @param painter to draw
* @param contentDescription text used by accessibility services to describe what this image
* represents. This should always be provided unless this image is used for decorative purposes,
* and does not represent a meaningful action that a user can take. This text should be
* localized, such as by using [androidx.compose.ui.res.stringResource] or similar
* @param modifier Modifier used to adjust the layout algorithm or draw decoration content (ex.
* background)
* @param alignment Optional alignment parameter used to place the [Painter] in the given
* bounds defined by the width and height.
* @param contentScale Optional scale parameter used to determine the aspect ratio scaling to be used
* if the bounds are a different size from the intrinsic size of the [Painter]
* @param alpha Optional opacity to be applied to the [Painter] when it is rendered onscreen
* the default renders the [Painter] completely opaque
* @param colorFilter Optional colorFilter to apply for the [Painter] when it is rendered onscreen
* @param clipToBounds Optional controls whether content that is out of scope should be cropped
*/
@Composable
internal fun MyImage(
painter: Painter,
contentDescription: String?,
modifier: Modifier = Modifier,
alignment: Alignment = Alignment.Center,
contentScale: ContentScale = ContentScale.Fit,
alpha: Float = DefaultAlpha,
colorFilter: ColorFilter? = null,
clipToBounds: Boolean = true,
) {
val semantics = if (contentDescription != null) {
Modifier.semantics {
this.contentDescription = contentDescription
this.role = Role.Image
}
} else {
Modifier
}
// Explicitly use a simple Layout implementation here as Spacer squashes any non fixed
// constraint with zero
Layout(
{},
modifier
.then(semantics)
.let { if (clipToBounds) it.clipToBounds() else it }
.paint(
painter,
alignment = alignment,
contentScale = contentScale,
alpha = alpha,
colorFilter = colorFilter
)
) { _, constraints ->
layout(constraints.minWidth, constraints.minHeight) {}
}
}