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commonMain.androidx.compose.ui.graphics.drawscope.CanvasDrawScope.kt Maven / Gradle / Ivy
/*
* 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.ui.graphics.drawscope
import androidx.annotation.FloatRange
import androidx.compose.ui.geometry.CornerRadius
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.geometry.center
import androidx.compose.ui.graphics.BlendMode
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Canvas
import androidx.compose.ui.graphics.ClipOp
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ColorFilter
import androidx.compose.ui.graphics.FilterQuality
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.Matrix
import androidx.compose.ui.graphics.Paint
import androidx.compose.ui.graphics.PaintingStyle
import androidx.compose.ui.graphics.Path
import androidx.compose.ui.graphics.PathEffect
import androidx.compose.ui.graphics.PointMode
import androidx.compose.ui.graphics.StrokeCap
import androidx.compose.ui.graphics.StrokeJoin
import androidx.compose.ui.graphics.drawscope.DrawScope.Companion.DefaultFilterQuality
import androidx.compose.ui.graphics.layer.GraphicsLayer
import androidx.compose.ui.graphics.requirePrecondition
import androidx.compose.ui.unit.Density
import androidx.compose.ui.unit.IntOffset
import androidx.compose.ui.unit.IntSize
import androidx.compose.ui.unit.LayoutDirection
/**
* Implementation of [DrawScope] that issues drawing commands
* into the specified canvas and bounds via [CanvasDrawScope.draw]
*/
class CanvasDrawScope : DrawScope {
@PublishedApi internal val drawParams = DrawParams()
override val layoutDirection: LayoutDirection
get() = drawParams.layoutDirection
override val density: Float
get() = drawParams.density.density
override val fontScale: Float
get() = drawParams.density.fontScale
override val drawContext = object : DrawContext {
override var canvas: Canvas
get() = drawParams.canvas
set(value) { drawParams.canvas = value }
override var size: Size
get() = drawParams.size
set(value) {
drawParams.size = value
}
override val transform: DrawTransform = asDrawTransform()
override var layoutDirection: LayoutDirection
get() = drawParams.layoutDirection
set(value) { drawParams.layoutDirection = value }
override var density: Density
get() = drawParams.density
set(value) { drawParams.density = value }
override var graphicsLayer: GraphicsLayer? = null
}
/**
* Internal [Paint] used only for drawing filled in shapes with a color or gradient
* This is lazily allocated on the first drawing command that uses the [Fill] [DrawStyle]
* and re-used across subsequent calls
*/
private var fillPaint: Paint? = null
/**
* Internal [Paint] used only for drawing stroked shapes with a color or gradient
* This is lazily allocated on the first drawing command that uses the [Stroke] [DrawStyle]
* and re-used across subsequent calls
*/
private var strokePaint: Paint? = null
/**
* @see [DrawScope.drawLine]
*/
override fun drawLine(
brush: Brush,
start: Offset,
end: Offset,
strokeWidth: Float,
cap: StrokeCap,
pathEffect: PathEffect?,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawLine(
start,
end,
configureStrokePaint(
brush,
strokeWidth,
Stroke.DefaultMiter,
cap,
StrokeJoin.Miter,
pathEffect,
alpha,
colorFilter,
blendMode
)
)
/**
* @see [DrawScope.drawLine]
*/
override fun drawLine(
color: Color,
start: Offset,
end: Offset,
strokeWidth: Float,
cap: StrokeCap,
pathEffect: PathEffect?,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawLine(
start,
end,
configureStrokePaint(
color,
strokeWidth,
Stroke.DefaultMiter,
cap,
StrokeJoin.Miter,
pathEffect,
alpha,
colorFilter,
blendMode
)
)
/**
* @see [DrawScope.drawRect]
*/
override fun drawRect(
brush: Brush,
topLeft: Offset,
size: Size,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawRect(
left = topLeft.x,
top = topLeft.y,
right = topLeft.x + size.width,
bottom = topLeft.y + size.height,
paint = configurePaint(brush, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawRect]
*/
override fun drawRect(
color: Color,
topLeft: Offset,
size: Size,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawRect(
left = topLeft.x,
top = topLeft.y,
right = topLeft.x + size.width,
bottom = topLeft.y + size.height,
paint = configurePaint(color, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawImage]
*/
override fun drawImage(
image: ImageBitmap,
topLeft: Offset,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawImage(
image,
topLeft,
configurePaint(null, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawImage]
*/
@Deprecated(
"Prefer usage of drawImage that consumes an optional FilterQuality parameter",
replaceWith = ReplaceWith(
"drawImage(image, srcOffset, srcSize, dstOffset, dstSize, alpha, style," +
" colorFilter, blendMode, FilterQuality.Low)",
"androidx.compose.ui.graphics.drawscope",
"androidx.compose.ui.graphics.FilterQuality"
),
level = DeprecationLevel.HIDDEN
)
override fun drawImage(
image: ImageBitmap,
srcOffset: IntOffset,
srcSize: IntSize,
dstOffset: IntOffset,
dstSize: IntSize,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawImageRect(
image,
srcOffset,
srcSize,
dstOffset,
dstSize,
configurePaint(null, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawImage]
*/
override fun drawImage(
image: ImageBitmap,
srcOffset: IntOffset,
srcSize: IntSize,
dstOffset: IntOffset,
dstSize: IntSize,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode,
filterQuality: FilterQuality
) = drawParams.canvas.drawImageRect(
image,
srcOffset,
srcSize,
dstOffset,
dstSize,
configurePaint(null, style, alpha, colorFilter, blendMode, filterQuality)
)
/**
* @see [DrawScope.drawRoundRect]
*/
override fun drawRoundRect(
brush: Brush,
topLeft: Offset,
size: Size,
cornerRadius: CornerRadius,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawRoundRect(
topLeft.x,
topLeft.y,
topLeft.x + size.width,
topLeft.y + size.height,
cornerRadius.x,
cornerRadius.y,
configurePaint(brush, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawRoundRect]
*/
override fun drawRoundRect(
color: Color,
topLeft: Offset,
size: Size,
cornerRadius: CornerRadius,
style: DrawStyle,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawRoundRect(
topLeft.x,
topLeft.y,
topLeft.x + size.width,
topLeft.y + size.height,
cornerRadius.x,
cornerRadius.y,
configurePaint(color, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawCircle]
*/
override fun drawCircle(
brush: Brush,
radius: Float,
center: Offset,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawCircle(
center,
radius,
configurePaint(brush, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawCircle]
*/
override fun drawCircle(
color: Color,
radius: Float,
center: Offset,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawCircle(
center,
radius,
configurePaint(color, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawOval]
*/
override fun drawOval(
brush: Brush,
topLeft: Offset,
size: Size,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawOval(
left = topLeft.x,
top = topLeft.y,
right = topLeft.x + size.width,
bottom = topLeft.y + size.height,
paint = configurePaint(brush, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawOval]
*/
override fun drawOval(
color: Color,
topLeft: Offset,
size: Size,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawOval(
left = topLeft.x,
top = topLeft.y,
right = topLeft.x + size.width,
bottom = topLeft.y + size.height,
paint = configurePaint(color, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawArc]
*/
override fun drawArc(
brush: Brush,
startAngle: Float,
sweepAngle: Float,
useCenter: Boolean,
topLeft: Offset,
size: Size,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawArc(
left = topLeft.x,
top = topLeft.y,
right = topLeft.x + size.width,
bottom = topLeft.y + size.height,
startAngle = startAngle,
sweepAngle = sweepAngle,
useCenter = useCenter,
paint = configurePaint(brush, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawArc]
*/
override fun drawArc(
color: Color,
startAngle: Float,
sweepAngle: Float,
useCenter: Boolean,
topLeft: Offset,
size: Size,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawArc(
left = topLeft.x,
top = topLeft.y,
right = topLeft.x + size.width,
bottom = topLeft.y + size.height,
startAngle = startAngle,
sweepAngle = sweepAngle,
useCenter = useCenter,
paint = configurePaint(color, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawPath]
*/
override fun drawPath(
path: Path,
color: Color,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawPath(
path,
configurePaint(color, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawPath]
*/
override fun drawPath(
path: Path,
brush: Brush,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
style: DrawStyle,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawPath(
path,
configurePaint(brush, style, alpha, colorFilter, blendMode)
)
/**
* @see [DrawScope.drawPoints]
*/
override fun drawPoints(
points: List,
pointMode: PointMode,
color: Color,
strokeWidth: Float,
cap: StrokeCap,
pathEffect: PathEffect?,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawPoints(
pointMode,
points,
configureStrokePaint(
color,
strokeWidth,
Stroke.DefaultMiter,
cap,
StrokeJoin.Miter,
pathEffect,
alpha,
colorFilter,
blendMode
)
)
/**
* @see [DrawScope.drawPoints]
*/
override fun drawPoints(
points: List,
pointMode: PointMode,
brush: Brush,
strokeWidth: Float,
cap: StrokeCap,
pathEffect: PathEffect?,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode
) = drawParams.canvas.drawPoints(
pointMode,
points,
configureStrokePaint(
brush,
strokeWidth,
Stroke.DefaultMiter,
cap,
StrokeJoin.Miter,
pathEffect,
alpha,
colorFilter,
blendMode
)
)
/**
* Draws into the provided [Canvas] with the commands specified in the lambda with this
* [DrawScope] as a receiver
*
* @param density [Density] used to assist in conversions of density independent pixels to raw
* pixels to draw
* @param layoutDirection [LayoutDirection] of the layout being drawn in.
* @param canvas target canvas to render into
* @param size bounds relative to the current canvas translation in which the [DrawScope]
* should draw within
* @param block lambda that is called to issue drawing commands on this [DrawScope]
*/
inline fun draw(
density: Density,
layoutDirection: LayoutDirection,
canvas: Canvas,
size: Size,
block: DrawScope.() -> Unit
) {
// Remember the previous drawing parameters in case we are temporarily re-directing our
// drawing to a separate Layer/RenderNode only to draw that content back into the original
// Canvas. If there is no previous canvas that was being drawing into, this ends up
// resetting these parameters back to defaults defensively
val (prevDensity, prevLayoutDirection, prevCanvas, prevSize) = drawParams
drawParams.apply {
this.density = density
this.layoutDirection = layoutDirection
this.canvas = canvas
this.size = size
}
canvas.save()
this.block()
canvas.restore()
drawParams.apply {
this.density = prevDensity
this.layoutDirection = prevLayoutDirection
this.canvas = prevCanvas
this.size = prevSize
}
}
/**
* Internal published APIs used to support inline scoped extension methods
* on DrawScope directly, without exposing the underlying stateful APIs
* to conduct the transformations themselves as inline methods require
* all methods called within them to be public
*/
/**
* Helper method to instantiate the paint object on first usage otherwise
* return the previously allocated Paint used for drawing filled regions
*/
private fun obtainFillPaint(): Paint =
fillPaint ?: Paint().apply { style = PaintingStyle.Fill }.also {
fillPaint = it
}
/**
* Helper method to instantiate the paint object on first usage otherwise
* return the previously allocated Paint used for drawing strokes
*/
private fun obtainStrokePaint(): Paint =
strokePaint ?: Paint().apply { style = PaintingStyle.Stroke }.also {
strokePaint = it
}
/**
* Selects the appropriate [Paint] object based on the style
* and applies the underlying [DrawStyle] parameters
*/
private fun selectPaint(drawStyle: DrawStyle): Paint =
when (drawStyle) {
Fill -> obtainFillPaint()
is Stroke ->
obtainStrokePaint()
.apply {
if (strokeWidth != drawStyle.width) strokeWidth = drawStyle.width
if (strokeCap != drawStyle.cap) strokeCap = drawStyle.cap
if (strokeMiterLimit != drawStyle.miter) strokeMiterLimit = drawStyle.miter
if (strokeJoin != drawStyle.join) strokeJoin = drawStyle.join
if (pathEffect != drawStyle.pathEffect) pathEffect = drawStyle.pathEffect
}
}
/**
* Helper method to configure the corresponding [Brush] along with other properties
* on the corresponding paint specified by [DrawStyle]
*/
private fun configurePaint(
brush: Brush?,
style: DrawStyle,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode,
filterQuality: FilterQuality = DefaultFilterQuality
): Paint = selectPaint(style).apply {
if (brush != null) {
brush.applyTo(size, this, alpha)
} else {
if (this.shader != null) this.shader = null
if (this.color != Color.Black) this.color = Color.Black
if (this.alpha != alpha) this.alpha = alpha
}
if (this.colorFilter != colorFilter) this.colorFilter = colorFilter
if (this.blendMode != blendMode) this.blendMode = blendMode
if (this.filterQuality != filterQuality) this.filterQuality = filterQuality
}
/**
* Helper method to configure the corresponding [Color] along with other properties
* on the corresponding paint specified by [DrawStyle]
*/
private fun configurePaint(
color: Color,
style: DrawStyle,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode,
filterQuality: FilterQuality = DefaultFilterQuality
): Paint = selectPaint(style).apply {
// Modulate the color alpha directly
// instead of configuring a separate alpha parameter
val targetColor = color.modulate(alpha)
if (this.color != targetColor) this.color = targetColor
if (this.shader != null) this.shader = null
if (this.colorFilter != colorFilter) this.colorFilter = colorFilter
if (this.blendMode != blendMode) this.blendMode = blendMode
if (this.filterQuality != filterQuality) this.filterQuality = filterQuality
}
private fun configureStrokePaint(
color: Color,
strokeWidth: Float,
miter: Float,
cap: StrokeCap,
join: StrokeJoin,
pathEffect: PathEffect?,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode,
filterQuality: FilterQuality = DefaultFilterQuality
) =
obtainStrokePaint().apply {
// Modulate the color alpha directly
// instead of configuring a separate alpha parameter
val targetColor = color.modulate(alpha)
if (this.color != targetColor) this.color = targetColor
if (this.shader != null) this.shader = null
if (this.colorFilter != colorFilter) this.colorFilter = colorFilter
if (this.blendMode != blendMode) this.blendMode = blendMode
if (this.strokeWidth != strokeWidth) this.strokeWidth = strokeWidth
if (this.strokeMiterLimit != miter) this.strokeMiterLimit = miter
if (this.strokeCap != cap) this.strokeCap = cap
if (this.strokeJoin != join) this.strokeJoin = join
if (this.pathEffect != pathEffect) this.pathEffect = pathEffect
if (this.filterQuality != filterQuality) this.filterQuality = filterQuality
}
private fun configureStrokePaint(
brush: Brush?,
strokeWidth: Float,
miter: Float,
cap: StrokeCap,
join: StrokeJoin,
pathEffect: PathEffect?,
@FloatRange(from = 0.0, to = 1.0) alpha: Float,
colorFilter: ColorFilter?,
blendMode: BlendMode,
filterQuality: FilterQuality = DefaultFilterQuality
) = obtainStrokePaint().apply {
if (brush != null) {
brush.applyTo(size, this, alpha)
} else if (this.alpha != alpha) {
this.alpha = alpha
}
if (this.colorFilter != colorFilter) this.colorFilter = colorFilter
if (this.blendMode != blendMode) this.blendMode = blendMode
if (this.strokeWidth != strokeWidth) this.strokeWidth = strokeWidth
if (this.strokeMiterLimit != miter) this.strokeMiterLimit = miter
if (this.strokeCap != cap) this.strokeCap = cap
if (this.strokeJoin != join) this.strokeJoin = join
if (this.pathEffect != pathEffect) this.pathEffect = pathEffect
if (this.filterQuality != filterQuality) this.filterQuality = filterQuality
}
/**
* Returns a [Color] modulated with the given alpha value
*/
private fun Color.modulate(alpha: Float): Color =
if (alpha != 1.0f) {
copy(alpha = this.alpha * alpha)
} else {
this
}
/**
* Internal parameters to represent the current CanvasDrawScope
* used to reduce the size of the inline draw call to avoid
* bloat of additional assignment calls for each parameter
* individually
*/
@PublishedApi internal data class DrawParams(
var density: Density = DefaultDensity,
var layoutDirection: LayoutDirection = LayoutDirection.Ltr,
var canvas: Canvas = EmptyCanvas(),
var size: Size = Size.Zero
)
}
/**
* Convenience method for creating a [DrawTransform] from the current [DrawContext]
*/
private fun DrawContext.asDrawTransform(): DrawTransform = object : DrawTransform {
override val size: Size
get() = [email protected]
override val center: Offset
get() = size.center
override fun inset(left: Float, top: Float, right: Float, bottom: Float) {
[email protected] {
val updatedSize = Size(size.width - (left + right), size.height - (top + bottom))
requirePrecondition(updatedSize.width >= 0 && updatedSize.height >= 0) {
"Width and height must be greater than or equal to zero"
}
[email protected] = updatedSize
it.translate(left, top)
}
}
override fun clipRect(
left: Float,
top: Float,
right: Float,
bottom: Float,
clipOp: ClipOp
) {
[email protected] (left, top, right, bottom, clipOp)
}
override fun clipPath(path: Path, clipOp: ClipOp) {
[email protected] (path, clipOp)
}
override fun translate(left: Float, top: Float) {
[email protected] (left, top)
}
override fun rotate(degrees: Float, pivot: Offset) {
[email protected] {
translate(pivot.x, pivot.y)
rotate(degrees)
translate(-pivot.x, -pivot.y)
}
}
override fun scale(scaleX: Float, scaleY: Float, pivot: Offset) {
[email protected] {
translate(pivot.x, pivot.y)
scale(scaleX, scaleY)
translate(-pivot.x, -pivot.y)
}
}
override fun transform(matrix: Matrix) {
[email protected] (matrix)
}
}
