Compose Graphics

Version-sensitive. Every API name, SDK gate and browser-support claim below was verified on 2026-09-08 against primary sources. What against, and when, is in _jutsu/VERSIONS.md. If that date is old, re-verify before acting on a version number.

Compose Graphics

Advanced Compose visuals: M3 Expressive motion physics, AGSL shaders (Android 13+), Canvas / DrawScope, graphicsLayer effects. Loaded for advanced thesis (shader, expressive, M3 Expressive, AGSL, Canvas, holographic). Foundation: ../compose-motion/SKILL.md covers basics. Concise rules here. Deep-dive in references/.

Decision Tree: Which API for Which Need

Domain 1: Material 3 Expressive

What It Is

The 2025 Material 3 evolution introduces spring-based motion physics replacing fixed-duration tweens. New shape morphing API via androidx.graphics.shapes. New MotionScheme selectable on the theme. Aimed at hero moments, key interactions, brand-defining UI.

MotionScheme

Apply on the theme:

MaterialTheme(motionScheme = MotionScheme.expressive()) {
    // children read tokens via MaterialTheme.motionScheme.*
}

Tokens exposed:

Spatial vs Effects: spatial = anything physical (height, offset, scale). Effects = visual properties without inertia (alpha, color, elevation). Both families are springs - the effects ones are just critically damped (dampingRatio = 1.0) and much stiffer, so they never overshoot. Only the spatial springs differ between standard() and expressive().

Availability: MotionScheme, MaterialTheme(motionScheme = ...) and MaterialExpressiveTheme are stable in material3 1.4.0 (no opt-in needed). MaterialShapes and the shape-morphing helpers are not - they need 1.5.0-alpha and @OptIn(ExperimentalMaterial3ExpressiveApi::class).

Hero Card Expand (Expressive Springs)

@Composable
fun ExpressiveHero() {
    var expanded by remember { mutableStateOf(false) }
    MaterialTheme(motionScheme = MotionScheme.expressive()) {
        val transition = updateTransition(targetState = expanded, label = "expand")
        val height by transition.animateDp(
            transitionSpec = { MaterialTheme.motionScheme.slowSpatialSpec() },
            label = "height"
        ) { if (it) 400.dp else 100.dp }
        val alpha by transition.animateFloat(
            transitionSpec = { MaterialTheme.motionScheme.defaultEffectsSpec() },
            label = "alpha"
        ) { if (it) 1f else 0f }

        Card(
            modifier = Modifier
                .fillMaxWidth()
                .height(height)
                .clickable { expanded = !expanded }
        ) {
            Box(modifier = Modifier.alpha(alpha)) {
                Text("Detail content", modifier = Modifier.padding(24.dp))
            }
        }
    }
}

Spring Tuning Recipes

Shape Morphing (MaterialShapes + Morph)

Two different libraries, and the split matters:

• androidx.graphics.shapes:graphics-shapes (stable 1.1.0) ships RoundedPolygon, CornerRounding and Morph(start, end). Its Morph.toPath(progress) returns an android.graphics.Path.
• The predefined Material shapes (MaterialShapes.Circle, Pentagon, Cookie4Sided, Sunny, Heart, ...) live in material3, not in graphics-shapes. They are still @ExperimentalMaterial3ExpressiveApi and ship only in androidx.compose.material3:material3:1.5.0-alpha* - they are not in stable material3 1.4.0. material3 also adds Morph.toPath(progress) returning a Compose Path, plus RoundedPolygon.toShape().

Never write .asAndroidPath().asComposePath(): with the graphics-shapes import it does not compile (android.graphics.Path has no asAndroidPath()), and with the material3 import it is a pointless round trip. And because MaterialShapes are normalized to a 0..1 box, the path must be scaled to the draw size - dropping the raw path into GenericShape yields a ~1px shape in the top-left corner.

import androidx.compose.material3.MaterialShapes
import androidx.compose.material3.toPath          // Morph.toPath -> androidx.compose.ui.graphics.Path
import androidx.graphics.shapes.Morph

@OptIn(ExperimentalMaterial3ExpressiveApi::class)
@Composable
fun MorphingBadge(active: Boolean) {
    val morph = remember { Morph(MaterialShapes.Circle, MaterialShapes.Cookie4Sided) }
    val progress by animateFloatAsState(
        targetValue = if (active) 1f else 0f,
        animationSpec = MaterialTheme.motionScheme.slowSpatialSpec(),
        label = "morph",
    )
    Box(
        modifier = Modifier
            .size(96.dp)
            .clip(MorphShape(morph, progress))
            .background(MaterialTheme.colorScheme.primary)
    )
}

/** MaterialShapes are normalized to 0..1: scale the path to the draw size, then centre it. */
@OptIn(ExperimentalMaterial3ExpressiveApi::class)
private class MorphShape(private val morph: Morph, private val progress: Float) : Shape {
    override fun createOutline(
        size: Size,
        layoutDirection: LayoutDirection,
        density: Density,
    ): Outline {
        val path = morph.toPath(progress = progress)
        path.transform(Matrix().apply { scale(x = size.width, y = size.height) })
        path.translate(size.center - path.getBounds().center)
        return Outline.Generic(path)
    }
}

For a static (non-morphing) shape, skip all of this: MaterialShapes.Cookie4Sided.toShape() returns a ready-to-use Shape that already handles the scaling.

When to Use Expressive vs Standard

• Expressive: hero moments, key interactions, FABs, primary CTAs. 1-3% of UI.
• Standard: default for the rest of the app. Mixing too much Expressive feels chaotic - every element fighting for attention.

Domain 2: AGSL Shaders (Android 13+)

What It Is

AGSL is Android's shader language. Similar to GLSL with simplifications (half4 instead of vec4, restricted feature set, sandbox-safe). RuntimeShader compiles your AGSL source. Bind to a Compose modifier via Modifier.graphicsLayer { renderEffect = ... }.

Setup

@Composable
fun ShaderEffect(content: @Composable () -> Unit) {
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
        // Android 12 and below: skip the shader, render content as-is.
        content()
        return
    }
    val shader = remember { RuntimeShader(AGSL_SOURCE) }
    val time by produceState(0f) {
        while (true) {
            withFrameMillis { ms ->
                value = ms / 1000f
            }
        }
    }
    Box(
        modifier = Modifier
            .onSizeChanged {
                shader.setFloatUniform("resolution", it.width.toFloat(), it.height.toFloat())
            }
            .graphicsLayer {
                shader.setFloatUniform("time", time)
                renderEffect = RenderEffect
                    .createRuntimeShaderEffect(shader, "image")
                    .asComposeRenderEffect()
            }
    ) { content() }
}

Always gate on Build.VERSION.SDK_INT >= 33. Pre-Android 13 fallback: render the content unmodified, or use Modifier.blur() / a static gradient overlay.

Recipe: Touch Ripple

AGSL source:

// ripple.agsl
uniform float2 resolution;
uniform float2 origin;
uniform float time;
uniform shader image;

half4 main(float2 fragCoord) {
    float2 toOrigin = fragCoord - origin;
    float dist = length(toOrigin);
    float wave = sin(dist * 0.05 - time * 8.0) * 0.05;
    float falloff = 1.0 / max(dist * 0.01, 1.0);
    float2 dir = toOrigin / max(dist, 0.0001);
    float2 displaced = fragCoord + dir * wave * falloff * 50.0;
    return image.eval(displaced);
}

Compose binding (state-driven time, animated via LaunchedEffect):

@Composable
fun RippleSurface(content: @Composable BoxScope.() -> Unit) {
    if (Build.VERSION.SDK_INT < 33) { Box { content() }; return }
    val shader = remember { RuntimeShader(RIPPLE_AGSL) }
    var origin by remember { mutableStateOf(Offset.Zero) }
    var startMs by remember { mutableStateOf<Long?>(null) }
    val time by produceState(0f, startMs) {
        if (startMs == null) { value = 0f; return@produceState }
        val begin = startMs!!
        while (true) {
            withFrameMillis { now ->
                value = (now - begin) / 1000f
            }
        }
    }
    Box(
        modifier = Modifier
            .onSizeChanged {
                shader.setFloatUniform("resolution", it.width.toFloat(), it.height.toFloat())
            }
            .pointerInput(Unit) {
                detectTapGestures { tap ->
                    origin = tap
                    startMs = System.currentTimeMillis()
                }
            }
            .graphicsLayer {
                shader.setFloatUniform("origin", origin.x, origin.y)
                shader.setFloatUniform("time", time)
                renderEffect = RenderEffect
                    .createRuntimeShaderEffect(shader, "image")
                    .asComposeRenderEffect()
            },
        content = content
    )
}

Recipe: Holographic Gradient

uniform float time;
uniform shader image;

half4 main(float2 fragCoord) {
    half4 color = image.eval(fragCoord);
    float n = fragCoord.x * 0.01 + fragCoord.y * 0.005 + time * 0.3;
    half3 rainbow = half3(
        sin(n * 2.0) * 0.5 + 0.5,
        sin(n * 2.0 + 2.094) * 0.5 + 0.5,
        sin(n * 2.0 + 4.188) * 0.5 + 0.5
    );
    half luma = dot(color.rgb, half3(0.299, 0.587, 0.114));
    return half4(mix(color.rgb, rainbow * luma * 2.0, 0.5), color.a);
}

Multiplies the underlying view's luminance by a phase-shifted RGB sine wave - shimmer over text or icons. time animates the wave drift.

Recipe: Liquid Glass / Glassmorphism

Android lacks a native iOS-26-style glassEffect. Compose this with blur + chromatic aberration + soft edge tint:

uniform float2 resolution;
uniform shader image;

half4 main(float2 fragCoord) {
    float2 uv = fragCoord / resolution;
    // Chromatic aberration: sample R, G, B at slightly different offsets
    float2 ca = (uv - 0.5) * 0.004;
    half r = image.eval(fragCoord + ca * resolution).r;
    half g = image.eval(fragCoord).g;
    half b = image.eval(fragCoord - ca * resolution).b;
    half4 base = half4(r, g, b, 1.0);
    // Soft edge tint: brighten near borders for that frosted look
    float edge = smoothstep(0.45, 0.5, max(abs(uv.x - 0.5), abs(uv.y - 0.5)));
    half3 tinted = base.rgb + half3(edge * 0.08);
    return half4(tinted, 0.85);
}

Pair with Modifier.blur(20.dp, BlurredEdgeTreatment.Unbounded) upstream for the actual blur (cheaper than computing it in AGSL).

Performance Notes

• Each RuntimeShader is a render pass. Compounds at 60fps - benchmark via Macrobenchmark.
• image.eval(coord) samples the underlying view as a texture. Heavy if the view is complex (long lists, nested layouts). Cache static parts in a parent that doesn't recompose.
• On Android 12 and below: graceful fallback (static image, no shader). Never hard-crash.
• Prefer 1 well-crafted shader over chaining 4 shaders in series.

Domain 3: Canvas / DrawScope

Canvas API

Canvas(modifier = Modifier.size(200.dp)) {
    // 'this' is DrawScope - size, drawCircle, drawPath, drawRect...
    drawCircle(Color.Blue, radius = size.minDimension / 2)
    drawPath(myPath, color = Color.White, style = Stroke(width = 4.dp.toPx()))
}

Recipe: Animated Sine Wave

@Composable
fun AnimatedWave() {
    val infinite = rememberInfiniteTransition(label = "wave")
    val phase by infinite.animateFloat(
        initialValue = 0f,
        targetValue = 2 * PI.toFloat(),
        animationSpec = infiniteRepeatable(
            animation = tween(3000, easing = LinearEasing)
        ),
        label = "phase"
    )
    Canvas(modifier = Modifier.fillMaxWidth().height(80.dp)) {
        val path = Path()
        var x = 0
        while (x <= size.width.toInt()) {
            val y = size.height / 2 + sin(x * 0.05f + phase) * 20f
            if (x == 0) path.moveTo(x.toFloat(), y) else path.lineTo(x.toFloat(), y)
            x += 2
        }
        drawPath(path, color = Color.Blue, style = Stroke(width = 2.dp.toPx()))
    }
}

Recipe: Particle System (50 Particles)

data class Particle(var x: Float, var y: Float, var vx: Float, var vy: Float, var life: Float)

@Composable
fun ParticleField() {
    val particles = remember {
        mutableStateListOf<Particle>().apply {
            repeat(50) {
                add(Particle(
                    x = Random.nextFloat() * 1000f,
                    y = Random.nextFloat() * 1000f,
                    vx = (Random.nextFloat() - 0.5f) * 4f,
                    vy = (Random.nextFloat() - 0.5f) * 4f,
                    life = 1f
                ))
            }
        }
    }
    LaunchedEffect(Unit) {
        while (true) {
            withFrameMillis { /* tick */ }
            particles.forEachIndexed { i, p ->
                p.x += p.vx
                p.y += p.vy
                p.life -= 0.01f
                if (p.life <= 0f) {
                    p.x = Random.nextFloat() * 1000f
                    p.y = Random.nextFloat() * 1000f
                    p.life = 1f
                }
            }
        }
    }
    Canvas(modifier = Modifier.fillMaxSize()) {
        particles.forEach { p ->
            drawCircle(
                color = Color.White.copy(alpha = p.life),
                radius = 2.dp.toPx(),
                center = Offset(p.x, p.y)
            )
        }
    }
}

Recipe: Generative Pattern (Flow Field)

Quick mention: noise-driven particle motion. See references/canvas-generative.md for the full deep-dive (Perlin noise, particle pools, advection loop).

Performance Notes

• Canvas redraws on every state change of any state it reads. Wrap volatile state in derivedStateOf to gate redraws.
• LaunchedEffect(Unit) { while(true) { withFrameMillis { ... } } } is fine for 60fps. Avoid delay(16) - it drifts.
• Heavy generative work: precompute paths once in remember, only animate transforms via translate { drawPath(...) }.
• 200 simple draws per frame = OK on most devices. 2000+ starts to lag.

Anti-Patterns

1. Expressive Everywhere

// BAD - every interaction overshoots, UI feels like a bouncy castle
MaterialTheme(motionScheme = MotionScheme.expressive()) {
    AppRoot()
}

// GOOD - Standard for chrome, scope Expressive to hero moments
MaterialTheme(motionScheme = MotionScheme.standard()) {
    NavigationScaffold {
        // Hero detail screen overrides locally
        MaterialTheme(motionScheme = MotionScheme.expressive()) {
            HeroDetail()
        }
    }
}

2. RuntimeShader Without API Gate

// BAD - crashes on Android 12 and below
val shader = remember { RuntimeShader(AGSL_SOURCE) }

// GOOD - gate on SDK level, provide fallback
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
    ShaderEffect { content() }
} else {
    Box(modifier = Modifier.background(fallbackGradient)) { content() }
}

3. Canvas Reading State Directly Each Frame

// BAD - any state change in the parent triggers a recompose of the Canvas
Canvas(modifier = Modifier.fillMaxSize()) {
    drawCircle(color = if (viewModel.isActive) Color.Red else Color.Blue, radius = 50f)
}

// GOOD - hoist the reads, derive a stable value
val color by remember { derivedStateOf { if (viewModel.isActive) Color.Red else Color.Blue } }
Canvas(modifier = Modifier.fillMaxSize()) {
    drawCircle(color = color, radius = 50f)
}

4. Chaining 4 AGSL Shaders in Series

// BAD - 4 render passes per frame, GPU melts on mid-range devices
.graphicsLayer { renderEffect = blurEffect }
.graphicsLayer { renderEffect = chromaticEffect }
.graphicsLayer { renderEffect = noiseEffect }
.graphicsLayer { renderEffect = vignetteEffect }

// GOOD - one shader doing all the math in a single pass
.graphicsLayer { renderEffect = combinedGlassEffect }

5. Allocating in DrawScope

// BAD - new Path every frame, GC stutter
Canvas(modifier = Modifier.fillMaxSize()) {
    val path = Path()
    points.forEach { path.lineTo(it.x, it.y) }
    drawPath(path, color = Color.Black)
}

// GOOD - reuse a remembered Path, rewind each frame
val path = remember { Path() }
Canvas(modifier = Modifier.fillMaxSize()) {
    path.rewind()
    points.forEach { path.lineTo(it.x, it.y) }
    drawPath(path, color = Color.Black)
}

Quick Reference: Loading Sub-resources

Sources

• drinkthestars/shady - AGSL shaders rendered in Compose
• Mortd3kay/liquid-glass-android
• JumpingKeyCaps/DynamicVisualEffectsAGSL
• Material 3 Expressive blog
• Material Design 3 Motion specs
• Android AGSL docs
• androidx.graphics.shapes - shape morphing