app

commit 6eb5b7b534360955432904a24cba0904ce648166
parent 643337eb6af242892777fb9f4b00da642f811b18
Author: triesap <tyson@radroots.org>
Date:   Tue, 11 Aug 2026 16:25:16 +0000

ui: implement the canvas scaffold

- fix the canvas header and action regions
- center the bounded nine-hundred-sixty-dp body
- expose navigation and workflow-step slots
- enable body scrolling only for very large text

Diffstat:
A
app/shared/src/commonMain/kotlin/org/harvestcircle/ui/shell/CanvasScaffold.kt
 | 
68
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
app/shared/src/desktopTest/kotlin/org/harvestcircle/ui/shell/CanvasScaffoldTest.kt
 | 
47
+++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 115 insertions(+), 0 deletions(-)
diff --git a/app/shared/src/commonMain/kotlin/org/harvestcircle/ui/shell/CanvasScaffold.kt b/app/shared/src/commonMain/kotlin/org/harvestcircle/ui/shell/CanvasScaffold.kt
@@ -0,0 +1,68 @@
+package org.harvestcircle.ui.shell
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.unit.dp
+import org.harvestcircle.design.TextSizePreference
+
+@Composable
+fun CanvasScaffold(
+    textSize: TextSizePreference,
+    navigation: @Composable () -> Unit = {},
+    header: @Composable () -> Unit,
+    step: @Composable () -> Unit = {},
+    body: @Composable () -> Unit,
+    actionBar: @Composable () -> Unit,
+) {
+    Column(Modifier.fillMaxSize().testTag("canvas-scaffold")) {
+        Row(
+            Modifier
+                .fillMaxWidth()
+                .height(64.dp)
+                .semantics { contentDescription = "Canvas header" }
+                .testTag("canvas-header"),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Box(Modifier.testTag("canvas-navigation")) { navigation() }
+            Box(Modifier.weight(1f)) { header() }
+            Box(Modifier.testTag("canvas-step")) { step() }
+        }
+        val bodyModifier =
+            Modifier
+                .weight(1f)
+                .fillMaxWidth()
+                .let { modifier ->
+                    if (canvasBodyScroll(textSize) == ScrollOwnership.CanvasBodyAccessibility) {
+                        modifier.verticalScroll(rememberScrollState())
+                    } else {
+                        modifier
+                    }
+                }.semantics { contentDescription = "Canvas body" }
+                .testTag("canvas-body")
+        Box(bodyModifier, contentAlignment = Alignment.TopCenter) {
+            Box(Modifier.fillMaxWidth().widthIn(max = 960.dp)) { body() }
+        }
+        Box(
+            Modifier
+                .fillMaxWidth()
+                .height(72.dp)
+                .semantics { contentDescription = "Canvas action bar" }
+                .testTag("canvas-action-bar"),
+        ) {
+            actionBar()
+        }
+    }
+}
diff --git a/app/shared/src/desktopTest/kotlin/org/harvestcircle/ui/shell/CanvasScaffoldTest.kt b/app/shared/src/desktopTest/kotlin/org/harvestcircle/ui/shell/CanvasScaffoldTest.kt
@@ -0,0 +1,47 @@
+package org.harvestcircle.ui.shell
+
+import androidx.compose.ui.semantics.SemanticsActions
+import androidx.compose.ui.test.ExperimentalTestApi
+import androidx.compose.ui.test.assertCountEquals
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.onAllNodesWithTag
+import androidx.compose.ui.test.onNodeWithTag
+import androidx.compose.ui.test.v2.runComposeUiTest
+import org.harvestcircle.design.TextSizePreference
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+@OptIn(ExperimentalTestApi::class)
+class CanvasScaffoldTest {
+    @Test
+    fun baselineCanvasKeepsHeaderBodyAndActionRegionsFixed() =
+        runComposeUiTest {
+            setContent { canvas(TextSizePreference.Default) }
+            onNodeWithTag("canvas-header").assertIsDisplayed()
+            onNodeWithTag("canvas-body").assertIsDisplayed()
+            onNodeWithTag("canvas-action-bar").assertIsDisplayed()
+            onAllNodesWithTag("canvas-navigation").assertCountEquals(1)
+            assertFalse(onNodeWithTag("canvas-body").fetchSemanticsNode().config.contains(SemanticsActions.ScrollBy))
+        }
+
+    @Test
+    fun veryLargeTextEnablesOnlyBoundedBodyScrolling() =
+        runComposeUiTest {
+            setContent { canvas(TextSizePreference.VeryLarge) }
+            assertTrue(onNodeWithTag("canvas-body").fetchSemanticsNode().config.contains(SemanticsActions.ScrollBy))
+            onNodeWithTag("canvas-action-bar").assertIsDisplayed()
+        }
+}
+
+@androidx.compose.runtime.Composable
+private fun canvas(textSize: TextSizePreference) {
+    CanvasScaffold(
+        textSize = textSize,
+        navigation = {},
+        header = {},
+        step = {},
+        body = {},
+        actionBar = {},
+    )
+}