i tucked everything into gesture detector, wheel-scrolling too

pier-bezuhoff · Jan 16, 2024 · b7763aa · b7763aa
1 parent 177af6b
commit b7763aa
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Showing 2 changed files with 45 additions and 32 deletions.
diff --git a/composeApp/src/commonMain/kotlin/ui/EditClusterScreen.kt b/composeApp/src/commonMain/kotlin/ui/EditClusterScreen.kt
@@ -224,13 +224,15 @@ fun EditClusterContent(
                         }
                         else { // only long-press drag in other modes
                             // navigate canvas
-//                            offset = offset + pan // ought to be something more sophisticated
                             offset = (offset + centroid/scale) - (centroid/(scale*zoom) + pan/scale)
-                            scale *= zoom
+                            scale *= zoom // MAYBE: add zoom slider for non-mobile
                         }
                     }
 
                 },
+                onVerticalScroll = { yDelta ->
+                    1 // maybe scale as onPanZoom
+                },
                 onDragStart = {
                     // draggables = circles
                     // grab circle or handle
@@ -244,7 +246,6 @@ fun EditClusterContent(
             )
             .graphicsLayer(
                 scaleX = scale, scaleY = scale,
-//                translationX = offset.x, translationY = offset.y,
                 translationX = -scale*offset.x, translationY = -scale*offset.y,
                 transformOrigin = TransformOrigin(0f, 0f)
             )

diff --git a/composeApp/src/commonMain/kotlin/ui/Gestures.kt b/composeApp/src/commonMain/kotlin/ui/Gestures.kt
@@ -5,53 +5,65 @@ import androidx.compose.foundation.gestures.awaitFirstDown
 import androidx.compose.foundation.gestures.detectDragGesturesAfterLongPress
 import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.gestures.detectTransformGestures
-import androidx.compose.foundation.gestures.waitForUpOrCancellation
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.input.pointer.PointerEventPass
+import androidx.compose.ui.input.pointer.PointerEventType
 import androidx.compose.ui.input.pointer.pointerInput
 
 inline fun Modifier.reactiveCanvas(
     vararg keys: Any?,
     crossinline onPanZoom: (pan: Offset, centroid: Offset, zoom: Float) -> Unit,
+    crossinline onVerticalScroll: (yDelta: Float) -> Unit = { },
     crossinline onDown: (position: Offset) -> Unit = { },
     crossinline onTap: (position: Offset) -> Unit = { },
     crossinline onDragStart: (position: Offset) -> Unit = { },
     crossinline onDrag: (delta: Offset) -> Unit,
     crossinline onDragEnd: () -> Unit = { },
 ): Modifier =
-    pointerInput(*keys) {
-    detectTransformGestures { centroid, pan, zoom, rotation ->
+    this
+        .pointerInput(*keys) {
+            awaitEachGesture {
+                val event = awaitPointerEvent(PointerEventPass.Initial)
+                if (event.type == PointerEventType.Scroll) {
+                    val yDelta = event.changes.map { it.scrollDelta.y }.sum()
+//                    println("scroll")
+                    onVerticalScroll(yDelta)
+                }
+            }
+        }
+        .pointerInput(*keys) {
+            detectTransformGestures { centroid, pan, zoom, rotation ->
 //        println("transform")
-        onPanZoom(pan, centroid, zoom)
-    }
-}
-    .pointerInput(*keys) {
-        awaitEachGesture {
-            val down = awaitFirstDown(requireUnconsumed = false)
+                onPanZoom(pan, centroid, zoom)
+            }
+        }
+        .pointerInput(*keys) {
+            awaitEachGesture {
+                val down = awaitFirstDown(requireUnconsumed = false)
 //            println("down")
-            onDown(down.position)
+                onDown(down.position)
+            }
         }
-    }
-    .pointerInput(*keys) {
-        detectTapGestures { position ->
+        .pointerInput(*keys) {
+            detectTapGestures { position ->
 //            println("tap")
-            onTap(position)
+                onTap(position)
+            }
         }
-    }
-    // NOTE: the later pointInput-s *can* consume events before passing it higher
-    .pointerInput(*keys) {
-        detectDragGesturesAfterLongPress(
-            onDragStart = { position ->
+        // NOTE: the later pointInput-s *can* consume events before passing it higher
+        .pointerInput(*keys) {
+            detectDragGesturesAfterLongPress(
+                onDragStart = { position ->
 //                println("long drag start")
-                onDragStart(position)
-            },
-            onDrag = { change, dragAmount ->
-                onDrag(dragAmount)
-            },
-            onDragEnd = {
+                    onDragStart(position)
+                },
+                onDrag = { change, dragAmount ->
+                    onDrag(dragAmount)
+                },
+                onDragEnd = {
 //                println("long drag end")
-                onDragEnd()
-            }
-        )
-    }
+                    onDragEnd()
+                }
+            )
+        }