feat(rstream-gestures): add zoomDelta output

thi-ng · Apr 11, 2019 · 68c4b45 · 68c4b45
1 parent f2efaa5
commit 68c4b45
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Showing 2 changed files with 11 additions and 11 deletions.
diff --git a/packages/rstream-gestures/README.md b/packages/rstream-gestures/README.md
@@ -13,7 +13,7 @@ Unified mouse, mouse wheel & single-touch event stream abstraction.
 Stream emits tuples of:
 
 ```ts
-[type, {pos, click?, delta?, zoom}]
+[type, { pos, click?, delta?, zoom, zoomDelta }]
 ```
 
 The `click` and `delta` values are only present if `type ==
@@ -25,7 +25,7 @@ events. The value will be constrained to `minZoom` ... `maxZoom`
 interval (provided via options object).
 
 Also see the
-[`GestureStreamOpts`](https://github.com/thi-ng/umbrella/tree/master/packages/rstream-gestures/src/index.ts#L26)
+[`GestureStreamOpts`](https://github.com/thi-ng/umbrella/tree/master/packages/rstream-gestures/src/index.ts#L31)
 config options for further details.
 
 ## Installation
@@ -60,15 +60,15 @@ import { trace } from "@thi.ng/rstream";
 import { comp, dedupe, filter, map } from "@thi.ng/transducers";
 
 // create event stream with custom option
-const gestures = gestureStream(document.body, { smooth: 0.5 });
+const gestures = gestureStream(document.body, { smooth: 0.01 });
 
 // subscription logging zoom value changes
 gestures.subscribe(
     // trace is simply logging received values to console
     trace("zoom"),
     // composed transducer, `dedupe` ensures only changed values are received
     comp(
-        map(([_, {zoom}]) => zoom),
+        map(([_, { zoom }]) => zoom),
         dedupe()
     )
 );
@@ -78,7 +78,7 @@ gestures.subscribe(
     trace("distance"),
     comp(
         filter(([type]) => type === GestureType.DRAG),
-        map(([_, {delta}]) => Math.hypot(...delta))
+        map(([_, { delta }]) => Math.hypot(...delta))
     )
 );
 ```

diff --git a/packages/rstream-gestures/src/index.ts b/packages/rstream-gestures/src/index.ts
@@ -20,6 +20,7 @@ export interface GestureInfo {
     click: number[];
     delta: number[];
     zoom: number;
+    zoomDelta: number;
 }
 
 export interface GestureEvent {
@@ -172,7 +173,7 @@ export const gestureStream = (
                 pos[0] *= dpr;
                 pos[1] *= dpr;
             }
-            const body = <GestureInfo>{ pos, zoom };
+            const body = <GestureInfo>{ pos, zoom, zoomDelta: 0 };
             switch (type) {
                 case GestureType.START:
                     isDown = true;
@@ -187,15 +188,14 @@ export const gestureStream = (
                     body.delta = [pos[0] - clickPos[0], pos[1] - clickPos[1]];
                     break;
                 case GestureType.ZOOM:
+                    const zdelta = (<WheelEvent>e).deltaY * opts.smooth;
                     body.zoom = zoom = opts.absZoom
                         ? Math.min(
-                              Math.max(
-                                  zoom + (<WheelEvent>e).deltaY * opts.smooth,
-                                  opts.minZoom
-                              ),
+                              Math.max(zoom + zdelta, opts.minZoom),
                               opts.maxZoom
                           )
-                        : (<WheelEvent>e).deltaY * opts.smooth;
+                        : zdelta;
+                    body.zoomDelta = zdelta;
                     break;
                 default:
             }