Adding support for mouse wheel events. cleaning up click handler to take functions

src/cg/03-ui-components.cg

@@ -12,21 +12,10 @@ center = parentW parentH child \
   childSize = ui.measure child;
   ui.positioned { x = (parentW - childSize.width) / 2, y = (parentH - childSize.height) / 2, child = child };
 
-scrollable = config \
-  ui.clip {
-    w = config.w,
-    h = config.h,
-    child = ui.positioned {
-      x = 0 - config.scrollX,
-      y = 0 - config.scrollY,
-      child = config.child
-    }
-  };
-
 # button : Record -> ui
 button = config \
   ui.clickable {
-    event = config.event,
+    onClick = config.event,
     child = ui.stack {
       children = [
         ui.rect { w = 100, h = 40, color = "#eee" },

src/cg/05-palette.cg

@@ -50,7 +50,7 @@ palette = config \
     color = (config.selected | True \ "rgba(255,255,255,0.2)" | False \ "transparent");
 
     ui.clickable {
-      event = config.onClick,
+      onClick = config.onClick,
       child = ui.stack {
         children = [
           ui.rect { w = config.w, h = config.h, color = color },
@@ -109,11 +109,12 @@ palette = config \
                     onChange = text \ batch [paletteState.query := text],
                   },
 
-                  scrollable {
+                  ui.scrollable {
                     w = contentWidth,
                     h = listHeight,
                     scrollX = 0,
                     scrollY = paletteState.scrollOffset,
+                    onScroll = _ \ noOp,
                     child = ui.column {
                       gap = 1,
                       children = [
@@ -131,7 +132,7 @@ palette = config \
                               w = contentWidth,
                               h = textInputHeight,
                               selected = (effectiveIndex == i),
-                              onClick = config.onSelect data.label
+                              onClick = _ \ config.onSelect data.label
                             }
                           | _ \ empty
                         ) results)

src/cg/10-os.cg

@@ -100,7 +100,7 @@ renderWindow = window isActive \
               children = [
                 # close button
                 ui.clickable {
-                  event = closeWindowById window.id,
+                  onClick = _ \ closeWindowById window.id,
                   child = ui.stack {
                     children = [
                       # button background

src/runtime-compiled.ts

@@ -1,4 +1,4 @@
-import { render, hitTest } from './ui';
+import { render, hitTest, scrollHitTest } from './ui';
 
 type UIValue = any;
 
@@ -99,7 +99,7 @@ export function runAppCompiled(canvas: HTMLCanvasElement, store: any) {
                     viewUI = {
                         kind: 'clickable',
                         child: viewUI,
-                        event: { _tag: 'FocusAndClick', _0: fullKey }
+                        onClick: (coords: any) => ({ _tag: 'FocusAndClick', _0: fullKey, _1: coords })
                     };
                 }
                 return expandStateful(viewUI, [...path, ui.key], renderedKeys);
@@ -117,6 +117,7 @@ export function runAppCompiled(canvas: HTMLCanvasElement, store: any) {
             }
 
             case 'clickable':
+            case 'scrollable':
             case 'padding':
             case 'positioned':
             case 'opacity':
@@ -204,6 +205,21 @@ export function runAppCompiled(canvas: HTMLCanvasElement, store: any) {
             return;
     }
 
+    function dispatchToFocused(event: any) {
+        if (focusedComponentKey) {
+            // send to focused component
+            handleComponentEvent(focusedComponentKey, event);
+
+            // bubble up to ancestors
+            for (const key of componentInstances.keys()) {
+                if (key !== focusedComponentKey && focusedComponentKey.startsWith(key + '.')) {
+                    handleComponentEvent(key, event);
+                }
+            }
+        }
+
+    }
+
     canvas.addEventListener('click', (e) => {
         const rect = canvas.getBoundingClientRect();
         const x = e.clientX - rect.left;
@@ -211,24 +227,15 @@ export function runAppCompiled(canvas: HTMLCanvasElement, store: any) {
 
         const hitResult = hitTest(x, y);
         if (hitResult) {
-            const { event, relativeX, relativeY } = hitResult;
-
-            if (event._tag === 'FocusAndClick') {
-                handleEvent({
-                    _tag: 'FocusAndClick',
-                    _0: event._0,
-                    _1: { x: Math.floor(relativeX), y: Math.floor(relativeY) }
-                });
-            } else {
-                handleEvent(event);
-            }
+            const coords = { x: Math.floor(hitResult.relativeX), y: Math.floor(hitResult.relativeY) };
+            handleEvent(hitResult.onClick(coords));
         }
 
         rerender();
     });
 
     window.addEventListener('keydown', (e) => {
-        const event = {
+        dispatchToFocused({
             _tag: 'Key',
             _0: {
                 key: e.key,
@@ -238,19 +245,32 @@ export function runAppCompiled(canvas: HTMLCanvasElement, store: any) {
                 shift: { _tag: e.shiftKey ? 'True' : 'False' },
                 printable: { _tag: (e.key.length === 1 && !e.metaKey && !e.ctrlKey && !e.altKey) ? 'True' : 'False' }
             }
-        };
+        });
 
-        if (focusedComponentKey) {
-            // send to focused component
-            handleComponentEvent(focusedComponentKey, event);
+        e.preventDefault();
+        rerender();
+    });
 
-            // bubble up to ancestors
-            for (const key of componentInstances.keys()) {
-                if (key !== focusedComponentKey && focusedComponentKey.startsWith(key + '.')) {
-                    handleComponentEvent(key, event);
-                }
+    canvas.addEventListener('wheel', (e) => {
+        const rect = canvas.getBoundingClientRect();
+        const x = e.clientX - rect.left;
+        const y = e.clientY - rect.top;
+
+        const hit = scrollHitTest(x, y);
+        if (hit) {
+            const delta = { deltaX: Math.round(e.deltaX), deltaY: Math.round(e.deltaY) };
+            handleEvent(hit.onScroll(delta));
         }
+
+        /*
+        dispatchToFocused({
+            _tag: 'Scroll',
+            _0: {
+                deltaX: Math.round(e.deltaX),
+                deltaY: Math.round(e.deltaY)
             }
+        });
+        */
 
         e.preventDefault();
         rerender();

src/runtime-js.ts

@@ -36,6 +36,7 @@ export const _rt = {
         padding: (config: any) => ({ kind: 'padding', ...config }),
         positioned: (config: any) => ({ kind: 'positioned', ...config }),
         clickable: (config: any) => ({ kind: 'clickable', ...config }),
+        scrollable: (config: any) => ({ kind: 'scrollable', ...config }),
         clip: (config: any) => ({ kind: 'clip', ...config }),
         opacity: (config: any) => ({ kind: 'opacity', ...config }),
         stateful: (config: any) => ({ kind: 'stateful', ...config }),

src/ui.ts

@@ -4,12 +4,13 @@ export type UIValue =
     | { kind: 'text', content: string, color?: string }
     | { kind: 'row', children: UIValue[], gap: number }
     | { kind: 'column', children: UIValue[], gap: number }
-    | { kind: 'clickable', child: UIValue, event: any }
     | { kind: 'padding', child: UIValue, amount: number }
     | { kind: 'positioned', x: number, y: number, child: UIValue }
     | { kind: 'opacity', child: UIValue, opacity: number }
     | { kind: 'clip', child: UIValue, w: number, h: number }
     | { kind: 'stack', children: UIValue[] }
+    | { kind: 'clickable', child: UIValue, onClick: any }
+    | { kind: 'scrollable', child: UIValue, w: number, h: number, scrollX: number, scrollY: number, onScroll: any }
     | { kind: 'stateful', key: string, focusable: boolean, init: any, update: any, view: any }
 
 type ClickRegion = {
@@ -17,11 +18,21 @@ type ClickRegion = {
     y: number;
     width: number;
     height: number;
-    event: any;
+    onClick: any;
 };
 
 let clickRegions: ClickRegion[] = [];
 
+type ScrollRegion = {
+    x: number;
+    y: number;
+    width: number;
+    height: number;
+    onScroll: any;
+};
+
+let scrollRegions: ScrollRegion[] = [];
+
 export function render(ui: UIValue, canvas: HTMLCanvasElement) {
     const ctx = canvas.getContext('2d');
     if (ctx) {
@@ -32,6 +43,7 @@ export function render(ui: UIValue, canvas: HTMLCanvasElement) {
         ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
 
         clickRegions = [];
+        scrollRegions = [];
         renderUI(ui, ctx, 0, 0);
     }
 }
@@ -88,7 +100,7 @@ function renderUI(ui: UIValue, ctx: CanvasRenderingContext2D, x: number, y: numb
         case 'row': {
             let offsetX = 0;
             for (const child of ui.children) {
-                const size = measure(child);
+                // const size = measure(child);
                 renderUI(child, ctx, x + offsetX, y);
                 offsetX += measure(child).width + (ui.gap || 0);
             }
@@ -106,11 +118,22 @@ function renderUI(ui: UIValue, ctx: CanvasRenderingContext2D, x: number, y: numb
 
         case 'clickable': {
             const size = measure(ui.child);
-            clickRegions.push({ x, y, width: size.width, height: size.height, event: ui.event })
+            clickRegions.push({ x, y, width: size.width, height: size.height, onClick: ui.onClick })
             renderUI(ui.child, ctx, x, y);
             break;
         }
 
+        case 'scrollable': {
+            ctx.save();
+            ctx.beginPath();
+            ctx.rect(x, y, ui.w, ui.h);
+            ctx.clip();
+            renderUI(ui.child, ctx, x - ui.scrollX, y - ui.scrollY);
+            ctx.restore();
+            scrollRegions.push({ x, y, width: ui.w, height: ui.h, onScroll: ui.onScroll })
+            break;
+        }
+
         case 'padding':
             renderUI(ui.child, ctx, x + ui.amount, y + ui.amount);
             break;
@@ -187,6 +210,9 @@ export function _measure(ui: UIValue): { width: number, height: number } {
         case 'clickable':
             return measure(ui.child);
 
+        case 'scrollable':
+            return { width: ui.w, height: ui.h };
+
         case 'opacity':
             return measure(ui.child);
 
@@ -223,14 +249,14 @@ export function _measure(ui: UIValue): { width: number, height: number } {
     }
 }
 
-export function hitTest(x: number, y: number): { event: any, relativeX: number, relativeY: number } | null {
+export function hitTest(x: number, y: number): { onClick: any, relativeX: number, relativeY: number } | null {
     for (let i = clickRegions.length - 1; i >= 0; i--) {
         const region = clickRegions[i];
 
         if (x >= region.x && x < region.x + region.width &&
            y >= region.y && y < region.y + region.height) {
             return {
-                event: region.event,
+                onClick: region.onClick,
                 relativeX: x - region.x,
                 relativeY: y - region.y,
             };
@@ -238,3 +264,14 @@ export function hitTest(x: number, y: number): { event: any, relativeX: number,
     }
     return null;
 }
+
+export function scrollHitTest(x: number, y: number): { onScroll: any } | null {
+    for (let i = scrollRegions.length - 1; i >= 0; i--) {
+        const region = scrollRegions[i];
+        if (x >= region.x && x < region.x + region.width &&
+           y >= region.y && y < region.y + region.height) {
+            return { onScroll: region.onScroll };
+        }
+    }
+    return null;
+}