Improve fit/focus viewport behavior and add viewport QA coverage

README.md

@@ -158,6 +158,7 @@ Tools:
 ## Workspace behavior highlights
 
 - Fit-to-view default on load/import/apply
+- Focus-selection + reset-view controls for faster navigation in dense schematics
 - `Reset Sample` one-click deterministic baseline restore for QA/demo loops
 - Space + drag pan, wheel zoom, fit button
 - Net/component/pin selection with dimming + isolate toggles
@@ -168,6 +169,7 @@ Tools:
   - `Ctrl/Cmd+Z` undo
   - `Ctrl/Cmd+Shift+Z` or `Ctrl/Cmd+Y` redo
   - `Space` rotate selected components (or pan when no selection)
+  - `F` focus current selection
   - `Alt+Enter` apply current selection editor (component/pin/net)
   - `Alt+C` connect selected pin to chosen net
 

frontend/app.js

@@ -7,6 +7,10 @@ const PIN_SIDES = ["left", "right", "top", "bottom"];
 const PIN_TYPES = ["power_in", "power_out", "input", "output", "bidirectional", "passive", "analog", "ground"];
 const LIST_ROW_HEIGHT = 36;
 const LIST_OVERSCAN_ROWS = 8;
+const MIN_SCALE = 0.2;
+const MAX_SCALE = 5;
+const FIT_MARGIN = 56;
+const FOCUS_MARGIN = 96;
 
 const state = {
   model: null,
@@ -120,6 +124,7 @@ const el = {
   zoomOutBtn: document.getElementById("zoomOutBtn"),
   zoomResetBtn: document.getElementById("zoomResetBtn"),
   fitViewBtn: document.getElementById("fitViewBtn"),
+  focusSelectionBtn: document.getElementById("focusSelectionBtn"),
   showLabelsInput: document.getElementById("showLabelsInput"),
   applyJsonBtn: document.getElementById("applyJsonBtn"),
   showSchemaBtn: document.getElementById("showSchemaBtn"),
@@ -422,11 +427,11 @@ function updateTransform() {
   }
 }
 
-function fitView(layout) {
+function layoutBounds(layout, margin = FIT_MARGIN) {
   const w = layout?.width ?? 0;
   const h = layout?.height ?? 0;
   if (!w || !h) {
-    return;
+    return null;
   }
 
   let minX = Number.POSITIVE_INFINITY;
@@ -456,37 +461,104 @@ function fitView(layout) {
     maxY = h;
   }
 
-  const pad = 80;
+  return {
-  const bbox = {
+    x: Math.max(0, minX - margin),
-    x: Math.max(0, minX - pad),
+    y: Math.max(0, minY - margin),
-    y: Math.max(0, minY - pad),
+    w: Math.max(1, Math.min(w, maxX - minX + margin * 2)),
-    w: Math.min(w, maxX - minX + pad * 2),
+    h: Math.max(1, Math.min(h, maxY - minY + margin * 2))
-    h: Math.min(h, maxY - minY + pad * 2)
   };
+}
 
+function centerOnBBox(bbox, fillRatio = 0.93, stickyAdjusted = false) {
+  if (!bbox) {
+    return false;
+  }
   const viewport = el.canvasViewport.getBoundingClientRect();
-  const sx = (viewport.width * 0.98) / Math.max(1, bbox.w);
+  if (!viewport.width || !viewport.height) {
-  const sy = (viewport.height * 0.98) / Math.max(1, bbox.h);
+    return false;
-  state.scale = Math.max(0.2, Math.min(4, Math.min(sx, sy)));
+  }
+  const sx = (viewport.width * fillRatio) / Math.max(1, bbox.w);
+  const sy = (viewport.height * fillRatio) / Math.max(1, bbox.h);
+  state.scale = Math.max(MIN_SCALE, Math.min(MAX_SCALE, Math.min(sx, sy)));
   state.panX = viewport.width / 2 - (bbox.x + bbox.w / 2) * state.scale;
   state.panY = viewport.height / 2 - (bbox.y + bbox.h / 2) * state.scale;
-  state.userAdjustedView = false;
+  state.userAdjustedView = stickyAdjusted;
   updateTransform();
+  return true;
+}
+
+function fitView(layout) {
+  const bbox = layoutBounds(layout, FIT_MARGIN);
+  if (!bbox) {
+    return;
+  }
+  centerOnBBox(bbox, 0.93, false);
+}
+
+function refsBBox(refs, margin = FOCUS_MARGIN) {
+  if (!refs?.size || !state.compile?.layout || !state.model) {
+    return null;
+  }
+  const placed = new Map((state.compile.layout.placed ?? []).map((p) => [p.ref, p]));
+  let minX = Number.POSITIVE_INFINITY;
+  let minY = Number.POSITIVE_INFINITY;
+  let maxX = Number.NEGATIVE_INFINITY;
+  let maxY = Number.NEGATIVE_INFINITY;
+  for (const ref of refs) {
+    const inst = instanceByRef(ref);
+    const p = placed.get(ref);
+    const sym = inst ? state.model.symbols?.[inst.symbol] : null;
+    if (!p || !sym?.body) {
+      continue;
+    }
+    minX = Math.min(minX, p.x);
+    minY = Math.min(minY, p.y);
+    maxX = Math.max(maxX, p.x + sym.body.width);
+    maxY = Math.max(maxY, p.y + sym.body.height);
+  }
+  if (!Number.isFinite(minX) || !Number.isFinite(minY) || !Number.isFinite(maxX) || !Number.isFinite(maxY)) {
+    return null;
+  }
+  const w = state.compile.layout.width ?? maxX;
+  const h = state.compile.layout.height ?? maxY;
+  return {
+    x: Math.max(0, minX - margin),
+    y: Math.max(0, minY - margin),
+    w: Math.max(1, Math.min(w, maxX - minX + margin * 2)),
+    h: Math.max(1, Math.min(h, maxY - minY + margin * 2))
+  };
+}
+
+function selectedFocusBBox() {
+  if (!state.model || !state.compile?.layout) {
+    return null;
+  }
+  if (state.selectedPin) {
+    return refsBBox(new Set([state.selectedPin.ref]), FOCUS_MARGIN);
+  }
+  if (state.selectedRefs.length) {
+    return refsBBox(new Set(state.selectedRefs), FOCUS_MARGIN);
+  }
+  if (state.selectedNet) {
+    const refs = refsConnectedToNet(state.selectedNet);
+    return refsBBox(refs, FOCUS_MARGIN);
+  }
+  return layoutBounds(state.compile.layout, FIT_MARGIN);
+}
+
+function focusSelection() {
+  const bbox = selectedFocusBBox();
+  if (!bbox) {
+    return false;
+  }
+  return centerOnBBox(bbox, 0.88, true);
 }
 
 function zoomToBBox(bbox) {
   if (!bbox) {
     return;
   }
-
+  centerOnBBox(bbox, 0.8, true);
-  const viewport = el.canvasViewport.getBoundingClientRect();
-  const scaleX = (viewport.width * 0.75) / Math.max(1, bbox.w);
-  const scaleY = (viewport.height * 0.75) / Math.max(1, bbox.h);
-  state.scale = Math.max(0.3, Math.min(4, Math.min(scaleX, scaleY)));
-  state.panX = viewport.width / 2 - (bbox.x + bbox.w / 2) * state.scale;
-  state.panY = viewport.height / 2 - (bbox.y + bbox.h / 2) * state.scale;
-  state.userAdjustedView = true;
-  updateTransform();
 }
 
 function canvasToSvgPoint(clientX, clientY) {
@@ -2760,23 +2832,27 @@ function setupEvents() {
   });
 
   el.zoomInBtn.addEventListener("click", () => {
-    state.scale = Math.min(4, state.scale + 0.1);
+    state.scale = Math.min(MAX_SCALE, state.scale + 0.1);
     state.userAdjustedView = true;
     updateTransform();
   });
 
   el.zoomOutBtn.addEventListener("click", () => {
-    state.scale = Math.max(0.2, state.scale - 0.1);
+    state.scale = Math.max(MIN_SCALE, state.scale - 0.1);
     state.userAdjustedView = true;
     updateTransform();
   });
 
   el.zoomResetBtn.addEventListener("click", () => {
-    state.scale = 1;
+    if (state.compile?.layout) {
-    state.panX = 40;
+      fitView(state.compile.layout);
-    state.panY = 40;
+    } else {
-    state.userAdjustedView = true;
+      state.scale = 1;
-    updateTransform();
+      state.panX = 40;
+      state.panY = 40;
+      state.userAdjustedView = false;
+      updateTransform();
+    }
   });
 
   el.fitViewBtn.addEventListener("click", () => {
@@ -2785,6 +2861,10 @@ function setupEvents() {
     }
   });
 
+  el.focusSelectionBtn.addEventListener("click", () => {
+    focusSelection();
+  });
+
   el.showLabelsInput.addEventListener("change", () => {
     state.showLabels = el.showLabelsInput.checked;
     setLabelLayerVisibility();
@@ -2812,7 +2892,7 @@ function setupEvents() {
     (evt) => {
       evt.preventDefault();
       const oldScale = state.scale;
-      state.scale = Math.min(4, Math.max(0.2, state.scale + (evt.deltaY < 0 ? 0.08 : -0.08)));
+      state.scale = Math.min(MAX_SCALE, Math.max(MIN_SCALE, state.scale + (evt.deltaY < 0 ? 0.08 : -0.08)));
 
       const rect = el.canvasViewport.getBoundingClientRect();
       const px = evt.clientX - rect.left;
@@ -3042,6 +3122,21 @@ function setupEvents() {
       el.connectPinBtn.click();
       return;
     }
+
+    if (!mod && !evt.altKey && !evt.shiftKey && evt.key.toLowerCase() === "f") {
+      if (isTypingContext(evt.target)) {
+        return;
+      }
+      evt.preventDefault();
+      focusSelection();
+    }
+  });
+
+  window.addEventListener("resize", () => {
+    if (!state.compile?.layout || state.userAdjustedView) {
+      return;
+    }
+    fitView(state.compile.layout);
   });
 
   window.addEventListener("keyup", (evt) => {

frontend/index.html

@@ -68,9 +68,10 @@
       <section class="pane center">
         <div class="canvasTools">
           <button id="zoomOutBtn" aria-label="Zoom out">-</button>
-          <button id="zoomResetBtn" aria-label="Reset zoom">100%</button>
+          <button id="zoomResetBtn" aria-label="Reset view">Reset</button>
           <button id="zoomInBtn" aria-label="Zoom in">+</button>
           <button id="fitViewBtn" aria-label="Fit schematic to viewport">Fit</button>
+          <button id="focusSelectionBtn" aria-label="Focus current selection">Focus</button>
           <label class="inlineCheck"><input id="showLabelsInput" type="checkbox" checked /> Labels</label>
           <span id="compileStatus">Idle</span>
         </div>

tests/ui-regression-runner.js

@@ -127,6 +127,11 @@ function parseStatusMetrics(statusText) {
   };
 }
 
+function parseZoomPercent(text) {
+  const m = /(\d+)%/.exec(String(text ?? ""));
+  return m ? Number(m[1]) : NaN;
+}
+
 async function run() {
   await ensureDirs();
   const port = await getFreePort();
@@ -143,6 +148,12 @@ async function run() {
 
     await page.getByRole("button", { name: /Instance U2, symbol dac_i2s/ }).click();
     await expectText(page, "#selectedSummary", /U2 \(dac_i2s\)/);
+    const preFocusZoom = parseZoomPercent(await page.locator("#zoomResetBtn").textContent());
+    await page.getByRole("button", { name: "Focus current selection" }).click();
+    const postFocusZoom = parseZoomPercent(await page.locator("#zoomResetBtn").textContent());
+    assert.ok(Number.isFinite(preFocusZoom) && Number.isFinite(postFocusZoom), "zoom label should remain parseable");
+    assert.ok(postFocusZoom >= preFocusZoom, `focus should not zoom out selected view (${preFocusZoom}% -> ${postFocusZoom}%)`);
+    await page.getByRole("button", { name: "Reset view" }).click();
     await compareScene(page, "selected-u2");
 
     await page.locator("#canvasViewport").click({ position: { x: 40, y: 40 } });
@@ -200,6 +211,12 @@ async function run() {
     assert.ok(metrics.crossings <= 2, `dense analog crossings too high: ${metrics.crossings}`);
     assert.ok(metrics.overlaps <= 2, `dense analog overlaps too high: ${metrics.overlaps}`);
     await compareScene(page, "dense-analog");
+
+    await page.setViewportSize({ width: 1280, height: 720 });
+    await page.getByRole("button", { name: "Fit schematic to viewport" }).click();
+    await expectText(page, "#compileStatus", /Compiled/);
+    assert.ok(await page.locator("#applyJsonBtn").isVisible(), "Apply JSON button should remain visible at laptop viewport");
+    await compareScene(page, "laptop-viewport");
   } finally {
     await page.close().catch(() => {});
     await browser.close().catch(() => {});