Canvas minimap: adaptive density (up to 10k buckets) + GPU-rendered heatmap

- Analyzer: DENSITY_BUCKETS now adaptive based on file size (max 10,000)
  vs fixed 200 — 50x better resolution at same O(N) cost
- Minimap: replaced DOM density strip with <canvas> + ImageData.putImageData()
  — GPU-rendered, O(canvas_height) render regardless of file size
- Compare: removed redundant + button, added Compare button that opens
  two files side by side with a three-panel comparison header:
  File A minimap | pixel-diff strip (bright = different) | File B minimap
- Diff strip: normalised bucket comparison, error-weighted — bright red
  where error density differs, dark where files have similar patterns

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ozgesolidkey

src/main/analyzers/columnAwareAnalyzer.ts

@@ -65,9 +65,9 @@ export class ColumnAwareAnalyzer implements LogAnalyzer {
         error: 0, warning: 0, info: 0, debug: 0, trace: 0
       };
 
-      // Density buckets — 200 buckets keyed by byte position
+      // Density buckets — adaptive count based on file size (500–10,000)
       // Used by the minimap to draw a heat map by log level
-      const DENSITY_BUCKETS = 200;
+      const DENSITY_BUCKETS = Math.min(Math.max(Math.ceil(fileSize / 500), 500), 10000);
       const densityError = new Uint32Array(DENSITY_BUCKETS);
       const densityWarning = new Uint32Array(DENSITY_BUCKETS);
       const densityInfo = new Uint32Array(DENSITY_BUCKETS);

src/main/index.ts

@@ -4123,6 +4123,27 @@ ipcMain.handle('analyze-file', async (_, analyzerName?: string, options?: Analyz
   }
 });
 
+// Run analysis on a specific file path (used by compare feature)
+ipcMain.handle('analyze-file-path', async (_, filePath: string) => {
+  if (!filePath) {
+    return { success: false, error: 'No file path provided' };
+  }
+
+  const analyzer = analyzerRegistry.getDefault();
+  if (!analyzer) {
+    return { success: false, error: 'Analyzer not found' };
+  }
+
+  const compareSignal = { cancelled: false };
+  try {
+    const result = await analyzer.analyze(filePath, {}, undefined, compareSignal);
+    cacheAnalysisResult(filePath, result);
+    return { success: true, result };
+  } catch (error) {
+    return { success: false, error: String(error) };
+  }
+});
+
 // Cancel analysis
 ipcMain.handle('cancel-analysis', async () => {
   analyzeSignal.cancelled = true;

src/preload/index.ts

@@ -234,6 +234,9 @@ const api = {
   analyzeFile: (analyzerName?: string, options?: any): Promise<{ success: boolean; result?: any; error?: string }> =>
     ipcRenderer.invoke('analyze-file', analyzerName, options),
 
+  analyzeFilePath: (filePath: string): Promise<{ success: boolean; result?: any; error?: string }> =>
+    ipcRenderer.invoke('analyze-file-path', filePath),
+
   cancelAnalysis: (): Promise<{ success: boolean }> =>
     ipcRenderer.invoke('cancel-analysis'),
 

src/renderer/index.html

@@ -41,7 +41,9 @@
       </div>
       <div id="tabs-container" class="tabs-container"></div>
       <div class="tab-bar-right">
-        <button id="btn-new-tab" class="tab-bar-btn" title="Open new file">+</button>
+        <button id="btn-compare" class="tab-bar-btn" title="Compare two log files (Ctrl+Shift+C)">
+          <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><rect x="2" y="3" width="9" height="18" rx="1"/><rect x="13" y="3" width="9" height="18" rx="1"/></svg>
+        </button>
         <div class="tab-bar-separator"></div>
         <button id="btn-search-toggle" class="tab-bar-btn" title="Search (Ctrl+F)">
           <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="11" cy="11" r="8"/><line x1="21" y1="21" x2="16.65" y2="16.65"/></svg>