fix: sửa lỗi audio clip dán từ clipboard không đúng duration

8_TRACK_ZOOM.md

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+# Technical Specification: Minimum Zoom Constraint Specification
+
+This document defines the algorithm and graphical rendering mechanics (Rendering Logic) to solve the following problem: When zooming out to the absolute minimum, the audio waveforms of all tracks must fit perfectly within the horizontal width of the Editor viewport, as realistically illustrated in `image_f0c1e0.png`.
+
+---
+
+## 1. Current State & Design Problem Analysis
+
+Based on `image_f0c1e0.png`, when a user performs a zoom-out operation to the absolute minimum limit:
+
+* **Visual Requirement:** The entire audio range from the starting point ($0.00\text{ s}$) to the termination point ($T_{\text{max}}$) must be captured completely within the "Display Width" ($W_{\text{viewport}}$) of the screen.
+* **Desired Outcomes:**
+* No redundant horizontal scrollbars appear underneath the timeline.
+* No massive black voids (dead space) exist on the right side if the track duration is shorter than the viewport bounding container.
+* All audio tracks are scaled down synchronously in physical size to fully display their respective waveforms from start to finish.
+
+
+
+```text
+                      Editor Viewport Width (W_viewport)
+|<───────────────────────────────────────────────────────────────────────────────────>|
++─────────────────────────────────────────────────────────────────────────────────────+
+| Ruler: 0:00        0:10        0:20        0:30        0:40        0:50        1:00     |
++─────────────────────────────────────────────────────────────────────────────────────+
+| Track 1: [███████████████████████████████████████████████████████████████████████]  |
+|                                                                                     |
+| Track 2: [███████████████████████████████████████████████████████████████████████]  |
++─────────────────────────────────────────────────────────────────────────────────────+
+
+```
+
+---
+
+## 2. Dynamic Min-Zoom Calculation Algorithm
+
+To guarantee that the waveforms always fit perfectly even when the user resizes the browser window (or a Python application window), the minimum boundary zoom value ($Z_{\text{min}}$) must be evaluated dynamically.
+
+Let:
+
+* **$W_{\text{viewport}}$ (pixels):** The actual horizontal visible width of the timeline container viewport.
+* **$T_{\text{max}}$ (seconds):** The maximum duration among all active tracks residing on the timeline.
+* **$Z$ (pixels/second):** The current zoom scale factor (Zoom Level—the number of physical pixels representing $1$ second of audio).
+
+The bounding minimum zoom level ($Z_{\text{min}}$) is determined by the formula:
+
+$$Z_{\text{min}} = \frac{W_{\text{viewport}}}{T_{\text{max}}}$$
+
+### 2.1. Zoom Level Constraints
+
+Throughout mouse wheel interaction events triggered to adjust $Z$, the system must check bounds and strictly clamp the value within a safe operating spectrum:
+
+$$Z_{\text{clipped}} = \text{clamp}(Z_{\text{min}}, Z_{\text{target}}, Z_{\text{max}})$$
+
+*Where:*
+
+* **$Z_{\text{max}}$:** The upper zoom-in boundary limit (e.g., fixed at $2000\text{ pixels/s}$ to eliminate canvas rendering memory overflow vulnerabilities).
+* **$Z_{\text{min}}$:** The dynamic lower zoom-out boundary limit (re-calculated based on fluctuations of $W_{\text{viewport}}$ and $T_{\text{max}}$).
+
+---
+
+## 3. Synchronized Implementation Manual (Frontend JS & Python Porting)
+
+### 3.1. Client-side Integration (JavaScript / React)
+
+Utilize a `ResizeObserver` to systematically recompute $Z_{\text{min}}$ as soon as the user scales the browser viewport:
+
+```javascript
+// Initialize element targeting for the Timeline container frame
+const timelineWrapper = document.getElementById('timeline-wrapper');
+
+const resizeObserver = new ResizeObserver(entries => {
+    for (let entry of entries) {
+        const viewportWidth = entry.contentRect.width;
+        
+        // Compute dynamic Z_min boundary condition
+        const computedMinZoom = viewportWidth / maxDuration;
+        
+        // Update state and instantly clamp current zoom so it doesn't fall below Z_min
+        setZoom(prevZoom => {
+            const nextZoom = Math.max(computedMinZoom, prevZoom);
+            return nextZoom;
+        });
+    }
+});
+resizeObserver.observe(timelineWrapper);
+
+```
+
+### 3.2. Server-side / Desktop App Integration (Python PyQt6 / PySide6)
+
+When porting this layout system and mathematical constraint model to a Python desktop application context, hook into the `resizeEvent` method of the `QWidget` class to handle container adjustments:
+
+```python
+from PyQt6.QtWidgets import QWidget
+from PyQt6.QtCore import QSize
+
+class TimelineContainerWidget(QWidget):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self.max_duration_seconds = 60.0  # Track duration benchmark (seconds)
+        self.current_zoom = 100.0         # Current scale metric (pixels/second)
+        self.max_zoom = 2000.0            # Strict upper ceiling for zoom-in operations
+
+    def resizeEvent(self, event):
+        """
+        Intercepts the window/widget resizing event to refresh the minimum zoom bounds.
+        """
+        viewport_width = self.width()
+        
+        # 1. Evaluate the dynamic Z_min constraint from the new physical container width
+        min_zoom = float(viewport_width) / self.max_duration_seconds
+        
+        # 2. Hard clamp the active zoom level to prevent dropping underneath min_zoom
+        if self.current_zoom < min_zoom:
+            self.current_zoom = min_zoom
+            
+        # 3. Request a graphical redraw of the waveform lanes
+        self.update_waveform_painter()
+        super().resizeEvent(event)
+
+    def update_waveform_painter(self):
+        # Triggers the QPainter paintEvent routine redraw execution block
+        self.update()
+
+```