xterm

[VSoRC/.git] / node_modules / xterm / src / browser / RenderDebouncer.ts

diff --git a/node_modules/xterm/src/browser/RenderDebouncer.ts b/node_modules/xterm/src/browser/RenderDebouncer.ts
new file mode 100644 (file)
index 0000000..27c866d
--- /dev/null
+++ b/node_modules/xterm/src/browser/RenderDebouncer.ts
@@ -0,0 +1,63 @@
+/**
+ * Copyright (c) 2018 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { IDisposable } from 'common/Types';
+
+/**
+ * Debounces calls to render terminal rows using animation frames.
+ */
+export class RenderDebouncer implements IDisposable {
+  private _rowStart: number | undefined;
+  private _rowEnd: number | undefined;
+  private _rowCount: number | undefined;
+  private _animationFrame: number | undefined;
+
+  constructor(
+    private _renderCallback: (start: number, end: number) => void
+  ) {
+  }
+
+  public dispose(): void {
+    if (this._animationFrame) {
+      window.cancelAnimationFrame(this._animationFrame);
+      this._animationFrame = undefined;
+    }
+  }
+
+  public refresh(rowStart: number, rowEnd: number, rowCount: number): void {
+    this._rowCount = rowCount;
+    // Get the min/max row start/end for the arg values
+    rowStart = rowStart !== undefined ? rowStart : 0;
+    rowEnd = rowEnd !== undefined ? rowEnd : this._rowCount - 1;
+    // Set the properties to the updated values
+    this._rowStart = this._rowStart !== undefined ? Math.min(this._rowStart, rowStart) : rowStart;
+    this._rowEnd = this._rowEnd !== undefined ? Math.max(this._rowEnd, rowEnd) : rowEnd;
+
+    if (this._animationFrame) {
+      return;
+    }
+
+    this._animationFrame = window.requestAnimationFrame(() => this._innerRefresh());
+  }
+
+  private _innerRefresh(): void {
+    // Make sure values are set
+    if (this._rowStart === undefined || this._rowEnd === undefined || this._rowCount === undefined) {
+      return;
+    }
+
+    // Clamp values
+    this._rowStart = Math.max(this._rowStart, 0);
+    this._rowEnd = Math.min(this._rowEnd, this._rowCount - 1);
+
+    // Run render callback
+    this._renderCallback(this._rowStart, this._rowEnd);
+
+    // Reset debouncer
+    this._rowStart = undefined;
+    this._rowEnd = undefined;
+    this._animationFrame = undefined;
+  }
+}