xterm

[VSoRC/.git] / node_modules / xterm / src / browser / renderer / atlas / BaseCharAtlas.ts

diff --git a/node_modules/xterm/src/browser/renderer/atlas/BaseCharAtlas.ts b/node_modules/xterm/src/browser/renderer/atlas/BaseCharAtlas.ts
new file mode 100644 (file)
index 0000000..dc11460
--- /dev/null
+++ b/node_modules/xterm/src/browser/renderer/atlas/BaseCharAtlas.ts
@@ -0,0 +1,56 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { IGlyphIdentifier } from 'browser/renderer/atlas/Types';
+import { IDisposable } from 'common/Types';
+
+export abstract class BaseCharAtlas implements IDisposable {
+  private _didWarmUp: boolean = false;
+
+  public dispose(): void { }
+
+  /**
+   * Perform any work needed to warm the cache before it can be used. May be called multiple times.
+   * Implement _doWarmUp instead if you only want to get called once.
+   */
+  public warmUp(): void {
+    if (!this._didWarmUp) {
+      this._doWarmUp();
+      this._didWarmUp = true;
+    }
+  }
+
+  /**
+   * Perform any work needed to warm the cache before it can be used. Used by the default
+   * implementation of warmUp(), and will only be called once.
+   */
+  protected _doWarmUp(): void { }
+
+  /**
+   * Called when we start drawing a new frame.
+   *
+   * TODO: We rely on this getting called by TextRenderLayer. This should really be called by
+   * Renderer instead, but we need to make Renderer the source-of-truth for the char atlas, instead
+   * of BaseRenderLayer.
+   */
+  public beginFrame(): void { }
+
+  /**
+   * May be called before warmUp finishes, however it is okay for the implementation to
+   * do nothing and return false in that case.
+   *
+   * @param ctx Where to draw the character onto.
+   * @param glyph Information about what to draw
+   * @param x The position on the context to start drawing at
+   * @param y The position on the context to start drawing at
+   * @returns The success state. True if we drew the character.
+   */
+  public abstract draw(
+    ctx: CanvasRenderingContext2D,
+    glyph: IGlyphIdentifier,
+    x: number,
+    y: number
+  ): boolean;
+}