Clear state when resizing as canvases get cleared

src/renderer/BackgroundRenderLayer.ts

@@ -15,6 +15,8 @@ export class BackgroundRenderLayer extends BaseRenderLayer {
 
   public resize(terminal: ITerminal, canvasWidth: number, canvasHeight: number, charSizeChanged: boolean): void {
     super.resize(terminal, canvasWidth, canvasHeight, charSizeChanged);
+    // Resizing the canvas discards the contents of the canvas so clear state
+    this._state.clear();
     this._state.resize(terminal.cols, terminal.rows);
   }
 

src/renderer/CursorRenderLayer.ts

@@ -43,6 +43,18 @@ export class CursorRenderLayer extends BaseRenderLayer {
     // TODO: Consider initial options? Maybe onOptionsChanged should be called at the end of open?
   }
 
+  public resize(terminal: ITerminal, canvasWidth: number, canvasHeight: number, charSizeChanged: boolean): void {
+    super.resize(terminal, canvasWidth, canvasHeight, charSizeChanged);
+    // Resizing the canvas discards the contents of the canvas so clear state
+    this._state = {
+      x: null,
+      y: null,
+      isFocused: null,
+      style: null,
+      width: null,
+    };
+  }
+
   public reset(terminal: ITerminal): void {
     this._clearCursor();
     if (this._cursorBlinkStateManager) {

src/renderer/ForegroundRenderLayer.ts

@@ -16,6 +16,8 @@ export class ForegroundRenderLayer extends BaseRenderLayer {
 
   public resize(terminal: ITerminal, canvasWidth: number, canvasHeight: number, charSizeChanged: boolean): void {
     super.resize(terminal, canvasWidth, canvasHeight, charSizeChanged);
+    // Resizing the canvas discards the contents of the canvas so clear state
+    this._state.clear();
     this._state.resize(terminal.cols, terminal.rows);
   }
 

src/renderer/SelectionRenderLayer.ts

@@ -16,6 +16,15 @@ export class SelectionRenderLayer extends BaseRenderLayer {
     };
   }
 
+  public resize(terminal: ITerminal, canvasWidth: number, canvasHeight: number, charSizeChanged: boolean): void {
+    super.resize(terminal, canvasWidth, canvasHeight, charSizeChanged);
+    // Resizing the canvas discards the contents of the canvas so clear state
+    this._state = {
+      start: null,
+      end: null
+    };
+  }
+
   public reset(terminal: ITerminal): void {
     if (this._state.start && this._state.end) {
       this._state = {

src/utils/TestUtils.test.ts

@@ -5,6 +5,7 @@
 import { ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, IListenerType, IInputHandlingTerminal, IViewport, ICircularList, ICompositionHelper } from '../Interfaces';
 import { LineData } from '../Types';
 import * as Browser from './Browser';
+import { IColorSet } from '../renderer/Interfaces';
 
 export class MockTerminal implements ITerminal {
   isFocused: boolean;
@@ -180,6 +181,7 @@ export class MockInputHandlingTerminal implements IInputHandlingTerminal {
 }
 
 export class MockBuffer implements IBuffer {
+  isCursorInViewport: boolean;
   lines: ICircularList<[number, string, number][]>;
   ydisp: number;
   ybase: number;