From 94f6f8908560c2f378117c66093086a02fceb826 Mon Sep 17 00:00:00 2001
From: Mykola Morhun <mmorhun@redhat.com>
Date: Tue, 29 Oct 2019 12:13:46 +0000
Subject: [PATCH] Add terminal renderer option into terminal preferences

Signed-off-by: Mykola Morhun <mmorhun@redhat.com>
---
 .../src/browser/terminal-preferences.ts       | 16 ++++++++++-
 .../src/browser/terminal-widget-impl.ts       | 27 +++++++++++++++++--
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/packages/terminal/src/browser/terminal-preferences.ts b/packages/terminal/src/browser/terminal-preferences.ts
index ad4692e279ba1..7cd508729322a 100644
--- a/packages/terminal/src/browser/terminal-preferences.ts
+++ b/packages/terminal/src/browser/terminal-preferences.ts
@@ -68,7 +68,13 @@ export const TerminalConfigSchema: PreferenceSchema = {
         'terminal.integrated.scrollback': {
             description: 'Controls the maximum amount of lines the terminal keeps in its buffer.',
             type: 'number',
-            default: 1000,
+            default: 1000
+        },
+        'terminal.integrated.rendererType': {
+            description: 'Controls how the terminal is rendered.',
+            type: 'string',
+            enum: ['canvas', 'dom'],
+            default: 'canvas'
         }
     }
 };
@@ -83,10 +89,18 @@ export interface TerminalConfiguration {
     'terminal.integrated.letterSpacing': number
     'terminal.integrated.lineHeight': number,
     'terminal.integrated.scrollback': number,
+    'terminal.integrated.rendererType': TerminalRendererType
 }
 
 type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900';
 
+export type TerminalRendererType = 'canvas' | 'dom';
+export const DEFAULT_TERMINAL_RENDERER_TYPE = 'canvas';
+// tslint:disable-next-line:no-any
+export function isTerminalRendererType(arg: any): arg is TerminalRendererType {
+    return typeof arg === 'string' && (arg === 'canvas' || arg === 'dom');
+}
+
 export const TerminalPreferences = Symbol('TerminalPreferences');
 export type TerminalPreferences = PreferenceProxy<TerminalConfiguration>;
 
diff --git a/packages/terminal/src/browser/terminal-widget-impl.ts b/packages/terminal/src/browser/terminal-widget-impl.ts
index 3566e11207bbc..86ebb64f9885a 100644
--- a/packages/terminal/src/browser/terminal-widget-impl.ts
+++ b/packages/terminal/src/browser/terminal-widget-impl.ts
@@ -29,7 +29,7 @@ import { ThemeService } from '@theia/core/lib/browser/theming';
 import { TerminalWidgetOptions, TerminalWidget } from './base/terminal-widget';
 import { MessageConnection } from 'vscode-jsonrpc';
 import { Deferred } from '@theia/core/lib/common/promise-util';
-import { TerminalPreferences } from './terminal-preferences';
+import { TerminalPreferences, TerminalRendererType, isTerminalRendererType, DEFAULT_TERMINAL_RENDERER_TYPE } from './terminal-preferences';
 import { TerminalContribution } from './terminal-contribution';
 import URI from '@theia/core/lib/common/uri';
 import { TerminalService } from './base/terminal-service';
@@ -109,6 +109,7 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
             letterSpacing: this.preferences['terminal.integrated.letterSpacing'],
             lineHeight: this.preferences['terminal.integrated.lineHeight'],
             scrollback: this.preferences['terminal.integrated.scrollback'],
+            rendererType: this.getTerminalRendererType(this.preferences['terminal.integrated.rendererType']),
             theme: {
                 foreground: cssProps.foreground,
                 background: cssProps.background,
@@ -137,7 +138,17 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
             const lastSeparator = change.preferenceName.lastIndexOf('.');
             if (lastSeparator > 0) {
                 const preferenceName = change.preferenceName.substr(lastSeparator + 1);
-                this.term.setOption(preferenceName, this.preferences[change.preferenceName]);
+                let preferenceValue = this.preferences[change.preferenceName];
+
+                if (preferenceName === 'rendererType') {
+                    const newRendererType: string = this.preferences[change.preferenceName] as string;
+                    if (newRendererType !== this.getTerminalRendererType(newRendererType)) {
+                        // given terminal renderer type is not supported or invalid
+                        preferenceValue = DEFAULT_TERMINAL_RENDERER_TYPE;
+                    }
+                }
+
+                this.term.setOption(preferenceName, preferenceValue);
                 this.needsResize = true;
                 this.update();
             }
@@ -191,6 +202,18 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
         }
     }
 
+    /**
+     * Returns given renderer type if it is valid and supported or default renderer otherwise.
+     *
+     * @param terminalRendererType desired terminal renderer type
+     */
+    private getTerminalRendererType(terminalRendererType?: string | TerminalRendererType): Xterm.RendererType {
+        if (terminalRendererType && isTerminalRendererType(terminalRendererType)) {
+            return terminalRendererType;
+        }
+        return DEFAULT_TERMINAL_RENDERER_TYPE;
+    }
+
     showHoverMessage(x: number, y: number, message: string): void {
         this.hoverMessage.innerText = message;
         this.hoverMessage.style.display = 'inline';