From dac44623ee2488e43e9718bf4bc1fde76f1d9c9f Mon Sep 17 00:00:00 2001
From: Victor Woeltjen <victor.woeltjen@nasa.gov>
Date: Fri, 19 Jun 2015 15:47:22 -0700
Subject: [PATCH 1/3] [Plot] Begin adding WebGL fallback

Begin adding code to handle case where WebGL context
is lost, WTD-475.
---
 platform/features/plot/src/MCTChart.js | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/platform/features/plot/src/MCTChart.js b/platform/features/plot/src/MCTChart.js
index b8350e9171..d07eb398aa 100644
--- a/platform/features/plot/src/MCTChart.js
+++ b/platform/features/plot/src/MCTChart.js
@@ -155,6 +155,15 @@ define(
                     }
                 }
 
+                function fallbackFromWebGL() {
+                    element.html(TEMPLATE);
+                    canvas = element.find("canvas")[0];
+                    chart = getChart([Canvas2DChart], canvas);
+                    if (chart) {
+                        doDraw(scope.draw);
+                    }
+                }
+
                 // Try to initialize a chart.
                 chart = getChart([GLChart, Canvas2DChart], canvas);
 
@@ -192,4 +201,4 @@ define(
 
         return MCTChart;
     }
-);
\ No newline at end of file
+);

From b6fdf4d6ab815718d3e3210a0947f25850f1df52 Mon Sep 17 00:00:00 2001
From: Victor Woeltjen <victor.woeltjen@nasa.gov>
Date: Fri, 19 Jun 2015 16:02:52 -0700
Subject: [PATCH 2/3] [Plot] Fall back from WebGL on context loss

When a WebGL context is loss, fall back to displaying
plots using regular canvas 2d API. WTD-475.
---
 platform/features/plot/src/MCTChart.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/platform/features/plot/src/MCTChart.js b/platform/features/plot/src/MCTChart.js
index d07eb398aa..2ca51b2309 100644
--- a/platform/features/plot/src/MCTChart.js
+++ b/platform/features/plot/src/MCTChart.js
@@ -155,6 +155,7 @@ define(
                     }
                 }
 
+                // Switch from WebGL to plain 2D if context is lost
                 function fallbackFromWebGL() {
                     element.html(TEMPLATE);
                     canvas = element.find("canvas")[0];
@@ -173,6 +174,11 @@ define(
                     return;
                 }
 
+                // WebGL is a bit of a special case; it may work, then fail
+                // later for various reasons, so we need to listen for this
+                // and fall back to plain canvas drawing when it occurs.
+                canvas.addEventListener("webglcontextlost", fallbackFromWebGL);
+
                 // Check for resize, on a timer
                 activeInterval = $interval(drawIfResized, 1000);
 

From 5ca954deafa9bd11655a8494c3e36fd6e402559a Mon Sep 17 00:00:00 2001
From: Victor Woeltjen <victor.woeltjen@nasa.gov>
Date: Fri, 19 Jun 2015 16:14:49 -0700
Subject: [PATCH 3/3] [Plot] Test fallback on webglcontextlost

Add test case to verify that fallback occurs when a
WebGL context is lost, WTD-475.
---
 platform/features/plot/test/MCTChartSpec.js | 22 +++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/platform/features/plot/test/MCTChartSpec.js b/platform/features/plot/test/MCTChartSpec.js
index 93be797114..9c60b034a6 100644
--- a/platform/features/plot/test/MCTChartSpec.js
+++ b/platform/features/plot/test/MCTChartSpec.js
@@ -36,6 +36,7 @@ define(
                 mockElement,
                 mockCanvas,
                 mockGL,
+                mockC2d,
                 mockPromise,
                 mctChart;
 
@@ -47,13 +48,14 @@ define(
                 mockScope =
                     jasmine.createSpyObj("$scope", ["$watchCollection", "$on"]);
                 mockElement =
-                    jasmine.createSpyObj("element", ["find"]);
+                    jasmine.createSpyObj("element", ["find", "html"]);
                 mockInterval.cancel = jasmine.createSpy("cancelInterval");
                 mockPromise = jasmine.createSpyObj("promise", ["then"]);
 
 
                 // mct-chart uses GLChart, so it needs WebGL API
-                mockCanvas = jasmine.createSpyObj("canvas", [ "getContext" ]);
+                mockCanvas =
+                    jasmine.createSpyObj("canvas", [ "getContext", "addEventListener" ]);
                 mockGL = jasmine.createSpyObj(
                     "gl",
                     [
@@ -81,6 +83,7 @@ define(
                         "drawArrays"
                     ]
                 );
+                mockC2d = jasmine.createSpyObj('c2d', ['clearRect']);
                 mockGL.ARRAY_BUFFER = "ARRAY_BUFFER";
                 mockGL.DYNAMIC_DRAW = "DYNAMIC_DRAW";
                 mockGL.TRIANGLE_FAN = "TRIANGLE_FAN";
@@ -93,7 +96,9 @@ define(
                 });
 
                 mockElement.find.andReturn([mockCanvas]);
-                mockCanvas.getContext.andReturn(mockGL);
+                mockCanvas.getContext.andCallFake(function (type) {
+                    return { webgl: mockGL, '2d': mockC2d }[type];
+                });
                 mockInterval.andReturn(mockPromise);
 
                 mctChart = new MCTChart(mockInterval, mockLog);
@@ -169,6 +174,15 @@ define(
                 expect(mockLog.warn).toHaveBeenCalled();
             });
 
+            it("falls back to Canvas 2d API if WebGL context is lost", function () {
+                mctChart.link(mockScope, mockElement);
+                expect(mockCanvas.addEventListener)
+                    .toHaveBeenCalledWith("webglcontextlost", jasmine.any(Function));
+                expect(mockCanvas.getContext).not.toHaveBeenCalledWith('2d');
+                mockCanvas.addEventListener.mostRecentCall.args[1]();
+                expect(mockCanvas.getContext).toHaveBeenCalledWith('2d');
+            });
+
             it("logs nothing in nominal situations (WebGL available)", function () {
                 // Complement the previous test
                 mctChart.link(mockScope, mockElement);
@@ -197,4 +211,4 @@ define(
 
         });
     }
-);
\ No newline at end of file
+);