| <!doctype html> |
| <title>Canvas loss and restoration when size is extremely large and then restored to a reasonable value</title> |
| <script src="../../resources/testharness.js"></script> |
| <script src="../../resources/testharnessreport.js"></script> |
| <script> |
| async_test(t => { |
| var canvas = document.createElement('canvas') |
| canvas.addEventListener('contextlost', t.step_func(contextLost)); |
| canvas.addEventListener('contextrestored', t.step_func(contextRestored)); |
| var ctx = canvas.getContext('2d'); |
| var lostEventHasFired = false; |
| verifyContextLost(false); |
| |
| var bigsize = 1000000000; |
| canvas.width = bigsize; |
| canvas.height = bigsize; |
| verifyContextLost(true); |
| canvas.width = bigsize; |
| verifyContextLost(true); |
| // Restore a reasonable dimension |
| canvas.width = 100; |
| canvas.height = 100; |
| verifyContextLost(true); // Restoration is async. |
| |
| function verifyContextLost(shouldBeLost) { |
| // Verify context loss experimentally as well as isContextLost() |
| ctx.fillStyle = '#0f0'; |
| ctx.fillRect(0, 0, 1, 1); |
| var contextLostTest = ctx.getImageData(0, 0, 1, 1).data[1] == 0; |
| assert_equals(contextLostTest, shouldBeLost, 'image data is blank'); |
| assert_equals(ctx.isContextLost(), shouldBeLost, 'context is lost'); |
| } |
| |
| function contextLost() { |
| assert_false(lostEventHasFired, 'contextlost event has fired'); |
| lostEventHasFired = true; |
| verifyContextLost(true); |
| } |
| |
| function contextRestored() { |
| assert_true(lostEventHasFired, 'contextlost event has fired'); |
| verifyContextLost(false); |
| t.done(); |
| } |
| }); |
| </script> |
