Fix to zoom on Vulkan Viewer

tools/vulkan/viewer/VulkanViewer.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "VulkanViewer.h"
 
 #include "GMSlide.h"
@@ skipping 37 matching lines @@
                "^ requires the start of the bench to match\n"
                "$ requires the end of the bench to match\n"
                "^ and $ requires an exact match\n"
                "If a bench does not match any list entry,\n"
                "it is skipped unless some list entry starts with ~");
 DEFINE_string(skps, "skps", "Directory to read skps from.");
 
 VulkanViewer::VulkanViewer(int argc, char** argv, void* platformData)
     : fCurrentMeasurement(0)
     , fDisplayStats(false)
+    , fZoomCenterX(0.0f)
+    , fZoomCenterY(0.0f)
+    , fZoomLevel(0.0f)
+    , fZoomScale(SK_Scalar1)
 {
     memset(fMeasurements, 0, sizeof(fMeasurements));
 
     SkDebugf("Command line arguments: ");
     for (int i = 1; i < argc; ++i) {
         SkDebugf("%s ", argv[i]);
     }
     SkDebugf("\n");
 
     SkCommandLineFlags::Parse(argc, argv);
@@ skipping 146 matching lines @@
                 }
                 SkString title("VulkanViewer: ");
                 title.append(fSlides[fCurrentSlide]->getName());
                 fWindow->setTitle(title.c_str());
                 setupCurrentSlide(previousSlide);
                 return true;
             }
 
             case Window::kUp_Key: {
                 this->changeZoomLevel(1.f / 32.f);
+                fWindow->inval();
                 return true;
             }
 
             case Window::kDown_Key: {
                 this->changeZoomLevel(-1.f / 32.f);
+                fWindow->inval();
                 return true;
             }
 
             default:
                 break;
         }
     }
 
     return false;
 }
@@ skipping 68 matching lines @@
     // Record measurements
     fMeasurements[fCurrentMeasurement++] = ms;
     fCurrentMeasurement &= (kMeasurementCount - 1);  // fast mod
     SkASSERT(fCurrentMeasurement < kMeasurementCount);
 
     fAnimTimer.updateTime();
     if (fDisplayStats || fSlides[fCurrentSlide]->animate(fAnimTimer)) {
         fWindow->inval();
     }
 }