Figure out how to write a different HelloWorld.

experimental/example.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ */
+
+
+#include "SkSurface.h"
+#include "SkWindow.h"
+
+#include "gl/GrGLInterface.h"
+#include "SkApplication.h"
+#include "SkCanvas.h"
+#include "SkGradientShader.h"
+#include "SkGraphics.h"
+#include "SkGr.h"
+#include "SkString.h"
+
+class SkCanvas;
+
+void application_init() {
+    SkGraphics::Init();
+    SkEvent::Init();
+}
+
+void application_term() {
+    SkEvent::Term();
+    SkGraphics::Term();
+}
+
+class ExampleWindow : public SkOSWindow {
+public:
+    enum DeviceType {
+        kRaster_DeviceType,
+        kGPU_DeviceType,
+    };
+
+    ExampleWindow(void* hwnd) : INHERITED(hwnd) {
+        fType = kGPU_DeviceType;
+        fRenderTarget = NULL;
+        fRotationAngle = 0;
+        fName = "Example";
+        this->setUpBackend();
+    }
+
+    ~ExampleWindow() {
+        SkSafeUnref(fContext);
+        fContext = NULL;
+
+        SkSafeUnref(fInterface);
+        fInterface = NULL;
+
+        SkSafeUnref(fRenderTarget);
+        fRenderTarget = NULL;
+
+        INHERITED::detach();
+    }
+
+protected:
+    SkSurface* createSurface() override {
+            SkSurfaceProps props(INHERITED::getSurfaceProps());
+            return SkSurface::NewRenderTargetDirect(fRenderTarget, &props);
+   }
+
+    void draw(SkCanvas* canvas) override {
+        // Clear background
+        canvas->drawColor(SK_ColorWHITE);
+        SkPaint paint;
+        // Draw a message with a nice black paint.
+        paint.setFlags(SkPaint::kAntiAlias_Flag);
+        paint.setColor(SK_ColorBLACK);
+        paint.setTextSize(SkIntToScalar(20));
+
+        static const char message[] = "Hello World!";
+
+        // Translate and draw the text:
+        canvas->save();
+        canvas->translate(SkIntToScalar(50), SkIntToScalar(100));
+        canvas->drawText(message, strlen(message), SkIntToScalar(0), SkIntToScalar(0), paint);
+        canvas->restore();
+        fContext->flush();
+        INHERITED::present();
+    }
+
+    bool setUpBackend() {
+        this->setColorType(kN32_SkColorType);
+        this->setVisibleP(true);
+        this->setClipToBounds(false);
+
+        bool result = attach(kNativeGL_BackEndType, 0 /*msaa*/, &fAttachmentInfo);
+        if (false == result) {
+            SkDebugf("Not possible to create backend.\n");
+            detach();
+            return false;
+        }
+
+        fInterface = GrGLCreateNativeInterface();
+
+        SkASSERT(NULL != fInterface);
+
+        fContext = GrContext::Create(kOpenGL_GrBackend, (GrBackendContext)fInterface);
+        SkASSERT(NULL != fContext);
+
+        this->setUpRenderTarget();
+        return true;
+    }
+
+    void setUpRenderTarget() {
+        SkSafeUnref(fRenderTarget);
+        fRenderTarget = this->renderTarget(fAttachmentInfo, fInterface, fContext);
+    }
+
+
+private:
+    typedef SkOSWindow INHERITED;
+
+    SkScalar fRotationAngle;
+    SkString fName;
+    DeviceType fType;
+    SkSurface* fSurface;
+    GrContext* fContext;
+    GrRenderTarget* fRenderTarget;
+    AttachmentInfo fAttachmentInfo;
+    const GrGLInterface* fInterface;
+
+
+}; 
+
+SkOSWindow* create_sk_window(void* hwnd, int , char** ) {
+    return new ExampleWindow(hwnd);
+}
+