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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  *
      8  */
      9 
     10 #include "SkExample.h"
     11 
     12 #include "SkApplication.h"
     13 #include "SkDraw.h"
     14 #include "SkGradientShader.h"
     15 #include "SkGraphics.h"
     16 
     17 class HelloSkia : public SkExample {
     18 public:
     19     HelloSkia(SkExampleWindow* window) : SkExample(window) {
     20         fName = "HelloSkia";
     21         fBGColor = SK_ColorWHITE;
     22         fRotationAngle = SkIntToScalar(0);
     23 
     24         fWindow->setupBackend(SkExampleWindow::kGPU_DeviceType);
     25         // Another option is software rendering:
     26         // fWindow->setupBackend(SkExampleWindow::kRaster_DeviceType);
     27     }
     28 
     29 protected:
     30     void draw(SkCanvas* canvas) {
     31         // Clear background
     32         canvas->drawColor(fBGColor);
     33 
     34         SkPaint paint;
     35         paint.setColor(SK_ColorRED);
     36 
     37         // Draw a rectangle with blue paint
     38         SkRect rect = {
     39                 SkIntToScalar(10), SkIntToScalar(10),
     40                 SkIntToScalar(128), SkIntToScalar(128)
     41         };
     42         canvas->drawRect(rect, paint);
     43 
     44         // Set up a linear gradient and draw a circle
     45         {
     46             SkPoint linearPoints[] = {
     47                     {SkIntToScalar(0), SkIntToScalar(0)},
     48                     {SkIntToScalar(300), SkIntToScalar(300)}
     49             };
     50             SkColor linearColors[] = {SK_ColorGREEN, SK_ColorBLACK};
     51 
     52             SkShader* shader = SkGradientShader::CreateLinear(
     53                     linearPoints, linearColors, NULL, 2,
     54                     SkShader::kMirror_TileMode);
     55             SkAutoUnref shader_deleter(shader);
     56 
     57             paint.setShader(shader);
     58             paint.setFlags(SkPaint::kAntiAlias_Flag);
     59 
     60             canvas->drawCircle(SkIntToScalar(200), SkIntToScalar(200),
     61                     SkIntToScalar(64), paint);
     62 
     63             // Detach shader
     64             paint.setShader(NULL);
     65         }
     66 
     67         // Draw a message with a nice black paint.
     68         paint.setFlags(
     69                 SkPaint::kAntiAlias_Flag |
     70                 SkPaint::kSubpixelText_Flag |  // ... avoid waggly text when rotating.
     71                 SkPaint::kUnderlineText_Flag);
     72         paint.setColor(SK_ColorBLACK);
     73         paint.setTextSize(SkIntToScalar(20));
     74 
     75         canvas->save();
     76 
     77         static const char message[] = "Hello Skia!!!";
     78 
     79         // Translate and rotate
     80         canvas->translate(SkIntToScalar(300), SkIntToScalar(300));
     81         fRotationAngle += SkDoubleToScalar(0.2);
     82         if (fRotationAngle > SkDoubleToScalar(360.0)) {
     83             fRotationAngle -= SkDoubleToScalar(360.0);
     84         }
     85         canvas->rotate(fRotationAngle);
     86 
     87         // Draw the text:
     88         canvas->drawText(message, strlen(message), SkIntToScalar(0), SkIntToScalar(0), paint);
     89 
     90         canvas->restore();
     91 
     92         // Invalidate the window to force a redraw. Poor man's animation mechanism.
     93         this->fWindow->inval(NULL);
     94     }
     95 
     96 private:
     97     SkScalar fRotationAngle;
     98     SkColor fBGColor;
     99 };
    100 
    101 static SkExample* MyFactory(SkExampleWindow* window) {
    102     return new HelloSkia(window);
    103 }
    104 
    105 // Register this class as a Skia Example.
    106 SkExample::Registry registry(MyFactory);
    107