Skia（４）SkBitmapをwxWidgetsで表示

// https://docs.wxwidgets.org/3.0/overview_helloworld.html

// プリプロセッサに以下二つを追加
// __WXMSW__
// WXUSINGDLL

// サブシステムをWindowsに設定(WinMainで呼び出すので)
// Windows (/SUBSYSTEM:WINDOWS)

#ifndef WX_PRECOMP
#include <wx/wx.h>
#endif

#include <wx/gdicmn.h> // wxPointに必要
#include <wx/frame.h>  // wxFrameに必要

#ifdef _DEBUG
#pragma comment(lib,"wxbase32ud.lib")
#pragma comment(lib,"wxbase32ud_net.lib")
#pragma comment(lib,"wxbase32ud_xml.lib")
#pragma comment(lib,"wxmsw32ud_adv.lib")
#pragma comment(lib,"wxmsw32ud_aui.lib")
#pragma comment(lib,"wxmsw32ud_core.lib")
#pragma comment(lib,"wxmsw32ud_gl.lib")
#pragma comment(lib,"wxmsw32ud_html.lib")
#pragma comment(lib,"wxmsw32ud_media.lib")
#pragma comment(lib,"wxmsw32ud_propgrid.lib")
#pragma comment(lib,"wxmsw32ud_qa.lib")
#pragma comment(lib,"wxmsw32ud_ribbon.lib")
#pragma comment(lib,"wxmsw32ud_richtext.lib")
#pragma comment(lib,"wxmsw32ud_stc.lib")
#pragma comment(lib,"wxmsw32ud_webview.lib")
#pragma comment(lib,"wxmsw32ud_xrc.lib")

#else

#pragma comment(lib,"wxbase32u.lib")
#pragma comment(lib,"wxbase32u_net.lib")
#pragma comment(lib,"wxbase32u_xml.lib")
#pragma comment(lib,"wxmsw32u_adv.lib")
#pragma comment(lib,"wxmsw32u_aui.lib")
#pragma comment(lib,"wxmsw32u_core.lib")
#pragma comment(lib,"wxmsw32u_gl.lib")
#pragma comment(lib,"wxmsw32u_html.lib")
#pragma comment(lib,"wxmsw32u_media.lib")
#pragma comment(lib,"wxmsw32u_propgrid.lib")
#pragma comment(lib,"wxmsw32u_qa.lib")
#pragma comment(lib,"wxmsw32u_ribbon.lib")
#pragma comment(lib,"wxmsw32u_richtext.lib")
#pragma comment(lib,"wxmsw32u_stc.lib")
#pragma comment(lib,"wxmsw32u_webview.lib")
#pragma comment(lib,"wxmsw32u_xrc.lib")

#endif

#pragma comment(lib,"skia.dll.lib")

/////////////////////////////////////

#include "skia/include/core/SkCanvas.h"
#include "skia/include/core/SkBitmap.h"


/////////////////////////////////////
/////////////////////////////////////
/////////////////////////////////////

#include <string>

// SkBitmapをRGBの配列に変換
void PixelRGB(std::vector<std::uint8_t>& rgb,const SkBitmap& skbmp) {
  if (!skbmp.readyToDraw()) {
    return;
  }

  if (skbmp.colorType() != kRGBA_8888_SkColorType && skbmp.colorType() != kBGRA_8888_SkColorType) {
    return; 
  }

  rgb.clear();

  int Width = skbmp.width();
  int Height = skbmp.height();
  size_t rowBytes = skbmp.rowBytes();
  const SkImageInfo& info = skbmp.info();
  int channels = info.bytesPerPixel();
  std::uint8_t* pixels = (std::uint8_t*)skbmp.getPixels();


  rgb.resize(Width * Height * 3);
  for (int i = 0; i < Height; i++) {
    for (int j = 0; j < Width; j++) {
      size_t pos_ppm = (i * Width + j) * 3;
      size_t pos_sk = (i * rowBytes + j * channels);
      rgb[pos_ppm + 0] = pixels[pos_sk + 2];
      rgb[pos_ppm + 1] = pixels[pos_sk + 1];
      rgb[pos_ppm + 2] = pixels[pos_sk + 0];
    }
  }
}

// ウィンドウ作成
class MyFrame : public wxFrame
{
  SkBitmap my_bitmap;
public:

    void PostCreate() {

      // 画像の作成・描画
      my_bitmap.setInfo(SkImageInfo::Make(400, 400, kBGRA_8888_SkColorType, kPremul_SkAlphaType));
      my_bitmap.allocPixels();
      SkCanvas canvas(my_bitmap);
      // 背景を白にクリア
      canvas.clear(SK_ColorWHITE);
      // 図形の描画
      SkPaint paint;
      paint.setStyle(SkPaint::kStroke_Style);
      paint.setStrokeWidth(5);
      paint.setColor(SK_ColorRED);
      canvas.drawCircle(200, 200, 100, paint);

      // OnPaintイベントを設定
      Bind(wxEVT_PAINT, &MyFrame::OnPaint, this);

      this->Layout(); // レイアウトの更新
    }


    MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
        : wxFrame(NULL, wxID_ANY, title, pos, size)
    
    {
      // CallAfter : 現在処理中のイベントが終わったらPostCreateを実行
      // コンストラクタはウィンドウ生成イベント扱い
      CallAfter(&MyFrame::PostCreate);
    }

    // OnPaintイベント
    void OnPaint(wxPaintEvent& event) {

      // SkBitmapをRGBへ変換
      int width = my_bitmap.width();
      int height = my_bitmap.height();
      std::vector<std::uint8_t> rgb;
      rgb.resize(width * height * 3);

      // 変換関数（自作）呼び出し
      PixelRGB(rgb, my_bitmap);

      // RGBをwxImageへ変換
      wxImage img(width,height, (unsigned char*)rgb.data(), true);
      wxBitmap wxbitmap(img);

      // wxWidgetsのウィンドウに表示
      wxPaintDC dc(this);
      dc.DrawBitmap(wxbitmap, 0, 0, true);

    }

};

/////////////////////////////////////
/////////////////////////////////////
/////////////////////////////////////

// wxWidgetsのアプリケーション作成
class MyApp : public wxApp {
public:

  virtual bool OnInit() {
    MyFrame* frame = new MyFrame("Hello World", wxPoint(50, 50), wxSize(550, 550));
    frame->Show(true);

    return true;
  }

};

/////////////////////////////////////
/////////////////////////////////////
/////////////////////////////////////

// WinMainをマクロで定義
wxIMPLEMENT_APP(MyApp);