Canvas可以做什麼。

[Nikolai Semko]

在動態中展示Сanvas的可能性。

圖片從不重複。

這個腳本也適用於MQL4，但速度要慢得多。

#include <Canvas\Canvas.mqh>

void OnStart()
  {
   ChartSetInteger(0,CHART_FOREGROUND,true);
   CCanvas C;
   int Width=(ushort)ChartGetInteger(0,CHART_WIDTH_IN_PIXELS);                               // get Window width
   int Height=(ushort)ChartGetInteger(0,CHART_HEIGHT_IN_PIXELS);                             // get Window height 
   if(!C.CreateBitmapLabel(0,0,"CanvasExamlple",0,0,Width,Height,COLOR_FORMAT_XRGB_NOALPHA)) // create canvas with the size of the current window
   Print("Error creating canvas: ",GetLastError()); 
   uint i=0,j=100000;
   int size=Width*Height;
   uchar h[25600];
   for (int w=0;w<25600;w++) 
   h[w]= uchar(128+128*sin(double(w)/256)); //create an array to speed up the work
   double X1=0,Y1=0,X2=0,Y2=0,X3=0,Y3=0,X4=0,Y4=0;
   while(!IsStopped())
     {
      int pos=int(i%size);
      if(pos==0)
        {
         //Sleep(20); //For those who have a too powerful computer.
         C.Update();
         X1= Width/2-(sin((double)j/100)*(double)Width/2);
         Y1= Height/2-(cos((double)j/140)*(double)Height/2);
         X2= Width/2+(cos((double)j/80)*(double)Width/2);
         Y2= Height/2+(sin((double)j/20)*(double)Height/2);
         X3= Width/2+(cos((double)j/85)*(double)Width/2);
         Y3= Height/2+(sin((double)j/65)*(double)Height/2);
         X4= Width/2+(cos((double)j/152)*(double)Width/2);
         Y4= Height/2+(sin((double)j/42)*(double)Height/2);
         j++;
        }
      int X=pos%Width;
      int Y=int(pos/Width);
      double D1=sqrt((X1-X)*(X1-X)+(Y1-Y)*(Y1-Y));
      double D2=sqrt((X2-X)*(X2-X)+(Y2-Y)*(Y2-Y));
      double D3=sqrt((X3-X)*(X3-X)+(Y3-Y)*(Y3-Y));
      double D4=sqrt((X4-X)*(X4-X)+(Y4-Y)*(Y4-Y));
      double d= (D1+D2)/(D1+D2+D3+D4);
      //C.m_pixels[pos]=XRGB(h[int(d*11520)],h[int(d*17920)],h[int(d*6400)]);// works a little faster, but requires transferring the array m_pixels from protected to public in Canvas.mqh
      C.PixelSet(X,Y,XRGB(h[int(d*11520)],h[int(d*17920)],h[int(d*6400)]));
      i++;
     }
   C.Destroy();
  }
//+------------------------------------------------------------------+