Task: Archimedean spiral


C++: #include <windows.h>
#include <string>
#include <iostream>
 
const int BMP_SIZE = 600;
 
class myBitmap {
public:
    myBitmap() : pen( NULL ), brush( NULL ), clr( 0 ), wid( 1 ) {}
    ~myBitmap() {
        DeleteObject( pen ); DeleteObject( brush );
        DeleteDC( hdc ); DeleteObject( bmp );
    }
    bool create( int w, int h ) {
        BITMAPINFO bi;
        ZeroMemory( &bi, sizeof( bi ) );
        bi.bmiHeader.biSize        = sizeof( bi.bmiHeader );
        bi.bmiHeader.biBitCount    = sizeof( DWORD ) * 8;
        bi.bmiHeader.biCompression = BI_RGB;
        bi.bmiHeader.biPlanes      = 1;
        bi.bmiHeader.biWidth       =  w;
        bi.bmiHeader.biHeight      = -h;
        HDC dc = GetDC( GetConsoleWindow() );
        bmp = CreateDIBSection( dc, &bi, DIB_RGB_COLORS, &pBits, NULL, 0 );
        if( !bmp ) return false;
        hdc = CreateCompatibleDC( dc );
        SelectObject( hdc, bmp );
        ReleaseDC( GetConsoleWindow(), dc );
        width = w; height = h;
        return true;
    }
    void clear( BYTE clr = 0 ) {
        memset( pBits, clr, width * height * sizeof( DWORD ) );
    }
    void setBrushColor( DWORD bClr ) {
        if( brush ) DeleteObject( brush );
        brush = CreateSolidBrush( bClr );
        SelectObject( hdc, brush );
    }
    void setPenColor( DWORD c ) {
        clr = c; createPen();
    }
    void setPenWidth( int w ) {
        wid = w; createPen();
    }
    void saveBitmap( std::string path ) {
        BITMAPFILEHEADER fileheader;
        BITMAPINFO       infoheader;
        BITMAP           bitmap;
        DWORD            wb;
        GetObject( bmp, sizeof( bitmap ), &bitmap );
        DWORD* dwpBits = new DWORD[bitmap.bmWidth * bitmap.bmHeight];
        ZeroMemory( dwpBits, bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ) );
        ZeroMemory( &infoheader, sizeof( BITMAPINFO ) );
        ZeroMemory( &fileheader, sizeof( BITMAPFILEHEADER ) );
        infoheader.bmiHeader.biBitCount = sizeof( DWORD ) * 8;
        infoheader.bmiHeader.biCompression = BI_RGB;
        infoheader.bmiHeader.biPlanes = 1;
        infoheader.bmiHeader.biSize = sizeof( infoheader.bmiHeader );
        infoheader.bmiHeader.biHeight = bitmap.bmHeight;
        infoheader.bmiHeader.biWidth = bitmap.bmWidth;
        infoheader.bmiHeader.biSizeImage = bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD );
        fileheader.bfType    = 0x4D42;
        fileheader.bfOffBits = sizeof( infoheader.bmiHeader ) + sizeof( BITMAPFILEHEADER );
        fileheader.bfSize    = fileheader.bfOffBits + infoheader.bmiHeader.biSizeImage;
        GetDIBits( hdc, bmp, 0, height, ( LPVOID )dwpBits, &infoheader, DIB_RGB_COLORS );
        HANDLE file = CreateFile( path.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 
                                  FILE_ATTRIBUTE_NORMAL, NULL );
        WriteFile( file, &fileheader, sizeof( BITMAPFILEHEADER ), &wb, NULL );
        WriteFile( file, &infoheader.bmiHeader, sizeof( infoheader.bmiHeader ), &wb, NULL );
        WriteFile( file, dwpBits, bitmap.bmWidth * bitmap.bmHeight * 4, &wb, NULL );
        CloseHandle( file );
        delete [] dwpBits;
    }
    HDC getDC() const     { return hdc; }
    int getWidth() const  { return width; }
    int getHeight() const { return height; }
private:
    void createPen() {
        if( pen ) DeleteObject( pen );
        pen = CreatePen( PS_SOLID, wid, clr );
        SelectObject( hdc, pen );
    }
    HBITMAP bmp; HDC    hdc;
    HPEN    pen; HBRUSH brush;
    void    *pBits; int    width, height, wid;
    DWORD    clr;
};
class spiral {
public:
    spiral() {
        bmp.create( BMP_SIZE, BMP_SIZE );
    }
    void draw( int c, int s ) {
        double a = .2, b = .3, r, x, y;
        int w = BMP_SIZE >> 1;
        HDC dc = bmp.getDC();
        for( double d = 0; d < c * 6.28318530718; d += .002 ) {
            r = a + b * d; x = r * cos( d ); y = r * sin( d );
            SetPixel( dc, ( int )( s * x + w ), ( int )( s * y + w ), 255 );
        }
        
        bmp.saveBitmap( "./spiral.bmp" );
    }
private:
    myBitmap bmp;
};
int main(int argc, char* argv[]) {
    spiral s; s.draw( 16, 8 ); return 0;
}



Go: package main

import (
	"image"
	"image/color"
	"image/draw"
	"image/png"
	"log"
	"math"
	"os"
)

func main() {
	const (
		width, height = 600, 600
		centre        = width / 2.0
		degreesIncr   = 0.1 * math.Pi / 180
		turns         = 2
		stop          = 360 * turns * 10 * degreesIncr
		fileName      = "spiral.png"
	)

	img := image.NewNRGBA(image.Rect(0, 0, width, height)) 
	bg := image.NewUniform(color.RGBA{255, 255, 255, 255}) 
	draw.Draw(img, img.Bounds(), bg, image.ZP, draw.Src)   
	fgCol := color.RGBA{255, 0, 0, 255}                    

	a := 1.0
	b := 20.0

	for theta := 0.0; theta < stop; theta += degreesIncr {
		r := a + b*theta
		x := r * math.Cos(theta)
		y := r * math.Sin(theta)
		img.Set(int(centre+x), int(centre-y), fgCol)
	}

	imgFile, err := os.Create(fileName)
	if err != nil {
		log.Fatal(err)
	}
	defer imgFile.Close()

	if err := png.Encode(imgFile, img); err != nil {
		imgFile.Close()
		log.Fatal(err)
	}
}