demo_M_pixel.f90

     program demo_M_pixel
     use M_pixel
     use M_pixel__writegif, only :  writegif
     use M_pixel,    only : cosd, sind
     implicit none

     integer  :: i
     integer  :: j
     integer  :: icolor

        ! initialize image
        call prefsize(400,400)  ! set size before starting
        call vinit()            ! start graphics
        call clear(0)           ! clear to color 0

        ! put some colored boxes into pixmap by address
        ! so show how the pixel map can be edited easily with
        ! other routines that can manipulate a pixel array.
        ! The P_pixel array was created when vinit(3f) was called
        icolor=1
        do i=1,4
           do j=1,4
              P_pixel((i-1)*100+1+3:i*100-3,(j-1)*100+1+3:j*100-3)=icolor
              icolor=icolor+1
           enddo
        enddo

        ! map area of virtual world to pixel array
        ! notice Y-axis for viewport is zero at TOP
           ! viewport(left, right, bottom, top)
        call viewport(0.0,  400.0,  400.0, 0.0)
        ! define the virtual world area we want to work in
            !ortho2(left, right, bottom,   top)
        call ortho2(0.0,  400.0,    0.0, 400.0)
        ! the drawing routines use these world units

        ! draw polar grids
        call linewidth(100)
        call color(14)
        call target(200.0,200.0,200.0)

        call linewidth(75)
        call color(0)
        call target(100.0,200.0,50.0)

        ! draw some lines
        call color(1)
        call linewidth(200)
        call line(1.0,1.0,400.0,400.0)

        call color(4)
        call line(350.0,200.0,350.0,300.0)

        ! print some text
        call color(1)
        !call hershey(x,y,height,itext,theta,ntext)
        call linewidth(125)
        call hershey(40.0, 40.0,35.0,'Hello World',0.0,11)
        call color(7)
        call linewidth(25)
        call hershey(40.0, 80.0,35.0,'Hello World',0.0,11)
        call linewidth(100)
        call hershey(40.0,120.0,35.0,'Hello World',30.0,11)

        call hershey( 40.0,350.0,35.0,'\COMPLEX\Hello World',0.0,20)
        call hershey( 40.0,310.0,35.0,'\DUPLEX\Hello World',0.0,19)
        call hershey( 350.0,400.0,35.0,'\ITALIC\Hello World',90.0,19)
        call linewidth(50)
        call hershey(200.0,120.0,15.0,'\SIMPLEX\Hello World',20.0,20)

        ! change background color directly
        where (P_pixel.eq.0) P_pixel=9
        ! write standard gif file
        call writegif('M_pixel.3M_pixel.gif',P_pixel,P_ColorMap)

     contains

        subroutine target(xc,yc,rc)
        use M_pixel,    only : cosd, sind
        real     :: xc,yc,rc
        integer  :: i
        real     :: x,y
           do i=0,360,10
              x=rc*cosd(i)
              y=rc*sind(i)
              call line(xc,yc,xc+x,yc+y)
           enddo
           do i=1,int(rc),10
              call circle(xc,yc,real(i))
           enddo
        end subroutine target
     end program demo_M_pixel