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Flash, Ming, & C++


December, 2004: Flash, Ming, & C++

Listing 2

#include <cmath>    //For M_PI and similar constants
#include <mingpp.h>
class Shape{
private:
unsigned short line_sz;
int line_col,line_op;
int fill_col,fill_op;
public:
Shape(unsigned short s=1,int c1=0x000000,int c2=0x000000,int o1=100,
  int o2=100)
    :line_sz(s),line_col(c1),line_op(o1),fill_col(c2),fill_op(o2){}
/** Splits a RGB colour into its components */
static void get_rgb(const int col,int &r,int &g,int &b){
r=(col&0xFF0000)>>16;
g=(col&0xFF00)>>8;
b=(col&0xFF);
}
/** Convert a 0..100 opacity to 0x00 to 0xff*/
static int get_opacity(const int op){
if(op>=100)return 0xff;
if(op<=0)return 0;
return (op*256)/100;
}
/** Initialize pen : called before other drawing functions */
void init_pen(SWFShape *shape,float sx,float sy)const{
int r,g,b;get_rgb(line_col,r,g,b);
shape->setLine(line_sz,r,g,b,get_opacity(line_op));
shape->movePenTo(sx,sy);
}
/** Draw arc, anticlockwise */
void draw_arc_helper_ac(SWFShape *shape,float sx,float sy,double sa,
                                         double ea,float xr,float yr)const{
const double PIBy4=M_PI_4;
const double PIBy8=M_PI_4/2.0;
double control_xr=xr/cos(PIBy8);
double control_yr=yr/cos(PIBy8);
while(ea>sa){
    double ma;
    if((ea-sa)>PIBy4){  //Draw a 45 degree segment
        ma=sa+PIBy8;    //Add 22.5 degrees
        sa+=PIBy4;      //Add 45 degrees
        }
    else{               //Final segment
        ma=(sa+ea)/2;
        control_xr=xr/cos((ea-sa)/2);
        control_yr=yr/cos((ea-sa)/2);
        sa=ea;
        }
    double cx=sx+(cos(ma)*control_xr);
    double cy=sy-(sin(ma)*control_yr);
    double ex=sx+(cos(sa)*xr);
    double ey=sy-(sin(sa)*yr);
    shape->drawCurveTo(cx,cy,ex,ey);
    }
}
/** Draw a pie-slice */
void draw_pie_slice(SWFSprite *movieclip,const float sx,const float sy,
    const double sa,const double ea,const float xr,const float yr)const{
float x=sx+(cos(sa)*xr);
float y=sy-(sin(sa)*yr);
SWFShape *shape=new SWFShape;
int r,g,b;get_rgb(fill_col,r,g,b);
shape->setLeftFill(shape->addSolidFill(r,g,b,get_opacity(fill_op)));
init_pen(shape,sx,sy);
shape->drawLineTo(x,y);
draw_arc_helper_ac(shape,sx,sy,sa,ea,xr,yr);
shape->drawLineTo(sx,sy);

movieclip->add(shape);
}
};


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