求解关于C++写ghostview画图程序的问题
本帖最后由 丶不离不弃 于 2019-10-16 10:36 编辑我们老师布置了一个作业就是利用C++来写ghostview（或者adobe）的指令，生成一个test.ps文件来画各种图形，然后来填充颜色。填充颜色是setrgbcolor,分别画出一个填充红色的矩形，画一个边框为红色的矩形，
连续画6个填充红色的矩形，接着画一个绿色边框的圆，直线，和6边形。里面的数据分别是起始点x，y，宽，高。polygon中时外接圆圆心的左边，外接圆半径以及边的数目。
然后我遇到个问题就是，我这个程序setrgbcolor只是在最开始出现2个语句，并不是在画每个图形的时候都出现，这导致绿色把红色都覆盖了，请问哪位大神能帮我把程序改改？谢谢！！
#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
const double PI=3.141592653;
using namespace std;
class Shape{
private:
double r, g, b;
ofstream f;
public:
void setrgb(double r, double g, double b){
f<<r<<' '<<g<<' '<<b<<" setrgbcolor "<<endl;
}
virtual void draw(ostream& s) = 0;
};
class Circle:public Shape{
private:
double x,y,radius;
public:
Circle(double x, double y, double radius):x(x),y(y),radius(radius){}
void draw(ostream& f){
f<<x<<' '<<y<<' '<<radius<<" 0 360 arc stroke"<<endl;
}
};
class Line:public Shape{
private:
double x1, x2,y1, y2;
public:
Line(double x1, double y1,double x2, double y2):x1(x1),y1(y1),x2(x2),y2(y2){}
void draw(ostream& f){
f<<x1<<' '<<y1<<" moveto "<<'\n'<<x2<<' '<<y2<<" lineto"<<'\n'<< "stroke " <<endl;
}
};
class Rect:public Shape{
private:
double x, y, width, height;
public:
Rect(double x, double y, double width, double height):x(x),y(y),width(width),height(height){}
void draw(ostream& f){
f<<x<<' '<<y<<" moveto "<<'\n'<<x+width<<' '<<y<<" lineto "<<'\n'<<x+width
<<' '<<y+height<<" lineto "<<'\n'<<x<<' '<<y+height<<" lineto"<<'\n'<< "closepath stroke"<<endl;
}
};
class Polygon:public Shape{
private:
double x, y, radius,side;
public:
Polygon(double x, double y, double radius, double side):x(x),y(y),radius(radius),side(side){}
void draw(ostream& f){
f<<x+radius<<' '<<y<<" moveto "<<endl;
for(int i=1; i<side; i++){
f<<x+radius*cos(2*i*PI/side)<<' '<<y+radius*sin(PI*2*i/side)<<" lineto "<<'\n';
}
f<<"closepath stroke"<<endl;
}
};
class FilledRect:public Shape{
private:
double x, y, width,height ;
public:
FilledRect(double x, double y, double width, double height)
:x(x),y(y),width(width),height(height){}
void draw(ostream& f){
f <<x << ' ' << y << " moveto " <<'\n'<< x+width
<< ' ' << y<< " lineto " <<'\n'<< x + width << ' ' << y + height
<< " lineto " <<'\n'<< x<< ' ' << y +height << " lineto"<<'\n'<< "closepath fill"<<endl;
}
};
class FilledCircle:public Shape{
private:
double x, y, radius;
public:
FilledCircle(double x, double y, double radius):x(x),y(y),radius(radius){}
void draw(ostream& f){
f<<x<<' '<<y<<' '<<radius
<<" 0 360 arc fill"<<endl;
}
};
class Drawing {
private:
ofstream f;
vector<Shape*> shapes;
int r, g, b;
public:
void setrgb(double r, double g, double b){
f<<r<<' '<<g<<' '<<b<<" setrgbcolor "<<endl;
}
Drawing(string filename) : f(filename.c_str()), shapes() {
}
void add( Shape* s ) {
shapes.push_back(s);
}
void draw() {
for (int i = 0; i <shapes.size(); i++)
shapes->draw(f);
}
};
int main() {
ofstream f();
Drawing d("../test2.txt");
d.setrgb(1,0,0); // set drawing color to be bright red:1 0 0 setrgbcolor
d.add(new FilledRect(100.0, 150.0, 200.0, 50)); // x y moveto x y lineto ... fill
d.add(new Rect(100.0, 150.0, 200.0, 50)); // x y moveto x y lineto ... stroke
for (int x = 0; x < 600; x += 100)
d.add(new FilledCircle(x,200,50.0)); // x y r 0 360 arc fill
d.setrgb(0,1,0); // the rest are green
d.add(new Circle(0,0, 100)); // 0 0 100 0 360 stroke
d.add(new Line(400,500, 600,550));
d.add(new Polygon(200,200, 50, 6));
d.draw();
} 本帖最后由 superbe 于 2019-10-16 20:57 编辑
main里面只在最后d.draw()的时候才会输出全部图形，第一个和第二个d.setrgb之间的图形并没有输出，所以等于连续向文件中输出了两个setrgb，这样只是第二个setrgb才会对后面的图形起作用。
你可以在class Drawing里增加一个函数，用来清空shapes。
void clear(){
shapes.clear();
}
在输出前几个红色的图形后，调用clear清空shapes，然后设置绿色再输出后面几个绿色图形。
main函数修改如下，为了图形不重叠，我调整了图形坐标(注释未改)，根据实际情况修改吧：
int main() {
//ofstream f();
Drawing d("../test2.txt");
d.setrgb(1, 0, 0); // set drawing color to be bright red:1 0 0 setrgbcolor
d.add(new FilledRect(100.0, 150.0, 200.0, 50)); // x y moveto x y lineto ... fill
d.add(new Rect(100.0, 250.0, 200.0, 50)); // x y moveto x y lineto ... stroke
for (int x = 50; x < 650; x += 100)
d.add(new FilledCircle(x, 400, 50.0)); // x y r 0 360 arc fill
d.draw();//增加的行
d.clear();//增加的行
d.setrgb(0, 1, 0); // the rest are green
d.add(new Circle(400, 100, 100)); // 0 0 100 0 360 stroke
d.add(new Line(400, 500, 550, 550));
d.add(new Polygon(200, 500, 50, 6));
d.draw();
return 0;
}
最后的效果是这样的：
生成的ps文件内容如下：
superbe 发表于 2019-10-16 20:45
main里面只在最后d.draw()的时候才会输出全部图形，第一个和第二个d.setrgb之间的图形并没有输出，所以等于 ...
我们的main函数是老师先写好的，老师说不可以改，请问你可以说一下不改main函数只在class中编辑的解决方法嘛？谢谢！ 本帖最后由 superbe 于 2019-10-17 00:05 编辑
重新修改过了，试试可以吗
#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
const double PI=3.141592653;
using namespace std;
class Shape{
private:
double r, g, b;
//ofstream f;
public:
void setrgb(double r, double g, double b){//修改的函数
//f<<r<<' '<<g<<' '<<b<<" setrgbcolor "<<endl;
this->r = r;
this->g = g;
this->b = b;
}
void writergb(ostream& f){//增加的函数
f<<r<<' '<<g<<' '<<b<<" setrgbcolor "<<endl;
}
virtual void draw(ostream& s) = 0;
};
class Circle:public Shape{
private:
double x,y,radius;
public:
Circle(double x, double y, double radius):x(x),y(y),radius(radius){}
void draw(ostream& f){
f<< x << ' ' << y <<' '<< radius <<" 0 360 arc stroke"<< endl;
}
};
class Line:public Shape{
private:
double x1, x2,y1, y2;
public:
Line(double x1, double y1,double x2, double y2):x1(x1),y1(y1),x2(x2),y2(y2){}
void draw(ostream& f){
f<<x1<<' '<<y1<<" moveto "<<'\n'<<x2<<' '<<y2<<" lineto"<<'\n'<<"stroke "<<endl;
}
};
class Rect:public Shape{
private:
double x, y, width, height;
public:
Rect(double x, double y, double width, double height):x(x),y(y),width(width),height(height){}
void draw(ostream& f){
f<<x<<' '<<y<<" moveto "<<'\n'<<x+width<<' '<<y<<" lineto "<<'\n'<<x+width
<<' '<<y+height<<" lineto "<<'\n'<<x<<' '<<y+height<<" lineto"<<'\n'<< "closepath stroke"<<endl;
}
};
class Polygon:public Shape{
private:
double x, y, radius,side;
public:
Polygon(double x, double y, double radius, double side):x(x),y(y),radius(radius),side(side){}
void draw(ostream& f){
f<<x+radius<<' '<<y<<" moveto "<<endl;
for(int i=1; i<side; i++){
f<<x+radius*cos(2*i*PI/side)<<' '<<y+radius*sin(PI*2*i/side)<<" lineto "<<'\n';
}
f<<"closepath stroke"<<endl;
}
};
class FilledRect:public Shape{
private:
double x, y, width,height ;
public:
FilledRect(double x, double y, double width, double height)
:x(x),y(y),width(width),height(height){}
void draw(ostream& f){
f <<x << ' ' << y << " moveto " <<'\n'<< x+width
<< ' ' << y<< " lineto " <<'\n'<< x + width << ' ' << y + height
<< " lineto " <<'\n'<< x<< ' ' << y +height << " lineto"<<'\n'<< "closepath fill"<<endl;
}
};
class FilledCircle:public Shape{
private:
double x, y, radius;
public:
FilledCircle(double x, double y, double radius):x(x),y(y),radius(radius){}
void draw(ostream& f){
f<<x<<' '<<y<<' '<<radius<<" 0 360 arc fill"<<endl;
}
};
class Drawing {
private:
ofstream f;
vector<Shape*> shapes;
double r, g, b;
public:
void setrgb(double r, double g, double b){//修改的函数
//f<<r<<' '<<g<<' '<<b<<" setrgbcolor "<<endl;
this->r = r;
this->g = g;
this->b = b;
}
Drawing(string filename) : f(filename.c_str()), shapes() {
}
void add( Shape *s ) {//修改的函数
s->setrgb(r, g, b);
shapes.push_back(s);
}
void draw() { //修改的函数
for (int i = 0; i <shapes.size(); i++){
shapes->writergb(f);
shapes->draw(f);
}
}
};
int main() { //main未改动
ofstream f();
Drawing d("../test2.txt");
d.setrgb(1,0,0); // set drawing color to be bright red:1 0 0 setrgbcolor
d.add(new FilledRect(100.0, 150.0, 200.0, 50)); // x y moveto x y lineto ... fill
d.add(new Rect(100.0, 150.0, 200.0, 50)); // x y moveto x y lineto ... stroke
for (int x = 0; x < 600; x += 100)
d.add(new FilledCircle(x,200,50.0)); // x y r 0 360 arc fill
d.setrgb(0,1,0); // the rest are green
d.add(new Circle(0,0, 100)); // 0 0 100 0 360 stroke
d.add(new Line(400,500, 600,550));
d.add(new Polygon(200,200, 50, 6));
d.draw();
} 解决思路是这样的：
调用d.setrgb时把rgb值存储在d中，以后添加每个图形时把rgb值设置到图形中。
最后输出时，先调用图形的writergb将其rgb值写到文件，接着再调用该图形的draw方法写入画图的命令。 superbe 发表于 2019-10-17 00:13
解决思路是这样的：
调用d.setrgb时把rgb值存储在d中，以后添加每个图形时把rgb值设置到图形中。
最后输 ...
奥，我明白啦，谢谢你，你真厉害哇~~！我要是有你学的这么好就好了-。-
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