//
// This is a GUI support code to the chapters 12-16 of the book
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//
#include <FL/Fl_GIF_Image.H>
#include <FL/Fl_JPEG_Image.H>
#include "Graph.h"
//------------------------------------------------------------------------------
namespace Graph_lib {
//------------------------------------------------------------------------------
Shape::Shape() :
lcolor(fl_color()), // default color for lines and characters
ls(0), // default style
fcolor(Color::invisible) // no fill
{}
//------------------------------------------------------------------------------
void Shape::add(Point p) // protected
{
points.push_back(p);
}
//------------------------------------------------------------------------------
void Shape::set_point(int i,Point p) // not used; not necessary so far
{
points[i] = p;
}
//------------------------------------------------------------------------------
void Shape::draw_lines() const
{
if (color().visibility() && 1<points.size()) // draw sole pixel?
for (unsigned int i=1; i<points.size(); ++i)
fl_line(points[i-1].x,points[i-1].y,points[i].x,points[i].y);
}
//------------------------------------------------------------------------------
void Shape::draw() const
{
Fl_Color oldc = fl_color();
// there is no good portable way of retrieving the current style
fl_color(lcolor.as_int()); // set color
fl_line_style(ls.style(),ls.width()); // set style
draw_lines();
fl_color(oldc); // reset color (to previous)
fl_line_style(0); // reset line style to default
}
//------------------------------------------------------------------------------
void Shape::move(int dx, int dy) // move the shape +=dx and +=dy
{
for (int i = 0; i<points.size(); ++i) {
points[i].x+=dx;
points[i].y+=dy;
}
}
//------------------------------------------------------------------------------
Line::Line(Point p1, Point p2) // construct a line from two points
{
add(p1); // add p1 to this shape
add(p2); // add p2 to this shape
}
//------------------------------------------------------------------------------
void Lines::add(Point p1, Point p2)
{
Shape::add(p1);
Shape::add(p2);
}
//------------------------------------------------------------------------------
// draw lines connecting pairs of points
void Lines::draw_lines() const
{
if (color().visibility())
for (int i=1; i<number_of_points(); i+=2)
fl_line(point(i-1).x,point(i-1).y,point(i).x,point(i).y);
}
//------------------------------------------------------------------------------
// does two lines (p1,p2) and (p3,p4) intersect?
// if se return the distance of the intersect point as distances from p1
inline pair<double,double> line_intersect(Point p1, Point p2, Point p3, Point p4, bool& parallel)
{
double x1 = p1.x;
double x2 = p2.x;
double x3 = p3.x;
double x4 = p4.x;
double y1 = p1.y;
double y2 = p2.y;
double y3 = p3.y;
double y4 = p4.y;
double denom = ((y4 - y3)*(x2-x1) - (x4-x3)*(y2-y1));
if (denom == 0){
parallel= true;
return pair<double,double>(0,0);
}
parallel = false;
return pair<double,double>( ((x4-x3)*(y1-y3) - (y4-y3)*(x1-x3))/denom,
((x2-x1)*(y1-y3) - (y2-y1)*(x1-x3))/denom);
}
//------------------------------------------------------------------------------
//intersection between two line segments
//Returns true if the two segments intersect,
//in which case intersection is set to the point of intersection
bool line_segment_intersect(Point p1, Point p2, Point p3, Point p4, Point& intersection){
bool parallel;
pair<double,double> u = line_intersect(p1,p2,p3,p4,parallel);
if (parallel || u.first < 0 || u.first > 1 || u.second < 0 || u.second > 1) return false;
intersection.x = p1.x + u.first*(p2.x - p1.x);
intersection.y = p1.y + u.first*(p2.y - p1.y);
return true;
}
//------------------------------------------------------------------------------
void Polygon::add(Point p)
{
int np = number_of_points();
if (1<np) { // check that thenew line isn't parallel to the previous one
if (p==point(np-1)) error("polygon point equal to previous point");
bool parallel;
line_intersect(point(np-1),p,point(np-2),point(np-1),parallel);
if (parallel)
error("two polygon points lie in a straight line");
}
for (int i = 1; i<np-1; ++i) { // check that new segment doesn't interset and old point
Point ignore(0,0);
if (line_segment_intersect(point(np-1),p,point(i-1),point(i),ignore))
error("intersect in polygon");
}
Closed_polyline::add(p);
}
//------------------------------------------------------------------------------
void Polygon::draw_lines() const
{
if (number_of_points() < 3) error("less than 3 points in a Polygon");
Closed_polyline::draw_lines();
}
//------------------------------------------------------------------------------
void Open_polyline::draw_lines() const
{
if (fill_color().visibility()) {
fl_color(fill_color().as_int());
fl_begin_complex_polygon();
for(int i=0; i<number_of_points(); ++i){
fl_vertex(point(i).x, point(i).y);
}
fl_end_complex_polygon();
fl_color(color().as_int()); // reset color
}
if (color().visibility())
Shape::draw_lines();
}
//------------------------------------------------------------------------------
void Closed_polyline::draw_lines() const
{
Open_polyline::draw_lines(); // first draw the "open poly line part"
// then draw closing line:
if (color().visibility())
fl_line(point(number_of_points()-1).x,
point(number_of_points()-1).y,
point(0).x,
point(0).y);
}
//------------------------------------------------------------------------------
void draw_mark(Point xy, char c)
{
static const int dx = 4;
static const int dy = 4;
string m(1,c);
fl_draw(m.c_str(),xy.x-dx,xy.y+dy);
}
//------------------------------------------------------------------------------
void Marked_polyline::draw_lines() const
{
Open_polyline::draw_lines();
for (int i=0; i<number_of_points(); ++i)
draw_mark(point(i),mark[i%mark.size()]);
}
//------------------------------------------------------------------------------
void Rectangle::draw_lines() const
{
if (fill_color().visibility()) { // fill
fl_color(fill_color().as_int());
fl_rectf(point(0).x,point(0).y,w,h);
fl_color(color().as_int()); // reset color
}
if (color().visibility()) { // lines on top of fill
fl_color(color().as_int());
fl_rect(point(0).x,point(0).y,w,h);
}
}
//------------------------------------------------------------------------------
Circle::Circle(Point p, int rr) // center and radius
:r(rr)
{
add(Point(p.x-r,p.y-r)); // store top-left corner
}
//------------------------------------------------------------------------------
Point Circle::center() const
{
return Point(point(0).x+r, point(0).y+r);
}
//------------------------------------------------------------------------------
void Circle::draw_lines() const
{
if (fill_color().visibility()) { // fill
fl_color(fill_color().as_int());
fl_pie(point(0).x,point(0).y,r+r-1,r+r-1,0,360);
fl_color(color().as_int()); // reset color
}
if (color().visibility()) {
fl_color(color().as_int());
fl_arc(point(0).x,point(0).y,r+r,r+r,0,360);
}
}
//------------------------------------------------------------------------------
void Ellipse::draw_lines() const
{
if (fill_color().visibility()) { // fill
fl_color(fill_color().as_int());
fl_pie(point(0).x,point(0).y,w+w-1,h+h-1,0,360);
fl_color(color().as_int()); // reset color
}
if (color().visibility()) {
fl_color(color().as_int());
fl_arc(point(0).x,point(0).y,w+w,h+h,0,360);
}
}
//------------------------------------------------------------------------------
void Text::draw_lines() const
{
int ofnt = fl_font();
int osz = fl_size();
fl_font(fnt.as_int(),fnt_sz);
fl_draw(lab.c_str(),point(0).x,point(0).y);
fl_font(ofnt,osz);
}
//------------------------------------------------------------------------------
Axis::Axis(Orientation d, Point xy, int length, int n, string lab) :
label(Point(0,0),lab)
{
if (length<0) error("bad axis length");
switch (d){
case Axis::x:
{
Shape::add(xy); // axis line
Shape::add(Point(xy.x+length,xy.y));
if (0<n) { // add notches
int dist = length/n;
int x = xy.x+dist;
for (int i = 0; i<n; ++i) {
notches.add(Point(x,xy.y),Point(x,xy.y-5));
x += dist;
}
}
// label under the line
label.move(length/3,xy.y+20);
break;
}
case Axis::y:
{
Shape::add(xy); // a y-axis goes up
Shape::add(Point(xy.x,xy.y-length));
if (0<n) { // add notches
int dist = length/n;
int y = xy.y-dist;
for (int i = 0; i<n; ++i) {
notches.add(Point(xy.x,y),Point(xy.x+5,y));
y -= dist;
}
}
// label at top
label.move(xy.x-10,xy.y-length-10);
break;
}
case Axis::z:
error("z axis not implemented");
}
}
//------------------------------------------------------------------------------
void Axis::draw_lines() const
{
Shape::draw_lines();
notches.draw(); // the notches may have a different color from the line
label.draw(); // the label may have a different color from the line
}
//------------------------------------------------------------------------------
void Axis::set_color(Color c)
{
Shape::set_color(c);
notches.set_color(c);
label.set_color(c);
}
//------------------------------------------------------------------------------
void Axis::move(int dx, int dy)
{
Shape::move(dx,dy);
notches.move(dx,dy);
label.move(dx,dy);
}
//------------------------------------------------------------------------------
Function::Function(Fct f, double r1, double r2, Point xy,
int count, double xscale, double yscale)
// graph f(x) for x in [r1:r2) using count line segments with (0,0) displayed at xy
// x coordinates are scaled by xscale and y coordinates scaled by yscale
{
if (r2-r1<=0) error("bad graphing range");
if (count <=0) error("non-positive graphing count");
double dist = (r2-r1)/count;
double r = r1;
for (int i = 0; i<count; ++i) {
add(Point(xy.x+int(r*xscale),xy.y-int(f(r)*yscale)));
r += dist;
}
}
//------------------------------------------------------------------------------
bool can_open(const string& s)
// check if a file named s exists and can be opened for reading
{
ifstream ff(s.c_str());
return ff;
}
//------------------------------------------------------------------------------
#define ARRAY_SIZE(a) (sizeof(a)/sizeof((a)[0]))
Suffix::Encoding get_encoding(const string& s)
{
struct SuffixMap
{
const char* extension;
Suffix::Encoding suffix;
};
static SuffixMap smap[] = {
{".jpg", Suffix::jpg},
{".jpeg", Suffix::jpg},
{".gif", Suffix::gif},
};
for (int i = 0, n = ARRAY_SIZE(smap); i < n; i++)
{
int len = strlen(smap[i].extension);
if (s.length() >= len && s.substr(s.length()-len, len) == smap[i].extension)
return smap[i].suffix;
}
return Suffix::none;
}
//------------------------------------------------------------------------------
// somewhat over-elaborate constructor
// because errors related to image files can be such a pain to debug
Image::Image(Point xy, string s, Suffix::Encoding e)
:w(0), h(0), fn(xy,"")
{
add(xy);
if (!can_open(s)) { // can we open s?
fn.set_label("cannot open \""+s+'\"');
p = new Bad_image(30,20); // the "error image"
return;
}
if (e == Suffix::none) e = get_encoding(s);
switch(e) { // check if it is a known encoding
case Suffix::jpg:
p = new Fl_JPEG_Image(s.c_str());
break;
case Suffix::gif:
p = new Fl_GIF_Image(s.c_str());
break;
default: // Unsupported image encoding
fn.set_label("unsupported file type \""+s+'\"');
p = new Bad_image(30,20); // the "error image"
}
}
//------------------------------------------------------------------------------
void Image::draw_lines() const
{
if (fn.label()!="") fn.draw_lines();
if (w&&h)
p->draw(point(0).x,point(0).y,w,h,cx,cy);
else
p->draw(point(0).x,point(0).y);
}
//------------------------------------------------------------------------------
} // of namespace Graph_lib
