fltk/test/mandelbrot.cxx

#include "mandelbrot_ui.C"
#include <FL/fl_draw.H>
#include <stdio.h>
#include <stdlib.h>

Drawing_Window mbrot;
Drawing_Window jbrot;

void idle() {
  if (!mbrot.d->idle() && !(jbrot.d && jbrot.d->idle())) Fl::set_idle(0);
}

void set_idle() {
  Fl::set_idle(idle);
}

static void window_callback(Fl_Widget*, void*) {exit(0);}

int main(int argc, char **argv) {
  make_window(mbrot);
  mbrot.d->X = -.75;
  mbrot.d->scale = 2.5;
  mbrot.update_label();
  int i = 0;
  if (Fl::args(argc,argv,i) < argc) Fl::fatal(Fl::help);
  Fl::visual(FL_RGB);
  mbrot.window->callback(window_callback);
  mbrot.window->show(argc,argv);
  Fl::run();
  return 0;
}

void Drawing_Window::update_label() {
  char buffer[128];
  sprintf(buffer, "%+.10f", d->X); x_input->value(buffer);
  sprintf(buffer, "%+.10f", d->Y); y_input->value(buffer);
  sprintf(buffer, "%.2g", d->scale); w_input->value(buffer);
}

void Drawing_Area::draw() {
  draw_box();
  drawn = 0;
  set_idle();
}

int Drawing_Area::idle() {
  if (!window()->visible()) return 0;
  if (drawn < nextline) {
    window()->make_current();
    int yy = drawn+y()+4;
    if (yy >= sy && yy <= sy+sh) erase_box();
    fl_draw_image_mono(buffer+drawn*W,x()+3,yy,W,1,1,W);
    drawn++;
    return 1;
  }
  if (nextline < H) {
    if (!buffer) buffer = new uchar[W*H];
    double yy = Y+(H/2-nextline)*scale/W;
    double yi = yy; if (julia) yy = jY;
    uchar *p = buffer+nextline*W;
    for (int xi = 0; xi < W; xi++) {
      double xx = X+(xi-W/2)*scale/W;
      double wx = xx; double wy = yi;
      if (julia) xx = jX;
      for (int i=0; ; i++) {
	if (i >= iterations) {*p = 0; break;}
	double t = wx*wx - wy*wy + xx;
	wy = 2*wx*wy + yy;
	wx = t;
	if (wx*wx + wy*wy > 4) {
	  wx = t = 1-double(i)/(1<<10);
	  if (t <= 0) t = 0; else for (i=brightness; i--;) t*=wx;
	  *p = 255-int(254*t);
	  break;
	}
      }
      p++;
    }
    nextline++;
    return nextline < H;
  }
  return 0;
}

void Drawing_Area::erase_box() {
  window()->make_current();
  fl_overlay_clear();
}

int Drawing_Area::handle(int event) {
  static int ix, iy;
  static int dragged;
  static int button;
  int x2,y2;
  switch (event) {
  case FL_PUSH:
    erase_box();
    ix = Fl::event_x(); if (ix<x()) ix=x(); if (ix>=x()+w()) ix=x()+w()-1;
    iy = Fl::event_y(); if (iy<y()) iy=y(); if (iy>=y()+h()) iy=y()+h()-1;
    dragged = 0;
    button = Fl::event_button();
    return 1;
  case FL_DRAG:
    dragged = 1;
    erase_box();
    x2 = Fl::event_x(); if (x2<x()) x2=x(); if (x2>=x()+w()) x2=x()+w()-1;
    y2 = Fl::event_y(); if (y2<y()) y2=y(); if (y2>=y()+h()) y2=y()+h()-1;
    if (button != 1) {ix = x2; iy = y2; return 1;}
    if (ix < x2) {sx = ix; sw = x2-ix;} else {sx = x2; sw = ix-x2;}
    if (iy < y2) {sy = iy; sh = y2-iy;} else {sy = y2; sh = iy-y2;}
    window()->make_current();
    fl_overlay_rect(sx,sy,sw,sh);
    return 1;
  case FL_RELEASE:
    if (button == 1) {
      erase_box();
      if (dragged && sw > 3 && sh > 3) {
	X = X + (sx+sw/2-x()-W/2)*scale/W;
	Y = Y + (-sy-sh/2+y()+H/2)*scale/W;
	scale = sw*scale/W;
      } else if (!dragged) {
	scale = 2*scale;
	if (julia) {
	  if (scale >= 4) {
	    scale = 4;
	    X = Y = 0;
	  }
	} else {
	  if (scale >= 2.5) {
	    scale = 2.5;
	    X = -.75;
	    Y = 0;
	  }
	}
      } else return 1;
      ((Drawing_Window*)(user_data()))->update_label();
      new_display();
    } else if (!julia) {
      if (!jbrot.d) {
	make_window(jbrot);
	jbrot.d->julia = 1;
	jbrot.d->X = 0;
	jbrot.d->Y = 0;
	jbrot.d->scale = 4;
	jbrot.update_label();
      }
      jbrot.d->jX = X + (ix-x()-W/2)*scale/W;
      jbrot.d->jY = Y + (H/2-iy+y())*scale/W;
      static char buffer[128];
      sprintf(buffer, "Julia %.7f %.7f",jbrot.d->jX,jbrot.d->jY);
      jbrot.window->label(buffer);
      jbrot.window->show();
      jbrot.d->new_display();
    }
    return 1;
  }
  return 0;
}

void Drawing_Area::new_display() {
  drawn = nextline = 0;
  set_idle();
}

void Drawing_Area::resize(int X,int Y,int W,int H) {
  if (W != w() || H != h()) {
    this->W = W-6;
    this->H = H-8;
    if (buffer) {delete[] buffer; buffer = 0; new_display();}
  }
  Fl_Box::resize(X,Y,W,H);
}

void brightness_slider_cb(Fl_Slider* o, Drawing_Window* s) {
  s->d->brightness = int(o->value());
  s->d->new_display();
}

void iterations_slider_cb(Fl_Slider* o, Drawing_Window* s) {
  s->d->iterations = 1<<int(o->value());
  s->d->new_display();
}

void x_callback(Fl_Input* o, Drawing_Window* s) {
  double v = atof(o->value());
  s->d->X = v;
  s->d->new_display();
}

void y_callback(Fl_Input* o, Drawing_Window* s) {
  double v = atof(o->value());
  s->d->Y = v;
  s->d->new_display();
}

void w_callback(Fl_Input* o, Drawing_Window* s) {
  double v = atof(o->value());
  s->d->scale = v;
  s->d->new_display();
}