diff options
Diffstat (limited to 'test/offscreen.cxx')
| -rw-r--r-- | test/offscreen.cxx | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/test/offscreen.cxx b/test/offscreen.cxx new file mode 100644 index 0000000..f044c2e --- /dev/null +++ b/test/offscreen.cxx @@ -0,0 +1,260 @@ +// +// "$Id: offscreen.cxx 11287 2016-03-05 00:39:40Z AlbrechtS $" +// +// Offscreen drawing test program for the Fast Light Tool Kit (FLTK). +// +// Copyright 1998-2016 by Bill Spitzak and others. +// +// This library is free software. Distribution and use rights are outlined in +// the file "COPYING" which should have been included with this file. If this +// file is missing or damaged, see the license at: +// +// http://www.fltk.org/COPYING.php +// +// Please report all bugs and problems on the following page: +// +// http://www.fltk.org/str.php +// + +/* Standard headers */ +#include <stdlib.h> +#include <time.h> // time() - used to seed rand() + +/* Fltk headers */ +#include <FL/Fl.H> +#include <FL/Fl_Double_Window.H> +#include <FL/x.H> +#include <FL/Fl_Box.H> +#include <FL/fl_draw.H> + +static Fl_Double_Window *main_window = 0; + +// constants to define the view etc. +static const int offscreen_size = 1000; +static const int win_size = 512; +static const int first_useful_color = 56; +static const int last_useful_color = 255; +static const int num_iterations = 300; +static const double max_line_width = 9.0; +static const double delta_time = 0.1; + +/*****************************************************************************/ +class oscr_box : public Fl_Box +{ +public: + oscr_box(int x, int y, int w, int h); + void oscr_drawing(void); + bool has_oscr() const + { + if (oscr) return true; + return false; + } +private: + void draw(); + int handle(int event); + // Generate "random" values for the line display + double random_val(int v) const + { + double dr = (double)(rand()) / (double)(RAND_MAX); // 0.0 to 1.0 + dr = dr * (double)(v); // 0 to v + return dr; + } + // The offscreen surface + Fl_Offscreen oscr; + // variables used to handle "dragging" of the view within the box + int x1, y1; // drag start positions + int xoff, yoff; // drag offsets + int drag_state; // non-zero if drag is in progress + int page_x, page_y; // top left of view area + // Width and height of the offscreen surface + int offsc_w, offsc_h; +}; + +/*****************************************************************************/ +oscr_box::oscr_box(int x, int y, int w, int h) : + Fl_Box(x, y, w, h), // base box + oscr(0), // offscreen is not set at start + x1(0), y1(0), drag_state(0), // not dragging view + page_x((offscreen_size - win_size) / 2), // roughly centred in view + page_y((offscreen_size - win_size) / 2), + offsc_w(0), offsc_h(0) // offscreen size - initially none +{ } // Constructor + +/*****************************************************************************/ +void oscr_box::draw() +{ + int wd = w(); + int ht = h(); + int xo = x(); + int yo = y(); + + fl_color(fl_gray_ramp(19)); // a light grey background shade + fl_rectf(xo, yo, wd, ht); // fill the box with this colour + + // then add the offscreen on top of the grey background + if (has_oscr()) // offscreen exists + { + fl_copy_offscreen(xo, yo, wd, ht, oscr, page_x, page_y); + } + else // create offscreen + { + // some hosts may need a valid window context to base the offscreen on... + main_window->make_current(); + offsc_w = offscreen_size; + offsc_h = offscreen_size; + oscr = fl_create_offscreen(offsc_w, offsc_h); + } +} // draw method + +/*****************************************************************************/ +int oscr_box::handle(int ev) +{ + int ret = Fl_Box::handle(ev); + // handle dragging of visible page area - if a valid context exists + if (has_oscr()) + { + switch (ev) + { + case FL_ENTER: + main_window->cursor(FL_CURSOR_MOVE); + ret = 1; + break; + + case FL_LEAVE: + main_window->cursor(FL_CURSOR_DEFAULT); + ret = 1; + break; + + case FL_PUSH: + x1 = Fl::event_x_root(); + y1 = Fl::event_y_root(); + drag_state = 1; // drag + ret = 1; + break; + + case FL_DRAG: + if (drag_state == 1) // dragging page + { + int x2 = Fl::event_x_root(); + int y2 = Fl::event_y_root(); + xoff = x1 - x2; + yoff = y1 - y2; + x1 = x2; + y1 = y2; + page_x += xoff; + page_y += yoff; + // check the page bounds + if (page_x < -w()) + { + page_x = -w(); + } + else if (page_x > offsc_w) + { + page_x = offsc_w; + } + if (page_y < -h()) + { + page_y = -h(); + } + else if (page_y > offsc_h) + { + page_y = offsc_h; + } + redraw(); + } + ret = 1; + break; + + case FL_RELEASE: + drag_state = 0; + ret = 1; + break; + + default: + break; + } + } + return ret; +} // handle + +/*****************************************************************************/ +void oscr_box::oscr_drawing(void) +{ + Fl_Color col; + static int icol = first_useful_color; + static int ox = (offscreen_size / 2); + static int oy = (offscreen_size / 2); + static int iters = num_iterations + 1; // Must be set on first pass! + + if (!has_oscr()) + { + return; // no valid offscreen, nothing to do here + } + + fl_begin_offscreen(oscr); /* Open the offscreen context for drawing */ + { + if (iters > num_iterations) // clear the offscreen and start afresh + { + fl_color(FL_WHITE); + fl_rectf(0, 0, offsc_w, offsc_h); + iters = 0; + } + iters++; + + icol++; + if (icol > last_useful_color) + { + icol = first_useful_color; + } + col = static_cast<Fl_Color>(icol); + fl_color(col); // set the colour + + double drx = random_val(offsc_w); + double dry = random_val(offsc_h); + double drt = random_val(max_line_width); + + int ex = static_cast<int>(drx); + int ey = static_cast<int>(dry); + fl_line_style(FL_SOLID, static_cast<int>(drt)); + fl_line(ox, oy, ex, ey); + ox = ex; + oy = ey; + } + fl_end_offscreen(); // close the offscreen context + redraw(); +} // oscr_drawing + +/*****************************************************************************/ +static oscr_box *os_box = 0; // a widget to view the offscreen with + +/*****************************************************************************/ +static void oscr_anim(void *) +{ + os_box->oscr_drawing(); // if the offscreen exists, draw something + Fl::repeat_timeout(delta_time, oscr_anim); +} // oscr_anim + +/*****************************************************************************/ +int main(int argc, char **argv) +{ + int dim1 = win_size; + main_window = new Fl_Double_Window(dim1, dim1, "Offscreen demo"); + main_window->begin(); + + dim1 -= 10; + os_box = new oscr_box(5, 5, dim1, dim1); + main_window->end(); + main_window->resizable(os_box); + + main_window->show(argc, argv); + + srand(time(NULL)); // seed the random sequence generator + + Fl::add_timeout(delta_time, oscr_anim); + + return Fl::run(); +} // main + +// +// End of "$Id: offscreen.cxx 11287 2016-03-05 00:39:40Z AlbrechtS $". +// |