From 30aad07c9f4c5a989f4a3499d60f749db7717937 Mon Sep 17 00:00:00 2001
From: Bob Polis <rpb.polis@avans.nl>
Date: Sun, 25 Oct 2020 20:31:59 +0100
Subject: [PATCH] refactored to do drawing from a runloop action

---
 main.cpp | 117 +++++++++++++++++++++++++++++++------------------------
 1 file changed, 66 insertions(+), 51 deletions(-)

diff --git a/main.cpp b/main.cpp
index 4212e5a..471b782 100644
--- a/main.cpp
+++ b/main.cpp
@@ -15,6 +15,14 @@
 #include <unistd.h>
 #include <cairo/cairo.h>
 
+const int WIDTH {700};
+const int HEIGHT {700};
+
+sc::gui::Window* main_window {nullptr};
+sc::gui::Image* main_image {nullptr};
+cairo_t* cr {nullptr};
+bool timer_expired {true};
+
 void print_help() {
     std::cout << "usage: screensaver [-h|--version]\n";
     std::cout << "  -h, --help    show this help text and exit\n";
@@ -25,55 +33,40 @@ void print_version() {
     std::cout << "screensaver version 1.0\n";
 }
 
-void draw(sc::gui::Window& window) {
-    SDL_Surface* s {SDL_CreateRGBSurface(0, 700, 700, 32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0)};
-    sc::gui::Image image {s};
-    sc::gui::ImageLock lock {image};
-    cairo_surface_t* cs {cairo_image_surface_create_for_data(static_cast<unsigned char*>(s->pixels),
-                                                             CAIRO_FORMAT_RGB24, s->w, s->h, s->pitch)};
-    cairo_t* cr {cairo_create(cs)};
+void draw() {
+    if (timer_expired) {
+        timer_expired = false;
+        sc::gui::ImageLock lock {*main_image};
 
-    // white background
-    cairo_set_source_rgb(cr, 1, 1, 1);
-    cairo_rectangle(cr, 0, 0, s->w, s->h);
-    cairo_fill(cr);
+        // white background
+        cairo_set_source_rgb(cr, 1, 1, 1);
+        cairo_rectangle(cr, 0, 0, WIDTH, HEIGHT);
+        cairo_fill(cr);
 
-    // orange rectangle
-    cairo_rectangle(cr, 300, 300, 100, 100);
-    cairo_set_source_rgb(cr, 1, 0.5, 0);
-    cairo_fill(cr);
+        // orange rectangle
+        cairo_rectangle(cr, 300, 300, 100, 100);
+        cairo_set_source_rgb(cr, 1, 0.5, 0);
+        cairo_fill(cr);
 
-    // black rectangle
-    cairo_rectangle(cr, 200, 200, 100, 100);
-    cairo_set_source_rgb(cr, 0, 0, 0);
-    cairo_fill(cr);
+        // black rectangle
+        cairo_rectangle(cr, 200, 200, 100, 100);
+        cairo_set_source_rgb(cr, 0, 0, 0);
+        cairo_fill(cr);
 
-    // dark green text
-    cairo_set_source_rgb(cr, 0.2, 0.5, 0);
-    cairo_select_font_face(cr, "Helvetica", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
-    cairo_set_font_size(cr, 42);
-    cairo_move_to(cr, 100, 150);
-    cairo_show_text(cr, "Cairo on SDL");
+        // dark green text
+        cairo_set_source_rgb(cr, 0.2, 0.5, 0);
+        cairo_select_font_face(cr, "Helvetica", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
+        cairo_set_font_size(cr, 42);
+        cairo_move_to(cr, 50, 100);
+        cairo_show_text(cr, "abcdefghijklmnopqrstuvwxyz");
 
-    // show
-    window.show_image(image);
-    cairo_surface_destroy(cs);
-    cairo_destroy(cr);
+        // show
+        main_window->show_image(*main_image);
+    }
 }
 
 int main(int argc, const char * argv[]) {
     try {
-        // RAII instances
-        sc::gui::SDLWrapper sdl2;
-        sc::gui::SDLImageWrapper sdl_image;
-
-        // main window
-        sc::gui::Window& window {sc::gui::Window::new_window("screensaver")};
-        window.add_event_handler([](const SDL_Event& event, bool quit) -> bool {
-            std::cerr << "closing window " << event.window.windowID << '\n';
-            return quit;
-        }, SDL_WINDOWEVENT_CLOSE);
-
         int opt_char, opt_val;
         struct option long_options[] = {
             {"help", no_argument, nullptr, 'h'},
@@ -99,20 +92,42 @@ int main(int argc, const char * argv[]) {
                     throw std::runtime_error("unrecognized option");
             }
         }
-        if (optind == argc) {
-            // here when no file args
-        }
-        for (int i = optind; i < argc; ++i) {
-            try {
-                // process file argv[i]
-            } catch (const std::runtime_error& ex) {
-                std::cerr << "screensaver: " << ex.what() << '\n';
-            }
-        }
+        // if (optind == argc) {
+        //     // here when no file args
+        // }
+        // for (int i = optind; i < argc; ++i) {
+        //     try {
+        //         // process file argv[i]
+        //     } catch (const std::runtime_error& ex) {
+        //         std::cerr << "screensaver: " << ex.what() << '\n';
+        //     }
+        // }
 
-        draw(window);
+        // RAII instances
+        sc::gui::SDLWrapper sdl2;
+        sc::gui::SDLImageWrapper sdl_image;
+
+        // main window
+        sc::gui::Window& window {sc::gui::Window::new_window("screensaver")};
+        main_window = &window;
+        window.add_event_handler([](const SDL_Event& event, bool quit) -> bool {
+            std::cerr << "closing window " << event.window.windowID << '\n';
+            return quit;
+        }, SDL_WINDOWEVENT_CLOSE);
+
+        SDL_Surface* s {SDL_CreateRGBSurface(0, WIDTH, HEIGHT, 32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0)};
+        sc::gui::Image image {s};
+        main_image = &image;
+        cairo_surface_t* cs {cairo_image_surface_create_for_data(static_cast<unsigned char*>(s->pixels),
+                                                                 CAIRO_FORMAT_RGB24, s->w, s->h, s->pitch)};
+        cr = cairo_create(cs);
+
+        sc::gui::app().add_run_loop_action(draw);
         sc::gui::app().run();
 
+        cairo_surface_destroy(cs);
+        cairo_destroy(cr);
+
     } catch (const std::exception& ex) {
         std::cerr << "screensaver: " << ex.what() << '\n';
         return EXIT_FAILURE;