From f5bc7fcf65b954c84347db237c728896c3cb340c Mon Sep 17 00:00:00 2001
From: Bob Polis <rpb.polis@avans.nl>
Date: Mon, 1 Feb 2021 10:35:59 +0100
Subject: [PATCH] Refactored to support window resizing

---
 main.cpp | 45 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 32 insertions(+), 13 deletions(-)

diff --git a/main.cpp b/main.cpp
index 3dbb6a2..fb5a0a9 100644
--- a/main.cpp
+++ b/main.cpp
@@ -11,7 +11,6 @@
 #include <cstdlib>
 #include <string>
 #include <stdexcept>
-#include <time.h>
 #include <cmath>
 #include <thread>
 
@@ -31,8 +30,10 @@ const int WIDTH {1600};
 const int HEIGHT {900};
 
 sc::gui::Window* main_window {nullptr};
-sc::gui::Image* main_image {nullptr};
 ScreensaverPlugin* main_saver {nullptr};
+std::unique_ptr<sc::gui::Image> main_image {nullptr};
+std::unique_ptr<cairo_t, void(*)(cairo_t*)> main_context {nullptr, cairo_destroy};
+std::unique_ptr<cairo_surface_t, void(*)(cairo_surface_t*)> main_surface {nullptr, cairo_surface_destroy};
 
 void print_help() {
     std::cout << "usage: screensaver [-h|-l|--version]\n";
@@ -51,6 +52,17 @@ void list_plugins() {
     }
 }
 
+void create_image(int w, int h) {
+    // create an SDL drawing surface and connect it to cairo
+    main_image.reset(new sc::gui::Image {w, h});
+    SDL_Surface* s = main_image->surface();
+    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)};
+    main_surface.reset(cs);
+    cairo_t* cr {cairo_create(cs)};
+    main_context.reset(cr);
+}
+
 void draw() {
     main_saver->update();
     sc::gui::ImageLock lock {*main_image};
@@ -59,6 +71,18 @@ void draw() {
     main_window->show_image(*main_image);
 }
 
+bool handle_window_resize(const SDL_Event& event, bool quit) {
+    if (event.window.data1 != main_image->width() || event.window.data2 != main_image->height()) {
+        std::cerr << "window resized to " << event.window.data1 << "×" << event.window.data2 << " pixels\n";
+        create_image(event.window.data1, event.window.data2);
+        cairo_rectangle_t r {0, 0, static_cast<double>(event.window.data1), static_cast<double>(event.window.data2)};
+        if (main_saver) {
+            main_saver->setup(main_context.get(), r);
+        }
+    }
+    return quit;
+}
+
 int main(int argc, const char * argv[]) {
     try {
         // gather plugins
@@ -115,18 +139,13 @@ int main(int argc, const char * argv[]) {
         sc::gui::SDLImageWrapper sdl_image;
 
         // main window
-        sc::gui::Window& window {sc::gui::Window::new_window("living art")};
+        sc::gui::Window& window {sc::gui::Window::new_window("Living Art")};
         main_window = &window;
+        window.add_event_handler(handle_window_resize, SDL_WINDOWEVENT_RESIZED);
+        window.add_event_handler(handle_window_resize, SDL_WINDOWEVENT_SIZE_CHANGED);
 
-        // create an SDL drawing surface and connect it to cairo
-        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)};
-        std::unique_ptr<cairo_surface_t, void(*)(cairo_surface_t*)> cs_ {cs, cairo_surface_destroy};
-        cairo_t* cr {cairo_create(cs)};
-        std::unique_ptr<cairo_t, void(*)(cairo_t*)> cr_ {cr, cairo_destroy};
+        // setup sdl surface and connect to cairo
+        create_image(WIDTH, HEIGHT);
 
         // setup screen saver module
         if (!saver) {
@@ -134,7 +153,7 @@ int main(int argc, const char * argv[]) {
             std::cerr << "screensaver: using standard 'Default' module\n";
         }
         main_saver = saver.get();
-        main_saver->setup(cr, {0, 0, WIDTH, HEIGHT});
+        main_saver->setup(main_context.get(), {0, 0, WIDTH, HEIGHT});
 
         sc::gui::app().fps(main_saver->fps());
         sc::gui::app().add_run_loop_action(draw);