添加Cairo使用文字的例子

L07CairoCircle/main.c

@@ -16,15 +16,14 @@ void draw(cairo_surface_t *cairosurf) {
 int main(int argc, char *argv[]) {
     SDL_Surface *screen; // even with SDL2, we can still bring ancient code back
     SDL_Window *window;
-    SDL_Surface *image;
 
     SDL_Init(SDL_INIT_VIDEO); // init video
 
     // create the window like normal
     window = SDL_CreateWindow(
             "Draw on surface",
             SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
-            550, 400, SDL_WINDOW_OPENGL
+            550, 400, SDL_WINDOW_SHOWN
     );
 
     // but instead of creating a renderer, we can draw directly to the screen

L07CairoText/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.17)
+project(L07CairoCircle)
+
+set(CMAKE_CXX_STANDARD 14)
+
+add_compile_definitions(THREAD_SAFE)
+
+include_directories(
+        /usr/local/include/SDL2
+        /usr/local/include/cairo
+)
+
+link_directories(
+        /usr/local/lib
+)
+
+link_libraries(
+        SDL2
+        cairo
+)
+
+add_executable(L07CairoCircle main.c)

L07CairoText/main.c

@@ -0,0 +1,55 @@
+#include <SDL.h> // include SDL header
+#include <cairo.h>
+
+
+#define FONT_SIZE 50
+
+void draw(cairo_surface_t *cairosurf) {
+    cairo_t *cr = cairo_create(cairosurf);
+
+    cairo_set_font_size(cr, FONT_SIZE);
+    cairo_move_to(cr, 0, FONT_SIZE);
+    cairo_show_text(cr, "Hello Cairo");
+
+    cairo_destroy(cr);
+}
+
+int main(int argc, char *argv[]) {
+    SDL_Surface *screen; // even with SDL2, we can still bring ancient code back
+    SDL_Window *window;
+
+    SDL_Init(SDL_INIT_VIDEO); // init video
+
+    // create the window like normal
+    window = SDL_CreateWindow(
+            "Draw on surface",
+            SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+            550, 400, SDL_WINDOW_SHOWN
+    );
+
+    // but instead of creating a renderer, we can draw directly to the screen
+    screen = SDL_GetWindowSurface(window);
+    cairo_surface_t *cairosurf = cairo_image_surface_create_for_data(
+            screen->pixels, CAIRO_FORMAT_RGB24,
+            screen->w, screen->h, screen->pitch
+    );
+
+    while (1) {
+        // fill background
+        SDL_FillRect(screen, NULL, 0xffffffff);
+        draw(cairosurf);
+        SDL_UpdateWindowSurface(window);
+
+        SDL_Event event;
+        if (SDL_PollEvent(&event)) {
+            if (event.type == SDL_QUIT) {
+                break;
+            }
+        }
+    }
+
+    cairo_surface_destroy(cairosurf);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+    return 0;
+}