begin

2025-10-14 02:17:36 +08:00 · 2019-03-31 23:29:23 -07:00
parent 2f5ca954c4
commit 182e3cf06e
1 changed files with 103 additions and 0 deletions
--- a/experiments/cairo/cairo1.cpp
+++ b/experiments/cairo/cairo1.cpp
@@ -0,0 +1,103 @@
+
+#include <cairo.h>
+
+#include <SDL.h>
+
+int main() {
+    if (SDL_Init(SDL_INIT_VIDEO) != 0)
+        return 1;
+
+    SDL_Window *window = SDL_CreateWindow("Cairo",SDL_WINDOWPOS_UNDEFINED,SDL_WINDOWPOS_UNDEFINED,320,240,SDL_WINDOW_SHOWN);
+    if (window == NULL)
+        return 1;
+
+    SDL_Surface *surface = SDL_GetWindowSurface(window);
+    if (surface == NULL)
+        return 1;
+
+    cairo_format_t csurffmt = CAIRO_FORMAT_INVALID;
+    if (surface->format->BytesPerPixel == 4) {
+        csurffmt = CAIRO_FORMAT_ARGB32;
+    }
+    else if (surface->format->BytesPerPixel == 3) {
+        csurffmt = CAIRO_FORMAT_RGB24;
+    }
+    else if (surface->format->BytesPerPixel == 2) {
+        csurffmt = CAIRO_FORMAT_RGB16_565;
+    }
+    else {
+        return 1;
+    }
+
+    cairo_surface_t* csurf = cairo_image_surface_create(csurffmt, 320, 240);
+    if (csurf == NULL)
+        return 1;
+
+    cairo_t* cactx = cairo_create(csurf);
+    if (cactx == NULL)
+        return 1;
+
+    bool run = true;
+    while (run) {
+        SDL_Event ev;
+
+        if (SDL_PollEvent(&ev)) {
+            switch (ev.type) {
+                case SDL_WINDOWEVENT:
+                    switch (ev.window.event) {
+                        case SDL_WINDOWEVENT_CLOSE:
+                            run = false;
+                            break;
+                    }
+                    break;
+                case SDL_KEYDOWN:
+                    switch (ev.key.keysym.sym) {
+                        case SDLK_ESCAPE:
+                            run = false;
+                            break;
+                    }
+                    break;
+            }
+        }
+
+        // clear
+        cairo_reset_clip(cactx);
+        cairo_set_source_rgba(cactx,0.25,0.25,0.25,1.0);
+        cairo_paint(cactx);
+
+        // copy Cairo output to display
+        cairo_surface_flush(csurf);
+        {
+            unsigned char *cbuf = cairo_image_surface_get_data(csurf);
+            int width = cairo_image_surface_get_width(csurf);
+            int height = cairo_image_surface_get_height(csurf);
+            int stride = cairo_image_surface_get_stride(csurf);
+
+            SDL_LockSurface(surface);
+
+            if (cbuf != NULL && surface->pixels != NULL) {
+                if (width > surface->w) width = surface->w;
+                if (height > surface->h) height = surface->h;
+
+                for (int y=0;y < height;y++) {
+                    unsigned char *d = (unsigned char*)(surface->pixels) + (surface->pitch * y);
+                    unsigned char *s = (unsigned char*)(cbuf) + (stride * y);
+                    memcpy(d,s,width*surface->format->BytesPerPixel);
+                }
+            }
+
+            SDL_UnlockSurface(surface);
+            SDL_UpdateWindowSurface(window);
+        }
+    }
+
+    cairo_surface_flush(csurf);
+    cairo_destroy(cactx);
+    cairo_surface_destroy(csurf);
+
+    // do not free surface, owned by dinwo
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+    return 0;
+}
+