Start hashing out a gauge cluster in Cairo

examples/Makefile

@@ -8,7 +8,7 @@ CFLAGS		+= -I$(INCLUDE_PATH)
 LDFLAGS		= -L../src -lhexagram
 STATIC		= ../src/libhexagram.a
 
-EXAMPLES	= view
+EXAMPLES	= view cluster
 
 RM		= rm
 
@@ -17,6 +17,9 @@ all: $(EXAMPLES)
 $(EXAMPLES): %: %.c $(STATIC)
 	$(CC) $(CFLAGS) $< -o $@ $(STATIC)
 
+cluster: cluster.c $(STATIC)
+	$(CC) $(CFLAGS) $< -o $@ $(STATIC) $(shell pkg-config --cflags --libs cairo x11)
+
 view: view.c $(STATIC)
 	$(CC) $(CFLAGS) $< -o $@ $(STATIC) -lncurses
 

examples/cluster.c

@@ -0,0 +1,115 @@
+#include <X11/Xlib.h>
+#include <X11/Xatom.h>
+#include <X11/Xutil.h>
+#include <cairo.h>
+#include <cairo-xlib.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+static void redraw(cairo_surface_t *sfc, cairo_t *ctx) {
+    /*
+     * Paint canvas black
+     */
+    cairo_set_source_rgb(ctx, 0, 0, 0);
+    cairo_paint(ctx);
+
+    /*
+     * Draw two identical circles
+     */
+    cairo_set_source_rgb(ctx, 1, 1, 1);
+    cairo_arc(ctx, 208, 240, 192, 0, 360);
+    cairo_stroke(ctx);
+
+    cairo_arc(ctx, 816, 240, 192, 0, 360);
+    cairo_stroke(ctx);
+
+    /*
+     * Draw two smaller circles
+     */
+    cairo_arc(ctx, 442, 368, 64, 0, 360);
+    cairo_stroke(ctx);
+
+    cairo_arc(ctx, 578, 368, 64, 0, 360);
+    cairo_stroke(ctx);
+
+    /*
+     * Draw a rectangle
+     */
+    cairo_move_to(ctx, 432, 48);
+    cairo_line_to(ctx, 592, 48);
+    cairo_line_to(ctx, 592, 288);
+    cairo_line_to(ctx, 432, 288);
+    cairo_line_to(ctx, 432, 48);
+    cairo_stroke(ctx);
+}
+
+int main(int argc, char **argv) {
+    Display *display;
+    Window win;
+    Pixmap buf;
+    GC gc;
+
+    int screen, x = 1024, y = 480;
+
+    XGCValues values = {
+        .foreground         = 0x000000,
+        .background         = 0xffffff,
+        .graphics_exposures = 0
+    };
+
+    cairo_surface_t *sfc;
+    cairo_t *ctx;
+
+    XEvent e;
+
+    if ((display = XOpenDisplay(NULL)) == NULL)
+        exit(1);
+
+    screen = DefaultScreen(display);
+    win = XCreateSimpleWindow(display, DefaultRootWindow(display), 0, 0, x, y, 0, 0, 0);
+    gc  = XCreateGC(display, win, GCForeground | GCBackground | GCGraphicsExposures, &values);
+    buf = XCreatePixmap(display, win, x, y, 24);
+
+    XSelectInput(display, win, ExposureMask | ButtonPressMask | KeyPressMask);
+    XMapWindow(display, win);
+
+    sfc = cairo_xlib_surface_create(display, buf, DefaultVisual(display, screen), x, y);
+    cairo_xlib_surface_set_size(sfc, x, y);
+
+    ctx = cairo_create(sfc);
+
+    redraw(sfc, ctx);
+
+    while (1) {
+        XExposeEvent *expose;
+
+        XNextEvent(cairo_xlib_surface_get_display(sfc), &e);
+
+        switch (e.type) {
+            case Expose:
+                expose = (XExposeEvent *)&e;
+
+                XCopyArea(display, buf, win, gc, expose->x, expose->y,
+                          expose->width, expose->height,
+                          expose->x, expose->y);
+
+                break;
+                    
+            case ButtonPress:
+            case KeyPress:
+                goto done;
+
+            default:
+                fprintf(stderr, "Dropping unhandled XEvent.type = %d.\n", e.type);
+        }
+    }
+
+done:
+    cairo_destroy(ctx);
+
+    cairo_surface_destroy(sfc);
+    XCloseDisplay(display);
+
+    return 0;
+}