Cairo编程

一、简介

cairo 是一个免费的矢量绘图软件库，它可以绘制多种输出格式。cairo 支持许多平台，包括 Linux、BSD、Microsoft® Windows® 和 OSX（BeOS 和 OS2 后端也正在开发）。Linux 绘图可以通过 X Window 系统、Quartz、图像缓冲格式或 OpenGL 上下文来实现。另外，cairo 还支持生成 PostScript 或 PDF 输出，从而产生高质量的打印结果。在理想情况下，cairo 的用户可以在打印机和屏幕上获得非常接近的输出效果。

专业术语

 

1、环境 (Context)
使用 Cairo 绘图，必须要首先创建 Cairo 环境 (Context)。Cairo 环境保存着所有的图形状态参数，这些参数描述了图形的构成，譬如线条宽度、颜色、要绘制的外观 (Surface) 以及其它一些信息。Cairo 环境允许真正的绘图函数使用很少的一部分参数，以此提高接口的易用性。调用 gdk_cairo_create () 函数可为所绘制的图形创建一个 Cairo 环境。

cairo_t * cr;
cr = gdk_cairo_create (widget->window);

这两行代码创建了一个 Cairo 环境，并且这个 Cairo 环境是关联到 GdkDrawable 对象上的。cairo_t 结构体包含了当前渲染设备的状态，也包含了所绘制图形的坐标。从技术上来讲，cairo_t 就是所谓的 Cairo 环境。

Cairo 所有的绘图函数都要去操作 cairo_t 对象。一个 Cairo 环境可以被关联到一种特定的外观，譬如 pdf、svg、png、GdkDrawable 等。

GDK 没有对 Cairo API 进行封装，它只允许创建一个可基于 GdkDrawable 对象绘制图形的 Cairo 环境。有一些 GDK 函数可以将 GDK 的矩形或填充区域转换为 Cairo Path (路径)，然后使用 Cairo 绘图与渲染。

2、路径 (Path)
一条 Path（路径）通常是由一条或多条首尾相接的直线段构成的，也可以由直线段与曲线段构成。路径可分为 Open（开放）类型与 Closed（闭合）类型，前者的首尾端点不重合，后者的首尾端点重合。

在 Cairo 中，绘图要从一条空路径开始，首先定义一条路径，然后通过绘制/填充操作使之可见。要注意的是，每次调用 cairo_stroke () 或 cairo_fill () 函数之后，路径会被清空，不得不再定义新的路径。
一条路径可由一些子路径构成。

3、源 (Source)
源好比绘图中所使用的画笔/颜料，使用它来绘制/填充图形轮廓。有 4 种基本的源：color、gradient、pattern 与 image。

4、外观 (Surface)
Surface 就是要绘制图形的最终体现形式，譬如可使用 PDF 或 PostScript 外观实现文本内容的渲染，或者使用 Xlib、Win32 外观实现屏幕绘图。
Cairo 具体有那些外观类型，可参考其定义：

typedef enum _cairo_surface_type {
  CAIRO_SURFACE_TYPE_IMAGE,
  CAIRO_SURFACE_TYPE_PDF,
  CAIRO_SURFACE_TYPE_PS,
  CAIRO_SURFACE_TYPE_XLIB,
  CAIRO_SURFACE_TYPE_XCB,
  CAIRO_SURFACE_TYPE_GLITZ,
  CAIRO_SURFACE_TYPE_QUARTZ,
  CAIRO_SURFACE_TYPE_WIN32,
  CAIRO_SURFACE_TYPE_BEOS,
  CAIRO_SURFACE_TYPE_DIRECTFB,
  CAIRO_SURFACE_TYPE_SVG,
  CAIRO_SURFACE_TYPE_OS2
} cairo_surface_type_t;

5、蒙板 (Mask)
在源作用于外观之前，可对其实现过滤，蒙板 (mask) 即是过滤器。蒙板决定哪些源可被显示。蒙板不透明的部分允许复制源至外观，蒙板透明的部分则禁止复制源至外观。、

6、图案 (Pattern)
图案表示被绘制到外观的源。在 Cairo 中，图案是一种可以读取的内容，可用作绘图操作的源或蒙板。图案可以是纯色模式、基于外观的模式以及渐变模式。

 

 

二、编译与安装

参考：http://cairographics.org/download/

执行以下命令，即可完成安装

sudo yum install cairo-devel

如下图

三、编程

程序1：用于生成 PNG 图像

#include <cairo.h>

int main (int argc, char *argv[])
{
        cairo_surface_t *surface;
        cairo_t *cr;

        surface =cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 400, 800);
        cr = cairo_create (surface);

        cairo_set_source_rgb (cr, 1, 0, 0);
        cairo_rectangle(cr,0,0,400,800);

        cairo_fill(cr);

         cairo_select_font_face (cr, "Adobe Heiti Std", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
        cairo_set_font_size (cr, 30.0);

        cairo_move_to (cr, 100, 400);
        cairo_set_source_rgb (cr, 0, 1, 0);
        cairo_show_text (cr, "I Love Chinese !");

        cairo_surface_write_to_png (surface, "image.png");

        cairo_destroy (cr);
        cairo_surface_destroy (surface);

        return 0;
}

编译

gcc -o example-1.o example-1.c -lcairo -I/usr/include/cairo

运行

程序2：用于生成 PDF 图像

#include <cairo.h>
#include <cairo-pdf.h>

int main (int argc, char *argv[])
{
        cairo_surface_t *surface;
        cairo_t *cr;

        surface = cairo_pdf_surface_create ("pdffile.pdf", 20, 40);
        cr = cairo_create (surface);

        cairo_set_source_rgb (cr, 1, 0, 0);
        cairo_rectangle(cr,0,0,20,40);

        cairo_fill(cr);

         cairo_select_font_face (cr, "WenQuanYi Zen Hei", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
        cairo_set_font_size (cr, 5);

        cairo_move_to (cr, 0, 20);
        cairo_set_source_rgb (cr, 0, 1, 0);
        cairo_show_text (cr, "热爱编程");

        cairo_show_page (cr);

        cairo_destroy (cr);
        cairo_surface_destroy (surface);

        return 0;
}

编译

gcc -o example-2.o example-2.c -lcairo -I/usr/include/cairo

运行

程序3：用于生成 SVG 图像

#include <cairo.h>
#include <cairo-svg.h>

int main (int argc, char *argv[])
{
        cairo_surface_t *surface;
        cairo_t *cr;

        surface = cairo_svg_surface_create ("svgfile.svg", 20, 40);
        cr = cairo_create (surface);

        cairo_set_source_rgb (cr, 1, 0, 0);
        cairo_rectangle(cr,0,0,20,40);

        cairo_fill(cr);

         cairo_select_font_face (cr, "WenQuanYi Zen Hei", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
        cairo_set_font_size (cr, 5);

        cairo_move_to (cr, 0, 20);
        cairo_set_source_rgb (cr, 0, 1, 0);
        cairo_show_text (cr, "热爱编程");

        cairo_destroy (cr);
        cairo_surface_destroy (surface);

        return 0;
}

编译

gcc -o example-3.o example-3.c -lcairo -I/usr/include/cairo

运行

程序4：在 GTK 窗口中使用 Cairo 绘制图形

要在 GTK+ 窗口中绘制 Cairo 图形，可以使用 GtkDrawingArea widget 或者更为简单的 GtkWindow widget，本例选择 GtkWindow 。由 GtkWindow widget 对 expose-event 信号处理后，默认要重新绘制窗口背景，这会将我们在 on_expose_event () 函数中定义的 Cairo 图形覆盖掉，因此需要调用 gtk_widget_set_app_paintable () 函数通知 GTK+ 不要这么干。如果是在 GtkDrawingArea widget 中绘制 Cairo 图形，则可省区这一步。

#include <cairo.h>
#include <gtk/gtk.h>

static gboolean on_expose_event (GtkWidget * widget, GdkEventExpose * event, gpointer data)
{
    cairo_t *cr;

    cr = gdk_cairo_create (widget->window);

    cairo_set_source_rgb (cr, 0.627, 0, 0);
    cairo_select_font_face (cr, "WenQuanYi Zen Hei", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
    cairo_set_font_size (cr, 24.0);

    cairo_move_to (cr, 10.0, 34.0);
    cairo_show_text (cr, "编程艺术");

    cairo_destroy (cr);

    return FALSE;
}


int main (int argc, char *argv[])
{

    GtkWidget *window;

    gtk_init (&argc, &argv);

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

    g_signal_connect (window, "expose-event", G_CALLBACK (on_expose_event), NULL);
    g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

    gtk_window_set_position (GTK_WINDOW (window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size (GTK_WINDOW (window), 320, 48);
    gtk_widget_set_app_paintable (window, TRUE);

    gtk_widget_show_all (window);

    gtk_main ();

    return 0;
}

编译

gcc -o example-5.o example-5.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序5：绘制动态图形

#include <cairo.h>
#include <gtk/gtk.h>
#include <math.h>

cairo_surface_t *image;

static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;

    static gint pos_x = 128;
    static gint pos_y = 128;
    gint radius = 40;

    static gint delta[] = { 3, 3 };

    cr = gdk_cairo_create(widget->window);

    gint width, height;
    gtk_window_get_size(GTK_WINDOW(widget), &width, &height);

    if (pos_x < 0 + radius)
    {
        delta[0] = rand() % 4 + 5;
    }
    else if (pos_x > width - radius)
    {
        delta[0] = -(rand() % 4 + 5);
    }

    if (pos_y < 0 + radius)
    {
        delta[1] = rand() % 4 + 5;
    }
    else if (pos_y > height - radius)
    {
        delta[1] = -(rand() % 4 + 5);
    }

    pos_x += delta[0];
    pos_y += delta[1];

    cairo_set_source_surface(cr, image, 1, 1);
    cairo_arc(cr, pos_x, pos_y, radius, 0, 2*M_PI);
    cairo_clip(cr);
    cairo_paint(cr);

    cairo_destroy(cr);

    return FALSE;
}

static gboolean time_handler (GtkWidget *widget)
{
    if (widget->window == NULL) return FALSE;
    gtk_widget_queue_draw(widget);
    return TRUE;
}

int main(int argc, char *argv[])
{
    GtkWidget *window;
    gint width, height;

    image = cairo_image_surface_create_from_png("turnacastle.png");
    width = cairo_image_surface_get_width(image);
    height = cairo_image_surface_get_height(image);


    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(G_OBJECT(window), "expose-event", G_CALLBACK(on_expose_event), NULL);
    g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), width+2, height+2);

    gtk_widget_set_app_paintable(window, TRUE);
    gtk_widget_show_all(window);
    g_timeout_add(100, (GSourceFunc) time_handler, (gpointer) window);

    gtk_main();

    cairo_surface_destroy(image);

    return 0;
}

编译

gcc -o example-6.o example-6.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序6：相交区域处理示例

#include <cairo.h>
#include <gtk/gtk.h>
#include <math.h>

static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;
    cr = gdk_cairo_create(widget->window);

    static gboolean xdirection = TRUE;
    static gint counter = 0;

    int width, height;
    gtk_window_get_size(GTK_WINDOW(widget), &width, &height);

    static gdouble rotate = 0;

    static gint bigx = 20;
    static gint bigy = 200;
    static gint delta = 1;

    counter += 1;


    if (bigx > width)
    {
        xdirection = FALSE;
        delta = -delta;
        bigx = width;
    }

    if (bigx < 1)
    {
        bigx = 1;
        delta = -delta;
    }

    if (bigy > height)
    {
        xdirection = TRUE;
        delta = -delta;
        bigy = height;
    }

    if (bigy < 1)
    {
        delta = -delta;
        bigy = 1;
    }

    if (xdirection)
    {
        bigx += delta;
    }
    else
    {
        bigy += delta;
    }

    cairo_translate(cr, width / 2, height /2);

    cairo_rectangle(cr, -bigx/2, -bigy/2, bigx-2, bigy-2);
    cairo_set_source_rgb(cr, 0, 0, 0);
    cairo_set_line_width(cr, 1);
    cairo_stroke(cr);

    cairo_rotate(cr, rotate);
    rotate += 0.01;

    cairo_rectangle(cr, -50, -25, 100, 50);
    cairo_stroke(cr);

    GdkRectangle bigrect;
    GdkRectangle rect;
    GdkRectangle intersect;

    bigrect.x = -bigx/2;
    bigrect.y = -bigy/2;
    bigrect.width = bigx -2;
    bigrect.height = bigy -2;

    rect.x = -50;
    rect.y = -25;
    rect.width = 100;
    rect.height = 50;

    gdk_rectangle_intersect(&bigrect, &rect, &intersect);
    cairo_rectangle(cr, intersect.x, intersect.y, intersect.width, intersect.height);
    cairo_fill(cr);

    cairo_destroy(cr);

    return FALSE;
}

static gboolean time_handler (GtkWidget *widget)
{
    if (widget->window == NULL) return FALSE;
    gtk_widget_queue_draw(widget);
    return TRUE;
}

int main (int argc, char *argv[])
{

    GtkWidget *window;

    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(G_OBJECT(window), "expose-event", G_CALLBACK(on_expose_event), NULL);
    g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 250, 200);

    gtk_widget_set_app_paintable(window, TRUE);
    gtk_widget_show_all(window);
    g_timeout_add(5, (GSourceFunc) time_handler, (gpointer) window);

    gtk_main();

    return 0;
}

编译

gcc -o example-7.o example-7.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序7：遮蔽应用示例

#include <cairo.h>
#include <gtk/gtk.h>

static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;
    cairo_surface_t *surface;

    cr = gdk_cairo_create(widget->window);

    cairo_set_source_rgb(cr, 0, 0, 0);

    surface = cairo_image_surface_create_from_png("omen.png");
    cairo_mask_surface(cr, surface, 0, 0);
    cairo_fill(cr);

    cairo_surface_destroy(surface);
    cairo_destroy(cr);

    return FALSE;
}


int main(int argc, char *argv[])
{
    GtkWidget *window;

    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(G_OBJECT(window), "expose-event", G_CALLBACK(on_expose_event), NULL);
    g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 305, 100);

    gtk_window_set_title(GTK_WINDOW(window), "mask");
    gtk_widget_set_app_paintable(window, TRUE);
    gtk_widget_show_all(window);

    gtk_main();

    return 0;
}

编译

gcc -o example-8.o example-8.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序8：平移变换示例

#include <cairo.h>
#include <gtk/gtk.h>

static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;

    cr = gdk_cairo_create (widget->window);

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 20, 20, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);

    cairo_translate(cr, 100, 100);     //通过平移用于空间的原点来修改当前的变换矩阵

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 20, 20, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);

    cairo_destroy(cr);

    return FALSE;
}


int main(int argc, char *argv[])
{
    GtkWidget *window;

    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(window, "expose-event", G_CALLBACK (on_expose_event), NULL);
    g_signal_connect(window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 230);
    gtk_widget_set_app_paintable(window, TRUE);

    gtk_widget_show_all(window);

    gtk_main();

    return 0;
}

编译

gcc -o example-9.o example-9.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序9：旋转变换示例

#include <cairo.h>
#include <gtk/gtk.h>
#include <math.h>


static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;

    cr = gdk_cairo_create (widget->window);

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 20, 20, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);

    cairo_translate(cr, 150, 100);
    cairo_rotate(cr, M_PI/2);   //围绕原点旋转180°

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 20, 20, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);

    cairo_destroy(cr);

    return FALSE;
}


int main(int argc, char *argv[])
{
    GtkWidget *window;

    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(window, "expose-event", G_CALLBACK (on_expose_event), NULL);
    g_signal_connect(window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 230);
    gtk_widget_set_app_paintable(window, TRUE);

    gtk_widget_show_all(window);

    gtk_main();

    return 0;
}

编译

gcc -o example-10.o example-10.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序10：缩放变换示例

#include <cairo.h>
#include <gtk/gtk.h>


static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;

    cr = gdk_cairo_create (widget->window);

    cairo_save(cr);
    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 20, 30, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);
    cairo_restore(cr);

    cairo_save(cr);
    cairo_translate(cr, 130, 30);
    cairo_scale(cr, 0.7, 0.7);    //对图形进行缩小操作

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 0, 0, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);
    cairo_restore(cr);

    cairo_save(cr);
    cairo_translate(cr, 220, 30);
    cairo_scale(cr, 1.5, 1.5);    //对图形进行放大操作 

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 0, 0, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);
    cairo_restore(cr);

    cairo_destroy(cr);

    return FALSE;
}

int main(int argc, char *argv[])
{
    GtkWidget *window;

    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(window, "expose-event", G_CALLBACK (on_expose_event), NULL);
    g_signal_connect(window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 360, 140);
    gtk_widget_set_app_paintable(window, TRUE);

    gtk_widget_show_all(window);

    gtk_main();

    return 0;
}

编译

gcc -o example-11.o example-11.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行

程序11：错切变换示例

#include <cairo.h>
#include <gtk/gtk.h>


static gboolean on_expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    cairo_t *cr;
    cairo_matrix_t matrix;

    cr = gdk_cairo_create (widget->window);

    cairo_save(cr);
    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 20, 30, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);
    cairo_restore(cr);

    cairo_save(cr);
    cairo_translate(cr, 130, 30);
    cairo_matrix_init(&matrix,
                      1.0, 0.5,
                      0.0, 1.0,
                      0.0, 0.0);

    cairo_transform (cr, &matrix);

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 0, 0, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);
    cairo_restore(cr);

    cairo_save(cr);
    cairo_translate(cr, 220, 30);
    cairo_matrix_init(&matrix,
                      1.0, 0.0,
                      0.7, 1.0,
                      0.0, 0.0);

    cairo_transform(cr, &matrix);

    cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
    cairo_rectangle(cr, 0, 0, 80, 50);
    cairo_stroke_preserve(cr);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_fill(cr);
    cairo_restore(cr);

    cairo_destroy(cr);

    return FALSE;
}


int main(int argc, char *argv[])
{
    GtkWidget *window;

    gtk_init(&argc, &argv);

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(window, "expose-event", G_CALLBACK(on_expose_event), NULL);
    g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 360, 140);
    gtk_widget_set_app_paintable(window, TRUE);

    gtk_widget_show_all(window);

    gtk_main();

    return 0;
}

编译

gcc -o example-12.o example-12.c -lcairo -I/usr/include/cairo `pkg-config --cflags --libs gtk+-2.0`

运行