C语言实现生成新春福字的示例详解

#define FONT_DISPLAY "福"

 // g_fu_label中的每一个控件都是一个福字
static GtkWidget *g_fu_label[3][3];

// 记录所有的字体family
typedef struct {
    int n_faces;
    PangoFontFace **faces;
}custom_PangoFontFace_t;

//字体family 的总数
static int n_families=0;

//当前正在使用的family 字体的索引
static int family_id=0;

// 记录每个字体family中的face（字模）
static custom_PangoFontFace_t *custom_PangoFontFace;

static void
change_fu_cb(GtkButton *button , gpointer user_data)
{
    char *markup_fu_str = NULL;
    
    // 3*3 的矩阵中一共有9个福字，分别设置每个福字的字体
    for(int i=0;i<3;++i)
    {
        for(int j=0;j<3;++j)
        {
    		// 获取当前family中的下一个字模，如果当前family中的字模都是用了，自动更新family_id 指向下一个family
            if(family_id >= n_families) family_id=0;
            if(++face_id >= custom_PangoFontFace[family_id].n_faces){
                ++family_id;
                if(family_id >= n_families)
                    family_id=0;
                
                face_id = 0;
            }
            
            
            markup_fu_str = g_markup_printf_escaped("<span font-weight=\"Bold\" font_desc=\"%s 99\">%s</span>",
                    pango_font_description_to_string(pango_font_face_describe(custom_PangoFontFace[family_id].faces[0])),
                    FONT_DISPLAY);
            
            gtk_label_set_markup(GTK_LABEL(g_fu_label[i][j]),markup_fu_str);
    
            g_free(markup_fu_str);
        }
    }
}

static void
activate (GtkApplication* app,
          gpointer user_data)
{
    GtkWidget *window;
    GtkWidget *mainGrid;
    GtkWidget *overlay;
    GtkWidget *picture;
	GtkCssProvider *cssProvider;
	const char *cssMainGrid = "grid {background-color:#ed3c43;}";
	const char *cssButton = "* {background-color:#FF0000;}";
	PangoFontMap *pangoFontMap;
	GtkWidget *box;
	GtkWidget *button;
	
    window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), "");
    gtk_window_set_default_size (GTK_WINDOW (window), 900, 900);
    
    mainGrid = gtk_grid_new();
    gtk_widget_set_hexpand(mainGrid,TRUE);
    gtk_widget_set_vexpand(mainGrid,TRUE);
    
    box = gtk_box_new(GTK_ORIENTATION_VERTICAL,0);
    gtk_widget_set_hexpand(box,TRUE);
    gtk_widget_set_vexpand(box,TRUE);
    gtk_box_append(GTK_BOX(box),mainGrid);
    
    button = gtk_button_new_with_label("换一批");
    gtk_widget_set_hexpand(button,TRUE);
    gtk_widget_set_vexpand(button,TRUE);
    cssProvider = gtk_css_provider_new();
    gtk_css_provider_load_from_data(GTK_CSS_PROVIDER(cssProvider),
                                    cssButton,
                                    -1);
    gtk_style_context_add_provider(gtk_widget_get_style_context(button),
            GTK_STYLE_PROVIDER(cssProvider),
            GTK_STYLE_PROVIDER_PRIORITY_USER);
    gtk_style_context_add_provider(gtk_widget_get_style_context(gtk_widget_get_first_child(button)),
                                   GTK_STYLE_PROVIDER(cssProvider),
                                   GTK_STYLE_PROVIDER_PRIORITY_USER);
    g_object_unref(cssProvider);
    g_signal_connect(button,"clicked",G_CALLBACK(change_fu_cb),NULL);
    gtk_box_append(GTK_BOX(box),button);
    
    gtk_window_set_child(GTK_WINDOW(window),box);
    
    cssProvider = gtk_css_provider_new();
    gtk_css_provider_load_from_data(GTK_CSS_PROVIDER(cssProvider),
                                    cssMainGrid,
                                    -1);
    gtk_style_context_add_provider(gtk_widget_get_style_context(mainGrid),
            GTK_STYLE_PROVIDER(cssProvider),
            GTK_STYLE_PROVIDER_PRIORITY_USER);
    g_object_unref(cssProvider);
    
    
    //获取当前系统中可用的字体 family
    PangoFontFamily **families;
    pangoFontMap = pango_cairo_font_map_get_default();
    pango_font_map_list_families(pangoFontMap,&families,&n_families);
    
    custom_PangoFontFace = (custom_PangoFontFace_t *)g_malloc0(n_families*sizeof(custom_PangoFontFace_t));
    
    for(int i=0;i<n_families;++i)
    {
    	//获取每个字体 family 中可用的face
        pango_font_family_list_faces(families[i],
                &custom_PangoFontFace[i].faces,
                &custom_PangoFontFace[i].n_faces);
    }
    g_free(families);
    
    // 初始化每个福字控件
    for(int i=0;i<3;++i)
    {
        for(int j=0;j<3;++j)
        {
            overlay = gtk_overlay_new();
            gtk_widget_set_hexpand(overlay,TRUE);
            gtk_widget_set_vexpand(overlay,TRUE);
            
            // 福字的背景图，需要放在执行程序所在的目录
            picture = gtk_picture_new_for_filename("./fu.png");
            gtk_widget_set_hexpand(picture,TRUE);
            gtk_widget_set_vexpand(picture,TRUE);
            
            g_fu_label[i][j] = gtk_label_new("");
            gtk_widget_set_hexpand(g_fu_label[i][j],TRUE);
            gtk_widget_set_vexpand(g_fu_label[i][j],TRUE);
            
            gtk_overlay_set_child(GTK_OVERLAY(overlay),picture);
            gtk_overlay_add_overlay(GTK_OVERLAY(overlay),g_fu_label[i][j]);
            
            gtk_grid_attach(GTK_GRID(mainGrid),overlay,i,j,1,1);
        }
    }
    
    //初始化福字
    change_fu_cb(GTK_BUTTON(button) , NULL);
    
    gtk_window_set_resizable(GTK_WINDOW(window),FALSE);
    gtk_widget_show (window);
}

int
main(int argc, char *argv[])
{
    GtkApplication *app;
    int status;

    app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
    
    status = g_application_run (G_APPLICATION (app), argc, argv);
    g_object_unref (app);
    
    //释放资源
    for(int i=0;i<n_families;++i){
        g_free(custom_PangoFontFace[i].faces);
    }
    g_free(custom_PangoFontFace);

    return status;
}