Gtk中的文本視圖(GtkTexView Widget)
在本章的Gtk+程序設計教程中,我們將重點介紹 GtkTexView 構件。
GtkTexView
w構件被常常用來顯示和編輯多行的文本。正如我們一再提到的, GtkTexBuffer
構件也是給予MVC的設計。GtkTextView 就是顯示(view)元素而 GtkTexBuffer 則代表了model 元素。 GtkTexBuffer 常常被用來處理文本數據。GtkTextTag
則是一種被用於文本的屬性。 GtkTextIter
則是代表了兩個字符之間的空隙。那麼很好理解,文本的排版操作多用iterators。
簡單的例子(Simple example)
在我們的第一個例子中,我們將向大家展示GtkTexView 的一些功能。我們還將教大家怎麼樣去應用各種各樣的文本標記( tags )。
#include <gtk/gtk.h> int main( int argc, char *argv[]) { GtkWidget *window; GtkWidget *view; GtkWidget *vbox; GtkTextBuffer *buffer; GtkTextIter start, end; GtkTextIter iter; gtk_init(&argc, &argv); window = gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER); gtk_window_set_default_size(GTK_WINDOW(window), 250, 200); gtk_window_set_title(GTK_WINDOW(window), "TextView"); gtk_container_set_border_width(GTK_CONTAINER(window), 5); GTK_WINDOW(window)->allow_shrink = TRUE; vbox = gtk_vbox_new(FALSE, 0); view = gtk_text_view_new(); gtk_box_pack_start(GTK_BOX(vbox), view, TRUE, TRUE, 0); buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(view)); gtk_text_buffer_create_tag(buffer, "gap", "pixels_above_lines", 30, NULL); gtk_text_buffer_create_tag(buffer, "lmarg", "left_margin", 5, NULL); gtk_text_buffer_create_tag(buffer, "blue_fg", "foreground", "blue", NULL); gtk_text_buffer_create_tag(buffer, "gray_bg", "background", "gray", NULL); gtk_text_buffer_create_tag(buffer, "italic", "style", PANGO_STYLE_ITALIC, NULL); gtk_text_buffer_create_tag(buffer, "bold", "weight", PANGO_WEIGHT_BOLD, NULL); gtk_text_buffer_get_iter_at_offset(buffer, &iter, 0); gtk_text_buffer_insert(buffer, &iter, "Plain text\n", -1); gtk_text_buffer_insert_with_tags_by_name(buffer, &iter, "Colored Text\n", -1, "blue_fg", "lmarg", NULL); gtk_text_buffer_insert_with_tags_by_name (buffer, &iter, "Text with colored background\n", -1, "lmarg", "gray_bg", NULL); gtk_text_buffer_insert_with_tags_by_name (buffer, &iter, "Text in italics\n", -1, "italic", "lmarg", NULL); gtk_text_buffer_insert_with_tags_by_name (buffer, &iter, "Bold text\n", -1, "bold", "lmarg", NULL); gtk_container_add(GTK_CONTAINER(window), vbox); g_signal_connect_swapped(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), G_OBJECT(window)); gtk_widget_show_all(window); gtk_main(); return 0; }
這個例子展示瞭如何利用各種各樣的文本標記( GtkTextTags
)來顯示文本。
view = gtk_text_view_new();
生成一個GtkTextView
。
gtk_text_buffer_create_tag(buffer, "blue_fg", "foreground", "blue", NULL);
這就是一個運用 GtkTextTag
的例子,這個標記改變了文本的顏色。
gtk_text_buffer_insert_with_tags_by_name(buffer, &iter, "Colored Text\n", -1, "blue_fg", "lmarg", NULL);
這個代碼插入了一些文本,並運用了一個特殊的文本標記blue_fg
。
行和欄(Lines and Columns)
在接下來的示例中將要顯示文本編輯光標目前處於的行數和列數。
#include <gtk/gtk.h> update_statusbar(GtkTextBuffer *buffer, GtkStatusbar *statusbar) { gchar *msg; gint row, col; GtkTextIter iter; gtk_statusbar_pop(statusbar, 0); gtk_text_buffer_get_iter_at_mark(buffer, &iter, gtk_text_buffer_get_insert(buffer)); row = gtk_text_iter_get_line(&iter); col = gtk_text_iter_get_line_offset(&iter); msg = g_strdup_printf("Col %d Ln %d", col+1, row+1); gtk_statusbar_push(statusbar, 0, msg); g_free(msg); } static void mark_set_callback(GtkTextBuffer *buffer, const GtkTextIter *new_location, GtkTextMark *mark, gpointer data) { update_statusbar(buffer, GTK_STATUSBAR(data)); } int main( int argc, char *argv[]) { GtkWidget *window; GtkWidget *vbox; GtkWidget *toolbar; GtkWidget *view; GtkWidget *statusbar; GtkToolItem *exit; GtkTextBuffer *buffer; gtk_init(&argc, &argv); window = gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER); gtk_window_set_default_size(GTK_WINDOW(window), 250, 200); gtk_window_set_title(GTK_WINDOW(window), "lines & cols"); vbox = gtk_vbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(window), vbox); toolbar = gtk_toolbar_new(); gtk_toolbar_set_style(GTK_TOOLBAR(toolbar), GTK_TOOLBAR_ICONS); exit = gtk_tool_button_new_from_stock(GTK_STOCK_QUIT); gtk_toolbar_insert(GTK_TOOLBAR(toolbar), exit, -1); gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 5); view = gtk_text_view_new(); gtk_box_pack_start(GTK_BOX(vbox), view, TRUE, TRUE, 0); gtk_widget_grab_focus(view); buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(view)); statusbar = gtk_statusbar_new(); gtk_box_pack_start(GTK_BOX(vbox), statusbar, FALSE, FALSE, 0); g_signal_connect(G_OBJECT(exit), "clicked", G_CALLBACK(gtk_main_quit), NULL); g_signal_connect(buffer, "changed", G_CALLBACK(update_statusbar), statusbar); g_signal_connect_object(buffer, "mark_set", G_CALLBACK(mark_set_callback), statusbar, 0); g_signal_connect_swapped(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL); gtk_widget_show_all(window); update_statusbar(buffer, GTK_STATUSBAR (statusbar)); gtk_main(); return 0; }
在上面的代碼示例中,我們完成了在狀態欄中顯示當前文本編輯光標所處於的行和列數。
view = gtk_text_view_new();
生成一了 GtkTextView
構件。
g_signal_connect(buffer, "changed", G_CALLBACK(update_statusbar), statusbar);
如果我們要更改文本,我們只需要調用回調函數 update_statusbar()
就可以了。
g_signal_connect_object(buffer, "mark_set", G_CALLBACK(mark_set_callback), statusbar, 0);
當光標在移動的時候, mark_set
信號就被髮射出去了。
gtk_statusbar_pop(statusbar, 0);
這段代碼功能是清除了先前的任何一些狀態欄中的信息。
gtk_text_buffer_get_iter_at_mark(buffer, &iter, gtk_text_buffer_get_insert(buffer)); row = gtk_text_iter_get_line(&iter); col = gtk_text_iter_get_line_offset(&iter);
顯然上面的代碼是在獲取當前所處於的行號與列號。
msg = g_strdup_printf("Col %d Ln %d", col+1, row+1);
上面的代碼準備好,狀態欄中顯示出來的行號與列號的內容。
gtk_statusbar_push(statusbar, 0, msg);
然後,我們就在狀態欄上顯示文本。
監測& 突顯(Search & Highlight)
在接下來的例子中,我們將要在 GtkTextBuffer
中做一些監測的工作。我們還將把一些文本的內容進行“突顯”處理。
#include <gtk/gtk.h> #include <gdk/gdkkeysyms.h> gboolean key_pressed(GtkWidget * window, GdkEventKey* event, GtkTextBuffer *buffer) { GtkTextIter start_sel, end_sel; GtkTextIter start_find, end_find; GtkTextIter start_match, end_match; gboolean selected; gchar *text; if ((event->type == GDK_KEY_PRESS) && (event->state & GDK_CONTROL_MASK)) { switch (event->keyval) { case GDK_m : selected = gtk_text_buffer_get_selection_bounds(buffer, &start_sel, &end_sel); if (selected) { gtk_text_buffer_get_start_iter(buffer, &start_find); gtk_text_buffer_get_end_iter(buffer, &end_find); gtk_text_buffer_remove_tag_by_name(buffer, "gray_bg", &start_find, &end_find); text = (char *) gtk_text_buffer_get_text(buffer, &start_sel, &end_sel, FALSE); while ( gtk_text_iter_forward_search(&start_find, text, GTK_TEXT_SEARCH_TEXT_ONLY | GTK_TEXT_SEARCH_VISIBLE_ONLY, &start_match, &end_match, NULL) ) { gtk_text_buffer_apply_tag_by_name(buffer, "gray_bg", &start_match, &end_match); int offset = gtk_text_iter_get_offset(&end_match); gtk_text_buffer_get_iter_at_offset(buffer, &start_find, offset); } g_free(text); } break; case GDK_r: gtk_text_buffer_get_start_iter(buffer, &start_find); gtk_text_buffer_get_end_iter(buffer, &end_find); gtk_text_buffer_remove_tag_by_name(buffer, "gray_bg", &start_find, &end_find); break; } } return FALSE; } int main( int argc, char *argv[]) { GtkWidget *window; GtkWidget *view; GtkWidget *vbox; GtkTextBuffer *buffer; GtkTextIter start, end; GtkTextIter iter; gtk_init(&argc, &argv); window = gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER); gtk_window_set_default_size(GTK_WINDOW(window), 250, 200); gtk_window_set_title(GTK_WINDOW(window), "Search & Highlight"); gtk_container_set_border_width(GTK_CONTAINER(window), 5); GTK_WINDOW(window)->allow_shrink = TRUE; vbox = gtk_vbox_new(FALSE, 0); view = gtk_text_view_new(); gtk_widget_add_events(view, GDK_BUTTON_PRESS_MASK); gtk_box_pack_start(GTK_BOX(vbox), view, TRUE, TRUE, 0); buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(view)); gtk_text_buffer_create_tag(buffer, "gray_bg", "background", "gray", NULL); gtk_container_add(GTK_CONTAINER(window), vbox); g_signal_connect_swapped(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), G_OBJECT(window)); g_signal_connect(G_OBJECT(window), "key-press-event", G_CALLBACK(key_pressed), buffer); gtk_widget_show_all(window); gtk_main(); return 0; }
在我們的示例中,我們用到了鍵盤的快捷鍵。Ctrl + M 是用來突顯我們當前所選取的文本內容。Ctrl + R 則是用來取消上面的操作。
gtk_text_buffer_create_tag(buffer, "gray_bg", "background", "gray", NULL);
我們在例子中會再次用到 GtkTextTag
。這個標記可以使文本的背景反白。
selected = gtk_text_buffer_get_selection_bounds(buffer, &start_sel, &end_sel);
這裏我們得到我們選中的文本所具有的起始和終點位置。
gtk_text_buffer_get_start_iter(buffer, &start_find); gtk_text_buffer_get_end_iter(buffer, &end_find);
我們得到了文本緩衝區(text buffer)的起始和終點位置。
gtk_text_buffer_remove_tag_by_name(buffer, "gray_bg", &start_find, &end_find);
上面就是,把先前的標記去處。
text = (char *) gtk_text_buffer_get_text(buffer, &start_sel, &end_sel, FALSE);
接着我們得到了所選擇的文本內容,我們將要進行監測。
while ( gtk_text_iter_forward_search(&start_find, text, GTK_TEXT_SEARCH_TEXT_ONLY | GTK_TEXT_SEARCH_VISIBLE_ONLY, &start_match, &end_match, NULL) ) { gtk_text_buffer_apply_tag_by_name(buffer, "gray_bg", &start_match, &end_match); int offset = gtk_text_iter_get_offset(&end_match); gtk_text_buffer_get_iter_at_offset(buffer, &start_find, offset); }
這段代碼將檢測所有我們所選擇的文本後的所發生的事件,一旦發現與我們定義的內容有匹配就應用我們設定好的標記。在匹配工作完成之後,單詞的尾端將將被成下次監視操作的首端。