(1)編譯
$ gcc gtk_scrolling_canvas.c -Wall `pkg-config --cflags --libs gtk+-3.0` -export-dynamic -lm -o gtk_scrolling_canvas
(2a)執行
$ ./gtk_scrolling_canvas trkmap.jpg
map=trkmap.jpg
keyval=32
SPACE KEY PRESSED!
scwin minh=10.00, minw=10.00 vcurrent=1906.20 vupper=3804.00 vlower=0.00 v_step_inc=76.60 v_page_inc=689.40 v_page_size=766.00 v_min_inc=76.60
:
:
keyval=65453
KEY - PRESSED!
keyval=65451
KEY + PRESSED!
:
CTRL+HOME KEY PRESSED!
keyval=65367
CTRL+END KEY PRESSED!
keyval=65360
CTRL+HOME KEY PRESSED!
keyval=65367
CTRL+END KEY PRESSED!
keyval=65360
CTRL+HOME KEY PRESSED!
keyval=65506
keyval=65360
:
SHIFT+HOME KEY PRESSED!
keyval=65514
:
keyval=115
keyval=98
ALT+b KEY PRESSED!
(2b)畫面
(3)程式碼：
http://lfwiki.kmvs.km.edu.tw/lf/index.php?op=ViewResource&blogId=70&resource=gtk_scrolling_canvas.c
treehrt@hrt:~/mysqlc/gtk$ cat gtk_scrolling_canvas.c
// $ gcc gtk_scrolling_canvas.c -Wall `pkg-config --cflags --libs gtk+-3.0` -export-dynamic -lm -o gtk_scrolling_canvas
// $ ./gtk_scrolling_canvas trkmap.jpg
#include <gtk/gtk.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include <cairo.h>
#include <math.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
static double rab=1;
GtkWidget *window;
GtkWidget *scwin;
GtkWidget *canvas;
GdkPixbuf *pix,*pixC;
char fname[100];
static gboolean on_window_draw (GtkWidget *da, GdkEvent *event, gpointer data)
{
(void)event; (void)data;
cairo_t *cr;
cr = gdk_cairo_create (gtk_widget_get_window(da));
gdk_cairo_set_source_pixbuf(cr, pixC, 0, 0);
cairo_paint(cr);
cairo_destroy (cr);
return TRUE;
}
void showPixbuf(GdkPixbuf *p){
cairo_t *cr;
cr = gdk_cairo_create (gtk_widget_get_window(canvas));
gdk_cairo_set_source_pixbuf(cr, p, 0, 0);
cairo_paint(cr);
cairo_destroy (cr);
}
gboolean on_key_press (GtkWidget *widget, GdkEventKey *event, gpointer data) {
printf("keyval=%d\n",event->keyval);
if ((event->keyval == 65360) && (event->state & GDK_SHIFT_MASK)){
printf("SHIFT+HOME KEY PRESSED!\n");
return TRUE;
}
if ((event->keyval == 65360) && (event->state & GDK_CONTROL_MASK)){
printf("CTRL+HOME KEY PRESSED!\n");
return TRUE;
}
if ((event->keyval == 65367) && (event->state & GDK_CONTROL_MASK)){
printf("CTRL+END KEY PRESSED!\n");
return TRUE;
}
if ((event->keyval == 'a') && (event->state & GDK_CONTROL_MASK)){
printf("CTRL+a KEY PRESSED!\n");
return TRUE;
}
if ((event->keyval == 'b') && (event->state & GDK_MOD1_MASK)){
printf("ALT+b KEY PRESSED!\n");
return TRUE;
}
if (event->keyval == GDK_KEY_space){
gtk_scrolled_window_set_min_content_width(GTK_SCROLLED_WINDOW(scwin),10*rab);
gtk_scrolled_window_set_min_content_height(GTK_SCROLLED_WINDOW(scwin),10*rab);
printf("SPACE KEY PRESSED!\n");
double scwin_minh=gtk_scrolled_window_get_min_content_height(GTK_SCROLLED_WINDOW(scwin));
double scwin_minw=gtk_scrolled_window_get_min_content_width(GTK_SCROLLED_WINDOW(scwin));
GtkAdjustment *vad=gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scwin));
printf("scwin minh=%.2f, minw=%.2lf vcurrent=%.2lf vupper=%.2lf vlower=%.2lf v_step_inc=%.2lf v_page_inc=%.2lf v_page_size=%.2lf v_min_inc=%.2lf\n",
scwin_minh,scwin_minw,
gtk_adjustment_get_value(vad),
gtk_adjustment_get_upper(vad),
gtk_adjustment_get_lower(vad),
gtk_adjustment_get_step_increment(vad),
gtk_adjustment_get_page_increment(vad),
gtk_adjustment_get_page_size(vad),
gtk_adjustment_get_minimum_increment(vad)
);
return TRUE;
}
if (event->keyval == GDK_KEY_KP_Add){
rab=rab*1.01;
printf("KEY + PRESSED!\n");
int zw=gdk_pixbuf_get_width(pix)*rab;
int zh=gdk_pixbuf_get_height(pix)*rab;
g_object_unref(pixC);
pixC=gdk_pixbuf_scale_simple(pix,zw,zh, GDK_INTERP_BILINEAR);
showPixbuf(pixC);
return TRUE;
}
if (event->keyval == GDK_KEY_KP_Subtract){
rab=rab*0.99;
printf("KEY - PRESSED!\n");
int zw=gdk_pixbuf_get_width(pix)*rab;
int zh=gdk_pixbuf_get_height(pix)*rab;
g_object_unref(pixC);
pixC=gdk_pixbuf_scale_simple(pix,zw,zh, GDK_INTERP_BILINEAR);
showPixbuf(pixC);
return TRUE;
}
return FALSE;
}
int main (int argc, char *argv[])
{
if (argc != 2) {
g_print("Syntax Example : ./a.out a.jpg");
exit(-1);
}
strcpy(fname,argv[1]);
g_print("map=%s \n",fname);
GtkWidget *center_vbox;
gtk_init (&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_widget_add_events(window, GDK_KEY_PRESS_MASK);
center_vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
GError *err = NULL;
pix = gdk_pixbuf_new_from_file(fname, &err);
pixC = gdk_pixbuf_new_from_file(fname, &err);
if(err)
{
printf("Error : %s\n", err->message);
g_error_free(err);
return FALSE;
}
int w=gdk_pixbuf_get_width(pix);
int h=gdk_pixbuf_get_height(pix);
canvas = gtk_drawing_area_new ();
scwin = gtk_scrolled_window_new(NULL, NULL);
gtk_container_add(GTK_CONTAINER(scwin), canvas);
gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scwin), GTK_POLICY_AUTOMATIC, GTK_POLICY_ALWAYS);
gtk_box_pack_start(GTK_BOX(center_vbox), scwin, TRUE, TRUE, 1);
gtk_widget_add_events(window, GDK_BUTTON_PRESS_MASK);
gtk_widget_add_events(canvas, GDK_BUTTON_PRESS_MASK);
g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit) , NULL);
g_signal_connect (G_OBJECT (window), "key_press_event", G_CALLBACK (on_key_press), NULL);
g_signal_connect (canvas, "draw", (GCallback) on_window_draw, NULL);
gtk_widget_set_app_paintable(canvas, TRUE);
gtk_container_add (GTK_CONTAINER (window), center_vbox);
gtk_widget_set_size_request (window, 1024,768);
gtk_widget_set_size_request (center_vbox, 1020,760);
gtk_widget_set_size_request (canvas, w,h);
gtk_widget_show_all (window);
gtk_main();
return 0;
}