Thanks, Eric. I must have arrived at my "fix" the same time you came up with your much more elegant fix. I did remove the sleep call. But my only other change was to change the line in the call back from h = allocation->height; to h = allocation->height * 0.75;
I realized I was resizing the image to the size of the entire window, which would trigger another resize, and another....etc. Limiting to height to 3/4 of the window stops it from growing out of control. But the image degrades quickly. But seeing your code with two call backs makes me think I need to try gtkmm, as I actually need 7 images in a notebook. If I could make a class with the resize defined, I would not need 7 nearly identical callback routines. On Thu, Aug 2, 2018 at 11:25 AM, <cecas...@aol.com> wrote: > > Hi Jack, > > There are some problem spots in your code. There is a > > g_signal_connect(window, "size-allocate", G_CALLBACK(resize_image), NULL); > > in a loop and the resize_image function doesn't match the documentation. > > https://developer.gnome.org/gtk3/stable/GtkWidget.html# > GtkWidget-size-allocate > > Careful with this because GTK doesn't always warn if you get your > callbacks setup incorrectly. Then you might end up with some weird bugs > that are hard to find in your code. You can change the names of the > parameters in the callback but you need to keep the parameter types, number > of parameters and return value the same as in the documentation. > > There is a sleep(2) that you don't need in there. > > g_strdup_printf() is safer and easier to use than sprintf with a buffer. > > I am not sure how you want to have the images resized. If you want to have > them resized with the main window that can be done. It is best if you get a > pixbuf and keep it around so you can always resize the "original". This > helps with reducing pixel loss. You could also use a drawing area, draw a > frame in it and use that to drag and reduce or enlarge an image. > > I gave it a try and may have a few mistakes myself. Maybe between the two > you can figure out a good working solution. > > Eric > > > /* > gcc -Wall image1.c -o image1 `pkg-config gtk+-3.0 --cflags --libs` > > Tested on Ubuntu16.04 with GTK3.18. > */ > > #include<gtk/gtk.h> > > static void resize_image1(GtkWidget *scroll1, GdkRectangle *allocation, > gpointer *data1) > { > g_print("Resize1\n"); > gdouble width=(gdouble)gdk_pixbuf_get_width((GdkPixbuf*)data1[1]); > gdouble height=(gdouble)gdk_pixbuf_get_height((GdkPixbuf*)data1[1]); > gdouble new_width=(gdouble)allocation->width; > gdouble new_height=new_width/(width/height); > > if(new_height>(allocation->height)) > { > new_height=(gdouble)allocation->height; > new_width=new_height/(height/width); > } > > GdkPixbuf *pxbscaled=gdk_pixbuf_scale_simple((GdkPixbuf*)data1[1], > (gint)new_width, (gint)new_height, GDK_INTERP_BILINEAR); > gtk_image_set_from_pixbuf(GTK_IMAGE(data1[0]), pxbscaled); > g_object_unref(pxbscaled); > } > static void resize_image2(GtkWidget *scroll, GdkRectangle *allocation, > gpointer *data2) > { > g_print("Resize2\n"); > gdouble width=(gdouble)gdk_pixbuf_get_width((GdkPixbuf*)data2[1]); > gdouble height=(gdouble)gdk_pixbuf_get_height((GdkPixbuf*)data2[1]); > gdouble new_width=(gdouble)allocation->width; > gdouble new_height=new_width/(width/height); > > if(new_height>(allocation->height)) > { > new_height=(gdouble)allocation->height; > new_width=new_height/(height/width); > } > > GdkPixbuf *pxbscaled=gdk_pixbuf_scale_simple((GdkPixbuf*)data2[1], > (gint)new_width, (gint)new_height, GDK_INTERP_BILINEAR); > gtk_image_set_from_pixbuf(GTK_IMAGE(data2[0]), pxbscaled); > g_object_unref(pxbscaled); > } > int main(int argc, char *argv[]) > { > gtk_init(&argc, &argv); > > GtkWidget *window=gtk_window_new (GTK_WINDOW_TOPLEVEL); > gtk_window_set_title(GTK_WINDOW(window), "Notebook"); > gtk_window_set_default_size(GTK_WINDOW(window), 500, 500); > gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER); > g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL); > > GdkPixbuf *pixbuf1=gdk_pixbuf_new_from_file_at_scale("image1.jpg", > 500, 500, TRUE, NULL); > GdkPixbuf *pixbuf2=gdk_pixbuf_new_from_file_at_scale("image2.jpg", > 500, 500, TRUE, NULL); > > GtkWidget *image1=gtk_image_new_from_pixbuf(pixbuf1); > gtk_widget_set_hexpand(image1, TRUE); > gtk_widget_set_vexpand(image1, TRUE); > > GtkWidget *scroll1=gtk_scrolled_window_new(NULL, NULL); > gtk_container_add(GTK_CONTAINER(scroll1), image1); > gpointer data1[]={image1, pixbuf1}; > g_signal_connect(scroll1, "size-allocate", G_CALLBACK(resize_image1), > data1); > > GtkWidget *grid1=gtk_grid_new(); > gtk_grid_attach(GTK_GRID(grid1), scroll1, 0, 0, 1, 1); > > GtkWidget *image2=gtk_image_new_from_pixbuf(pixbuf2); > gtk_widget_set_hexpand(image2, TRUE); > gtk_widget_set_vexpand(image2, TRUE); > > GtkWidget *scroll2=gtk_scrolled_window_new(NULL, NULL); > gtk_container_add(GTK_CONTAINER(scroll2), image2); > gpointer data2[]={image2, pixbuf2}; > g_signal_connect(scroll2, "size-allocate", G_CALLBACK(resize_image2), > data2); > > GtkWidget *grid2=gtk_grid_new(); > gtk_grid_attach(GTK_GRID(grid2), scroll2, 0, 0, 1, 1); > > GtkWidget *nb_label1=gtk_label_new("Page 1"); > GtkWidget *nb_label2=gtk_label_new("Page 2"); > GtkWidget *notebook=gtk_notebook_new(); > gtk_container_set_border_width(GTK_CONTAINER(notebook), 15); > gtk_notebook_append_page(GTK_NOTEBOOK(notebook), grid1, nb_label1); > gtk_notebook_append_page(GTK_NOTEBOOK(notebook), grid2, nb_label2); > > gtk_container_add(GTK_CONTAINER(window), notebook); > > gtk_widget_show_all(window); > > gtk_main(); > > g_object_unref(pixbuf1); > g_object_unref(pixbuf2); > > return 0; > } > > >
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