gtkmm drawing single pixels

Question

Refering to the example on the Documentation for Gtkmms GdkRGB:

#include <gtk/gtk.h>
#define IMAGE_WIDTH 256
#define IMAGE_HEIGHT    256
guchar rgbbuf[IMAGE_WIDTH * IMAGE_HEIGHT * 3];
gboolean on_darea_expose (GtkWidget *widget,
          GdkEventExpose *event,
          gpointer user_data);
int
main (int argc, char *argv[])
{
  GtkWidget *window, *darea;
  gint x, y;
  guchar *pos;
  gtk_init (&argc, &argv);
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  darea = gtk_drawing_area_new ();
  gtk_widget_set_size_request (darea, IMAGE_WIDTH, IMAGE_HEIGHT);
  gtk_container_add (GTK_CONTAINER (window), darea);
  gtk_signal_connect (GTK_OBJECT (darea), "expose-event",
                  GTK_SIGNAL_FUNC (on_darea_expose), NULL);
  gtk_widget_show_all (window);
  /* Set up the RGB buffer. */
  pos = rgbbuf;
  for (y = 0; y < IMAGE_HEIGHT; y++)
    {
      for (x = 0; x < IMAGE_WIDTH; x++)
    {
      *pos++ = x - x % 32;          /* Red. */
      *pos++ = (x / 32) * 4 + y - y % 32;   /* Green. */
      *pos++ = y - y % 32;          /* Blue. */
    }
    }
  gtk_main ();
  return 0;
}
gboolean
on_darea_expose (GtkWidget *widget,
     GdkEventExpose *event,
     gpointer user_data)
{
  gdk_draw_rgb_image (widget->window, widget->style->fg_gc[GTK_STATE_NORMAL],
          0, 0, IMAGE_WIDTH, IMAGE_HEIGHT,
          GDK_RGB_DITHER_MAX, rgbbuf, IMAGE_WIDTH * 3);
  return TRUE;
}

But they say that "gdk_draw_rgb_image is deprecated and should not be used in newly-written code."

I would like to have an image in an array of pixels, where I can directly manipulate the pixels.

Basically, I just would like to "draw" an array of pixels I would like to modify before. Cairo is a nice tool, but not suitable for my purpose. Therefore, rectangle is not an option.

Isn't this possible anymore?

Well, the example I mentioned before works, but I prefer not to use deprecated libraries for new code.

How else can I draw my pixels then? And this is a gtk example. We're using GtkMM and I would like to know whether there's an equivalent to this.

Many Thanks and best regards

score 2 · Accepted Answer · answered Nov 05 '11 at 10:58

2

You have to use cairo.

All GDK drawing functions are deprecated and removed in GDK 3.

You can use a GdkPixbuf http://developer.gnome.org/gdk-pixbuf/unstable//gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf with Cairo interaction functions gdk_cairo_set_source_pixbuf and gdk_cairo_rectangle http://developer.gnome.org/gdk3/stable/gdk3-Cairo-Interaction.html.

answered Nov 05 '11 at 10:58

chill

16,470
2
40
44

this might work well in gtk, but in cairomm, there's no method called `set_source_*` in `Cairo::Context` taking a Pixbuf as argument. – Atmocreations Nov 09 '11 at 08:00
1

@Atmocreations, In cairomm, use can use `Cairo::Context::set_source` with a `Cairo::SurfacePattern` wrapped around `Cairo::ImageSurface`. – chill Nov 09 '11 at 08:34

score 0 · Answer 2 · answered Jan 29 '18 at 07:37

0

You can build your own "put_pixels(...)" function like discribed here. You will need to operate on the pixel-buffer.

I also used this approach.

answered Jan 29 '18 at 07:37

ArchLinuxTux

840
1
11
28

gtkmm drawing single pixels

2 Answers2

Linked