gdk_put_image() and ColorMap

["John Que" <qwejohn hotmail com>]

Hello ,
I have an X application which displays an XImgae instance.

This instance is created thus:
.....
XImage* image=  XCreateImage(dpy, visual, depth,
                                                                                                ZPixmap, 0, 
(char*)0, w, h, 8, 0);

Now , I do display this image correctly using XLib app (without gtk).

I should port this to gtk/gdk.

I read the documentation from gtk website and also from
gnome web site.
There are many explanations there but not many example (at least not
reagarding displaying images).


So I tried the following little "C" app;
This app reads a raw file (which was created from the Xlib application
that works) and tries to display it (after the user press
the button on the widget) using gtk (with gdk_new_image()
and gdk_draw_image();

Now in fact what happens after the user press
the button on the widget is that I can see a picture that has resemblance to
the original, but the colors are badly wrong (much more pale) and in fact 
this
result is not satisiable.

I assume it has to do with setting colormap or Visual or Graphic Conext.

(BTW: I am using gtk 1.2 (for legacy reasons) but my question will probably
stays the same also for gtk-2.)


Any help will be welcome.


// test.c

#include <gtk/gtk.h>
#include <gdk/gdk.h>
#include <gdk/gdkx.h>
#include <stdio.h>

//////////////////////////////////////////////////////////////////////////////

static void destroy(GtkWidget* widget,gpointer data)
        {
        gtk_main_quit();
        }


//////////////////////////////////////////////////////////////////////////////

static void hello(GtkWidget* window,
                                                            gpointer data)
        {
        g_print("IN TEST\n");
        int x,y;
        FILE* in;
        int max_frame_size = 202752;
        char* frame = NULL;

        GdkImage* image = NULL;
        char c;
        GdkWindowAttr attrs;
        GdkImage* gdkImage                = NULL;

        attrs.visual = gtk_widget_get_visual(window);

        gdkImage = gdk_image_new(GDK_IMAGE_NORMAL,
                                                                                                         
attrs.visual,
                                                                                                         352,
                                                                                                         288);

        // reading raw data which was created by an XWindows app
        // from file
        in = fopen("outvw.rgb","rb");
        frame = (char*)malloc(max_frame_size);
        fread(frame, 1, max_frame_size, in);
        fclose(in);

        for (y=0; y<288; y++)
                for (x = 0; x < 352; x++)
                        {
                        c = frame[352*y+x];
                        gdk_image_put_pixel(gdkImage,
                                                                                                x,
                                                                                                        y,
                                                                                                        c);
                        }

	gdk_draw_image( window->window, window->style->fg_gc[0], gdkImage, 0, 0, 0, 
0, 388, 252 );

        printf("after gdk_draw_image\n");

        getchar();
        }

//////////////////////////////////////////////////////////////////////////////



int main(int argc,char* argv[])
        {
        GtkWidget* window;
        GdkWindowAttr attrs;
        GdkImage* gdkImage                = NULL;
        GdkVisual* visual       = NULL;
        GtkWidget* button;
        GdkGC* gc                                                       = NULL;
        int x,y;

        if (!gtk_init_check(&argc,&argv))
                {
                printf("couldn't gtk_init_check\n");
                }


        window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
        button = gtk_button_new_with_label("test");
//      gtk_widget_set_usize(GTK_WIDGET(button),30,30);
//      gdk_window_set_colormap(window->window, gdk_colormap_get_system ());

        gtk_signal_connect(GTK_OBJECT(button),
                                                      "clicked",
                                                                        GTK_SIGNAL_FUNC(hello),
                                                                        NULL);

        gtk_signal_connect(GTK_OBJECT(window),
                                                      "destroy",
                                                                        GTK_SIGNAL_FUNC(destroy),
                                                                        NULL);


        gtk_widget_set_usize(window,352,288);

        gtk_container_add(GTK_CONTAINER(window),button);


        gtk_widget_show(window);
        gtk_widget_show(button);

        gtk_main();
        }


regards,
John

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