testpixbuf-save.c

Linux下gtk图形界面开发的各种gtk控件调用方法示例

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */

#include "config.h"
#include <stdio.h>

#include <gtk/gtk.h>

static void
compare_pixbufs (GdkPixbuf *pixbuf, GdkPixbuf *compare, const gchar *file_type)
{
        if ((gdk_pixbuf_get_width (pixbuf) !=
             gdk_pixbuf_get_width (compare)) ||
            (gdk_pixbuf_get_height (pixbuf) !=
             gdk_pixbuf_get_height (compare)) ||
            (gdk_pixbuf_get_n_channels (pixbuf) !=
             gdk_pixbuf_get_n_channels (compare)) ||
            (gdk_pixbuf_get_has_alpha (pixbuf) !=
             gdk_pixbuf_get_has_alpha (compare)) ||
            (gdk_pixbuf_get_bits_per_sample (pixbuf) !=
             gdk_pixbuf_get_bits_per_sample (compare))) {
                fprintf (stderr,
                         "saved %s file differs from copy in memory\n",
                         file_type);
        } else {
                guchar *orig_pixels;
                guchar *compare_pixels;
                gint    orig_rowstride;
                gint    compare_rowstride;
                gint    width;
                gint    height;
                gint    bytes_per_pixel;
                gint    x, y;
                guchar *p1, *p2;
                gint    count = 0;

                orig_pixels = gdk_pixbuf_get_pixels (pixbuf);
                compare_pixels = gdk_pixbuf_get_pixels (compare);

                orig_rowstride = gdk_pixbuf_get_rowstride (pixbuf);
                compare_rowstride = gdk_pixbuf_get_rowstride (compare);

                width = gdk_pixbuf_get_width (pixbuf);
                height = gdk_pixbuf_get_height (pixbuf);

                /*  well...  */
                bytes_per_pixel = gdk_pixbuf_get_n_channels (pixbuf);

                p1 = orig_pixels;
                p2 = compare_pixels;

                for (y = 0; y < height; y++) {
                        for (x = 0; x < width * bytes_per_pixel; x++)
                                count += (*p1++ != *p2++);

                        orig_pixels += orig_rowstride;
                        compare_pixels += compare_rowstride;

                        p1 = orig_pixels;
                        p2 = compare_pixels;
                }

                if (count > 0) {
                        fprintf (stderr,
                                 "saved %s file differs from copy in memory\n",
                                 file_type);
                }
        }
}

static gboolean
save_to_loader (const gchar *buf, gsize count, GError **err, gpointer data)
{
        GdkPixbufLoader *loader = data;

        return gdk_pixbuf_loader_write (loader, buf, count, err);
}

static GdkPixbuf *
buffer_to_pixbuf (const gchar *buf, gsize count, GError **err)
{
        GdkPixbufLoader *loader;
        GdkPixbuf *pixbuf;

        loader = gdk_pixbuf_loader_new ();
        if (gdk_pixbuf_loader_write (loader, buf, count, err) && 
            gdk_pixbuf_loader_close (loader, err)) {
                pixbuf = g_object_ref (gdk_pixbuf_loader_get_pixbuf (loader));
                g_object_unref (loader);
                return pixbuf;
        } else {
                return NULL;
        }
}

static void
do_compare (GdkPixbuf *pixbuf, GdkPixbuf *compare, GError *err)
{
        if (compare == NULL) {
                fprintf (stderr, "%s", err->message);
                g_error_free (err);
        } else {
                compare_pixbufs (pixbuf, compare, "jpeg");
                g_object_unref (compare);
        }
}

static void
keypress_check (GtkWidget *widget, GdkEventKey *evt, gpointer data)
{
        GdkPixbuf *pixbuf;
        GtkDrawingArea *da = (GtkDrawingArea*)data;
        GError *err = NULL;
        gchar *buffer;
        gsize count;
        GdkPixbufLoader *loader;

        pixbuf = (GdkPixbuf *) g_object_get_data (G_OBJECT (da), "pixbuf");

        if (evt->keyval == 'q')
                gtk_main_quit ();

        if (evt->keyval == 's' && (evt->state & GDK_CONTROL_MASK)) {
                /* save to callback */
                if (pixbuf == NULL) {
                        fprintf (stderr, "PIXBUF NULL\n");
                        return;
                }	

                loader = gdk_pixbuf_loader_new ();
                if (!gdk_pixbuf_save_to_callback (pixbuf, save_to_loader, loader, "jpeg",
                                                  &err,
                                                  "quality", "100",
                                                  NULL) ||
                    !gdk_pixbuf_loader_close (loader, &err)) {
                        fprintf (stderr, "%s", err->message);
                        g_error_free (err);
                } else {
                        do_compare (pixbuf,
                                    g_object_ref (gdk_pixbuf_loader_get_pixbuf (loader)),
                                    err);
                        g_object_unref (loader);
                }
        }
        else if (evt->keyval == 'S') {
                /* save to buffer */
                if (!gdk_pixbuf_save_to_buffer (pixbuf, &buffer, &count, "jpeg",
                                                &err,
                                                "quality", "100",
                                                NULL)) {
                        fprintf (stderr, "%s", err->message);
                        g_error_free (err);
                } else {
                        do_compare (pixbuf,
                                    buffer_to_pixbuf (buffer, count, &err),
                                    err);
                }
        }
        else if (evt->keyval == 's') {
                /* save normally */
                if (pixbuf == NULL) {
                        fprintf (stderr, "PIXBUF NULL\n");
                        return;
                }	

                if (!gdk_pixbuf_save (pixbuf, "foo.jpg", "jpeg",
                                      &err,
                                      "quality", "100",
                                      NULL)) {
                        fprintf (stderr, "%s", err->message);
                        g_error_free (err);
                } else {
                        do_compare (pixbuf,
                                    gdk_pixbuf_new_from_file ("foo.jpg", &err),
                                    err);
                }
        }

        if (evt->keyval == 'p' && (evt->state & GDK_CONTROL_MASK)) {
                /* save to callback */
                if (pixbuf == NULL) {
                        fprintf (stderr, "PIXBUF NULL\n");
                        return;
                }

                loader = gdk_pixbuf_loader_new ();
                if (!gdk_pixbuf_save_to_callback (pixbuf, save_to_loader, loader, "png",
                                                  &err,
                                                  "tEXt::Software", "testpixbuf-save",
                                                  NULL)
                    || !gdk_pixbuf_loader_close (loader, &err)) {
                        fprintf (stderr, "%s", err->message);
                        g_error_free (err);
                } else {
                        do_compare (pixbuf,
                                    g_object_ref (gdk_pixbuf_loader_get_pixbuf (loader)),
                                    err);
                        g_object_unref (loader);
                }
        }
        else if (evt->keyval == 'P') {
                /* save to buffer */
                if (!gdk_pixbuf_save_to_buffer (pixbuf, &buffer, &count, "png",
                                                &err,
                                                "tEXt::Software", "testpixbuf-save",
                                                NULL)) {
                        fprintf (stderr, "%s", err->message);