Set the cursor to a hand. (UIImagePrivate): Added fields for the anchor

1999-09-28  Federico Mena Quintero  <federico@redhat.com>

	* ui-image.c (canvas_realized): Set the cursor to a hand.
	(UIImagePrivate): Added fields for the anchor point for dragging.
	(drag_to): New function to allow dragging of the canvas.  It will
	perform badly for diagonal movement; see the comment in this
	source file to see why.

	* cursors.c (cursor_get): New file and new function to create
	mouse cursors.

	* Makefile.am: Added the cursors directory.  Added cursors.[ch] to
	the list of sources.

	* cursors/Makefile.am: Added the cursor data files.

3 files changed, 284 insertions, 5 deletions

diff --git a/libeog/cursors.c b/libeog/cursors.c
new file mode 100644
index 00000000..9896419d
--- /dev/null
+++ b/libeog/cursors.c
@@ -0,0 +1,103 @@
+/* Eye of Gnome image viewer - mouse cursors
+ *
+ * Copyright (C) 1999 The Free Software Foundation
+ *
+ * Author: Federico Mena-Quintero <federico@gimp.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <config.h>
+#include "cursors.h"
+
+
+
+/* Cursor definitions.  Keep in sync with the CursorType enumeration in
+ * cursors.h.
+ */
+
+#include "cursors/hand-open-data.xbm"
+#include "cursors/hand-open-mask.xbm"
+#include "cursors/hand-closed-data.xbm"
+#include "cursors/hand-closed-mask.xbm"
+
+static struct {
+	char *data;
+	char *mask;
+	int data_width;
+	int data_height;
+	int mask_width;
+	int mask_height;
+	int hot_x, hot_y;
+} cursors[] = {
+	{ hand_open_data_bits, hand_open_mask_bits,
+	  hand_open_data_width, hand_open_data_height,
+	  hand_open_mask_width, hand_open_mask_height,
+	  hand_open_data_width / 2, hand_open_data_height / 2 },
+	{ hand_closed_data_bits, hand_closed_mask_bits,
+	  hand_closed_data_width, hand_closed_data_height,
+	  hand_closed_mask_width, hand_closed_mask_height,
+	  hand_closed_data_width / 2, hand_closed_data_height / 2 },
+	{ NULL, NULL, 0, 0, 0, 0 }
+};
+
+
+
+/**
+ * cursor_get:
+ * @window: Window whose screen and colormap determine the cursor's.
+ * @type: A cursor type.
+ * 
+ * Creates a cursor.
+ * 
+ * Return value: The newly-created cursor.
+ **/
+GdkCursor *
+cursor_get (GdkWindow *window, CursorType type)
+{
+	GdkBitmap *data;
+	GdkBitmap *mask;
+	GdkColor black, white;
+	GdkCursor *cursor;
+
+	g_return_val_if_fail (window != NULL, NULL);
+	g_return_val_if_fail (type >= 0 && type < CURSOR_NUM_CURSORS, NULL);
+
+	g_assert (cursors[type].data_width == cursors[type].mask_width);
+	g_assert (cursors[type].data_height == cursors[type].mask_height);
+
+	data = gdk_bitmap_create_from_data (window,
+					    cursors[type].data,
+					    cursors[type].data_width,
+					    cursors[type].data_height);
+	mask = gdk_bitmap_create_from_data (window,
+					    cursors[type].mask,
+					    cursors[type].mask_width,
+					    cursors[type].mask_height);
+
+	g_assert (data != NULL && mask != NULL);
+
+	gdk_color_black (gdk_window_get_colormap (window), &black);
+	gdk_color_white (gdk_window_get_colormap (window), &white);
+
+	cursor = gdk_cursor_new_from_pixmap (data, mask, &white, &black,
+					     cursors[type].hot_x, cursors[type].hot_y);
+	g_assert (cursor != NULL);
+
+	gdk_bitmap_unref (data);
+	gdk_bitmap_unref (mask);
+
+	return cursor;
+}
diff --git a/libeog/cursors.h b/libeog/cursors.h
new file mode 100644
index 00000000..6e44b92a
--- /dev/null
+++ b/libeog/cursors.h
@@ -0,0 +1,39 @@
+/* Eye of Gnome image viewer - mouse cursors
+ *
+ * Copyright (C) 1999 The Free Software Foundation
+ *
+ * Author: Federico Mena-Quintero <federico@gimp.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef CURSORS_H
+#define CURSORS_H
+
+#include <gdk/gdk.h>
+
+
+
+typedef enum {
+	CURSOR_HAND_OPEN,
+	CURSOR_HAND_CLOSED,
+	CURSOR_NUM_CURSORS
+} CursorType;
+
+GdkCursor *cursor_get (GdkWindow *window, CursorType type);
+
+
+
+#endif
diff --git a/libeog/ui-image.c b/libeog/ui-image.c
index 3553cab2..e744d348 100644
--- a/libeog/ui-image.c
+++ b/libeog/ui-image.c
@@ -21,6 +21,7 @@
 
 #include <config.h>
 #include <gtk/gtksignal.h>
+#include "cursors.h"
 #include "image-item.h"
 #include "ui-image.h"
 #include "zoom.h"
@@ -41,6 +42,13 @@ typedef struct {
 
 	/* Zoom factor */
 	double zoom;
+
+	/* Anchor point for dragging */
+	int drag_anchor_x, drag_anchor_y;
+	int drag_ofs_x, drag_ofs_y;
+
+	/* Whether we are dragging or not */
+	guint dragging : 1;
 } UIImagePrivate;
 
 
@@ -158,15 +166,135 @@ ui_image_new (void)
 	return GTK_WIDGET (ui);
 }
 
+
+
+/* Signal handlers for the canvas */
+
 /* Called when the canvas in an image view is realized.  We set its background
  * pixmap to NULL so that X won't clear exposed areas and thus be faster.
  */
 static void
 canvas_realized (GtkWidget *widget, gpointer data)
 {
+	GdkCursor *cursor;
+
 	gdk_window_set_back_pixmap (GTK_LAYOUT (widget)->bin_window, NULL, FALSE);
+
+	cursor = cursor_get (GTK_LAYOUT (widget)->bin_window, CURSOR_HAND_OPEN);
+	gdk_window_set_cursor (GTK_LAYOUT (widget)->bin_window, cursor);
+	gdk_cursor_destroy (cursor);
+}
+
+/* Button press handler for the canvas.  We simply start dragging. */
+static guint
+canvas_button_press (GtkWidget *widget, GdkEventButton *event, gpointer data)
+{
+	UIImage *ui;
+	UIImagePrivate *priv;
+	GdkCursor *cursor;
+
+	ui = UI_IMAGE (data);
+	priv = ui->priv;
+
+	if (priv->dragging || event->button != 1)
+		return FALSE;
+
+	priv->dragging = TRUE;
+	priv->drag_anchor_x = event->x;
+	priv->drag_anchor_y = event->y;
+	gnome_canvas_get_scroll_offsets (GNOME_CANVAS (priv->canvas),
+					 &priv->drag_ofs_x,
+					 &priv->drag_ofs_y);
+
+	cursor = cursor_get (GTK_LAYOUT (priv->canvas)->bin_window, CURSOR_HAND_CLOSED);
+	gdk_pointer_grab (GTK_LAYOUT (priv->canvas)->bin_window,
+			  FALSE,
+			  (GDK_POINTER_MOTION_MASK
+			   | GDK_POINTER_MOTION_HINT_MASK
+			   | GDK_BUTTON_RELEASE_MASK),
+			  NULL,
+			  cursor,
+			  event->time);
+	gdk_cursor_destroy (cursor);
+
+	return TRUE;
+}
+
+/* Drags the canvas to the specified position */
+static void
+drag_to (UIImage *ui, int x, int y)
+{
+	UIImagePrivate *priv;
+	int dx, dy;
+	GtkAdjustment *adj;
+
+	priv = ui->priv;
+
+	dx = priv->drag_anchor_x - x;
+	dy = priv->drag_anchor_y - y;
+
+	/* Right now this will suck for diagonal movement.  GtkLayout does not
+	 * have a way to scroll itself diagonally, i.e. you have to change the
+	 * vertical and horizontal adjustments independently, leading to ugly
+	 * visual results.  The canvas freezes and thaws the layout in case of
+	 * diagonal movement, forcing it to repaint everything.
+	 *
+	 * I will put in an ugly hack to circumvent this later.
+	 */
+
+	gnome_canvas_scroll_to (GNOME_CANVAS (priv->canvas),
+				priv->drag_ofs_x + dx,
+				priv->drag_ofs_y + dy);
+}
+
+/* Button release handler for the canvas.  We terminate dragging. */
+static guint
+canvas_button_release (GtkWidget *widget, GdkEventButton *event, gpointer data)
+{
+	UIImage *ui;
+	UIImagePrivate *priv;
+
+	ui = UI_IMAGE (data);
+	priv = ui->priv;
+
+	if (!priv->dragging || event->button != 1)
+		return FALSE;
+
+	drag_to (ui, event->x, event->y);
+	priv->dragging = FALSE;
+	gdk_pointer_ungrab (event->time);
+
+	return TRUE;
 }
 
+/* Motion handler for the canvas.  We update the drag offset. */
+static guint
+canvas_motion (GtkWidget *widget, GdkEventMotion *event, gpointer data)
+{
+	UIImage *ui;
+	UIImagePrivate *priv;
+	gint x, y;
+	GdkModifierType mods;
+
+	ui = UI_IMAGE (data);
+	priv = ui->priv;
+
+	if (!priv->dragging)
+		return FALSE;
+
+	if (event->is_hint)
+		gdk_window_get_pointer (GTK_LAYOUT (priv->canvas)->bin_window, &x, &y, &mods);
+	else {
+		x = event->x;
+		y = event->y;
+	}
+
+	drag_to (ui, event->x, event->y);
+	return TRUE;
+}
+
+
+
 /**
  * ui_image_construct:
  * @ui: An image view.
@@ -191,7 +319,16 @@ ui_image_construct (UIImage *ui)
 	priv->canvas = gnome_canvas_new ();
 	gtk_signal_connect (GTK_OBJECT (priv->canvas), "realize",
 			    GTK_SIGNAL_FUNC (canvas_realized),
-			    NULL);
+			    ui);
+	gtk_signal_connect (GTK_OBJECT (priv->canvas), "button_press_event",
+			    GTK_SIGNAL_FUNC (canvas_button_press),
+			    ui);
+	gtk_signal_connect (GTK_OBJECT (priv->canvas), "button_release_event",
+			    GTK_SIGNAL_FUNC (canvas_button_release),
+			    ui);
+	gtk_signal_connect (GTK_OBJECT (priv->canvas), "motion_notify_event",
+			    GTK_SIGNAL_FUNC (canvas_motion),
+			    ui);
 
 	gtk_widget_pop_colormap ();
 	gtk_widget_pop_visual ();
@@ -265,7 +402,7 @@ ui_image_set_image (UIImage *ui, Image *image)
  * ui_image_set_zoom:
  * @ui: An image view.
  * @zoom: Desired zoom factor.
- * 
+ *
  * Sets the zoom factor of an image view.
  **/
 void
@@ -285,9 +422,9 @@ ui_image_set_zoom (UIImage *ui, double zoom)
 /**
  * ui_image_get_zoom:
  * @ui: An image view.
- * 
+ *
  * Gets the current zoom factor of an image view.
- * 
+ *
  * Return value: Current zoom factor.
  **/
 double
@@ -305,7 +442,7 @@ ui_image_get_zoom (UIImage *ui)
 /**
  * ui_image_zoom_fit:
  * @ui: An image view.
- * 
+ *
  * Sets the zoom factor to fit the size of an image view.
  **/
 void