forked from AuroraMiddleware/gtk
357 lines
11 KiB
C
357 lines
11 KiB
C
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/* Peg Solitaire
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*
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* This demo demonstrates how to use drag'n'drop to implement peg solitaire.
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*
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*/
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#include <gtk/gtk.h>
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static GtkWidget *window = NULL;
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/* Create an object for the pegs that get moved around in the game.
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*
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* We implement the GdkPaintable interface for them, so we can use GtkPicture
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* objects for the wholes we put the pegs into.
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*/
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#define SOLITAIRE_TYPE_PEG (solitaire_peg_get_type ())
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G_DECLARE_FINAL_TYPE (SolitairePeg, solitaire_peg, SOLITAIRE, PEG, GObject)
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/* Declare the struct. */
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struct _SolitairePeg
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{
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GObject parent_instance;
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int x;
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int y;
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};
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struct _SolitairePegClass
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{
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GObjectClass parent_class;
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};
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/* Here, we implement the functionality required by the GdkPaintable interface */
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static void
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solitaire_peg_snapshot (GdkPaintable *paintable,
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GdkSnapshot *snapshot,
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double width,
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double height)
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{
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/* The snapshot function is the only function we need to implement.
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* It does the actual drawing of the paintable.
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*/
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gtk_snapshot_append_color (snapshot,
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&(GdkRGBA) { 0.6, 0.3, 0.0, 1.0 },
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&GRAPHENE_RECT_INIT (0, 0, width, height));
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}
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static GdkPaintableFlags
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solitaire_peg_get_flags (GdkPaintable *paintable)
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{
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/* The flags are very useful to let GTK know that this image
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* is never going to change.
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* This allows many optimizations and should therefore always
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* be set.
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*/
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return GDK_PAINTABLE_STATIC_CONTENTS | GDK_PAINTABLE_STATIC_SIZE;
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}
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static void
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solitaire_peg_paintable_init (GdkPaintableInterface *iface)
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{
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iface->snapshot = solitaire_peg_snapshot;
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iface->get_flags = solitaire_peg_get_flags;
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}
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/* When defining the GType, we need to implement the GdkPaintable interface */
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G_DEFINE_TYPE_WITH_CODE (SolitairePeg, solitaire_peg, G_TYPE_OBJECT,
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G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
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solitaire_peg_paintable_init))
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/* Here's the boilerplate for the GObject declaration.
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* We don't need to do anything special here, because we keep no
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* data of our own.
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*/
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static void
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solitaire_peg_class_init (SolitairePegClass *klass)
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{
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}
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static void
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solitaire_peg_init (SolitairePeg *peg)
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{
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}
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/* Add a little setter for the peg's position.
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* We want to track those so that we can check for legal moves
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* during drag'n'drop operations.
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*/
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static void
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solitaire_peg_set_position (SolitairePeg *peg,
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guint x,
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guint y)
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{
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peg->x = x;
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peg->y = y;
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}
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/* And finally, we add a simple constructor.
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*/
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static SolitairePeg *
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solitaire_peg_new (void)
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{
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return g_object_new (SOLITAIRE_TYPE_PEG, NULL);
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}
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/*** DRAG AND DROP ***/
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/* The user tries to start a drag operation.
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* We check if the image contains a peg, and if so, we return the
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* peg as the content to be dragged.
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*/
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static GdkContentProvider *
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drag_prepare (GtkDragSource *source,
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double x,
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double y,
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GtkWidget *image)
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{
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GdkPaintable *paintable = gtk_image_get_paintable (GTK_IMAGE (image));
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if (!SOLITAIRE_IS_PEG (paintable))
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return NULL;
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return gdk_content_provider_new_typed (SOLITAIRE_TYPE_PEG, paintable);
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}
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/* This notifies us that the drag has begun.
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* We can now set up the icon and the widget for the ongoing drag.
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*/
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static void
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drag_begin (GtkDragSource *source,
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GdkDrag *drag,
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GtkWidget *image)
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{
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GdkPaintable *paintable = gtk_image_get_paintable (GTK_IMAGE (image));
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/* We guaranteed in the drag_prepare function above that we
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* only start a drag if a peg is available.
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* So let's make sure we did not screw that up.
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*/
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g_assert (SOLITAIRE_IS_PEG (paintable));
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/* We use the peg as the drag icon.
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*/
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gtk_drag_source_set_icon (source, paintable, -2, -2);
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/* We also attach it to the drag operation as custom user data,
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* so that we can get it back later if the drag fails.
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*/
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g_object_set_data (G_OBJECT (drag), "the peg", paintable);
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/* Because we are busy dragging the peg, we want to unset it
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* on the image.
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*/
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gtk_image_clear (GTK_IMAGE (image));
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}
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/* Thie is called once a drag operation has ended (successfully or not).
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* We want to undo what we did in drag_begin() above and react
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* to a potential move of the peg.
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*/
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static void
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drag_end (GtkDragSource *source,
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GdkDrag *drag,
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gboolean delete_data,
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GtkWidget *image)
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{
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SolitairePeg *peg;
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/* If the drag was successful, we should now delete the peg.
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* We did this in drag_begin() above to prepare for the drag, so
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* there's no need to do anything anymore.
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*/
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if (delete_data)
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return;
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/* However, if the drag did not succeed, we need to undo what
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* we did in drag_begin() and reinsert the peg here.
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* Because we used it as the drag data
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*/
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peg = g_object_get_data (G_OBJECT (drag), "the peg");
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gtk_image_set_from_paintable (GTK_IMAGE (image), GDK_PAINTABLE (peg));
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}
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/* Whenever a new drop operation starts, we need to check if we can
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* accept it.
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* The default check unfortunately is not good enough, because it only
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* checks the data type. But we also need to check if our image can
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* even accept data.
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*/
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static gboolean
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drop_accept (GtkDropTarget *target,
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GdkDrop *drop,
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GtkWidget *image)
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{
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/* First, check the drop is actually trying to drop a peg */
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if (!gdk_content_formats_contain_gtype (gdk_drop_get_formats (drop), SOLITAIRE_TYPE_PEG))
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return FALSE;
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/* If the image already contains a peg, we cannot accept another one */
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if (SOLITAIRE_IS_PEG (gtk_image_get_paintable (GTK_IMAGE (image))))
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return FALSE;
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return TRUE;
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}
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static gboolean
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drop_drop (GtkDropTarget *target,
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const GValue *value,
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double x,
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double y,
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GtkWidget *image)
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{
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GtkGrid *grid;
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SolitairePeg *peg;
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int image_x, image_y;
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GtkWidget *jumped;
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grid = GTK_GRID (gtk_widget_get_parent (image));
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/* The value contains the data in the type we demanded.
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* We demanded a SolitairePeg, so that's what we get.
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*/
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peg = g_value_get_object (value);
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/* Make sure this was a legal move. */
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/* First, figure out the image's position in the grid. */
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gtk_grid_query_child (grid,
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image,
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&image_x, &image_y,
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NULL, NULL);
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/* If the peg was not moved 2 spaces horizontally or vertically,
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* this was not a valid jump. Reject it.
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*/
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if (!((ABS (image_x - peg->x) == 2 && image_y == peg->y) ||
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(ABS (image_y - peg->y) == 2 && image_x == peg->x)))
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return FALSE;
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/* Get the widget that was jumped over
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*/
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jumped = gtk_grid_get_child_at (grid,
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(image_x + peg->x) / 2,
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(image_y + peg->y) / 2);
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/* If the jumped widget does not have a peg in it, this move
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* isn't valid.
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*/
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if (!SOLITAIRE_IS_PEG (gtk_image_get_paintable (GTK_IMAGE (jumped))))
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return FALSE;
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/* Finally, we know it's a legal move. */
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/* Clear the peg of the jumped-over image */
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gtk_image_clear (GTK_IMAGE (jumped));
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/* Add the peg to this image */
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solitaire_peg_set_position (peg, image_x, image_y);
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gtk_image_set_from_paintable (GTK_IMAGE (image), GDK_PAINTABLE (peg));
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/* Success! */
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return TRUE;
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}
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GtkWidget *
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do_peg_solitaire (GtkWidget *do_widget)
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{
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if (!window)
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{
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GtkWidget *header;
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GtkWidget *restart;
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GtkWidget *grid;
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GtkWidget *image;
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int x, y;
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GtkDragSource *source;
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GtkDropTarget *target;
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restart = gtk_button_new_from_icon_name ("view-refresh-symbolic");
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g_signal_connect (restart, "clicked", G_CALLBACK (restart), NULL);
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header = gtk_header_bar_new ();
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gtk_header_bar_set_title (GTK_HEADER_BAR (header), "Peg Solitaire");
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gtk_header_bar_set_show_title_buttons (GTK_HEADER_BAR (header), TRUE);
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gtk_header_bar_pack_start (GTK_HEADER_BAR (header), restart);
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window = gtk_window_new ();
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gtk_window_set_display (GTK_WINDOW (window),
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gtk_widget_get_display (do_widget));
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gtk_window_set_title (GTK_WINDOW (window), "Sliding Puzzle");
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gtk_window_set_titlebar (GTK_WINDOW (window), header);
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gtk_window_set_default_size (GTK_WINDOW (window), 400, 300);
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g_signal_connect (window, "destroy",
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G_CALLBACK (gtk_widget_destroyed), &window);
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grid = gtk_grid_new ();
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gtk_widget_set_halign (grid, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (grid, GTK_ALIGN_CENTER);
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gtk_grid_set_row_spacing (GTK_GRID (grid), 6);
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gtk_grid_set_column_spacing (GTK_GRID (grid), 6);
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gtk_grid_set_row_homogeneous (GTK_GRID (grid), TRUE);
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gtk_grid_set_column_homogeneous (GTK_GRID (grid), TRUE);
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gtk_container_add (GTK_CONTAINER (window), grid);
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for (x = 0; x < 7; x++)
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{
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for (y = 0; y < 7; y++)
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{
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if ((x < 2 || x >= 5) && (y < 2 || y >= 5))
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continue;
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image = gtk_image_new ();
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if (x != 3 || y != 3)
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{
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SolitairePeg *peg = solitaire_peg_new ();
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solitaire_peg_set_position (peg, x, y);
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gtk_image_set_from_paintable (GTK_IMAGE (image), GDK_PAINTABLE (peg));
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}
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gtk_grid_attach (GTK_GRID (grid), image, x, y, 1, 1);
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/* Set up the drag source.
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* This is rather straightforward: Set the supported actions
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* (in our case, pegs can only be moved) and connect all the
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* relevant signals.
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* And because all drag'n'drop handling is done via event controllers,
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* we need to add the controller to the widget.
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*/
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source = gtk_drag_source_new ();
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gtk_drag_source_set_actions (source, GDK_ACTION_MOVE);
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g_signal_connect (source, "prepare", G_CALLBACK (drag_prepare), image);
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g_signal_connect (source, "drag-begin", G_CALLBACK (drag_begin), image);
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g_signal_connect (source, "drag-end", G_CALLBACK (drag_end), image);
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gtk_widget_add_controller (image, GTK_EVENT_CONTROLLER (source));
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/* Set up the drop target.
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* This is more involved, because the game logic goes here.
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*/
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/* First we specify the data we accept: pegs.
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* And we only want moves.
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*/
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target = gtk_drop_target_new (SOLITAIRE_TYPE_PEG, GDK_ACTION_MOVE);
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/* Then we connect our signals.
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*/
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g_signal_connect (target, "accept", G_CALLBACK (drop_accept), image);
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g_signal_connect (target, "drop", G_CALLBACK (drop_drop), image);
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/* Finally, like above, we add it to the widget.
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*/
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gtk_widget_add_controller (image, GTK_EVENT_CONTROLLER (target));
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}
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}
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}
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if (!gtk_widget_get_visible (window))
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gtk_widget_show (window);
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else
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gtk_widget_destroy (window);
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return window;
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}
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