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-rw-r--r--liblogdiag/ld-canvas.c1417
1 files changed, 1417 insertions, 0 deletions
diff --git a/liblogdiag/ld-canvas.c b/liblogdiag/ld-canvas.c
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--- /dev/null
+++ b/liblogdiag/ld-canvas.c
@@ -0,0 +1,1417 @@
+/*
+ * ld-canvas.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010 - 2011. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include <math.h>
+#include <string.h>
+#include <gdk/gdkkeysyms.h>
+
+#include "liblogdiag.h"
+#include "config.h"
+
+
+/**
+ * SECTION:ld-canvas
+ * @short_description: A canvas.
+ * @see_also: #LdDiagram
+ *
+ * #LdCanvas displays and enables the user to manipulate with an #LdDiagram.
+ */
+
+/* Milimetres per inch. */
+#define MM_PER_INCH 25.4
+/* The default screen resolution in DPI units. */
+#define DEFAULT_SCREEN_RESOLUTION 96
+
+/* The maximal, minimal and default values of zoom. */
+#define ZOOM_MIN 0.01
+#define ZOOM_MAX 100
+#define ZOOM_DEFAULT 1
+/* Multiplication factor for zooming with mouse wheel. */
+#define ZOOM_WHEEL_STEP 1.4
+
+/* When drawing is requested, extend all sides of
+ * the rectangle to be drawn by this number of pixels.
+ */
+#define QUEUE_DRAW_EXTEND 3
+/* Cursor tolerance for object borders. */
+#define OBJECT_BORDER_TOLERANCE 3
+/* Tolerance on all sides of symbols for strokes. */
+#define SYMBOL_CLIP_TOLERANCE 5
+
+/* Size of a highlighted terminal. */
+#define TERMINAL_RADIUS 5
+/* Tolerance around terminal points. */
+#define TERMINAL_HOVER_TOLERANCE 8
+
+/*
+ * OperationEnd:
+ *
+ * Called upon ending an operation.
+ */
+typedef void (*OperationEnd) (LdCanvas *self);
+
+enum
+{
+ OPER_0,
+ OPER_ADD_OBJECT
+};
+
+typedef struct _AddObjectData AddObjectData;
+
+struct _AddObjectData
+{
+ LdDiagramObject *object;
+ gboolean visible;
+};
+
+enum
+{
+ COLOR_BASE,
+ COLOR_GRID,
+ COLOR_OBJECT,
+ COLOR_SELECTION,
+ COLOR_TERMINAL,
+ COLOR_COUNT
+};
+
+typedef struct _LdCanvasColor LdCanvasColor;
+
+struct _LdCanvasColor
+{
+ gdouble r;
+ gdouble g;
+ gdouble b;
+ gdouble a;
+};
+
+/*
+ * LdCanvasPrivate:
+ * @diagram: A diagram object assigned to this canvas as a model.
+ * @library: A library object assigned to this canvas as a model.
+ * @adjustment_h: An adjustment object for the horizontal axis, if any.
+ * @adjustment_v: An adjustment object for the vertical axis, if any.
+ * @x: The X coordinate of the center of view.
+ * @y: The Y coordinate of the center of view.
+ * @zoom: The current zoom of the canvas.
+ * @operation: The current operation.
+ * @operation_data: Data related to the current operation.
+ * @operation_end: A callback to end the operation.
+ * @palette: Colors used by the widget.
+ */
+struct _LdCanvasPrivate
+{
+ LdDiagram *diagram;
+ LdLibrary *library;
+
+ GtkAdjustment *adjustment_h;
+ GtkAdjustment *adjustment_v;
+
+ gdouble x;
+ gdouble y;
+ gdouble zoom;
+
+ LdPoint terminal;
+ gboolean terminal_highlighted;
+
+ gint operation;
+ union
+ {
+ AddObjectData add_object;
+ }
+ operation_data;
+ OperationEnd operation_end;
+
+ LdCanvasColor palette[COLOR_COUNT];
+};
+
+#define OPER_DATA(self, member) ((self)->priv->operation_data.member)
+#define COLOR_GET(self, name) (&(self)->priv->palette[name])
+
+/*
+ * DrawData:
+ * @self: Our #LdCanvas.
+ * @cr: A cairo context to draw on.
+ * @exposed_rect: The area that is to be redrawn.
+ * @scale: Computed size of one diagram unit in pixels.
+ */
+typedef struct _DrawData DrawData;
+
+struct _DrawData
+{
+ LdCanvas *self;
+ cairo_t *cr;
+ LdRectangle exposed_rect;
+ gdouble scale;
+};
+
+enum
+{
+ PROP_0,
+ PROP_DIAGRAM,
+ PROP_LIBRARY,
+ PROP_ZOOM
+};
+
+static void ld_canvas_get_property (GObject *object, guint property_id,
+ GValue *value, GParamSpec *pspec);
+static void ld_canvas_set_property (GObject *object, guint property_id,
+ const GValue *value, GParamSpec *pspec);
+static void ld_canvas_finalize (GObject *gobject);
+
+static void ld_canvas_real_set_scroll_adjustments
+ (LdCanvas *self, GtkAdjustment *horizontal, GtkAdjustment *vertical);
+static void on_adjustment_value_changed
+ (GtkAdjustment *adjustment, LdCanvas *self);
+static void on_size_allocate (GtkWidget *widget, GtkAllocation *allocation,
+ gpointer user_data);
+static void update_adjustments (LdCanvas *self);
+
+static void diagram_connect_signals (LdCanvas *self);
+static void diagram_disconnect_signals (LdCanvas *self);
+
+static gdouble ld_canvas_get_base_unit_in_px (GtkWidget *self);
+static gdouble ld_canvas_get_scale_in_px (LdCanvas *self);
+
+static void simulate_motion (LdCanvas *self);
+static gboolean on_motion_notify (GtkWidget *widget, GdkEventMotion *event,
+ gpointer user_data);
+static gboolean on_leave_notify (GtkWidget *widget, GdkEventCrossing *event,
+ gpointer user_data);
+static gboolean on_button_press (GtkWidget *widget, GdkEventButton *event,
+ gpointer user_data);
+static gboolean on_button_release (GtkWidget *widget, GdkEventButton *event,
+ gpointer user_data);
+static gboolean on_scroll (GtkWidget *widget, GdkEventScroll *event,
+ gpointer user_data);
+
+static void ld_canvas_color_set (LdCanvasColor *color,
+ gdouble r, gdouble g, gdouble b, gdouble a);
+static void ld_canvas_color_apply (LdCanvasColor *color, cairo_t *cr);
+
+static void move_object_to_coords (LdCanvas *self, LdDiagramObject *object,
+ gdouble x, gdouble y);
+static LdDiagramObject *get_object_at_coords (LdCanvas *self,
+ gdouble x, gdouble y);
+static gboolean is_object_selected (LdCanvas *self, LdDiagramObject *object);
+static LdSymbol *resolve_diagram_symbol (LdCanvas *self,
+ LdDiagramSymbol *diagram_symbol);
+static gboolean get_symbol_area (LdCanvas *self, LdDiagramSymbol *symbol,
+ LdRectangle *rect);
+static gboolean get_symbol_clip_area (LdCanvas *self, LdDiagramSymbol *symbol,
+ LdRectangle *rect);
+static gboolean get_object_area (LdCanvas *self, LdDiagramObject *object,
+ LdRectangle *rect);
+static gboolean object_hit_test (LdCanvas *self, LdDiagramObject *object,
+ gdouble x, gdouble y);
+static void check_terminals (LdCanvas *self, gdouble x, gdouble y);
+static void hide_terminals (LdCanvas *self);
+static void queue_draw (LdCanvas *self, LdRectangle *rect);
+static void queue_object_draw (LdCanvas *self, LdDiagramObject *object);
+static void queue_terminal_draw (LdCanvas *self, LdPoint *terminal);
+
+static void ld_canvas_real_cancel_operation (LdCanvas *self);
+static void ld_canvas_add_object_end (LdCanvas *self);
+
+static gboolean on_expose_event (GtkWidget *widget, GdkEventExpose *event,
+ gpointer user_data);
+static void draw_grid (GtkWidget *widget, DrawData *data);
+static void draw_diagram (GtkWidget *widget, DrawData *data);
+static void draw_terminal (GtkWidget *widget, DrawData *data);
+static void draw_object (LdDiagramObject *diagram_object, DrawData *data);
+static void draw_symbol (LdDiagramSymbol *diagram_symbol, DrawData *data);
+
+
+G_DEFINE_TYPE (LdCanvas, ld_canvas, GTK_TYPE_DRAWING_AREA);
+
+static void
+ld_canvas_class_init (LdCanvasClass *klass)
+{
+ GObjectClass *object_class;
+ GtkWidgetClass *widget_class;
+ GtkBindingSet *binding_set;
+ GParamSpec *pspec;
+
+ widget_class = GTK_WIDGET_CLASS (klass);
+
+ object_class = G_OBJECT_CLASS (klass);
+ object_class->get_property = ld_canvas_get_property;
+ object_class->set_property = ld_canvas_set_property;
+ object_class->finalize = ld_canvas_finalize;
+
+ klass->set_scroll_adjustments = ld_canvas_real_set_scroll_adjustments;
+ klass->cancel_operation = ld_canvas_real_cancel_operation;
+
+ binding_set = gtk_binding_set_by_class (klass);
+ gtk_binding_entry_add_signal (binding_set, GDK_Escape, 0,
+ "cancel-operation", 0);
+
+/**
+ * LdCanvas:diagram:
+ *
+ * The underlying #LdDiagram object of this canvas.
+ */
+ pspec = g_param_spec_object ("diagram", "Diagram",
+ "The underlying diagram object of this canvas.",
+ LD_TYPE_DIAGRAM, G_PARAM_READWRITE);
+ g_object_class_install_property (object_class, PROP_DIAGRAM, pspec);
+
+/**
+ * LdCanvas:library:
+ *
+ * The #LdLibrary that this canvas retrieves symbols from.
+ */
+ pspec = g_param_spec_object ("library", "Library",
+ "The library that this canvas retrieves symbols from.",
+ LD_TYPE_LIBRARY, G_PARAM_READWRITE);
+ g_object_class_install_property (object_class, PROP_LIBRARY, pspec);
+
+/**
+ * LdCanvas:zoom:
+ *
+ * The zoom of this canvas.
+ */
+ pspec = g_param_spec_double ("zoom", "Zoom",
+ "The zoom of this canvas.",
+ ZOOM_MIN, ZOOM_MAX, ZOOM_DEFAULT, G_PARAM_READWRITE);
+ g_object_class_install_property (object_class, PROP_ZOOM, pspec);
+
+/**
+ * LdCanvas::set-scroll-adjustments:
+ * @horizontal: The horizontal #GtkAdjustment.
+ * @vertical: The vertical #GtkAdjustment.
+ *
+ * Set scroll adjustments for the canvas.
+ */
+ widget_class->set_scroll_adjustments_signal = g_signal_new
+ ("set-scroll-adjustments", G_TYPE_FROM_CLASS (widget_class),
+ G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+ G_STRUCT_OFFSET (LdCanvasClass, set_scroll_adjustments),
+ NULL, NULL,
+ g_cclosure_user_marshal_VOID__OBJECT_OBJECT,
+ G_TYPE_NONE, 2, GTK_TYPE_ADJUSTMENT, GTK_TYPE_ADJUSTMENT);
+
+/**
+ * LdCanvas::cancel-operation:
+ *
+ * Cancel any current operation.
+ */
+ klass->cancel_operation_signal = g_signal_new
+ ("cancel-operation", G_TYPE_FROM_CLASS (klass),
+ G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+ G_STRUCT_OFFSET (LdCanvasClass, cancel_operation), NULL, NULL,
+ g_cclosure_marshal_VOID__VOID,
+ G_TYPE_NONE, 0);
+
+ g_type_class_add_private (klass, sizeof (LdCanvasPrivate));
+}
+
+static void
+ld_canvas_init (LdCanvas *self)
+{
+ self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+ (self, LD_TYPE_CANVAS, LdCanvasPrivate);
+
+ self->priv->x = 0;
+ self->priv->y = 0;
+ self->priv->zoom = ZOOM_DEFAULT;
+
+ ld_canvas_color_set (COLOR_GET (self, COLOR_BASE), 1, 1, 1, 1);
+ ld_canvas_color_set (COLOR_GET (self, COLOR_GRID), 0.5, 0.5, 0.5, 1);
+ ld_canvas_color_set (COLOR_GET (self, COLOR_OBJECT), 0, 0, 0, 1);
+ ld_canvas_color_set (COLOR_GET (self, COLOR_SELECTION), 0, 0, 1, 1);
+ ld_canvas_color_set (COLOR_GET (self, COLOR_TERMINAL), 1, 0.5, 0.5, 1);
+
+ g_signal_connect (self, "size-allocate",
+ G_CALLBACK (on_size_allocate), NULL);
+ g_signal_connect (self, "expose-event",
+ G_CALLBACK (on_expose_event), NULL);
+
+ g_signal_connect (self, "motion-notify-event",
+ G_CALLBACK (on_motion_notify), NULL);
+ g_signal_connect (self, "leave-notify-event",
+ G_CALLBACK (on_leave_notify), NULL);
+ g_signal_connect (self, "button-press-event",
+ G_CALLBACK (on_button_press), NULL);
+ g_signal_connect (self, "button-release-event",
+ G_CALLBACK (on_button_release), NULL);
+ g_signal_connect (self, "scroll-event",
+ G_CALLBACK (on_scroll), NULL);
+
+ g_object_set (self, "can-focus", TRUE, NULL);
+
+ gtk_widget_add_events (GTK_WIDGET (self),
+ GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK
+ | GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK
+ | GDK_LEAVE_NOTIFY_MASK);
+}
+
+static void
+ld_canvas_finalize (GObject *gobject)
+{
+ LdCanvas *self;
+
+ self = LD_CANVAS (gobject);
+
+ ld_canvas_real_set_scroll_adjustments (self, NULL, NULL);
+
+ if (self->priv->diagram)
+ {
+ diagram_disconnect_signals (self);
+ g_object_unref (self->priv->diagram);
+ }
+ if (self->priv->library)
+ g_object_unref (self->priv->library);
+
+ /* Chain up to the parent class. */
+ G_OBJECT_CLASS (ld_canvas_parent_class)->finalize (gobject);
+}
+
+static void
+ld_canvas_get_property (GObject *object, guint property_id,
+ GValue *value, GParamSpec *pspec)
+{
+ LdCanvas *self;
+
+ self = LD_CANVAS (object);
+ switch (property_id)
+ {
+ case PROP_DIAGRAM:
+ g_value_set_object (value, ld_canvas_get_diagram (self));
+ break;
+ case PROP_LIBRARY:
+ g_value_set_object (value, ld_canvas_get_library (self));
+ break;
+ case PROP_ZOOM:
+ g_value_set_double (value, ld_canvas_get_zoom (self));
+ break;
+ default:
+ G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+ }
+}
+
+static void
+ld_canvas_set_property (GObject *object, guint property_id,
+ const GValue *value, GParamSpec *pspec)
+{
+ LdCanvas *self;
+
+ self = LD_CANVAS (object);
+ switch (property_id)
+ {
+ case PROP_DIAGRAM:
+ ld_canvas_set_diagram (self, LD_DIAGRAM (g_value_get_object (value)));
+ break;
+ case PROP_LIBRARY:
+ ld_canvas_set_library (self, LD_LIBRARY (g_value_get_object (value)));
+ break;
+ case PROP_ZOOM:
+ ld_canvas_set_zoom (self, g_value_get_double (value));
+ break;
+ default:
+ G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+ }
+}
+
+static void
+ld_canvas_real_set_scroll_adjustments (LdCanvas *self,
+ GtkAdjustment *horizontal, GtkAdjustment *vertical)
+{
+ /* TODO: Infinite canvas. */
+ GtkWidget *widget;
+ gdouble scale;
+
+ widget = GTK_WIDGET (self);
+ scale = ld_canvas_get_scale_in_px (self);
+
+ if (horizontal != self->priv->adjustment_h)
+ {
+ if (self->priv->adjustment_h)
+ {
+ g_signal_handlers_disconnect_by_func (self->priv->adjustment_h,
+ on_adjustment_value_changed, self);
+ g_object_unref (self->priv->adjustment_h);
+
+ self->priv->adjustment_h = NULL;
+ }
+ if (horizontal)
+ {
+ g_object_ref (horizontal);
+ g_signal_connect (horizontal, "value-changed",
+ G_CALLBACK (on_adjustment_value_changed), self);
+
+ horizontal->upper = 100;
+ horizontal->lower = -100;
+ horizontal->step_increment = 0.5;
+ horizontal->page_increment = 5;
+ horizontal->page_size = widget->allocation.width / scale;
+ horizontal->value = -horizontal->page_size / 2;
+
+ self->priv->adjustment_h = horizontal;
+ }
+ }
+
+ if (vertical != self->priv->adjustment_v)
+ {
+ if (self->priv->adjustment_v)
+ {
+ g_signal_handlers_disconnect_by_func (self->priv->adjustment_v,
+ on_adjustment_value_changed, self);
+ g_object_unref (self->priv->adjustment_v);
+
+ self->priv->adjustment_v = NULL;
+ }
+ if (vertical)
+ {
+ g_object_ref (vertical);
+ g_signal_connect (vertical, "value-changed",
+ G_CALLBACK (on_adjustment_value_changed), self);
+
+ vertical->upper = 100;
+ vertical->lower = -100;
+ vertical->step_increment = 0.5;
+ vertical->page_increment = 5;
+ vertical->page_size = widget->allocation.height / scale;
+ vertical->value = -vertical->page_size / 2;
+
+ self->priv->adjustment_v = vertical;
+ }
+ }
+}
+
+static void
+on_adjustment_value_changed (GtkAdjustment *adjustment, LdCanvas *self)
+{
+ GtkWidget *widget;
+ gdouble scale;
+
+ widget = GTK_WIDGET (self);
+ scale = ld_canvas_get_scale_in_px (self);
+
+ if (adjustment == self->priv->adjustment_h)
+ {
+ self->priv->x = adjustment->value
+ + widget->allocation.width / scale / 2;
+ gtk_widget_queue_draw (widget);
+ }
+ else if (adjustment == self->priv->adjustment_v)
+ {
+ self->priv->y = adjustment->value
+ + widget->allocation.height / scale / 2;
+ gtk_widget_queue_draw (widget);
+ }
+}
+
+static void
+on_size_allocate (GtkWidget *widget, GtkAllocation *allocation,
+ gpointer user_data)
+{
+ LdCanvas *self;
+
+ self = LD_CANVAS (widget);
+
+ /* FIXME: If the new allocation is bigger, we may see more than
+ * what we're supposed to be able to see -> adjust X and Y.
+ *
+ * If the visible area is so large that we simply must see more,
+ * let's disable the scrollbars in question.
+ */
+ update_adjustments (self);
+}
+
+static void
+update_adjustments (LdCanvas *self)
+{
+ gdouble scale;
+
+ scale = ld_canvas_get_scale_in_px (self);
+
+ if (self->priv->adjustment_h)
+ {
+ self->priv->adjustment_h->page_size
+ = GTK_WIDGET (self)->allocation.width / scale;
+ self->priv->adjustment_h->value
+ = self->priv->x - self->priv->adjustment_h->page_size / 2;
+ gtk_adjustment_changed (self->priv->adjustment_h);
+ }
+ if (self->priv->adjustment_v)
+ {
+ self->priv->adjustment_v->page_size
+ = GTK_WIDGET (self)->allocation.height / scale;
+ self->priv->adjustment_v->value
+ = self->priv->y - self->priv->adjustment_v->page_size / 2;
+ gtk_adjustment_changed (self->priv->adjustment_v);
+ }
+}
+
+
+/* ===== Generic interface etc. ============================================ */
+
+/**
+ * ld_canvas_new:
+ *
+ * Create an instance.
+ */
+LdCanvas *
+ld_canvas_new (void)
+{
+ return g_object_new (LD_TYPE_CANVAS, NULL);
+}
+
+/**
+ * ld_canvas_set_diagram:
+ * @self: An #LdCanvas object.
+ * @diagram: The #LdDiagram to be assigned to the canvas.
+ *
+ * Assign an #LdDiagram object to the canvas.
+ */
+void
+ld_canvas_set_diagram (LdCanvas *self, LdDiagram *diagram)
+{
+ g_return_if_fail (LD_IS_CANVAS (self));
+ g_return_if_fail (LD_IS_DIAGRAM (diagram));
+
+ if (self->priv->diagram)
+ {
+ diagram_disconnect_signals (self);
+ g_object_unref (self->priv->diagram);
+ }
+
+ self->priv->diagram = diagram;
+ diagram_connect_signals (self);
+ g_object_ref (diagram);
+
+ g_object_notify (G_OBJECT (self), "diagram");
+}
+
+/**
+ * ld_canvas_get_diagram:
+ * @self: An #LdCanvas object.
+ *
+ * Get the #LdDiagram object assigned to this canvas.
+ * The reference count on the diagram is not incremented.
+ */
+LdDiagram *
+ld_canvas_get_diagram (LdCanvas *self)
+{
+ g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
+ return self->priv->diagram;
+}
+
+static void
+diagram_connect_signals (LdCanvas *self)
+{
+ g_return_if_fail (LD_IS_DIAGRAM (self->priv->diagram));
+
+ g_signal_connect_swapped (self->priv->diagram, "changed",
+ G_CALLBACK (gtk_widget_queue_draw), self);
+ g_signal_connect_swapped (self->priv->diagram, "selection-changed",
+ G_CALLBACK (gtk_widget_queue_draw), self);
+}
+
+static void
+diagram_disconnect_signals (LdCanvas *self)
+{
+ g_return_if_fail (LD_IS_DIAGRAM (self->priv->diagram));
+
+ g_signal_handlers_disconnect_matched (self->priv->diagram,
+ G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA, 0, 0, NULL,
+ gtk_widget_queue_draw, self);
+}
+
+/**
+ * ld_canvas_set_library:
+ * @self: An #LdCanvas object.
+ * @library: The #LdLibrary to be assigned to the canvas.
+ *
+ * Assign an #LdLibrary object to the canvas.
+ */
+void
+ld_canvas_set_library (LdCanvas *self, LdLibrary *library)
+{
+ g_return_if_fail (LD_IS_CANVAS (self));
+ g_return_if_fail (LD_IS_LIBRARY (library));
+
+ if (self->priv->library)
+ g_object_unref (self->priv->library);
+
+ self->priv->library = library;
+ g_object_ref (library);
+
+ g_object_notify (G_OBJECT (self), "library");
+}
+
+/**
+ * ld_canvas_get_library:
+ * @self: An #LdCanvas object.
+ *
+ * Get the #LdLibrary object assigned to this canvas.
+ * The reference count on the library is not incremented.
+ */
+LdLibrary *
+ld_canvas_get_library (LdCanvas *self)
+{
+ g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
+ return self->priv->library;
+}
+
+/*
+ * ld_canvas_get_base_unit_in_px:
+ * @self: A #GtkWidget object to retrieve DPI from (indirectly).
+ *
+ * Return value: Length of the base unit in pixels.
+ */
+static gdouble
+ld_canvas_get_base_unit_in_px (GtkWidget *self)
+{
+ gdouble resolution;
+
+ g_return_val_if_fail (GTK_IS_WIDGET (self), 1);
+
+ resolution = gdk_screen_get_resolution (gtk_widget_get_screen (self));
+ if (resolution == -1)
+ resolution = DEFAULT_SCREEN_RESOLUTION;
+
+ /* XXX: It might look better if the unit was rounded to a whole number. */
+ return resolution / MM_PER_INCH * LD_CANVAS_BASE_UNIT_LENGTH;
+}
+
+/*
+ * ld_canvas_get_scale_in_px:
+ * @self: An #LdCanvas object.
+ *
+ * Return value: Displayed length of the base unit in pixels.
+ */
+static gdouble
+ld_canvas_get_scale_in_px (LdCanvas *self)
+{
+ g_return_val_if_fail (LD_IS_CANVAS (self), 1);
+
+ return ld_canvas_get_base_unit_in_px (GTK_WIDGET (self))
+ * self->priv->zoom;
+}
+
+/**
+ * ld_canvas_widget_to_diagram_coords:
+ * @self: An #LdCanvas object.
+ * @wx: The X coordinate to be translated.
+ * @wy: The Y coordinate to be translated.
+ * @dx: (out): The translated X coordinate.
+ * @dy: (out): The translated Y coordinate.
+ *
+ * Translate coordinates located inside the canvas window
+ * into diagram coordinates.
+ */
+void
+ld_canvas_widget_to_diagram_coords (LdCanvas *self,
+ gdouble wx, gdouble wy, gdouble *dx, gdouble *dy)
+{
+ GtkWidget *widget;
+ gdouble scale;
+
+ g_return_if_fail (LD_IS_CANVAS (self));
+ g_return_if_fail (dx != NULL);
+ g_return_if_fail (dy != NULL);
+
+ widget = GTK_WIDGET (self);
+ scale = ld_canvas_get_scale_in_px (self);
+
+ /* We know diagram coordinates of the center of the canvas, so we may
+ * translate the given X and Y coordinates to this center and then scale
+ * them by dividing them by the current scale.
+ */
+ *dx = self->priv->x + (wx - (widget->allocation.width * 0.5)) / scale;
+ *dy = self->priv->y + (wy - (widget->allocation.height * 0.5)) / scale;
+}
+
+/**
+ * ld_canvas_diagram_to_widget_coords:
+ * @self: An #LdCanvas object.
+ * @dx: The X coordinate to be translated.
+ * @dy: The Y coordinate to be translated.
+ * @wx: (out): The translated X coordinate.
+ * @wy: (out): The translated Y coordinate.
+ *
+ * Translate diagram coordinates into canvas coordinates.
+ */
+void
+ld_canvas_diagram_to_widget_coords (LdCanvas *self,
+ gdouble dx, gdouble dy, gdouble *wx, gdouble *wy)
+{
+ GtkWidget *widget;
+ gdouble scale;
+
+ g_return_if_fail (LD_IS_CANVAS (self));
+ g_return_if_fail (wx != NULL);
+ g_return_if_fail (wy != NULL);
+
+ widget = GTK_WIDGET (self);
+ scale = ld_canvas_get_scale_in_px (self);
+
+ /* Just the reversal of ld_canvas_widget_to_diagram_coords(). */
+ *wx = scale * (dx - self->priv->x) + 0.5 * widget->allocation.width;
+ *wy = scale * (dy - self->priv->y) + 0.5 * widget->allocation.height;
+}
+
+/**
+ * ld_canvas_get_zoom:
+ * @self: An #LdCanvas object.
+ *
+ * Return value: Zoom of the canvas.
+ */
+gdouble
+ld_canvas_get_zoom (LdCanvas *self)
+{
+ g_return_val_if_fail (LD_IS_CANVAS (self), -1);
+ return self->priv->zoom;
+}
+
+/**
+ * ld_canvas_set_zoom:
+ * @self: An #LdCanvas object.
+ * @zoom: The zoom.
+ *
+ * Set zoom of the canvas.
+ */
+void
+ld_canvas_set_zoom (LdCanvas *self, gdouble zoom)
+{
+ gdouble clamped_zoom;
+
+ g_return_if_fail (LD_IS_CANVAS (self));
+
+ clamped_zoom = CLAMP (zoom, ZOOM_MIN, ZOOM_MAX);
+ if (self->priv->zoom == clamped_zoom)
+ return;
+
+ self->priv->zoom = clamped_zoom;
+
+ simulate_motion (self);
+ update_adjustments (self);
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+
+ g_object_notify (G_OBJECT (self), "zoom");
+}
+
+
+/* ===== Operations ======================================================== */
+
+static void
+ld_canvas_real_cancel_operation (LdCanvas *self)
+{
+ g_return_if_fail (LD_IS_CANVAS (self));
+
+ if (self->priv->operation)
+ {
+ if (self->priv->operation_end)
+ self->priv->operation_end (self);
+ self->priv->operation = OPER_0;
+ self->priv->operation_end = NULL;
+ }
+}
+
+/**
+ * ld_canvas_add_object_begin:
+ * @self: An #LdCanvas object.
+ * @object: (transfer full): The object to be added to the diagram.
+ *
+ * Begin an operation for adding an object into the diagram.
+ */
+void
+ld_canvas_add_object_begin (LdCanvas *self, LdDiagramObject *object)
+{
+ AddObjectData *data;
+
+ g_return_if_fail (LD_IS_CANVAS (self));
+ g_return_if_fail (LD_IS_DIAGRAM_OBJECT (object));
+
+ ld_canvas_real_cancel_operation (self);
+
+ self->priv->operation = OPER_ADD_OBJECT;
+ self->priv->operation_end = ld_canvas_add_object_end;
+
+ data = &OPER_DATA (self, add_object);
+ data->object = object;
+}
+
+static void
+ld_canvas_add_object_end (LdCanvas *self)
+{
+ AddObjectData *data;
+
+ data = &OPER_DATA (self, add_object);
+ if (data->object)
+ {
+ queue_object_draw (self, data->object);
+ g_object_unref (data->object);
+ data->object = NULL;
+ }
+}
+
+
+/* ===== Events, rendering ================================================= */
+
+static void
+ld_canvas_color_set (LdCanvasColor *color,
+ gdouble r, gdouble g, gdouble b, gdouble a)
+{
+ color->r = r;
+ color->g = g;
+ color->b = b;
+ color->a = a;
+}
+
+static void
+ld_canvas_color_apply (LdCanvasColor *color, cairo_t *cr)
+{
+ cairo_set_source_rgba (cr, color->r, color->g, color->b, color->a);
+}
+
+static void
+move_object_to_coords (LdCanvas *self, LdDiagramObject *object,
+ gdouble x, gdouble y)
+{
+ gdouble dx, dy;
+
+ ld_canvas_widget_to_diagram_coords (self, x, y, &dx, &dy);
+ ld_diagram_object_set_x (object, floor (dx + 0.5));
+ ld_diagram_object_set_y (object, floor (dy + 0.5));
+}
+
+static LdDiagramObject *
+get_object_at_coords (LdCanvas *self, gdouble x, gdouble y)
+{
+ GList *objects, *iter;
+
+ /* Iterate from the top object downwards. */
+ objects = (GList *) ld_diagram_get_objects (self->priv->diagram);
+ for (iter = objects; iter; iter = g_list_next (iter))
+ {
+ LdDiagramObject *object;
+
+ object = LD_DIAGRAM_OBJECT (iter->data);
+ if (object_hit_test (self, object, x, y))
+ return object;
+ }
+ return NULL;
+}
+
+static gboolean
+is_object_selected (LdCanvas *self, LdDiagramObject *object)
+{
+ return g_list_find (ld_diagram_get_selection (self->priv->diagram),
+ object) != NULL;
+}
+
+static LdSymbol *
+resolve_diagram_symbol (LdCanvas *self, LdDiagramSymbol *diagram_symbol)
+{
+ if (!self->priv->library)
+ return NULL;
+
+ return ld_library_find_symbol (self->priv->library,
+ ld_diagram_symbol_get_class (diagram_symbol));
+}
+
+static gboolean
+get_symbol_area (LdCanvas *self, LdDiagramSymbol *symbol, LdRectangle *rect)
+{
+ LdDiagramObject *object;
+ gdouble object_x, object_y;
+ LdSymbol *library_symbol;
+ LdRectangle area;
+ gdouble x1, x2;
+ gdouble y1, y2;
+
+ object = LD_DIAGRAM_OBJECT (symbol);
+ object_x = ld_diagram_object_get_x (object);
+ object_y = ld_diagram_object_get_y (object);
+
+ library_symbol = resolve_diagram_symbol (self, symbol);
+ if (library_symbol)
+ ld_symbol_get_area (library_symbol, &area);
+ else
+ return FALSE;
+
+ /* TODO: Rotate the rectangle for other orientations. */
+ ld_canvas_diagram_to_widget_coords (self,
+ object_x + area.x,
+ object_y + area.y,
+ &x1, &y1);
+ ld_canvas_diagram_to_widget_coords (self,
+ object_x + area.x + area.width,
+ object_y + area.y + area.height,
+ &x2, &y2);
+
+ rect->x = x1;
+ rect->y = y1;
+ rect->width = x2 - x1;
+ rect->height = y2 - y1;
+ return TRUE;
+}
+
+static gboolean
+get_symbol_clip_area (LdCanvas *self, LdDiagramSymbol *symbol,
+ LdRectangle *rect)
+{
+ LdRectangle object_rect;
+
+ if (!get_object_area (self, LD_DIAGRAM_OBJECT (symbol), &object_rect))
+ return FALSE;
+
+ *rect = object_rect;
+ ld_rectangle_extend (rect, SYMBOL_CLIP_TOLERANCE);
+ return TRUE;
+}
+
+static gboolean
+get_object_area (LdCanvas *self, LdDiagramObject *object, LdRectangle *rect)
+{
+ if (LD_IS_DIAGRAM_SYMBOL (object))
+ return get_symbol_area (self, LD_DIAGRAM_SYMBOL (object), rect);
+ return FALSE;
+}
+
+static gboolean
+object_hit_test (LdCanvas *self, LdDiagramObject *object, gdouble x, gdouble y)
+{
+ LdRectangle rect;
+
+ if (!get_object_area (self, object, &rect))
+ return FALSE;
+ ld_rectangle_extend (&rect, OBJECT_BORDER_TOLERANCE);
+ return ld_rectangle_contains (&rect, x, y);
+}
+
+static void
+check_terminals (LdCanvas *self, gdouble x, gdouble y)
+{
+ GList *objects, *iter;
+ LdDiagramSymbol *closest_symbol = NULL;
+ gdouble closest_distance = TERMINAL_HOVER_TOLERANCE;
+ LdPoint closest_terminal;
+
+ objects = (GList *) ld_diagram_get_objects (self->priv->diagram);
+ for (iter = objects; iter; iter = g_list_next (iter))
+ {
+ LdDiagramObject *diagram_object;
+ gdouble object_x, object_y;
+ LdDiagramSymbol *diagram_symbol;
+ LdSymbol *symbol;
+ const LdPointArray *terminals;
+ gint i;
+
+ if (!LD_IS_DIAGRAM_SYMBOL (iter->data))
+ continue;
+
+ diagram_symbol = LD_DIAGRAM_SYMBOL (iter->data);
+ symbol = resolve_diagram_symbol (self, diagram_symbol);
+ if (!symbol)
+ continue;
+
+ diagram_object = LD_DIAGRAM_OBJECT (iter->data);
+ object_x = ld_diagram_object_get_x (diagram_object);
+ object_y = ld_diagram_object_get_y (diagram_object);
+
+ terminals = ld_symbol_get_terminals (symbol);
+
+ for (i = 0; i < terminals->num_points; i++)
+ {
+ LdPoint cur_term;
+ gdouble distance;
+
+ cur_term = terminals->points[i];
+ cur_term.x += object_x;
+ cur_term.y += object_y;
+ ld_canvas_diagram_to_widget_coords (self,
+ cur_term.x, cur_term.y, &cur_term.x, &cur_term.y);
+
+ distance = ld_point_distance (&cur_term, x, y);
+ if (distance <= closest_distance)
+ {
+ closest_symbol = diagram_symbol;
+ closest_distance = distance;
+ closest_terminal = cur_term;
+ }
+ }
+ }
+
+ hide_terminals (self);
+
+ if (closest_symbol)
+ {
+ self->priv->terminal_highlighted = TRUE;
+ self->priv->terminal = closest_terminal;
+ queue_terminal_draw (self, &closest_terminal);
+ }
+}
+
+static void
+hide_terminals (LdCanvas *self)
+{
+ if (self->priv->terminal_highlighted)
+ {
+ self->priv->terminal_highlighted = FALSE;
+ queue_terminal_draw (self, &self->priv->terminal);
+ }
+}
+
+static void
+queue_draw (LdCanvas *self, LdRectangle *rect)
+{
+ LdRectangle area;
+
+ area = *rect;
+ ld_rectangle_extend (&area, QUEUE_DRAW_EXTEND);
+ gtk_widget_queue_draw_area (GTK_WIDGET (self),
+ area.x, area.y, area.width, area.height);
+}
+
+static void
+queue_object_draw (LdCanvas *self, LdDiagramObject *object)
+{
+ if (LD_IS_DIAGRAM_SYMBOL (object))
+ {
+ LdRectangle rect;
+
+ if (!get_symbol_clip_area (self, LD_DIAGRAM_SYMBOL (object), &rect))
+ return;
+ queue_draw (self, &rect);
+ }
+}
+
+static void
+queue_terminal_draw (LdCanvas *self, LdPoint *terminal)
+{
+ LdRectangle rect;
+
+ rect.x = terminal->x - TERMINAL_RADIUS;
+ rect.y = terminal->y - TERMINAL_RADIUS;
+ rect.width = 2 * TERMINAL_RADIUS;
+ rect.height = 2 * TERMINAL_RADIUS;
+ queue_draw (self, &rect);
+}
+
+static void
+simulate_motion (LdCanvas *self)
+{
+ GdkEventMotion event;
+ GtkWidget *widget;
+ gint x, y;
+ GdkModifierType state;
+
+ widget = GTK_WIDGET (self);
+
+ if (gdk_window_get_pointer (widget->window, &x, &y, &state)
+ != widget->window)
+ return;
+
+ memset (&event, 0, sizeof (event));
+ event.type = GDK_MOTION_NOTIFY;
+ event.window = widget->window;
+ event.x = x;
+ event.y = y;
+ event.state = state;
+
+ on_motion_notify (widget, &event, NULL);
+}
+
+static gboolean
+on_motion_notify (GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
+{
+ LdCanvas *self;
+
+ self = LD_CANVAS (widget);
+ switch (self->priv->operation)
+ {
+ AddObjectData *data;
+
+ case OPER_ADD_OBJECT:
+ data = &OPER_DATA (self, add_object);
+ data->visible = TRUE;
+
+ queue_object_draw (self, data->object);
+ move_object_to_coords (self, data->object, event->x, event->y);
+ queue_object_draw (self, data->object);
+ break;
+ case OPER_0:
+ check_terminals (self, event->x, event->y);
+ break;
+ }
+ return FALSE;
+}
+
+static gboolean
+on_leave_notify (GtkWidget *widget, GdkEventCrossing *event, gpointer user_data)
+{
+ LdCanvas *self;
+
+ self = LD_CANVAS (widget);
+ switch (self->priv->operation)
+ {
+ AddObjectData *data;
+
+ case OPER_ADD_OBJECT:
+ data = &OPER_DATA (self, add_object);
+ data->visible = FALSE;
+
+ queue_object_draw (self, data->object);
+ break;
+ }
+ return FALSE;
+}
+
+static gboolean
+on_button_press (GtkWidget *widget, GdkEventButton *event, gpointer user_data)
+{
+ LdCanvas *self;
+
+ if (!gtk_widget_has_focus (widget))
+ gtk_widget_grab_focus (widget);
+
+ self = LD_CANVAS (widget);
+ switch (self->priv->operation)
+ {
+ AddObjectData *data;
+
+ case OPER_ADD_OBJECT:
+ data = &OPER_DATA (self, add_object);
+
+ queue_object_draw (self, data->object);
+ move_object_to_coords (self, data->object, event->x, event->y);
+
+ if (self->priv->diagram)
+ ld_diagram_insert_object (self->priv->diagram, data->object, 0);
+
+ /* XXX: "cancel" causes confusion. */
+ ld_canvas_real_cancel_operation (self);
+ break;
+ case OPER_0:
+ if (self->priv->diagram)
+ {
+ LdDiagramObject *object;
+
+ if (event->state != GDK_SHIFT_MASK)
+ ld_diagram_unselect_all (self->priv->diagram);
+
+ object = get_object_at_coords (self, event->x, event->y);
+ if (object)
+ ld_diagram_selection_add (self->priv->diagram, object, 0);
+ }
+ break;
+ }
+ return FALSE;
+}
+
+static gboolean
+on_button_release (GtkWidget *widget, GdkEventButton *event, gpointer user_data)
+{
+ return FALSE;
+}
+
+static gboolean
+on_scroll (GtkWidget *widget, GdkEventScroll *event, gpointer user_data)
+{
+ gdouble prev_x, prev_y;
+ gdouble new_x, new_y;
+ LdCanvas *self;
+
+ self = LD_CANVAS (widget);
+
+ ld_canvas_widget_to_diagram_coords (self,
+ event->x, event->y, &prev_x, &prev_y);
+
+ switch (event->direction)
+ {
+ case GDK_SCROLL_UP:
+ ld_canvas_set_zoom (self, self->priv->zoom * ZOOM_WHEEL_STEP);
+ break;
+ case GDK_SCROLL_DOWN:
+ ld_canvas_set_zoom (self, self->priv->zoom / ZOOM_WHEEL_STEP);
+ break;
+ default:
+ return FALSE;
+ }
+
+ ld_canvas_widget_to_diagram_coords (self,
+ event->x, event->y, &new_x, &new_y);
+
+ /* Focus on the point under the cursor. */
+ self->priv->x += prev_x - new_x;
+ self->priv->y += prev_y - new_y;
+
+ check_terminals (self, event->x, event->y);
+ return TRUE;
+}
+
+static gboolean
+on_expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
+{
+ DrawData data;
+
+ data.cr = gdk_cairo_create (widget->window);
+ data.self = LD_CANVAS (widget);
+ data.scale = ld_canvas_get_scale_in_px (data.self);
+ data.exposed_rect.x = event->area.x;
+ data.exposed_rect.y = event->area.y;
+ data.exposed_rect.width = event->area.width;
+ data.exposed_rect.height = event->area.height;
+
+ gdk_cairo_rectangle (data.cr, &event->area);
+ cairo_clip (data.cr);
+
+ ld_canvas_color_apply (COLOR_GET (data.self, COLOR_BASE), data.cr);
+ cairo_paint (data.cr);
+
+ draw_grid (widget, &data);
+ draw_diagram (widget, &data);
+ draw_terminal (widget, &data);
+
+ cairo_destroy (data.cr);
+ return FALSE;
+}
+
+static void
+draw_grid (GtkWidget *widget, DrawData *data)
+{
+ gdouble grid_step;
+ gdouble x_init, y_init;
+ gdouble x, y;
+
+ grid_step = data->scale;
+ while (grid_step < 5)
+ grid_step *= 5;
+
+ ld_canvas_color_apply (COLOR_GET (data->self, COLOR_GRID), data->cr);
+ cairo_set_line_width (data->cr, 1);
+ cairo_set_line_cap (data->cr, CAIRO_LINE_CAP_ROUND);
+
+ /* Get coordinates of the top-left point. */
+ ld_canvas_widget_to_diagram_coords (data->self,
+ data->exposed_rect.x, data->exposed_rect.y, &x_init, &y_init);
+ ld_canvas_diagram_to_widget_coords (data->self,
+ ceil (x_init), ceil (y_init), &x_init, &y_init);
+
+ /* Iterate over all the points. */
+ for (x = x_init; x <= data->exposed_rect.x + data->exposed_rect.width;
+ x += grid_step)
+ {
+ for (y = y_init; y <= data->exposed_rect.y + data->exposed_rect.height;
+ y += grid_step)
+ {
+ cairo_move_to (data->cr, x, y);
+ cairo_line_to (data->cr, x, y);
+ }
+ }
+ cairo_stroke (data->cr);
+}
+
+static void
+draw_terminal (GtkWidget *widget, DrawData *data)
+{
+ LdCanvasPrivate *priv;
+
+ priv = data->self->priv;
+ if (!priv->terminal_highlighted)
+ return;
+
+ ld_canvas_color_apply (COLOR_GET (data->self, COLOR_TERMINAL), data->cr);
+ cairo_set_line_width (data->cr, 1);
+
+ cairo_new_path (data->cr);
+ cairo_arc (data->cr, priv->terminal.x, priv->terminal.y,
+ TERMINAL_RADIUS, 0, 2 * G_PI);
+ cairo_stroke (data->cr);
+}
+
+static void
+draw_diagram (GtkWidget *widget, DrawData *data)
+{
+ GList *objects, *iter;
+
+ if (!data->self->priv->diagram)
+ return;
+
+ cairo_save (data->cr);
+ cairo_set_line_width (data->cr, 1 / data->scale);
+
+ /* Draw objects from the diagram, from bottom to top. */
+ objects = (GList *) ld_diagram_get_objects (data->self->priv->diagram);
+ for (iter = g_list_last (objects); iter; iter = g_list_previous (iter))
+ draw_object (LD_DIAGRAM_OBJECT (iter->data), data);
+
+ switch (data->self->priv->operation)
+ {
+ AddObjectData *op_data;
+
+ case OPER_ADD_OBJECT:
+ op_data = &OPER_DATA (data->self, add_object);
+ if (op_data->visible)
+ draw_object (op_data->object, data);
+ break;
+ }
+
+ cairo_restore (data->cr);
+}
+
+static void
+draw_object (LdDiagramObject *diagram_object, DrawData *data)
+{
+ g_return_if_fail (LD_IS_DIAGRAM_OBJECT (diagram_object));
+ g_return_if_fail (data != NULL);
+
+ if (is_object_selected (data->self, diagram_object))
+ ld_canvas_color_apply (COLOR_GET (data->self,
+ COLOR_SELECTION), data->cr);
+ else
+ ld_canvas_color_apply (COLOR_GET (data->self,
+ COLOR_OBJECT), data->cr);
+
+ if (LD_IS_DIAGRAM_SYMBOL (diagram_object))
+ draw_symbol (LD_DIAGRAM_SYMBOL (diagram_object), data);
+}
+
+static void
+draw_symbol (LdDiagramSymbol *diagram_symbol, DrawData *data)
+{
+ LdSymbol *symbol;
+ LdRectangle clip_rect;
+ gdouble x, y;
+
+ symbol = resolve_diagram_symbol (data->self, diagram_symbol);
+
+ /* TODO: Resolve this better; draw a cross or whatever. */
+ if (!symbol)
+ {
+ g_warning ("Cannot find symbol %s in the library.",
+ ld_diagram_symbol_get_class (diagram_symbol));
+ return;
+ }
+
+ if (!get_symbol_clip_area (data->self, diagram_symbol, &clip_rect)
+ || !ld_rectangle_intersects (&clip_rect, &data->exposed_rect))
+ return;
+
+ cairo_save (data->cr);
+
+ cairo_rectangle (data->cr, clip_rect.x, clip_rect.y,
+ clip_rect.width, clip_rect.height);
+ cairo_clip (data->cr);
+
+ /* TODO: Rotate the space for other orientations. */
+ ld_canvas_diagram_to_widget_coords (data->self,
+ ld_diagram_object_get_x (LD_DIAGRAM_OBJECT (diagram_symbol)),
+ ld_diagram_object_get_y (LD_DIAGRAM_OBJECT (diagram_symbol)),
+ &x, &y);
+ cairo_translate (data->cr, x, y);
+ cairo_scale (data->cr, data->scale, data->scale);
+ ld_symbol_draw (symbol, data->cr);
+
+ cairo_restore (data->cr);
+}