432 lines
12 KiB
C
432 lines
12 KiB
C
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/* Paint
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* #Keywords: GdkDrawingArea, GtkGesture
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*
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* Demonstrates practical handling of drawing tablets in a real world
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* usecase.
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*/
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#include <glib/gi18n.h>
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#include <gtk/gtk.h>
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enum {
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COLOR_SET,
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N_SIGNALS
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};
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static guint area_signals[N_SIGNALS] = { 0, };
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typedef struct
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{
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GtkWidget parent_instance;
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cairo_surface_t *surface;
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cairo_t *cr;
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GdkRGBA draw_color;
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GtkPadController *pad_controller;
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double brush_size;
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GtkGesture *gesture;
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} DrawingArea;
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typedef struct
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{
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GtkWidgetClass parent_class;
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} DrawingAreaClass;
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static GtkPadActionEntry pad_actions[] = {
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{ GTK_PAD_ACTION_BUTTON, 1, -1, N_("Black"), "pad.black" },
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{ GTK_PAD_ACTION_BUTTON, 2, -1, N_("Pink"), "pad.pink" },
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{ GTK_PAD_ACTION_BUTTON, 3, -1, N_("Green"), "pad.green" },
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{ GTK_PAD_ACTION_BUTTON, 4, -1, N_("Red"), "pad.red" },
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{ GTK_PAD_ACTION_BUTTON, 5, -1, N_("Purple"), "pad.purple" },
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{ GTK_PAD_ACTION_BUTTON, 6, -1, N_("Orange"), "pad.orange" },
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{ GTK_PAD_ACTION_STRIP, -1, -1, N_("Brush size"), "pad.brush_size" },
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};
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static const char *pad_colors[] = {
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"black",
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"pink",
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"green",
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"red",
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"purple",
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"orange"
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};
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static GType drawing_area_get_type (void);
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G_DEFINE_TYPE (DrawingArea, drawing_area, GTK_TYPE_WIDGET)
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static void drawing_area_set_color (DrawingArea *area,
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const GdkRGBA *color);
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static void
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drawing_area_ensure_surface (DrawingArea *area,
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int width,
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int height)
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{
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if (!area->surface ||
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cairo_image_surface_get_width (area->surface) != width ||
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cairo_image_surface_get_height (area->surface) != height)
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{
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cairo_surface_t *surface;
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surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
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width, height);
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if (area->surface)
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{
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cairo_t *cr;
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cr = cairo_create (surface);
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cairo_set_source_surface (cr, area->surface, 0, 0);
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cairo_paint (cr);
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cairo_surface_destroy (area->surface);
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cairo_destroy (area->cr);
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cairo_destroy (cr);
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}
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area->surface = surface;
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area->cr = cairo_create (surface);
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}
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}
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static void
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drawing_area_size_allocate (GtkWidget *widget,
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int width,
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int height,
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int baseline)
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{
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DrawingArea *area = (DrawingArea *) widget;
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drawing_area_ensure_surface (area, width, height);
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GTK_WIDGET_CLASS (drawing_area_parent_class)->size_allocate (widget, width, height, baseline);
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}
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static void
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drawing_area_map (GtkWidget *widget)
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{
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GTK_WIDGET_CLASS (drawing_area_parent_class)->map (widget);
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drawing_area_ensure_surface ((DrawingArea *) widget,
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gtk_widget_get_width (widget),
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gtk_widget_get_height (widget));
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}
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static void
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drawing_area_unmap (GtkWidget *widget)
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{
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DrawingArea *area = (DrawingArea *) widget;
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g_clear_pointer (&area->cr, cairo_destroy);
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g_clear_pointer (&area->surface, cairo_surface_destroy);
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GTK_WIDGET_CLASS (drawing_area_parent_class)->unmap (widget);
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}
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static void
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drawing_area_snapshot (GtkWidget *widget,
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GtkSnapshot *snapshot)
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{
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DrawingArea *area = (DrawingArea *) widget;
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int width, height;
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cairo_t *cr;
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width = gtk_widget_get_width (widget);
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height = gtk_widget_get_height (widget);
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cr = gtk_snapshot_append_cairo (snapshot, &GRAPHENE_RECT_INIT (0, 0, width, height));
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cairo_set_source_rgb (cr, 1, 1, 1);
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cairo_paint (cr);
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cairo_set_source_surface (cr, area->surface, 0, 0);
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cairo_paint (cr);
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cairo_set_source_rgb (cr, 0.6, 0.6, 0.6);
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cairo_rectangle (cr, 0, 0, width, height);
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cairo_stroke (cr);
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cairo_destroy (cr);
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}
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static void
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on_pad_button_activate (GSimpleAction *action,
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GVariant *parameter,
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DrawingArea *area)
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{
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const char *color = g_object_get_data (G_OBJECT (action), "color");
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GdkRGBA rgba;
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gdk_rgba_parse (&rgba, color);
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drawing_area_set_color (area, &rgba);
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}
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static void
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on_pad_knob_change (GSimpleAction *action,
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GVariant *parameter,
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DrawingArea *area)
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{
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double value = g_variant_get_double (parameter);
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area->brush_size = value;
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}
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static void
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drawing_area_unroot (GtkWidget *widget)
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{
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DrawingArea *area = (DrawingArea *) widget;
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GtkWidget *toplevel;
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toplevel = GTK_WIDGET (gtk_widget_get_root (widget));
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if (area->pad_controller)
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{
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gtk_widget_remove_controller (toplevel, GTK_EVENT_CONTROLLER (area->pad_controller));
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area->pad_controller = NULL;
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}
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GTK_WIDGET_CLASS (drawing_area_parent_class)->unroot (widget);
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}
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static void
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drawing_area_root (GtkWidget *widget)
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{
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DrawingArea *area = (DrawingArea *) widget;
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GSimpleActionGroup *action_group;
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GSimpleAction *action;
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GtkWidget *toplevel;
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int i;
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GTK_WIDGET_CLASS (drawing_area_parent_class)->root (widget);
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toplevel = GTK_WIDGET (gtk_widget_get_root (GTK_WIDGET (area)));
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action_group = g_simple_action_group_new ();
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area->pad_controller = gtk_pad_controller_new (G_ACTION_GROUP (action_group), NULL);
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for (i = 0; i < G_N_ELEMENTS (pad_actions); i++)
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{
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if (pad_actions[i].type == GTK_PAD_ACTION_BUTTON)
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{
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action = g_simple_action_new (pad_actions[i].action_name, NULL);
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g_object_set_data (G_OBJECT (action), "color",
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(gpointer) pad_colors[i]);
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g_signal_connect (action, "activate",
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G_CALLBACK (on_pad_button_activate), area);
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}
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else
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{
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action = g_simple_action_new_stateful (pad_actions[i].action_name,
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G_VARIANT_TYPE_DOUBLE, NULL);
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g_signal_connect (action, "activate",
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G_CALLBACK (on_pad_knob_change), area);
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}
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g_action_map_add_action (G_ACTION_MAP (action_group), G_ACTION (action));
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g_object_unref (action);
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}
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gtk_pad_controller_set_action_entries (area->pad_controller, pad_actions,
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G_N_ELEMENTS (pad_actions));
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gtk_widget_add_controller (toplevel, GTK_EVENT_CONTROLLER (area->pad_controller));
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}
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static void
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drawing_area_class_init (DrawingAreaClass *klass)
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{
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GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
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widget_class->size_allocate = drawing_area_size_allocate;
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widget_class->snapshot = drawing_area_snapshot;
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widget_class->map = drawing_area_map;
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widget_class->unmap = drawing_area_unmap;
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widget_class->root = drawing_area_root;
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widget_class->unroot = drawing_area_unroot;
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area_signals[COLOR_SET] =
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g_signal_new ("color-set",
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G_TYPE_FROM_CLASS (widget_class),
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G_SIGNAL_RUN_FIRST,
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0, NULL, NULL, NULL,
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G_TYPE_NONE, 1, GDK_TYPE_RGBA);
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}
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static void
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drawing_area_apply_stroke (DrawingArea *area,
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GdkDeviceTool *tool,
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double x,
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double y,
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double pressure)
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{
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if (tool && gdk_device_tool_get_tool_type (tool) == GDK_DEVICE_TOOL_TYPE_ERASER)
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{
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cairo_set_line_width (area->cr, 10 * pressure * area->brush_size);
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cairo_set_operator (area->cr, CAIRO_OPERATOR_DEST_OUT);
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}
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else
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{
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cairo_set_line_width (area->cr, 4 * pressure * area->brush_size);
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cairo_set_operator (area->cr, CAIRO_OPERATOR_SATURATE);
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}
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cairo_set_source_rgba (area->cr, area->draw_color.red,
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area->draw_color.green, area->draw_color.blue,
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area->draw_color.alpha * pressure);
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cairo_line_to (area->cr, x, y);
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cairo_stroke (area->cr);
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cairo_move_to (area->cr, x, y);
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}
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static void
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stylus_gesture_down (GtkGestureStylus *gesture,
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double x,
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double y,
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DrawingArea *area)
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{
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cairo_new_path (area->cr);
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}
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static void
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stylus_gesture_motion (GtkGestureStylus *gesture,
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double x,
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double y,
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DrawingArea *area)
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{
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GdkTimeCoord *backlog;
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GdkDeviceTool *tool;
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double pressure;
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guint n_items;
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tool = gtk_gesture_stylus_get_device_tool (gesture);
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if (gtk_gesture_stylus_get_backlog (gesture, &backlog, &n_items))
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{
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guint i;
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for (i = 0; i < n_items; i++)
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{
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drawing_area_apply_stroke (area, tool,
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backlog[i].axes[GDK_AXIS_X],
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backlog[i].axes[GDK_AXIS_Y],
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backlog[i].flags & GDK_AXIS_FLAG_PRESSURE
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? backlog[i].axes[GDK_AXIS_PRESSURE]
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: 1);
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}
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g_free (backlog);
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}
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else
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{
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if (!gtk_gesture_stylus_get_axis (gesture, GDK_AXIS_PRESSURE, &pressure))
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pressure = 1;
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drawing_area_apply_stroke (area, tool, x, y, pressure);
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}
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gtk_widget_queue_draw (GTK_WIDGET (area));
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}
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static void
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drawing_area_init (DrawingArea *area)
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{
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GtkGesture *gesture;
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gesture = gtk_gesture_stylus_new ();
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g_signal_connect (gesture, "down",
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G_CALLBACK (stylus_gesture_down), area);
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g_signal_connect (gesture, "motion",
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G_CALLBACK (stylus_gesture_motion), area);
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gtk_widget_add_controller (GTK_WIDGET (area), GTK_EVENT_CONTROLLER (gesture));
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area->draw_color = (GdkRGBA) { 0, 0, 0, 1 };
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area->brush_size = 1;
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area->gesture = gesture;
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}
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static GtkWidget *
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drawing_area_new (void)
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{
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return g_object_new (drawing_area_get_type (), NULL);
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}
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static void
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drawing_area_set_color (DrawingArea *area,
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const GdkRGBA *color)
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{
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if (gdk_rgba_equal (&area->draw_color, color))
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return;
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area->draw_color = *color;
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g_signal_emit (area, area_signals[COLOR_SET], 0, &area->draw_color);
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}
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static void
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color_button_color_set (GtkColorDialogButton *button,
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GParamSpec *pspec,
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DrawingArea *draw_area)
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{
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const GdkRGBA *color;
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color = gtk_color_dialog_button_get_rgba (button);
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drawing_area_set_color (draw_area, color);
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}
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static void
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drawing_area_color_set (DrawingArea *area,
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GdkRGBA *color,
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GtkColorDialogButton *button)
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{
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gtk_color_dialog_button_set_rgba (button, color);
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}
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|
||
|
|
static GtkGesture *
|
||
|
|
drawing_area_get_gesture (DrawingArea *area)
|
||
|
|
{
|
||
|
|
return area->gesture;
|
||
|
|
}
|
||
|
|
|
||
|
|
GtkWidget *
|
||
|
|
do_paint (GtkWidget *toplevel)
|
||
|
|
{
|
||
|
|
static GtkWidget *window = NULL;
|
||
|
|
|
||
|
|
if (!window)
|
||
|
|
{
|
||
|
|
GtkWidget *draw_area, *headerbar, *button;
|
||
|
|
|
||
|
|
window = gtk_window_new ();
|
||
|
|
|
||
|
|
draw_area = drawing_area_new ();
|
||
|
|
gtk_window_set_child (GTK_WINDOW (window), draw_area);
|
||
|
|
|
||
|
|
headerbar = gtk_header_bar_new ();
|
||
|
|
|
||
|
|
button = gtk_color_dialog_button_new (gtk_color_dialog_new ());
|
||
|
|
g_signal_connect (button, "notify::rgba",
|
||
|
|
G_CALLBACK (color_button_color_set), draw_area);
|
||
|
|
g_signal_connect (draw_area, "color-set",
|
||
|
|
G_CALLBACK (drawing_area_color_set), button);
|
||
|
|
gtk_color_dialog_button_set_rgba (GTK_COLOR_DIALOG_BUTTON (button),
|
||
|
|
&(GdkRGBA) { 0, 0, 0, 1 });
|
||
|
|
|
||
|
|
gtk_header_bar_pack_end (GTK_HEADER_BAR (headerbar), button);
|
||
|
|
|
||
|
|
button = gtk_check_button_new_with_label ("Stylus only");
|
||
|
|
g_object_bind_property (button, "active",
|
||
|
|
drawing_area_get_gesture ((DrawingArea *)draw_area), "stylus-only",
|
||
|
|
G_BINDING_SYNC_CREATE);
|
||
|
|
gtk_header_bar_pack_start (GTK_HEADER_BAR (headerbar), button);
|
||
|
|
|
||
|
|
gtk_window_set_titlebar (GTK_WINDOW (window), headerbar);
|
||
|
|
gtk_window_set_title (GTK_WINDOW (window), "Paint");
|
||
|
|
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!gtk_widget_get_visible (window))
|
||
|
|
gtk_widget_set_visible (window, TRUE);
|
||
|
|
else
|
||
|
|
gtk_window_destroy (GTK_WINDOW (window));
|
||
|
|
|
||
|
|
return window;
|
||
|
|
}
|