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/*
* Copyright © 2016 Red Hat, Inc.
*
* 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, see <http://www.gnu.org/licenses/>.
*
* Author: Carlos Garnacho <carlosg@gnome.org>
*/
#include "config.h"
#include <cairo/cairo.h>
#include "cc-drawing-area.h"
typedef struct _CcDrawingArea CcDrawingArea;
struct _CcDrawingArea {
GtkDrawingArea parent;
GtkGesture *stylus_gesture;
cairo_surface_t *surface;
cairo_t *cr;
};
G_DEFINE_TYPE (CcDrawingArea, cc_drawing_area, GTK_TYPE_DRAWING_AREA)
static void
ensure_drawing_surface (CcDrawingArea *area,
gint width,
gint height)
{
if (!area->surface ||
cairo_image_surface_get_width (area->surface) != width ||
cairo_image_surface_get_height (area->surface) != height) {
cairo_surface_t *surface;
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
width, height);
if (area->surface) {
cairo_t *cr;
cr = cairo_create (surface);
cairo_set_source_surface (cr, area->surface, 0, 0);
cairo_paint (cr);
cairo_surface_destroy (area->surface);
cairo_destroy (area->cr);
cairo_destroy (cr);
}
area->surface = surface;
area->cr = cairo_create (surface);
}
}
static void
cc_drawing_area_map (GtkWidget *widget)
{
GtkAllocation allocation;
GTK_WIDGET_CLASS (cc_drawing_area_parent_class)->map (widget);
gtk_widget_get_allocation (widget, &allocation);
ensure_drawing_surface (CC_DRAWING_AREA (widget),
allocation.width, allocation.height);
}
static void
cc_drawing_area_unmap (GtkWidget *widget)
{
CcDrawingArea *area = CC_DRAWING_AREA (widget);
if (area->cr) {
cairo_destroy (area->cr);
area->cr = NULL;
}
if (area->surface) {
cairo_surface_destroy (area->surface);
area->surface = NULL;
}
GTK_WIDGET_CLASS (cc_drawing_area_parent_class)->unmap (widget);
}
static void
draw_cb (GtkDrawingArea *drawing_area,
cairo_t *cr,
gint width,
gint height,
gpointer user_data)
{
CcDrawingArea *area = CC_DRAWING_AREA (drawing_area);
ensure_drawing_surface (area, width, height);
cairo_set_source_rgb (cr, 1, 1, 1);
cairo_paint (cr);
cairo_set_source_surface (cr, area->surface, 0, 0);
cairo_paint (cr);
cairo_set_source_rgb (cr, 0.6, 0.6, 0.6);
cairo_rectangle (cr, 0, 0, width, height);
cairo_stroke (cr);
}
static void
stylus_down_cb (GtkGestureStylus *gesture,
double x,
double y,
CcDrawingArea *area)
{
cairo_new_path (area->cr);
}
static void
stylus_motion_cb (GtkGestureStylus *gesture,
double x,
double y,
CcDrawingArea *area)
{
GdkDeviceTool *tool;
gdouble pressure;
tool = gtk_gesture_stylus_get_device_tool (gesture);
gtk_gesture_stylus_get_axis (gesture,
GDK_AXIS_PRESSURE,
&pressure);
if (gdk_device_tool_get_tool_type (tool) == GDK_DEVICE_TOOL_TYPE_ERASER) {
cairo_set_line_width (area->cr, 10 * pressure);
cairo_set_operator (area->cr, CAIRO_OPERATOR_DEST_OUT);
} else {
cairo_set_line_width (area->cr, 4 * pressure);
cairo_set_operator (area->cr, CAIRO_OPERATOR_SATURATE);
}
cairo_set_source_rgba (area->cr, 0, 0, 0, pressure);
cairo_line_to (area->cr, x, y);
cairo_stroke (area->cr);
cairo_move_to (area->cr, x, y);
gtk_widget_queue_draw (GTK_WIDGET (area));
}
static void
cc_drawing_area_class_init (CcDrawingAreaClass *klass)
{
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
widget_class->map = cc_drawing_area_map;
widget_class->unmap = cc_drawing_area_unmap;
}
static void
cc_drawing_area_init (CcDrawingArea *area)
{
gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (area), draw_cb, NULL, NULL);
area->stylus_gesture = gtk_gesture_stylus_new ();
g_signal_connect (area->stylus_gesture, "down",
G_CALLBACK (stylus_down_cb), area);
g_signal_connect (area->stylus_gesture, "motion",
G_CALLBACK (stylus_motion_cb), area);
gtk_widget_add_controller (GTK_WIDGET (area),
GTK_EVENT_CONTROLLER (area->stylus_gesture));
}
GtkWidget *
cc_drawing_area_new (void)
{
return g_object_new (CC_TYPE_DRAWING_AREA, NULL);
}
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