/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; coding: utf-8 -*- 
 *
 * Copyright © 2007 Björn Lindqvist <bjourne@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2, or
 * (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */
#include <math.h>
#include "gtkimagetoolpainter.h"

/*************************************************************/
/***** Static stuff ******************************************/
/*************************************************************/
static gboolean
gtk_image_view_widget_to_image_pos (GtkImageView *view,
                                    int           wx,
                                    int           wy,
                                    int          *ix,
                                    int          *iy)
{
    GdkRectangle viewport, image_rect;
    if (!gtk_image_view_get_viewport (view, &viewport))
        return FALSE;
    if (!gtk_image_view_get_draw_rect (view, &image_rect))
        return FALSE;

    *ix = viewport.x - image_rect.x + wx;
    *iy = viewport.y - image_rect.y + wy;
    gdouble zoom = gtk_image_view_get_zoom (view);
    *ix = (int) ((gdouble) *ix / zoom);
    *iy = (int) ((gdouble) *iy / zoom);
    return TRUE;
}

static void
gtk_image_tool_painter_paint (GtkImageToolPainter *painter,
                              int                  x,
                              int                  y)
{
    GtkImageView *view = painter->view;
    GdkPixbuf *pixbuf = gtk_image_view_get_pixbuf (view);
    guchar *pixels = gdk_pixbuf_get_pixels (pixbuf);
    int stride = gdk_pixbuf_get_rowstride (pixbuf);

    int n_chans = gdk_pixbuf_get_n_channels (pixbuf);
    int ofs = y * stride + x * n_chans;
    for (int n = 0; n < 3; n++)
        pixels[ofs + n] = 0x00;
    if (n_chans == 4)
        pixels[ofs + 3] = 0xff;
}

static void
gtk_image_tool_painter_paint_at (GtkImageToolPainter *painter,
                                 int                  wx,
                                 int                  wy)
{
    GtkImageView *view = painter->view;
    int x, y;
    if (!gtk_image_view_widget_to_image_pos (view, wx, wy, &x, &y))
        return;
    gtk_image_tool_painter_paint (painter, x, y);

    image_view_drawer_force_scale (painter->drawer);
    gdouble zoom = gtk_image_view_get_zoom (view);

    int size = ceil(zoom);
    
    gtk_widget_queue_draw_area (GTK_WIDGET (view),
                                wx - size * 2, wy - size * 2,
                                size * 4, size * 4);
}

/*************************************************************/
/***** Implementation of the GtkIImageTool interface *********/
/*************************************************************/
static GdkCursor*
cursor_at_point (GtkIImageTool *tool,
                 int            x,
                 int            y)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (tool);
    return painter->crosshair;
}

static gboolean
button_press (GtkIImageTool  *tool,
              GdkEventButton *ev)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (tool);
    if (ev->button != 1)
        return FALSE;

    gtk_image_tool_painter_paint_at (painter, ev->x, ev->y);

    return mouse_handler_button_press (painter->mouse_handler, ev);
}

static gboolean
button_release (GtkIImageTool  *tool,
                GdkEventButton *ev)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (tool);
    return mouse_handler_button_release (painter->mouse_handler, ev);
}

static gboolean
motion_notify (GtkIImageTool  *tool,
               GdkEventMotion *ev)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (tool);
    mouse_handler_motion_notify (painter->mouse_handler, ev);
    if (!painter->mouse_handler->dragging)
        return FALSE;

    gtk_image_tool_painter_paint_at (painter, ev->x, ev->y);

    return FALSE;
}

static void
pixbuf_changed (GtkIImageTool *tool,
                gboolean       reset_fit)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (tool);
    image_view_drawer_force_scale (painter->drawer);
}

static void
paint_image (GtkIImageTool *tool,
             DrawSettings  *ds,
             GdkDrawable   *drawable)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (tool);
    image_view_drawer_draw (painter->drawer, ds, drawable);
}


/*************************************************************/
/***** Stuff that deals with the type ************************/
/*************************************************************/
static void
gtk_iimage_tool_interface_init (gpointer g_iface,
                                gpointer iface_data)
{
    GtkIImageToolClass *klass = (GtkIImageToolClass *) g_iface;
    klass->cursor_at_point = cursor_at_point;
    klass->button_press = button_press;
    klass->button_release = button_release;
    klass->motion_notify = motion_notify;
    klass->pixbuf_changed = pixbuf_changed;
    klass->paint_image = paint_image;
}

G_DEFINE_TYPE_EXTENDED (GtkImageToolPainter,
                        gtk_image_tool_painter,
                        G_TYPE_OBJECT,
                        0,
                        G_IMPLEMENT_INTERFACE (GTK_TYPE_IIMAGE_TOOL,
                                               gtk_iimage_tool_interface_init));

static void
gtk_image_tool_painter_finalize (GObject *object)
{
    GtkImageToolPainter *painter = GTK_IMAGE_TOOL_PAINTER (object);
    image_view_drawer_free (painter->drawer);
    gdk_cursor_unref (painter->crosshair);

    /* Chain up */
    G_OBJECT_CLASS (gtk_image_tool_painter_parent_class)->finalize (object);
}

static void
gtk_image_tool_painter_class_init (GtkImageToolPainterClass *klass)
{
    GObjectClass *object_class = (GObjectClass *) klass;
    object_class->finalize = gtk_image_tool_painter_finalize;
}

static void
gtk_image_tool_painter_init (GtkImageToolPainter *tool)
{
    tool->crosshair = gdk_cursor_new (GDK_CROSSHAIR);
    tool->drawer = image_view_drawer_new ();
    tool->mouse_handler = mouse_handler_new (tool->crosshair);
}

GtkIImageTool*
gtk_image_tool_painter_new (GtkImageView *view)
{
    g_return_val_if_fail (view, NULL);
    GtkImageToolPainter *painter = (GtkImageToolPainter *)
        g_object_new (GTK_TYPE_IMAGE_TOOL_PAINTER, NULL);
    painter->view = view;
    return GTK_IIMAGE_TOOL (painter);
}