DragNDrop.H

Go to the documentation of this file.

/* Copyright 2000-2018 Matt Flax <flatmax@flatmax.org>
   This file is part of GTK+ IOStream class set

   GTK+ IOStream 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.

   GTK+ IOStream 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 have received a copy of the GNU General Public License
   along with GTK+ IOStream
 */
#ifndef DRAGNDROP_H_
#define DRAGNDROP_H_

#include <vector>
#include <string.h>
#include "Debug.H"

#define DND_EMPTY_ERROR -0+DRAGNDROP_ERROR_OFFSET
#define DND_WHICHTARGET_ERROR -1+DRAGNDROP_ERROR_OFFSET

class DragNDropDebug : public Debug {
public:
    DragNDropDebug(void) {
#ifndef NDEBUG
        errors[DND_EMPTY_ERROR]=std::string("The DragNDrop known target list is empty. Fill the target list by constructing with a GdkDragContext, or possibly by using the operator<<. ");
        errors[DND_WHICHTARGET_ERROR]=std::string("The DragNDrop known target list is not empty and has more the one entry, please overload the Widget::chooseTheTargetToUse method to specify which target you want to use in this drop method. ");
#endif
    }
};

class Widget;

class DragNDrop : public std::vector<GtkTargetEntry> {
    gpointer userData; 

    GtkDestDefaults destFlags; 
    GdkDragAction dragAction; 
    GdkModifierType modifierType; 

    static void addToTargetsStatic(gpointer targetData, gpointer data) {
        static_cast<DragNDrop*>(data)->addToTargets(GDK_POINTER_TO_ATOM (targetData));
    }

    void addToTargets(GdkAtom targetData) {
        GtkTargetEntry gte;
        gte.target=gdk_atom_name(targetData);
        gte.flags=0;
        gte.info=0;
        push_back(gte);
    }

    void init() {
        userData=NULL;
        destFlags=(GtkDestDefaults)(GTK_DEST_DEFAULT_MOTION | GTK_DEST_DEFAULT_HIGHLIGHT);
        dragAction=GDK_ACTION_COPY;
        modifierType=GDK_BUTTON1_MASK; // first mouse button
    }

public:
    DragNDrop() {
        init();
    }

    DragNDrop(GdkDragContext *context) {
        init();
        g_list_foreach(gdk_drag_context_list_targets(context), reinterpret_cast<GFunc>(addToTargetsStatic), this);
        //for(GList *iter = gdk_drag_context_list_targets(context); iter != NULL; iter = g_list_next(iter))
        //    addToTargets((GtkTargetEntry*)iter->data);
    }

    virtual ~DragNDrop() {}

    void setUserData(gpointer w){
        userData=w;
    }

    gpointer getUserData(){
        return userData;
    }

    void setDestDefaults(GtkDestDefaults destFlagsIn) {
        destFlags=destFlagsIn;
    }

    GtkDestDefaults getDestDefaults() {
        return destFlags;
    }

    void setDragAction(GdkDragAction dragActionIn) {
        dragAction=dragActionIn;
    }

    GdkDragAction getDragAction() {
        return dragAction;
    }

    void getModifierType(GdkModifierType modifierTypeIn) {
        modifierType=modifierTypeIn;
    }

    GdkModifierType getModifierType() {
        return modifierType;
    }

    GtkTargetEntry *getTargetArray() {
        if (size()<1) {
            DragNDropDebug().evaluateError(DND_EMPTY_ERROR);
            return NULL;
        }
        return &operator[](0);
    }

    DragNDrop &operator<<(const GtkTargetEntry &gte) {
        push_back(gte);
        return *this;
    }

    DragNDrop &operator>>(const GtkTargetEntry &gte) {
        for (std::vector<GtkTargetEntry>::iterator gtei=begin(); gtei<end(); gtei++)
            if (strcmp(gtei->target, gte.target)==0)
                if (gtei->flags==gte.flags)
                    if (gtei->info==gte.info) {
                        erase(gtei);
                        break;
                    }
        return *this;
    }

    DragNDrop &operator<<(Widget &w){
        setUserData(&w);
    }
};
#endif // DRAGNDROP_H_