zoom-tool.cpp

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Handy zooming tool
 *
 * Authors:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *   Frank Felfe <innerspace@iname.com>
 *   bulia byak <buliabyak@users.sf.net>
 *
 * Copyright (C) 1999-2002 Authors
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#include "zoom-tool.h"
 
#include "desktop.h"
#include "rubberband.h"
#include "selection-chemistry.h"
#include "ui/widget/events/canvas-event.h"
 
namespace Inkscape::UI::Tools {
 
ZoomTool::ZoomTool(SPDesktop *desktop)
    : ToolBase(desktop, "/tools/zoom", "zoom-in.svg")
{
    auto prefs = Preferences::get();
 
    if (prefs->getBool("/tools/zoom/selcue")) {
        enableSelectionCue();
    }
 
    if (prefs->getBool("/tools/zoom/gradientdrag")) {
        enableGrDrag();
    }
}
 
ZoomTool::~ZoomTool()
{
    enableGrDrag(false);
    ungrabCanvasEvents();
}
 
bool ZoomTool::root_handler(CanvasEvent const &event)
{
    auto prefs = Preferences::get();
    tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
    double const zoom_inc = prefs->getDoubleLimited("/options/zoomincrement/value", M_SQRT2, 1.01, 10);
 
    bool ret = false;
 
    inspect_event(event,
        [&] (ButtonPressEvent const &event) {
            if (event.num_press != 1) {
                return;
            }
 
            auto const button_w = event.pos;
            auto const button_dt = _desktop->w2d(button_w);
 
            if (event.button == 1) {
                saveDragOrigin(event.pos);
                auto rubberband = Rubberband::get(_desktop);
                rubberband->start(_desktop, button_dt);
                escaped = false;
                ret = true;
            } else if (event.button == 3) {
                double const zoom_rel = (event.modifiers & GDK_SHIFT_MASK)
                                       ? zoom_inc
                                       : 1 / zoom_inc;
                _desktop->zoom_relative(button_dt, zoom_rel);
                ret = true;
            }
 
            grabCanvasEvents(EventType::KEY_PRESS      |
                             EventType::KEY_RELEASE    |
                             EventType::BUTTON_PRESS   |
                             EventType::BUTTON_RELEASE |
                             EventType::MOTION);
        },
 
        [&] (MotionEvent const &event) {
            if (!(event.modifiers & GDK_BUTTON1_MASK)) {
                return;
            }
 
            if (!checkDragMoved(event.pos)) {
                return;
            }
 
            auto const motion_dt = _desktop->w2d(event.pos);
            Rubberband::get(_desktop)->move(motion_dt);
            gobble_motion_events(GDK_BUTTON1_MASK);
 
            ret = true;
        },
 
        [&] (ButtonReleaseEvent const &event) {
            auto const button_dt = _desktop->w2d(event.pos);
 
            if (event.button == 1) {
                auto const b = Rubberband::get(_desktop)->getRectangle();
 
                if (b && !within_tolerance && !(event.modifiers & GDK_SHIFT_MASK)) {
                    _desktop->set_display_area(*b, 10);
                } else if (!escaped) {
                    double const zoom_rel = (event.modifiers & GDK_SHIFT_MASK)
                                          ? 1 / zoom_inc
                                          : zoom_inc;
                    _desktop->zoom_relative(button_dt, zoom_rel);
                }
 
                ret = true;
            }
 
            Rubberband::get(_desktop)->stop();
 
            ungrabCanvasEvents();
 
            xyp = {};
            escaped = false;
        },
 
        [&] (KeyPressEvent const &event) {
            switch (get_latin_keyval(event)) {
                case GDK_KEY_Escape:
                    xyp = {};
                    escaped = true;
                    if (!Rubberband::get(_desktop)->isStarted()) {
                        // DANGER: this operation may switch tool and delete *this instance from under us!
                        SelectionHelper::selectNone(_desktop);
                    }
                    else {
                        Rubberband::get(_desktop)->stop();
                    }
                    ret = true;
                    break;
 
                case GDK_KEY_Up:
                case GDK_KEY_Down:
                case GDK_KEY_KP_Up:
                case GDK_KEY_KP_Down:
                    // prevent the zoom field from activation
                    if (!mod_ctrl_only(event)) {
                        ret = true;
                    }
                    break;
 
                case GDK_KEY_Shift_L:
                case GDK_KEY_Shift_R:
                    set_cursor("zoom-out.svg");
                    break;
 
                case GDK_KEY_Delete:
                case GDK_KEY_KP_Delete:
                case GDK_KEY_BackSpace:
                    ret = deleteSelectedDrag(mod_ctrl_only(event));
                    break;
 
                default:
                    break;
            }
        },
 
        [&] (KeyReleaseEvent const &event) {
            switch (get_latin_keyval(event)) {
                case GDK_KEY_Shift_L:
                case GDK_KEY_Shift_R:
                    set_cursor("zoom-in.svg");
                    break;
                default:
                    break;
            }
        },
 
        [&] (CanvasEvent const &event) {}
    );
 
    return ret || ToolBase::root_handler(event);
}
 
} // namespace Inkscape::UI::Tools
 
/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :