TimeTooltip.cpp

/*****************************************************************************
 * QtVlc - C++ bindings for libVLC using Qt awesomeness
 * Copyright (C) 2013 Orochimarufan <orochimarufan.x3@gmail.com>
 *
 * This library 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 3 of the License, 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this library. If not, see <http://www.gnu.org/licenses/>.
 *****************************************************************************/
/* ATTENTION: this is GPL, not LGPL due to code from the VLC Qt Interface.
 * Original License: */
/*****************************************************************************
 * Copyright © 2011-2012 VideoLAN
 * $Id$
 *
 * Authors: Ludovic Fauvet <etix@l0cal.com>
 *
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#include "TimeTooltip.h"

#include <QApplication>
#include <QPainter>
#include <QPainterPath>
#include <QBitmap>
#include <QFontMetrics>
#include <QDesktopWidget>

#define TIP_HEIGHT 5

TimeTooltip::TimeTooltip(QWidget *parent) :
    QWidget(parent), mInitialized(false)
{
    setWindowFlags(Qt::/*Window*/ToolTip                  |
                   Qt::WindowStaysOnTopHint    |
                   Qt::FramelessWindowHint     |
                   Qt::X11BypassWindowManagerHint);

    // Tell Qt that it doesn't need to erase the background before
    // a paintEvent occurs. This should save some CPU cycles.
    setAttribute(Qt::WA_OpaquePaintEvent);

#if defined(Q_WS_WIN) || defined(Q_WS_PM)
    /*
    - This attribute is required on Windows and OS/2 to avoid focus stealing of other windows.
    - When set on Linux the TimeTooltip appears behind the FSController in fullscreen.
    */
    setAttribute(Qt::WA_ShowWithoutActivating);
#endif

    // Inherit from the system default font size -5
    mFont = QFont("Verdana", qMax(qApp->font().pointSize() - 5, 7));
    mTipX = -1;
}

void TimeTooltip::adjustPosition()
{
    // Get the bounding box required to print the text and add some padding
    QFontMetrics metrics(mFont);
    QRect textbox = metrics.boundingRect(mDisplayedText);
    textbox.adjust(-2, -2, 2, 2);
    textbox.moveTo(0, 0);

    // Resize the widget to fit our needs
    QSize size(textbox.width() + 1, textbox.height() + TIP_HEIGHT + 1);

    // The desired label position is just above the target
    QPoint position(mTarget.x() - size.width() / 2,
        mTarget.y() - size.height() + TIP_HEIGHT / 2);

    // Keep the tooltip on the same screen if possible
    QRect screen = QApplication::desktop()->screenGeometry(mTarget);
    position.setX(qMax(screen.left(), qMin(position.x(),
        screen.left() + screen.width() - size.width())));
    position.setY(qMax(screen.top(), qMin(position.y(),
        screen.top() + screen.height() - size.height())));

    move(position);

    int tipX = mTarget.x() - position.x();
    if(mBox != textbox || mTipX != tipX)
    {
        mBox = textbox;
        mTipX = tipX;

        resize(size);
        buildPath();
        setMask(mMask);
    }
}

void TimeTooltip::buildPath()
{
    // Prepare the painter path for future use so
    // we only have to generate the text at runtime.

    // Draw the text box
    mPainterPath = QPainterPath();
    mPainterPath.addRect(mBox);

    // Draw the tip
    QPolygon polygon;
    polygon << QPoint(qMax(0, mTipX - 3), mBox.height())
            << QPoint(mTipX, mBox.height() + TIP_HEIGHT)
            << QPoint(qMin(mTipX + 3, mBox.width()), mBox.height());
    mPainterPath.addPolygon(polygon);

    // Store the simplified version of the path
    mPainterPath = mPainterPath.simplified();

    // Create the mask used to erase the background
    // Note: this is a binary bitmap (black & white)
    mMask = QBitmap(size());
    QPainter painter(&mMask);
    painter.fillRect(mMask.rect(), Qt::white);
    painter.setPen(Qt::black);
    painter.setBrush(Qt::black);
    painter.drawPath(mPainterPath);
    painter.end();
}

void TimeTooltip::setTip(const QPoint& target, const QString& time, const QString& text)
{
    mInitialized = true;
    mDisplayedText = time;
    if (!text.isEmpty())
        mDisplayedText.append(" - ").append(text);

    if(mTarget != target || time.length() != mTime.length() || mText != text)
    {
        mTarget = target;
        mTime = time;
        mText = text;
        adjustPosition();
    }

    update();
}

void TimeTooltip::show()
{
    QWidget::setVisible(mInitialized);
#ifdef Q_WS_PM
    // Bring a tooltip on the top
    // Without this, tooltip does not appear on fullscreen
    // from the second fullscreen state change
    if(mInitialized)
        QWidget::raise();
#endif
}

void TimeTooltip::paintEvent(QPaintEvent *)
{
    QPainter p(this);
    p.setRenderHints(QPainter::HighQualityAntialiasing | QPainter::TextAntialiasing);

    p.setPen(Qt::black);
    p.setBrush(qApp->palette().base());
    p.drawPath(mPainterPath);

    p.setFont(mFont);
    p.setPen(QPen(qApp->palette().text(), 1));
    p.drawText(mBox, Qt::AlignCenter, mDisplayedText);
}